# European Red List of Habitats Table

Habitat Type Name:
5 Crustose algae communities on Baltic infralittoral rock and mixed substrata

Habitat Description:
This is a Baltic Sea benthic habitat in the photic zone , either with at least 90% coverage of rock, boulders or stones of more than 63 mm in diameter but also on mixed substrates with at least 10% coverage of rock, boulders or stones according to the HELCOM HUB classification. Soft crustose algae cover at least 10% of the seabed while all perennial attached erect groups cover less than 10%. This habitat covers the full salinity range of the Baltic Sea and is more common in areas exposed to waves and current.
Indicators of quality: 
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis.
Characteristic species:
These include Hildenbrandia spp., Pseudolithoderma spp. with different species present depending on the salinity regime.

Classification:
EUNIS: 
The closest correspondence in EUNIS (2004) level 4 is A3.4 Baltic exposed infralittoral rock, A3.5 Baltic moderately exposed infralittoral rock and A3.6 Baltic sheltered infralittoral rock.
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1160 Large shallow inlets and bays
1170 Reefs
1650 Boreal Baltic narrow inlets
 
MAES: 
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD: 
Shallow sublittoral rock and biogenic reef
Shallow sublittoral mixed sediment
 
EUSeaMap:
Shallow photic rock or biogenic reef
Shallow coarse or mixed sediments
 
IUCN ecosystem:
9.2 Subtidal rock and rocky reefs
9.3. Subtidal Loose Rock/Pebble/Gravel
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.A1R Baltic photic rock and boulder characterized by soft crustose algae
AA.M1R Baltic photic mixed substrate characterized by soft crustose algae

Justification Outstanding Example of Biogeographical Region:
It is unknown whether this habitat presents an outstanding example of the typical characteristics of the Baltic region.

Justification of Small Range/Regression:
This habitat occurs in all the Baltic sub-basins therefore does not have a small natural range.

Justification of Restricted Area:
This habitat occurs in all the Baltic sub-basins therefore does not have a small natural range.

Conservation and Management:
Crustose algae are generally very tolerant to extremes of temperature, light and salinity.This habitat is likely to benefit from measures which reduce the risk of eutrophication (nutrient enrichment) and which maintain water clarity.

Conservation Status:
Annex 1:
1160: MBAL U2
1170: MBAL U1
1650: MBAL U2
 
HELCOM (2013) assessments:
1160: VU C1 
1170: VU C1 
1650: VU C1 
HELCOM has assessed the associated biotopes AA.A1

Summary:
This benthic habitat is present throughout the Baltic where hard substrates are present and light levels enable the establishment of crustose algae communities. There are records of the characteristic species (Hildenbrandia spp. and Pseudolithoderma spp.) in all the Baltic sea sub-basins but no estimates of habitat extent and area, nor reporting of potential quality indicators. Activities which reduce light levels or lead to eutrophication (nutrient enrichment) could result in some deterioration of this habitat but the severity of such effects are unknown. Any potential effects on this habitat from changes in sea temperature and salinity that may result from future climate change are also unknown.

References:
HELCOM, 2013. HELCOM Red List Biotope information sheets. Available at: http://www.helcom.fi/Documents/Ministerial2013/Associated%20documents/Background/HELCOM%20Red%20List%20Biotope%20Information%20Sheets%20(BIS).pdf. (Accessed: 16/07/2015).
HELCOM, 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Avellan, L (Ed). Helsinki, Finland.

Criterion A Text:
There are no quantitative data on trends in the area covered by this habitat type in the Baltic but expert opinion is that there has been less than a 25% decline over the last 50 years. This habitat has therefore been assessed as Least Concern under Criteria A.

Criterion B Text:
Present in all Baltic Sea basins therefore EOO exceeds 50,000km2 however with no quantitative data on habitat extent or area, accurate calculation of EOO or AOO is not possible at the present time. This habitat has therefore been assessed as Data Deficient under criterion B.

Synthesis:
This habitat is present in all sub-basins of the Baltic and therefore the EOO exceeds 50,000 km2. It is not considered to have declined significantly (>25%) over the last 50 years but the lack of quantitative data on extent, quality and trends over time means that accurate calculations of EOO and AOO are not possible at the present time. This Red List assessment has therefore been based on expert opinion.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed the two associated Baltic biotopes (AA.A1R and AA.M1R) as Least Concern (based on criterion A1). With no additional information on changes in extent or quality of this habitat, the current expert opinion is an assessment of Least Concern for the EU 28 and EU 28+.


Habitat Type Name:
6 Annual algal communities on Baltic infralittoral rock and mixed substrata (predominantly hard)

Habitat Description:
This is a Baltic Sea benthic habitat in the photic zone where between 10-90% of the substrate is rock, boulders or stones or mixed  substrates according to the HELCOM HUB classification. Annual algae cover at least 10% of the seabed, while all other epibenthic biotic structures cover less than 10%. Annual algae can live as epiphytes (e.g. Pilayella/Ectocarpus on Fucus spp.or Aglaothamnion spp. on perennial red algae like Furcellaria or on Mytilus) where they may be considered quality descriptors, thus this habitat can be recognized only when annual algae grow directly on the hard substrate and not when they grow on perennial biotic structures. This habitat covers the full salinity range of the Baltic Sea and is more common in exposed areas, mainly within the surf zone, in which wave  energy prevents the establishment of perennial vegtation. Mapping should take place during the months when the vegetation is fully developed.
Indicators of quality:
The ratio of annual to perennial epibenthic components is used in several countries to describe habitat quality. As such the area of the habitat itself or the biomass of the corresponding species is used as an indicator for quality.In this particular case the lowest area or biomass is a sign of high quality as only in very high exposure levels should annual algae dominate. In all other circumstances perennials (Fucus) should dominate except where there is a low salinity (below 3 psu) as perennial algae growth does not generally occur under such conditions. 
Characteristic species:
Cladophora glomerata, Ceramium tenuicorne, , Chorda filum, Halosiphon tomentosus, Pilayella littoralis, Ulva spp. Dictypsiphon spp.

Classification:
EUNIS: 
The closest correspondence in EUNIS (2004) level 3 for rocks is A3.4 Baltic exposed infralittoral rock, A3.5 Baltic moderately exposed infralittoral rock and A3.6 Baltic sheltered infralittoral rock and for mixed substrate EUNIS (2004) level 4 A5.52 Kelp and seaweed communities on sublittoral sediment with A5.528 Filamentous green seaweeds on low salinity infralittoral mixed sediment or rock as best corresponding level 5 biotope.
 
Annex 1: 
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats: 
1130 Estuaries
1160 Large shallow inlets and bays 
1170 Reefs 
1650 Boreal Baltic narrow inlets 
 
MAES: 
Marine - Marine inlets and transitional waters 
Marine - Coastal 
 
MSFD: 
Shallow sublittoral rock and biogenic reef 
 
EUSeaMap: 
Shallow photic rock or biogenic reef 
 
IUCN: 
9.2 Subtidal rock and rocky reefs 
9.3 Subtidal Loose Rock/Pebble/Gravel
9.7 Macroalgal/Kelp
9.10 Estuaries
 
Other relationships: 
Level 5 of the HELCOM HUB classification (2013): 
AA.A1S Baltic photic rock characterised by annual algae 
AA.M1S Baltic photic mixed substrate characterised by annual algae 
 
This habitat has two associated biotopes on HUB level 6:  
AA.M1S1 Baltic photic mixed substrate dominated by filamentous annual algae 
AA.M1S2 Baltic photic mixed substrate dominated by Chorda filum and/or Halosiphon tomentosus.

Justification Outstanding Example of Biogeographical Region:
Hard substrates dominated by annual algae are found in all regional seas. The characteristic species may vary between regions, and the annual algae of the Baltic Sea represent a more or less only a reduced marine flora.

Comment EU28:
This habitat is present in all the Baltic sub-basins. occurs nearly everywhere, when light and substrate is adequate.

Comment EU28+:
This habitat is present in all the Baltic sub-basins. occurs nearly everywhere, when light and substrate is adequate.

Trends in Quantity:
This habitat is very common throughout the Baltic Sea and particularly common in areas with reduced salinity and/or high wave exposure. The extent has changed by less than 10% over the past 50 years at certain locations. The habitat has also gained in area in other locations where perennials like Fucus spp. have lost area (e.g. along the German coastline). There are no data available on historical trends and no significant future changes have been predicted. Overall it is considered to be stable.

Trends in Quality:
Moderate reductions in quality have been documented locally (<10%). No further declines in quality are estimated and overall the habitat quality is considered to be stable at the present time.

Conservation Status:
Annex 1:
1130: MBAL U2
1160: MBAL U2
1170: MBAL U1
1650: MBAL U2
 
HELCOM (2013) assessments:
1130 CR, C1 
1160: VU C1 
1170: VU C1 
1650: VU C1 
HELCOM (20

Summary:
This habitat occurs in all the Baltic Sea sub-basins but is especially common in areas with reduced salinity and/or high wave exposure. It is a benthic habitat in the photic zone where the substrates are a mixture of hard and soft sediment. Site records and distribution maps are available for some of the characteristic species but there are no quantitative data on extent and area of the habitat. Pressures, threats, and conservation and management measures have not been identified specifically for this habitat type.

Criterion A Text:
There are no quantitative data on trends in the area covered by this habitat type in the Baltic Sea. Expert opinion is that there has been less than a 25% decline over the last 50 years. This habitat has therefore been assessed as Least Concern under Criteria A.

Criterion B Text:
This habitat has a large natural range in the Baltic Sea extending from the Danish coast in the west to the Bothnian Bay in the north-east but its the precise extent over the last 50 years is unknown. EOO >50,000 km2 and AOO >50, and it is not limited to a few locations. As the quality and quanity of the habitat is considered to have been stable over the last 50 years there is no continuing decline, this habitat has been assessed as Least Concern under criterion B.

Synthesis:
There are no quantitative data on the extent and area of this habitat but site records and distribution maps are available for some of the associated characteristic species. Expert opinion is that the extent is believed to have changed in extent by less than 10% over the past 50 years and that there have been only moderate changes in quality in some parts of the Baltic (<10%). No significant changes in extent or quality are envisaged for the near future.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed the three relevant Baltic sub-biotopes (AA.A1S, AA.M1S1 and AA.M1S2) to be of Least Concern (based on criterion A1). With no additional information on changes in extent or quality of this habitat, the current expert opinion is an assessment of Least Concern for the EU 28 and EU 28+.


Habitat Type Name:
7 Epifaunal communities on Baltic infralittoral rock and mixed substrata (predominantly hard)

Habitat Description:
This is a Baltic Sea benthic habitat in the photic zone where at least 90% of the substrate is rock, boulders or stones and  mixed (predominantly hard), according to the HELCOM HUB classification. Eleven associated biotopes have been identified dominated (at least 50% of the biomass) by either epibenthic bivalves, chordates, cnidarians, bryozoans, crustaceans or sponges. They are typically present in a depths of between 2-20 meters but have varying distributions depending on salinity and exposure. For example those biotopes where Mytilidae such as Mytilus spp. or Modiolus modiolus dominate typically occur in depths of 5 – 20 meters, in all exposure classes and in salinities over 5 psu. Biotopes dominated by the mussel Dreissena polymorpha (AA.A1E2/AA.M1E2) usually occupy a depth zone of between  2 – 10 meters, in sheltered to moderate exposure and in salinities less than 5 psu. They occur in the eastern parts of the Gulf of Finland and along the Estonian west coast. ‘Baltic photic rock and boulders/mixed sediment dominated by erect moss animals (Flustra foliaceae)’ (AA.A1H2/AA.M1H2) is found only in western and southwestern Baltic Sea due to salinity constraints (15 psu).
Indicators of quality: 
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed
indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. Diversity, abundance and biomass of the dominate species and associated fauna are potential indicators of quality of this habitat
Characteristic species:
For mussel dominated biotopes Mytilus spp., Modiolus modiolus, Dreissena; for epibenthic chordate dominated biotopes - Sea squirts (Ascidiaceae), for example Ciona intestinalis, Dendrodoa grossularia, Molgula spp.; for epibenthic chordate dominated biotopes - Hydroids (e.g. Cordylophora caspia, Gonothraea loveni, Laomedea spp), sea anemones, corals. For moss animal dominated biotopes Electra crustulenta, Flustra foliacea, other Bryozoa (Eucratea loricata), also sponges, sea squirts or hydrozoans. For epibenthic crustacean dominated biotopes - Balanidae, for example Amphibalanus improvises, Balanus crenatus, Semibalanus balanoides. For sponge dominated biotopes - Ephydatia fluviatilis, Chalinula limbata, Halichondria panicea, Haliclona oculata.

Classification:
EUNIS:
The closest corresponsence in EUNIS (2004) level 4 is A3.4 Baltic exposed infralittoral rock, A3.5 Baltic moderately exposed infralittoral rock, and A3.6 Baltic sheltered infralittoral rock.
 
Annex 1: 
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1160 Large shallow inlets and bays
1170 Reefs
1650 Boreal Baltic narrow inlets 
 
MAES: 
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral rock and biogenic reef
Shallow sublittoral mixed sediment
 
EUSeaMap: 
Shallow photic rock or biogenic reef
Shallow coarse or mixed sediments
 
IUCN:
9.2 Subtidal rock and rocky reefs
9.3. Subtidal Loose Rock/Pebble/Gravel
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013):
AA.A1E Baltic photic rock and boulders characterized by epibenthic bivalves
AA.M1E Baltic photic mixed characterized by epibenthic bivalves
AA.A1F Baltic photic rock and boulders characterized by epibenthic chordates
AA.M1F Baltic photic mixed substrate characterized by epibenthic chordates
AA.A1G Baltic photic rock and boulders characterized by epibenthic cnidarians.
AA.M1G Baltic photic mixed substrate characterized by epibenthic cnidarians.
AA.A1H Baltic photic rock and boulders characterized by epibenthic moss animals (Bryozoa).
AA.M1H Baltic mixed substrate characterized by epibenthic moss animals (Bryozoa).
AA.A1I Baltic photic rock and boulders characterized by epibenthic crustaceans.
AA.M1I Baltic photic mixed substrate characterized by epibenthic crustaceans
AA.A1J Baltic photic rock and boulders characterized by epibenthic sponges (Porifera).
AA.M1J Baltic photic mixed substrate characterized by epibenthic sponges (Porifera)
AA.A1V Baltic photic rock and boulders characterized by mixed epibenthic macrocommunity
AA.M1V Baltic photic rock and boulders characterized by mixed epibenthic macrocommunity
 
Biotopes on HUB level 6: 
AA.A1E1 Baltic photic rock and boulders dominated by Mytilidae
AA.M1E1 Baltic photic mixed dominated by Mytilidae, 
AA.A1E2 Baltic photic rock and boulders dominated by zebra mussel (Dreissena polymorpha)
AA.M1E2 Baltic photic mixed dominated by zebra mussel (Dreissena polymorpha).
AA.A1F1 Baltic photic rock and boulders dominated by sea squirts (Ascidiacea).
AA.M1F1 Baltic photic mixed substrate dominated by sea squirts (Ascidiacea).
AA.A1G1 Baltic photic rock and boulders dominated by Hyroids (Hydrozoa).
AA.M1G1 Baltic photic mixed substrates dominated by Hydroids (Hydrozoa).
AA.A1H1 Baltic photic rock and boulders dominated by crustose moss animals (Electra crustulenta),
AA.A1H2 Baltic photic rock and boulders dominated by erect moss animals (Flustra foliaceae).
AA.M1H1 Baltic photic mixed substrate dominated by crustose moss animals (Electra crustulenta),
AA.M1H2 Baltic photic mixed substrate dominated by erect moss animals (Flustra foliaceae)
AA.A1I1 Baltic photic rock and boulders dominated by barnacles (Balanidae).
AA.A1I1 Baltic photic mixed substrate dominated by barnacles (Balanidae).

Justification Outstanding Example of Biogeographical Region:
This habitat occurs in all parts of the Baltic with the associated species composition characteristic of Baltic brackish waters.

Trends in Quantity:
This habitat is common throughout the Baltic although some of the associated biotopes have a more limited distribution due to differences in salinity. Baltic biotopes dominated by erect moss animals, for example, only occur in western-most areas; biotopes dominated by zebra mussel are restricted to eastern parts of the Gulf of Finland and along the Estonian west coast. There have been declines in some of the associated biotopes due to eutrophication, siltation of hard bottom areas and physical removal of hard substrates (stone fishing) but overall the decline is considered to be less than 25%. No historic data on trends in quantity are available. Decline in some of the associated biotopes is predicted in the future, where climate change is predicted to result in changes in the salinity regime.

Trends in Quality:
There has been a reduction in quality of some of the associated biotopes (e.g. AA.A1E Baltic photic rock and boulders dominated by mussels) (10-20% over the past 50 years) but a lack of quantitative data on trends in quality for the habitat. The alien species Dreissena polymorpha has been present in the Baltic for more than a century with expansion most notable since the 1990s.

% of Distribution of the Habitat Type within the EU 28:
Defined as a Baltic habitat therefore 100% occurs in the Baltic Sea. An estimated 95% occurs in EU 28. Similar habitats do occur in other European Regional Seas.

Pressures and Threats:
Eutrophication is a major threat to at least to some of the associated biotopes as the higher nutrient concentrations enhances the growth rate of annual macrophytic algae, restricting the available substrate for development of epifaunal turf communities. Increased siltation or turbidity further reduces the availability of hard substrates impeding the settlement of larvae while higher particle concentration in the water can also impede filter feeding. e.g. of adult Flustra foliacea. Oxygen depletion due to eutrophication is seen as a smaller threat. In contrast Mytilids are very tolerant to, and even favoured by, eutrophication (because it increases food availability). These biotopes have been shown to increase in coastal areas where perennial macrophyte habitats are lost due to eutrophication. Other pressures on this habitat are physical disturbance by bottom trawling, offshore construction and dredging.

Conservation and Management:
The distribution of this habitat and the type of environmental conditions it requires is unclear. All actions reducing eutrophication in the Baltic are likely to be of benefit. This includes measures to reduce the diffuse run off from agricultural land and nutrient run off from point-sources by constructing waste water treatment plants. Actions to reduce physical disturbance from bottom trawling, offshore construction work and dredging, including prohibition of these activies in protected areas would constitute effective conservation measures.

Conservation Status:
Annex 1:
1160: MBAL U2
1170: MBAL U1
1650: MBAL U2
 
HELCOM (2013) assessments:
1170 VU C1
1160 VU C1 
1650 VU C1 
HELCOM (2013) assessed all the associated biotopes as

Capacity to Recover its Typical Character and Functionality?:
This habitat has the potential to recover fairly quickly with epifauna recolonising damaged areas after pressure/threats have been removed and the environmental conditions have been restored.

Summary:
This habitat is very common being present along most coastal waters except possibly some of the eastern and southern Baltic where sand is the dominating substrate or in areas of low salinity, i.e. the Bothnian Bay and parts of Gulf of Finland. Detailed mapping of distribution and extent has not taken place although there are some data from regional studies (e.g. Estonia).
Eutrophication is a major threat to at least to some of the associated biotopes as the higher nutrient concentrations enhances the growth rate of annual macrophytic algae, restricting the available substrate for development of epifaunal turf communities. In contrast Mytilids are very tolerant to, and even favoured by, eutrophication (because it increases food availability). Potentially beneficial measures include reducing the diffuse run off from agricultural land and nutrient run off from point-sources by constructing waste water treatment plants. All actions to reduce physical disturbance from bottom trawling, offshore construction work and dredging, including prohibition in protected areas, would also be beneficial.

References:
Bitschofsky F., Forster S., Scholz J. 2011. Introduction in: ‘Regional and temporal changes in epizoobiontic bryozoan-communities of Flustra foliacea (Linnaeus, 1758) and implications for North Sea ecology’. Estuarine, Coastal and Shelf Science 91(3): 423–433.
HELCOM, 1998. Red List of marine and coastal biotopes and biotopes complexes of the Baltic Sea, Belt Sea and Kattegat. Baltic Sea Environmental Proceedings No. 75. Helsinki Commission, Helsinki. 115pp. Available at: http://www.helcom.fi/Lists/Publications/BSEP75.pdf (Accessed: 28/07/2015).
HELCOM 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Baltic Sea Environmental Proceedings No. 138.                                                                                                                     
HELCOM 2013. Biotope Information Sheet, Available at: http://helcom.fi/Red%20List%20of%20biotopes%20habitats%20and%20biotope%20complexe/HELCOM%20Red%20List%20AA.A1H2,%20AB.A1H2,%20AA.M1H2,%20AB.M1H2.pdf (Accessed: 28/07/2015).
Krzyminska, J., 2000. Bivalves in the surface deposits in the Southern Baltic. Folia Malacologica 8(1): 95-100. 
Martin, G., Kulla, J., Muller, T. & Herkul, K., 2013. Spatial distribution of marine benthic habitats in Estonia coastal sea, north-eastern Baltic sea. Estonian Journal Ecology, 62(3): 165-191. 
Picton, B.E., Morrow, C.C., 2010.Encyclopedia of Marine Life of Britain and Ireland. Available at: http://www.habitas.org.uk/marinelife/species.asp?item=Y6940 (Accessed: 28/07/2015).
Ryland J.S., Hayward P.J., 1977. British anascan bryozoans. Synopses of the British Fauna (New Series), No. 10. Academic Press, London, UK.
Stresemann E., Hannemann H.-J., Klausnitzer B. Senglaub K. 1992. Exkursionsfauna von Deutschland. Band 1, Wirbellose (ohne Insekten). Volk und Wissen Verlag gmbH Berlin.
Tyler-Walters H., Ballerstedt S. 2007. Flustra foliacea. Hornwrack. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. Available at: http://www.marlin.ac.uk/generalbiology.php?speciesID=3342 (Accessed: 28/07/2015).

Criterion A Text:
There has been some reduction in extent of at least one of the associated biotopes but expert opinion is that, overall, this habitat has not declined in extent by more than 25% over the last 50 years. This habitat has therefore been assessed as Least Concern under Criteria A.

Criterion B Text:
This habitat is very common being present along most coastal waters except possibly some of the eastern and southern Baltic where sand is the dominating substrate or in areas of low salinity. There has been some reduction in extent of at least one of the associated biotopes but overall trends in extent and area are unknown. EOO >50,000 km2 and AOO >50 (although exact figures are not available), and it is not limited to a few locations. This habitat has therefore been assessed as Least Concern under Criteria B.

Synthesis:
This habitat is present in all sub-basins of the Baltic Sea therefore EOO exceeds 50,000 km2 although the lack of quantitative data on extent, means that accurate calculations of EOO and AOO are not possible at the present time. There is believed to have been some deterioration in extent and quality of some of the associated biotopes, but expert opinion is that overall this habitat has not declined significantly in extent (>25%) over the last 50 years.  
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed all the associated Baltic biotopes as Least Concern (A1) except for those dominated by the bryozoan Flustra foliacea  (AA.A1H2 and AA.M1H2) which were assessed as Near Threatened (A1). With no additional information on changes in extent or quality of this habitat, and because the biotopes assessed as Near Threatened by HELCOM are less common than the other biotopes, current expert opinion is that this habitat should be assessed as Least Concern for the EU 28 and EU 28+.

Sub-habitats in Need of Examination:
AA.A1H2 : Baltic photic rock and boulders dominated by erect moss animals, Flustra foliacea 
AA.M1H2: Baltic photic mixed substrate dominated by erect moss animals, Flustra foliacea


Habitat Type Name:
A5.53: Seagrass beds (other than Posidonia) on Mediterranean infralittoral sand

Habitat Description:
Mediterranean seagrasses form dense and highly productive meadows or beds, between the surface to 15 m depth in coastal lagoons and down to 50 m depth in the open-sea, in clear water conditions. Besides the seagrass Posidonia oceanica, these meadows are built by several submerged magnoliophytes, such as: Cymodocea nodosa, Zostera marina, Zostera noltei or the introduced species Halophila stipulacea, and, in transitional waters and coastal lagoons by Ruppia sp. All these species can be found alone or combined among them to form mixed meadows. The basic physical requirements of seagrass meadows habitats are sufficient light, a suitable substratum (muddy or sandy bottom) and moderate levels of wave exposure. Their tolerance to variation of environmental factors (e.g. salinity, temperature, nutrient concentration) and their geographical distribution differ depending on the dominant seagrass species.
Seagrasses provide habitat for a large set of organisms. The leaf canopy and the network of rhizomes and roots provide substratum for attachment, and creates hiding places to avoid predation. As a result, the abundance and diversity of the fauna and flora living in seagrass meadows are consistently higher than those of adjacent unvegetated areas. In addition seagrass meadows play an important role as spawning zone and hatchery for several species of fishes and are wintering areas of several species of birds
Several sub-habitat can be distinguished. Cymodocea nodosa beds are widely distributed throughout the Mediterranean, and outside, around the Canary Islands and down the North African coast, and are usually frequent in areas with salinity fluctuations from 26 to 44%. These meadows are observed in coastal lagoons and in the open-sea. Eelgrass beds (Z. marina) are rare in the Mediterranean and it is found mostly as small isolated stands, down to 10-15 meters depth depending on water clarity. Dense meadows can however occur, especially, in coastal lagoons and transitional waters. They are distributed from the Arctic waters until the Mediterranean and are very abundant in the Baltic Sea, the North Sea and along the Atlantic coasts down to northern Spain. Ruppia beds grow in brackish waters, in permanent pools of mud or sand flats, as well as in inlets or estuaries. Mixed beds of Zostera and Ruppia can be observed in shallow sublittoral sediments. These communities are generally found in extremely sheltered bays and coastal lagoons, with very weak tidal currents.
Indicators of quality:
Extended seagrass beds with a good penetration to deep waters are characteristic of coastal waters with minimal anthropogenic impact. Since seagrasses are mostly perennial organisms, they reflect the temporally integrated environmental conditions, and, therefore, seagrasses are very good indicator on which environmental monitoring and management of coastal waters can focus. Cymodocea nodosa is considered at the Mediterranean level, as a biological quality element for the implementation of the Water Framework Directive and several indicators have been proposed for this assessment.
Characteristic species:
The leaf canopy hosts epiphytes community, made up of Rhodobiontes (e.g. Acrochaetium daviesii, Chondria mairei, Laurencia obtusa) and filamentous Phaeophyceae (e.g. Castagnea cylindrica, Myriactula gracilis, Myrionema orbiculare), small calcified incrusting rhodobionthes (few millimeters in general, like Hydrolithon...) (a few millimeters in general), Rhodobiontes calcified encrusting (e.g. Hydrolithon farinosum, Pneophyllum fragile by Bacillariophyceae (mainly Pennales) and by Dinobiontes (Prorocentrum lima, Ostreopsis siamensis and Coolia monotis). Several species of polychaetes (Sigalion mathildae, Onuphis eremita, Diopatra neapolitana, molluscs among them bivalves (Acanthocardia tuberculata, Mactra stultorum, Tellina fabula, Donax venustus and gastropods (Acteon tornatilis Nassarius mutabilis Nassarius pygmaeus, Neverita josephinia, crustacean (Ampelisca brevicornis, Hippomedon massiliensis, Pariambus typicus, Idothea linearis and echinoderms (Astropecten sp., Echinocardium cordatum, Paracentrotus lividus) are observed between the rhizomes or inside the sediment.
Teleost occupy all available habitats, from the sediment to the water column overcoming beds. Characteristic species are closely associated with the phyllosphere through a ventral sucker (Opeatogenys gracilis , Apletodon dentatus, or by hanging them by their tails (Hippocampus sp., Nerophis sp., Syngnathus sp.). Inside the canopy several species can be observed as Atherina boyeri, Pomatoschistus marmoratus, Liza aurata, Liza saliens or Aphanius iberus. Despite geographical differences, it is always the same families that dominate in number of species and individuals: Labridae (Coris julis , Symphodus sp., Labrus sp., Xyrichtys novacula), Sparidae (Diplodus sp., Sarpa salpa, Spondyliosoma cantharus, Sparus aurata, Dentex dentex, Scorpaenidae, Serranidae, Mullidae (Mullus surmuletus). Planktivorous species (Boops boops, Spicara sp., Chromis chromis) present in the water column during the day, find refuge in the beds at night.

Classification:
EUNIS (v1405):
Level 4: A subhabitat of 'Sublittoral macrophyte dominated sediment' (A5.5).
 
Annex 1:
1110 Sandbanks which are slightly covered by seawater all the time
1120 Posidonia beds
 
MAES:
Marine - Marine inlets and transitional waters
Marine – Coastal
 
MSFD:
Shallow sublittoral sediment (coarse, sand, mud, mixed)
 
EUSeaMap:
Seagrass meadows
 
IUCN:
9.9 Seagrass submerged
 
Barcelona convention (RAC/SPA):
III. 1. 1. 1. Association with Ruppia cirrhosa and/or Ruppia maritima
III. 1. 1. 4. Association with Zostera noltei in euryhaline and eurythermal environment
III. 1. 1. 5. Association with Zostera marina in euryhaline and eurythermal environment
III. 2. 2. 1. Association with Cymodocea nodosa on well sorted fine sands
III. 2. 2. 2. Association with Halophila stipulacea
III. 2. 3. 4. Association with Cymodocea nodosa on superficial muddy sands in sheltered waters
III. 2. 3. 5. Association with Zostera noltei on superficial muddy sands in sheltered waters

Justification Outstanding Example of Biogeographical Region:
Seagrass beds are a common feature in the Mediterranean and form an important ecosystem and nursery ground for many juvenile fish. This habitat is widespread across the Mediterranean.

Map Description:
There are insufficient data to provide a comprehensive and accurate map of the distribution of this habitat. This map has been generated using EMODnet data from modelled/surveyed records from the Mediterranean (and supplemented with expert opinion where applicable) (EMODnet, 2015 and IUCN database 2015). EOO and AOO have been calculated on the available data presented in this map however these should be treated with caution as expert opinion is that this is not the full distribution of the habitat.

Trends in Quantity:
Information regarding the habitat cover is known from some regions around the Mediterranean.  At few sites, a decrease on the habitat has been observed such as the Venice lagoon (Italy) for example where the subhabitat of Cymodocea nodosa beds had greatly declined since the beginning of the 20th century. Isolated patches of the subhabitat type with Zostera marina beds have also been reported to have almost disappeared along the Spanish coast and more than 50% of loss of habitat has been estimated in Montenegro over the last 36 years.  Overall, trends in the quantity of this habitat are unreported because the variability of methods used and the lack of long term monitoring programmes in place. Nevertheless, when pressures do not persist, recovery have been registered in multiple sites suggesting that this habitat is stable at present.

Trends in Quality:
Not much information seems available about the trends on quality of these seagrass beds. At few sites, a decrease on the quality has been observed such as those observed along the Catalan coast (Spain) with an estimated 36% of meadows affected. Isolated patches of the subhabitat of Zostera marina beds have also been reported to have almost disappeared along the Spanish coast and a general regression on the quality of the subhabitat of Cymodocea nodosa meadows in Spain has been observed. Overall, expert opinion is that there is a decline in quality for this habitat in the EU 28 but it cannot be quantified.

% of Distribution of the Habitat Type within the EU 28:
The habitat is well distributed along EU countries and varies depending which is the dominant seagrass species and its ecological characteristics. It can colonise different types of environment, such as open coastal waters, coastal lagoons and estuaries, and form both monospecific and mixed stands with a patch distribution. This habitat occurs in the EU 28+. The percentage hosted by the EU 28 is therefore less than 100% but there is insufficient information to establish the proportion.

Justification of Small Range/Regression:
This habitat does not have a small natural range. It is widespread, being found as far the Levantine Sea and as far west to the Gibraltar Strait.

Justification of Restricted Area:
This habitat does not have a small natural range and can be found in different types of environment, such as open coastal waters and coastal lagoons.

Pressures and Threats:
Seagrass beds occur in coastal regions where there is a high level of human disturbance. The habitat is threatened locally by mechanical damage from trawling and anchoring from boats as well as coastal development. Eutrophication, competition from alien macroalgae species like Caulerpa taxifolia and Caulerpa cylindracea, urban and industrial waste dumping, modification of lagoon environments and coastal development such as building and maintenance of ports, sea walls and artificial platforms.

Conservation and Management:
Cymodocea nodosa is considered at the Mediterranean level, as a biological quality element for the implementation of the Water Framework Directive and several indicators have been proposed for this assessment. Both Zosteras and Cymodocea are included in the Annex II of the Barcelona Conventions and some national legislations. Besides, the habitat formed by these seagrasses is also protected in various marine protected areas in the countries along the Mediterranean Sea.
To prevent physical damage caused by fishing trawling on the meadows, different measures should be considered such as placing artificial reefs along certain stretches of the coast, develop effective surveillance programmes and enforcing existint regulations to prevent illegal trawling. Awareness programmes with different sectors such as recreational boats and local councils will help to manage better coastal activities and identify areas where cost-effective schemes for threats reduction could be implemented.
Mapping and monitoring efforts are still much needed for most of its range of distribution.

Conservation Status:
Annex 1:
1110: MMED XX
1120: MMED U1
 
At Mediterranean level, Zostera noltei, Z. marina and Cymodocea nodosa species are included in the Annex II, List of endangered or threatened species of the Barcelona

Capacity to Recover its Typical Character and Functionality?:
The predicted recovery times is particularly short for fast-recovering species (e.g. Cymodocea nodosa – within 1 year) however the capacity for the habitat to recover its functionality would be longer.

Summary:
Seagrass habitats made by monospecific and mixed meadows of Zostera sp., Cymodosea nodosa and/or Ruppia sp. are widely distributed in the Mediterranean with a patchy distribution from a few meters to several kilometers wide. They provide habitat for a many organisms. The leaf canopy and the network of rhizomes and roots provide substratum for attachment, and refuges from predators.  As a result, the abundance and diversity of the fauna and flora living in seagrass meadows are consistently higher than those of adjacent unvegetated areas. Seagrass meadows are act as spawning grounds for several species of fishes and are wintering areas of several species of birds.
Detailed information in trends in quantity are unknown besides few locations where have been well studed but it is thought that there is a small decline in quality in some locations. Anthropogenic disturbances from fishing activities (eg. benthic trawling, shellfish digging or boat anchoring) and deteration of water quality (eg. euthrophication) and competition from invasive species are the main threats to this habitat and fragmentation of the meadows has been observed in some sites as a result of impacts by human activities. To prevent physical damage caused by trawling on the meadows, different measures should be considered such as placing artificial reefs along certain stretches of the coast, developing effective surveillance programmes and enforcing existing regulations to prevent illegal trawling. Awareness programmes with different sectors such as recreational boats and local councils will help to manage better coastal activities and identify areas where cost-effective schemes for threats reduction could be implemented.

References:
Borum, J., Duarte, C.M., Krause-Jensen, D. and Greve, T.M. (Eds) 2004. European Seagrasses: An introduction to monitoring and management. The M&MS project. ISBN: 87-89143-21-3.
Boudouresque, C.F., Bernard, G., Pergent, G., Shili, A. and Verlaque, M. 2009. Regression of Mediterranean seagrasses caused by natural processes and anthropogenic disturbances and stress: a critical review. Botanica Marina 52, 395 e 418.
Espinosa, F., Navarro-Barranco, C., González, A.R., Maestre, M.J.C., García-Gómez, J.C., Benhoussa, A., Limam, A. and Bazairi, H. 2014. A combined approach to assessing the conservation status of Cap des Trois Fourches as a potential MPA: is there a shortage of MPAs in the southern Mediterranean? Mediterranean Marine Science 654-666.
González-García, J.A., García-Peña, H. and Bueno del Campo, I. 2005. Especies singulares y protegidas de la flora y fauna de Melilla y las Islas Chafarinas, 264. Fundación Municipal Sociocultural. Excmo. Ayuntamiento de Melilla, Melilla.   
González-García, J.A. 1994. La flora marina de Melilla. Colección Ensayos Melillenses. 212 Fundación Municipal Sociocultural. Excmo. Ayuntamiento de Melilla, Melilla.
Luque, A. and Templado, M. (Ed). 2004. Praderas y bosques marinos de Andalucía. Junta de Andalucía. Consejería de Medio Ambiente, 2004.
Orfanidis, S., Papathanasiou, V., Gounaris, S. and Theodosiou, T.H. 2010. Size distribution approaches for monitoring and conservation of coastal Cymodocea habitats. Aquatic Conservation: Marine and Freshwater Ecosystems 20,177 e 188.
Pergent, G., Bazairi, H., Bianchi, C.N., Boudouresque, C.F., Buia, M.C., Clabaut, P., Harmelin-Vivien, M., Mateo, M.A., Montefalcone, M., Morri, C., Orfanidis, S., PergentMartini, C., Semroud, R., Serrano, O. and Verlaque, M. 2012. Mediterranean Seagrass Meadows: Las praderas de Magnoliofitas marinas del mar Mediterráneo: resiliencia y contribución a la mitigación del cambio climático, Resumen / Mediterranean Seagrass Meadows : Resilience and Contribution to Climate Change Mitigation, A Short Summary. Gland, Suiza y Málaga, España: IUCN. 40 páginas.
Pergent, G., Djellouli, A.A., Hamza, A.A., Etayeb, K.S., El Mansouri, A.A., Talha, F.M., Hamza, M.A., Pergent-Martini, C. and Platini, F. 2002. Characterization of the benthic vegetation in the Farwa Lagoon (Libya). Journal of Coastal Conservation 8: 119–126.
Pergent-Martini, C., Alami, S., Bonacorsi, M., Clabaut, P. and Pergent, G. 2014. Cartographie des peuplements benthiques du littoral de la Corse. Rapport CoralCorse, 79 AAMP, Université de Corse & GIS Posidonie Report.
Pergent, G., Djellouli, A., Hamza, A.A., Ettayeb, K.S., El Mansouri, A.A., Talha, F.M., Hamza, M.A., Pergent-Martini, C. and Platini, F. 2001.  The benthic vegetation in the Farwà Lagoon (Libya) 567-578. MEDCOAST. Proceeding of the 5fth International Conference on the Mediterranean Coastal Environment, MEDCOAST 01.
Pergent, G., Djellouli, A., Hamza, A., Ettayeb, K., Alkekli, A., Talha, M. and Alkunti, E. 2006. Etude des communautés végétales benthiques dans les lagunes côtières d’Ain Al-Ghazala et de Farwa (Libye). 64  CAR/ASP,  Report.
PNUE-PAM-CAR/ASP. 2013. Le Cap des Trois Fourches (Méditerranée, Maroc): caractérisation écologique et orientations de gestion. 113  RAC/SPA
MaÄiÄ‡, V. 2014. Regresia naselja morskih trava u risanskom zalivu (Crna Gora ) (Serbian language)  Voda 337-341.  Voda association Serbia               . Congress paper
Ruiz, J.M., Guillén, J.E., Ramos Segura, A. and Otero, M.M. (Eds.). 2015. Atlas de las praderas marinas de España. IEO/IEL/ UICN, Murcia-Alicante-Málaga,
681 pp.
Sghaier, Y.R., Limam, A., Samah, L., Bitar, G., Khalaf, G., Samaha, Z., El-Shaer, H., Forcada, A., Ocaña, O., Valle, C. and Ramos Esplá, A.A. 2014. Cymodocea nodosa distribution along the lebanase coast. Proceedings of the 5th Mediterranean 248-249 RAC/SPA Proceedings of the 5th Mediterranean Symposium on Marine Vegetation (PortoroÅ¾, Slovenia, 27-28 October 2014).
Shabaka, S.H. 2004. Ecological study of the benthic marine phanerogames meadows of Alexandria, coast, Egypt. M.Sc. Alexandria University, 210 pp.
Scarton, F., Curiel, D. and Rismondo, A. 1995. Aspetti della dinamica temporale di praterie afanerogame marine in Laguna di Venezi”, Lav. Soc. Ven. Sc. Nat ., 20, 95-102.
StjepÄeviÄ‡, J. and Parenzan, P. 1980. Il Golfo delle Bocche di Cattaro - condizioni generali e biocenosi bentoniche con carta ecologica delle sue due baie interne: di Kotor (Cattaro) e di Risan (Risano) Studia marina :  3-148 Institute of marine biology Kotor.
Tagliapietra, D., Cornello M., Pessa G. and Zitelli, A. 1999. Changes in seagrass beds distributionat the Lido outlet of the Venetian Lagoon (Italy),  Biol. Mar. Medit 6, 448-451.
Vela, A., Pasqualini, V., Leoni, V. Djelouli, A., Langar, H., Pergent, G., Pergent-Martini, C., Ferrat, L., Ridha, M. and Djabou, H. 2008. Use of SPOT 5 and IKONOS imagery for mapping biocenoses in a Tunisian Coastal Lagoon (Mediterranean Sea).  Estuarine Coastal and Shelf Science, 79 (4), 591-598.

Criterion A Text:
There are no precise figures of the extent of this habitat therefore it is not possible to estimate any changes in quantity over the last 50 years. No future estimates of extent have been made. Therefore the habitat type is assessed as Data Deficient under Criterion A.

Criterion B Text:
The habitat is known to occur along most of the Mediterranean coast. It has a large EOO >50,000km2 and AOO >50, which exceeds the thresholds for a threatened category on the basis of restricted geographic distribution. There are some reported declines in quality for this habitat but the distribution of the habitat is such that the identified threats are unlikely to affect all localities at once.The habitat type is assessed as Least Concern under Criterion B.

Criterion C/D Text:
Experts report that there has been slight or moderate declines in the quality of this habitat in few countries (Spain, Italy and Montenegro). Nonetheless there is a lack of quantitative data to calculate percentage change in abiotic and/or biotic quality even if substantial reductions in quality have occured in at least some parts of this habitat. Moreover, the adaptive plasticity and successful colonisation of the different structural species that form meadows and beds, has made possible the partial or full recovery of damaged habitats.
Based on this information and expert opinion,the habitat type is assessed as Least Concern under Criterion C/D.

Synthesis:
The habitat is known to occur along most of the Mediterranean coast. It has a large EOO >50,000km2 and AOO >50, which exceeds the thresholds for a threatened category on the basis of restricted geographic distribution. There is increasing anthropogenic pressure on this habitat from pollution, aquaculture and fishing gear and some declines in quality have been reported but trends in quantity are currently unknown. This habitat displays adaptive plasticity and successful colonisation after periods of pressure and can recover naturally in relatively short time periods. Based on the above and the knowledge of experts, this habitat assessed as Least Concern for both the EU 28 and EU 28+.

Sub-habitats in Need of Examination:
The association with Zostera marina in euryhaline and eurythermal environment is rare in the Mediterranean, mostly found as small isolated stands, but dense eelgrass beds do occur, especially, in lagoons. Some significant regres

Contributors:
H. Bazairi, G. Bitar, G. Pergent, V. MaÄiÄ‡ and J. Ruiz.


Habitat Type Name:
A3.13 Photophilic communities with canopy-forming algae in Mediterranean infralittoral and upper circalittoral rock

Habitat Description:
This habitat occurs on rocky bottoms and is characterised by communities macroalgae that form canopies. The structure includes bush-forming, turf forming algae, encrusting fauna and epiphytes. The coverage of the “bush” and turf strata is usually higher than in an assemblage dominated by canopy algae. Assemblages are also highly miniaturized (less than 20 cm high) and very rich in species (up to 110 species in a 400 cm2 area).
This habitat is present from the upper infalittoral zone (0 m) to the upper circalittoral zone. Assemblages are always algal-dominated, although some invertebrates can be common in the understory and growing as epiphytes. Species composition greatly differs according to the environmental conditions. Factors accounting for the variability on the assemblages include light availability, hydrodynamism, nutrient concentration in seawater, substrate, sedimentation, temperature, salinity, grazing intensity, predation, frequency of disturbances. High densities of sea urchins (Paracentrotus lividus) can graze the algae, producing structurally less complex assemblages and even barren areas. Grazing by other fish species (Sarpa salpa or the exotic Siganus rivulatus, S. luridus) can modify the species composition.
Several  associated biotopes have been described and are distinguished according to the dominant species. They include; Corallina elongata on shallow exposed shores; the red algae Haliptilon virgatum, growing on well-lit, shallow exposed shores in central and southern shores, usually accompanied by Laurencia obtusa, Laurencia majuscula and Dictyota fasciola; Colpomenia sinuosa growing on shallow sheltered rocks in nutrient-rich environments; Cladophoropsis membranacea growing on extremely sheltered zones in bays and lagoons; and Arthrocladia villosa and Sporochnus pedunculatus on moderately lit lower infralittoral to upper circalittoral rock, in places with strong unidirectional currents.
Indicators of quality:                                                                                                                            
This habitat is very variable according to the degree of anthropogenic disturbance. Indicators of quality can be measured by examining trends. The first signs of decline imply substitution of species, a decrease on diversity, an increase on invasive exotic species, and an increase in opportunistic, fast-growing species like some Ulva, Cladophora, Acinetospora, or stress resistant like Corallina elongata or Lithophyllum incrustans. Mussels can also replace the dominant algae in shallow waters when the charge of particulate organic matter is very high.
Characteristic species:
This community is characterised by the presence of many photophilic algae covering hard bottoms. The number of species is very large, and can be completely different according to the bathymetric level, exposure and geographical region.  They include:
Rhodophyta (red algae) - Liagora viscida, Liagora distenta, Amphiroa rigida, Corallina elongata, Haliptilon virgatum, Tricleocarpa fragilis, Ceramium virgatum, Wrangelia penicillata, Chylocladia verticillata, Chrysymenia ventricosa, Halymenia floresii, Gelidium spinosum, Predaea ollivieri, Chondracanthus acicularis, Jania rubens, Lithophyllum incrustans, Neogoniolithon brassica-florida, Mesophyllum alternans, Halopithys incurva, Lophocladia lallemandii, Peyssonnelia squamaria, Asparagopsis armata, Asparagopsis taxiformis, Sphaerococcus coronopifolius, Laurencia obtusa, Laurencia majuscula, Digenea simplex, Rytiphlaea tinctoria, Alsidium corallinum, Pterothamnion crispum, Compsothamnion thuyoides, Plocamium cartilagineum, Schottera nicaeensis, Pterocladiella capillacea, Botryocladia botryoides, Peyssonnelia squamaria, Palisada patentiramea
Phaeophyta - Dictyota fasciola, Colpomenia sinuosa, Taonia atomaria, Dictyota cf. dichotoma, Dictyota mediterranea, Stypopodium schimperi, Lobophora variegata, Dictyota spiralis, Zonaria tournefortii, Padina pavonicoides, Padina ditristromatica, Arthrocladia villosa, Sporochnus pedunculatus, Carpomitra costata, Acinetospora crinita, Hydroclathus clathratus, Dictyota dichotoma v. intricata, Sphacelaria cirrosa,  Halopteris scoparia, Halopteris filicina, Padina pavonica, Cladostephus spongiosus, Dictyopteris polypodioides.
Chlorophyta (green algae )- Ulva rigida, Umbraulva olivascens, Dasycladus vermicularis, Flabellia petiolata, Acetabularia acetabulum, Parvocaulis parvulus, Caulerpa prolifera, Caulerpa cylindracea, Codium bursa, Anadyomene  stellata, Cladophoropsis membranacea, Cladophora prolifera. 
Porifera - Crambe crambe, Phorbas topsentii, Sarcotragus fasciculatus, Sarcotragus spinosulus, Hemimycale columella. 
Mollusca - Bittium reticulatum, Conus ventricosus, Columbella rustica, Rissoa guerinii.
Crustacea - Macropodia longirostris, Maja crispata. 
Echinodermata - Echinaster sepositus, Marthasterias glacialis, Paracentrotus lividus, Arbacia lixula, Holothuria tubulosa, Ophidiaster ophidianus, Ophiothrix fragilis. 
Fish - Labrus merula, Coris julis, Serranus cabrilla, Serranus scriba, Symphodus ocellatus, Symphodus tinca, Scorpaena porcus, Epinephelus marginatus, Sciaena umbra, Diplodus sargus, Diplodus vulgaris, Diplodus cervinus, Diplodus puntazzo, Siganus rivulatus, Parablennius pilicornis, Trypterygion delaisi, Symphodus mediterraneus, Siganus luridus, Epinephelus costae, Sarpa salpa, Chromis chromis, Mullus surmuletus, Dentex dentex, Symphodus roissali, Sparisoma cretense.

Classification:
EUNIS (v1405)
Level 4: A sub-habitat of ‘Mediterranean infralittoral rock’ (A3.1).
 
Annex 1:
1160 Large shallow inlets and bays
1170 Reefs
 
MAES:
Marine - Marine inlets and transitional waters
Marine – Coastal
 
MSFD:
Shallow sublittoral rock and biogenic reef
 
EUSeaMap:
Shallow photic rock or biogenic reef
 
IUCN:
9.7 Macroalgal/kelp

Justification Outstanding Example of Biogeographical Region:
This habitat is common and widespread in the Mediterranean. The genus Cystoseira is represented by 42 species mostly distributed in the Mediterranean Sea. The Mediterranean basin is considered the hot-spot for Cystoseira genus with many endemic species.

Map Description:
This map has been generated using data from IUCN and supplemented with expert opinion. EOO and AOO have been calculated on the available data presented in this map however these should be treated with caution as expert opinion is that this may not indicate the full distribution of the habitat.

Trends in Quantity:
Cystoseira forests are regressing due to several impacts, among which are a decrease in water quality, coastline overbuilding, and the proliferation of herbivores (sometimes an indirect effect of overfishing). The decrease of Cystoseira-dominated communities has been described in several Mediterranean shores including the north and south Adriatic Sea, western Mediterranean as well as along the coasts of the Tyrrhenian and Ligurian seas. Along the Albéres coasts (south France) only 5 out of 14 species of Fucales (Cystoseira and Sargassum spp.) documented as abundant in 1912 were still present in 2003, with the genus Sargassum entirely lost with an average decline of 78% over the last 50 years. Similarly, over 212 km of the French Riviera, five Cystoseira and Sargassum shallow water species have disappeared since the early 19th century. Nine others have suffered a dramatic decline or become nearly extinct and only one, C. compressa var compressa is still considered stable and plays a significant structural role as a habitat-forming species. C. amentacea remained abundant in the entire French coast including Corsica but the complete extinction of C. squarrosa along the French coast has been reported.
In the North Adriatic, the canopy forest has been reduced from seven species of Cystoseira and one of Sargassum to two species of Cystoseira since the 1940´s, with a large decline in algae cover between 2002 and 2005. To date, a high level of fragmentation of Cystoseira canopy is still observed and it is estimated to have declined by more than 70%.
Local extinction of canopy-forming algal communities has also been reported in other parts of the Mediterranean: C. foeniculacea (as C. ercegovicii), C. sauvageaua­na and C. spinosa in Mar Piccolo, Southern Italy; C. dubia (as C. fucoides ErcegoviÄ‡), C. foe­niculacea (as C. ercegovicii); C. crin­ita, C. foeniculacea, C. humilis, C.spinosa, S. acinarium and S. hornschuchii at Tremiti Islands, Sicily; C. brachycarpa, C. sauvageauana, C. spinosa, C. zosteroides, S. acinarium and S. trichocar­pum at Linosa Island, off Tunisia; C. corniculata, C. foeniculacea f. tenuiramosa, C. spinosa, S. acinarium and S. hornschuchii along the Adriatic Ital­ian coastline; half of the species historically present in the Gulf of Naples were no longer collected; C. crinitophylla in the Gulf of Saronikos, Greece; C. brachycarpa, C. corniculata, C. crinita, foeniculacea and S. vulgare at Kos Island, Greece. Finally, S. acinarium, S. hornschuchii and S. trichocarpum were no longer observed in Algeria.
A recent study encompassing 2,970 km of the North-Western Mediterranean coastline, summarizes that all the species from the genus Sargassum (except the introduced S. muticum) are locally extinct or in more or less severe decline at all the sites.

Trends in Quality:
A decline in quality has been observed along different regions of the Mediterranean. In the North Adriatic (Monte Conero), well- formed canopy forest has been replaced by strands of simpler seaweeds with filamentous algal turfs and mixed mosaics with other dominant habitats and species (e.g. Mytilus galloprovincialis beds). It has also been observed that the decrease in size of the habitat and its dispersion along the French Riviera are also decreasing benthic assemblage diversity (i.e. homogenization of seascapes).

% of Distribution of the Habitat Type within the EU 28:
Much of the current known information regarding the distribution of this habitat is in the EU 28. However, this habitat is also known to occur in the EU 28+. The percentage hosted by the EU 28 is therefore less than 100% but there is insufficient information to establish the proportion.

Justification of Restricted Area:
The habitat is widespread along the Mediterranean coast and has a large EOO (>50,000km2)

Pressures and Threats:
This habitat is very vulnerable to different anthropogenic disturbances, both direct (pollution, increased sedimentation, coastal urbanization, direct habitat transformation) and indirect (overfishing, invasive species, climate change) as well as destructive fishing (date mussel fishery). These disturbances produce changes in the fauna and flora composition. Competition with two invasive macroalgae, Caulerpa taxifolia and C. cylindracea which are often present along the same coastlines as canopy-forming algae can also contribute to outcompeting Cystoseira spp.. Excessive collection for research and educational purposes has been indicated as another cause of the decrease of the habitat at some sites. Loss of Cystoseira and Sargassum forest has also been attributed to the outbreak of herbivores (e.g. sea urchins Paracentrotus lividus or Arbacia lixula, fishes Sarpa salpa) that is sometimes a consequence of overfishing predators. For deeper habitats, the decrease in water transparency, fishing nets and trawling could be the responsible for the observed declines.

Conservation and Management:
Some of these canopy-forming algae habitats are in protected areas and several Natura 2000 sites (e.g. Scandola,  Bouches de Bonifacio, Cerbères-Banyuls, Calanque and Port-Cros in France, Formentera- Espardell and Dragonera in Spain; Kimolos in Greece; St Peter´s Island and Maratea in Italy). The declaration of other MPAs and the effective management of the existing ones where dense Cystoseira and other large brown algae forests thrive could favour the conservation of this habitat and its recovery when the herbivore pressure is not too high. Nonetheless, the protection of existing forests formed by Cystoseira and other subhabitats of canopy forming communities should complement regular monitoring programs in order to highlight potential threats and early signs of regression. Restoration of this habitat in priority areas with re-forestation methods has been suggested as a potential solution to assist fragmented/lost forests to recover and stimulate natural restoration of lost populations assisted at the same time with other measures such as improving sewage treatment or limitation of excessive herbivory at specific sites. An ecosystem-based management applied to a network of MPAs with long-term monitoring programs and restoration actions, where necessary, is probably the best perspective for the preservation of this habitat in the Mediterranean Sea.

Conservation Status:
Annex 1: 
1160: MMED XX
1170: MMED XX
Six Mediterranean species of Cystoseira are listed in the Annex I of the Bern Convention. The Mediterranean Action Plan, adopted within the framework of the Barcelona Convention, ide

Capacity to Recover its Typical Character and Functionality?:
Little information exist about the recovery potential of this habitat over a certain degree of deterioration. The low dispersal capacity of most Cystoseira species makes natural recovery unlikely, so  artificial reforestation may be an extremely valuable solution for lost forest .
In the case of Sargassum canopy but also species like C. barbarta, C. compressa and C. foeniculacea, the presence of aericysts facilitates dispersion and the recovery of populations from distant areas.

Summary:
This habitat is represented by canopy forming algae that act as ecosystem-engineers forming 'forests' in infralittoral and circalittoral areas. It is recognized that this habitat of mostly large brown seaweeds (represented by the genera Cystoseira and Sargassum) is one of the most important marine habitats in the Mediterranean Sea, forming extended canopies comparable to land forests and providing refuge and subsistence for many organisms, including commercial species. 
This habitat is very vulnerable to different anthropogenic disturbances, both direct (pollution, increased sedimentation, coastal urbanization, direct habitat transformation) and indirect (overfishing, invasive species, climate change) as well as destructive fishing (date mussel fishery). These disturbances produce changes in the fauna and flora composition.  Excessive collection for research and educational purposes has been indicated as another cause of the decrease of the habitat at some sites as has outbreaks of herbivores which is sometimes a consequence of overfishing predators. Some of these canopy-forming algae habitats are in protected areas and several Natura 2000 sites. An ecosystem-based management applied to a network of MPAs with long-term monitoring programs and restoration actions, where necessary, is probably the best perspective for the preservation of this habitat in the Mediterranean Sea.

References:
Ballesteros, E. 1988. Estructura y dinámica de la comunidad de Cystoseira mediterranea Sauvageau en el Mediterráneo Noroccidental. Investigación Pesquera 52: 313-334.
Ballesteros, E. 1989. Estructura y dinámica de la comunidad infralitoral de Codium vermilara (Olivi) Delle Chiaje de la Costa Brava (Mediterráneo Occidental). Anales de Biología 19: 73-90.
Ballesteros, E., Pe´rez, M. and Zabala, M. 1984. Aproximacio´n al conocimiento de las comunidades algales de la zona infralitoral superior en la costa catalana. Collectanea Botanica 15, 69–100.
Ballesteros, E. 1990. Structure and dynamics of the Cystoseira caespitosa Sauvageau (Fucales, Phaeophyceae) community in the North-Western Mediterranean. Scientia Marina 54: 155-168.
Ballesteros, E. 1990. Structure and dynamics of the community of Cystoseira zosteroides (Turner) C. Agardh (Fucales, Phaeophyceae) in the Northwestern Mediterranean. Scientia Marina 54: 217-229.
Benedetti-Cecchi, L., Pannacciulli, F., Bulleri, F., Moschella, P.S., Airoldi, L., Relini, G. and Cinelli, F. 2001. Predicting the consequences of anthropogenic disturbance: Large-scale effects of loss of canopy algae on rocky shores. Marine Ecology Progress Series, 214: 137–150.
Bianchi, C.N., Corsini-Foka, M., Morri, C. and Zenetos, A. 2014. Thirty years after: dramatic changes in the coastal marine ecosystems of Kos Island (Greece), 1981–2013. Mediterranean Marine Science, 15: 482–497.
Blanfune A., Thibaut T. and Verlaque, M. 2013. Distribution of the rare Cystoseira jabukae along the french Mediterranean coast. Rapport Commission International Mer Mediterranee, 40:652.
Buia, M.C., Chiarore, A., Mulas, M. and Porzio, L. 2013. Historical changes in algal diversity in the Gulf of Naples. In: Proceedings of the Global Congress on ICM: Lessons Learned to Address New Challenges. EMECS 10— MEDCOAST 2013 Joint Conference, 30 Oct.–03 Nov. 2013, Marmaris: 837–846.
Curcó, A., Ferré, A., Font, J., Gesti, J., Vilar, L. and Ballesteros, E. 2008. Manual dels Hàbitats de Catalunya. Vol II. 1 Ambients litorals i salins. (Eds. J. Vigo, J. Carreras and A. Ferré). Departament de Medi Ambient i Habitatge. Generalitat de Catalunya. Barcelona. 312 pp.
Giaccone, G. 1972. Struttura, ecologia e corologia dei popolamenti a Laminarie dello stretto de Messina e del mare di Alboran. Memorie di Biologia Marina e di Oceanografia, 2: 37-59.
Gianni, F., Bartolini, F., Airoldi, L., Ballesteros, E., Francour, P., Meinesz, A., Thibaut, T. and Mangialajo, L. 2013. Conservation and restoration of marine forests in the Mediterranean Sea and the potential role of Marine Protected Areas. Advances in Oceanography and Limnology 4(2): 83–101.
Hereu, B., Mangialajo, L., Ballesteros, E. and Thibaut, T. 2008. On the occurrence, structure and distribution of deep-water Cystoseira populations in the Port-Cros National Park (Northwestern Mediterranean). European Journal of Phycology, 43:263-273.
Fraschetti, S, Bianchi, C.N., Terlizzi, A., Fanelli, G., Morri, C. and Boero, F. 2001. Spatial variability and human disturbance in shallow subtidal hard substrate assemblages: a regional approach. Marine Ecology Progress Series 212: 1–12.
Kocatas, et al. 2004. Crustacean Diversity Among the Cystoseira Facies of the Aegean Coast of Turkey. Turk J Zool 28: 309-316. 
Macic, V. and Antolic, B. 2015. Distribution of rare Cystoseira species along the Montenegro coast (South-Eastern Adriatic Sea). PERIODICUM BIOLOGORUM UDC 57:61 VOL. 117, No 3, 441–447.
Mangialajo, L., Ruggieri, N., Asnaghi, V., Chiantore, M., Povero, P. and Cattaneo-Vietti. R. 2007. Ecological status in the Ligurian Sea: the effect of coastline urbanisation and the importance of proper reference sites. Marine Pollution Bulletin, 55: 30–41.
Mangialajo, L., Chiantore, M. and Cattaneo-Vietti, R. 2008. Loss of fucoid algae along a gradient of urbanisation and relationships with the structure of benthic assemblages. Marine Ecology Progress Series, 358:63–74.
Mangialajo, et al. 2013. Conservation And Restoration Of Cystoseira Forests In The Mediterranean Sea: The Role Of Marine Protected Areas. Rapp. Comm. int. Mer Médit. 40: 621.
Montesanto, B. and Panayotidis, P. 2001. The Cystoseira spp. Communities from the Aegean Sea (NE Mediterranean). Mediterranean Marine Science, 2/1: 57-67
Munda, I.M. 1982. The effects of organic pollution on the distribution of fucoid algae from the Istrian coast (vicinity of Rovinj). Acta Adriatica, 23: 329–337.
Munda, I.M. 1993. Changes and degradation of seaweed stands in the Northern Adriatic. Hydrobiologia, 260 (261): 239–253.
Munda, I.M. 2000. Long-term marine floristic changes around Rovinj (Istrian coast, North Adriatic) estimated on the basis of historical data from Paul Kuckuck’s field diaries from the end of the 19th century. Nova Hedwigia, 71: 1–36.
Ould-Ahmed, N., Gómez Garreta, A., Ribera Siguan, M.A. and Bouguedoura, N. 2013. Checklist of the benthic marine macroalgae from Algeria. I. Phaeophyceae. Anales del Jardín Botánico de Madrid, 70(2): 136-143.
Perkol-Finkel, S. and Airoldi, L. 2010. Loss and recovery potential of marine habitats: An experimental study of factors maintaining resilience in subtidal algal forests at the Adriatic Sea. PLoS ONE 5: e10791.
Sala, E., Kizilkaya, Z., Yildirim, D. and Ballesteros, E. 2011. Alien marine fishes deplete algal biomass in the Eastern Mediterranean. PLoS ONE 6(2): e17356.
Sala, E., Ballesteros, E., Dendrinos, E., Di Franco, A., Ferretti, F., Foley, D., Fraschetti, S., Friedlander, A., Garrabou, J., Güçlüsoy, H., Guidetti, P., Halpern, B.S., Hereu, B., Karamanlidis, A., Kizilkaya, K., Macpherson, E., Mangialajo, L., Mariani, S., Micheli, F., Riser, K., Sales, M., Starr, R., Selkoe, K.A., Tomas, F. and Zabala, M. 2012. The structure of Mediterranean rocky reef ecosystems across environmental and human gradients. PlosONE, 7(2): e32742. doi:10.1371/journal.pone.0032742.
Serio, D., Alongi, G., Catra, M., Cormaci, M. and  Furnari, G. 2006. Changes in the benthic algal flora of Linosa Island (Strait of Sicily, Mediterranean Sea). Botanica Marina, 49:135–144.
Soltan, D., Verlaque, M., Boudouresque, C.F. and Francour, P. 2001. Changes in macroalgal communities in the vicinity of a mediterranean sewage outfall after the setting up of a treatment plant. Marine Pollution Bulletin 42:59-70.
Thibaut, T., Pinedo, S., Torras, X. and Ballesteros, E. 2005. Long-term decline of the populations of Fucales (Cystoseira spp. and Sargassum spp.) in the Alberes coast (France, North-western Mediterranean). Marine Pollution Bulletin 50:1472-1489
Thibaut T., Blanfune A., Verlaque M., Boudouresque, C. and Ruitton, S. 2015. The Sargassum conundrum: very rare, threatened or locally extinct in the NW Mediterranean and still lacking protection. Hydrobiologia. DOI 10.1007/s10750-015-2580-y
Thibaut T., Blanfune, A.V., Boudouresque, C.F. and Verlaque, M. 2015. Decline and local extinction of Fucales in the French Riviera: the harbinger of future extinctions? Mediterranean Marine Science 16/1, 000-000.
Verges, A., Alcoverro, T. and Ballesteros, E. 2009. Role of fish herbivory in structuring the vertical distribution of canopy algae (Cystoseira spp.) in the Mediterranean Sea. Marine Ecology Progress Series, 375: 1-11. 
Verges, A., Tomas, F., Cebrian, E., Ballesteros, E., Kizilkaya, Z., Dendrinos, P., Karamanlidis, A., Spiegel, D. and Sala, E. 2014. Tropical rabbitfish and the deforestation of a warming temperate sea. Journal of Ecology 102: 1518-1527.

Criterion A Text:
An average reduction in extent of this habitat by 77% has been reported from the Adriatic Sea, Ligurian and Western Mediterranean. The same pressures and threats are common in other regions, therefore the same percentage of reduction is inferred for the EU 28. Expert opinion is that reductions in quantity are also considered likely in the future although to a lesser extent. Historic losss are estimated to have exceeded 40%. This habitat has therefore been assessed as Endangered under Criterion A1 and A2b and Near Threatened under criteria A3 in the EU 28. This habitat has been assessed as Data Deficient in the EU 28+ although the majority of this habitat is likely to lie within the EU 28 area.

Criterion B Text:
The habitat is widespread in the Eastern and Western Mediterranean. The EOO is larger than 50,000 km2 and the AOO larger than 50, therefore exceeding the thresholds for a threatened category. The information available indicates a continuing decline in the spatial extent and the biotic and abiotic quality. The nature and size of threats to this habitat and the distribution data which are available suggest that no known threats are likely to affect all localities at once. This habitat has therefore been assessed as Least Concern under criterion B.

Criterion C/D Text:
Overall there has been a substantial reduction in quality of this habitat in the EU 28. An average intermediate decline (70% severity) affecting 50% of the extent of the habitat has been estimated in the EU 28. This decline in the number of erect algae species composing the forest is due to changes in biotic and abiotic conditions has been reported along a large part of the European Mediterranean coastline. Sea urchins outbreaks have also been reported at several sites causing the overgrazing of the macroalgal communities and the creation of barren grounds while contributing to the general loss of large brown algae forest by herbivores such as Sarpa salpa. The effects of these outbreaks cannot be quantified with the present knowledge. There is insufficient quantitative data to estimate the reduction in quality at the EU 28+ level. This habitat is therefore assessed as Vulnerable under Criterion C/D1 in the EU 28, and as Data Deficient for all other criteria in the EU 28 and in the EU 28+.

Synthesis:
Although territorial data was not provided for all countries, there is an overall consensus in the expert opinion that this habitat has declined in quantity and quality in the EU 28 in the past 50 years. There is a lack of quantitative data for countries outside the EU 28 to infer the situation for the EU 28+.
Expert opinion that there has been a 77% reduction in the quantity of this habitat. and a substantial reduction in quality . This habitat is therefore assessed as Endangered under Criteria A. Due to the lack of quantitative data for countries outside the EU 28, the habitat is assessed as Data Deficient at the EU 28+ level.

Assessors:
M. Otero, L. Mangialajo and E. Ballesteros.


Habitat Type Name:
A1.23: Communities of moderately exposed Mediterranean lower mediolittoral rock

Habitat Description:
This is an intertidal habitat which occurs on rocky and boulder shores, just above the mid tide levels. It is present in locations that are moderately exposed to wave action and may be subject to strong or moderate currents. The associated biotopes are dominated by the red alga Corallina elongata in the most exposed conditions, and Gelidium pusillum and G.crinale where there are elevated nutrient levels. In some situation the habitat is almost devoid of erect macroalgae, grazed by Patella spp., and characterised by crusts of the Lithophyllum spp. In the inner parts of bays or close to the beaches, other red algae species (mainly Laurencia pyramidalis, Laurencia glandulifera, Palisada perforata and Osmundea verlaquei) but also Hypnea musciformis and Ceramium ciliatum may dominate. There is also an associated biotope dominated by Palisada tenerrima which forms dense, almost monospecific turfs that completely cover the rock in the central and southern part of the Mediterranean and a dominance by Haliptilon virgatum in several Mediterranean regions characterised by warm waters and relatively high light irradiances.
Indicators of quality
An increase in the abundance of many organisms: green algae, Gelidium spp., Scytosiphon lomentaria, Petalonia fascia, Mytilus galloprovincialis and, occasionally, Corallina elongata can be indicators of poor quality. Conversely species of the genus Osmundea, Laurencia and Palisada seem to avoid polluted waters. Their absence may therefore also be a potential indicator of changes in quality of the habitat. 
A "Quality of Rocky Bottoms index" (CFR by its Spanish acronym) used in Spanish Atlantic waters for the assessment of macroalgae communities on rocky shores may have some potentially application in assessment of quality of this habitat.
Characteristic species:
Rhodophyta (red algae)-Corallina elongata, Hypnea musciformis, Callithamnion granulatum, Gastroclonium clavatum, Grateloupia filicina, Ceramium ciliatum, Boergeseniella fruticulosa, Chondria boryana, Laurencia glandulifera, Gelidium crinale, Laurencia pyramidalis, Haliptilon virgatum, Ceramium diaphanum, Lithophyllum byssoides, Lithophyllum incrustans, Gelidium pusillum, Osmundea verlaquei, Antithamnionella elegans, Asparagopsis armata (sporophyte), Jania rubens, Ceramium tenerrimum, Hildenbrandia crouaniorum, Polysiphonia sertularioides, Chondracanthus acicularis, Lophosiphonia obscura, Ceramium echionotum, Lithophyllum pustulatum, Lophosiphonia cristata, Palisada perforata, Ceramium virgatum, Liagora viscida, Gayliella flaccida.
Phaeophyta (brown algae)-Cystoseira compressa, Sphacelaria cirrosa, Dictyota sp., Ralfsia verrucosa, Padina pavonica, Halopteris scoparia, Pseudolithoderma adriaticum, Cystoseira mediterranea.
Chlorophyta (green algae)-Ulva rigida, Ulva fasciata, Ulva compressa, Cladophora laetevirens, Bryopsis muscosa, Chaetomorpha aerea, Anadyomene stellata.
Cnidaria-Actinia equina, Anemonia viridis.
Bivalvia-Mytilus galloprovincialis, Mytilaster minimus.
Gastropoda-Phorcus turbinatus, Patella rustica, Patella ulyssiponensis, Stramonita hemastoma.
Cirripedia-Perforatus perforatus.
Decapoda-Pachygrapsus marmoratus.

Classification:
EUNIS (v1405):
Level 4. A sub-habitat of A1.2 Moderate energy littoral rock.
Annex 1:
1160 Large shallow inlets and bays
1170 Reefs
 
MAES:
Marine - inlets and transitional waters
Marine – Coastal
MSFD:
Littoral rock and biogenic reef
EUSeaMap:
Not mapped
IUCN:
12.1 Rocky shoreline
Barcelona Convention (RAC/SPA):
II. 4. 2. Biocenosis of the lower mediolittoral rock

Justification Outstanding Example of Biogeographical Region:
Moderately exposed rocky shores are common and widespread in the Mediterranean.

Trends in Quantity:
This habitat is common along Mediterranean shores and tends to replace other communities (e.g. Cystoseira dominated communities) when affected by certain level of urban and industrial pollution or strong herbivore pressure. There is a lack of detailed information on trends in quantity except in a few localities where expert opinion indicates the habitat is stable (Cataluña, Spain). Overall this habitat is considered to be decreasing in response to coastal development and pollution pressures. These pressures and the decline are considered likely to continue.

% of Distribution of the Habitat Type within the EU 28:
This habitat does occur in the EU 28+ but the percentage is unknown.

Pressures and Threats:
This habitat is vulnerable to coastal development and particularly to schemes which modify the coastline or the hydrographic conditions immediately offshore. Nutrient enrichment from discharges and run-off is another pressure affecting the habitat by changing the composition and abundance of associated species. For example it can lead to an increased in the abundance of ephemeral green algae and decrease in species of the genus Osmundea, Laurencia and Palisada. Chemical contaminants can also result in reduced growth rates of algae and general degradation of the habitat.

Capacity to Recover its Typical Character and Functionality?:
Some of the dominant species of this habitat such as Corallina elongata turfs show greater capacity to some disturbance and recovery. Overall it is considered capable of recovering if suitable substrate is present and the environmental conditions (including water quality) are beneficial.

Summary:
This is mediolittoral habitat of rocky and boulder shores. It is present in locations that are moderately exposed to wave action and may be subject to strong or moderate currents. The associated biotopes are dominated by the red algae. It has been impacted by coastal development, particularly schemes which modify the coastline, and by nutrient enrichment which has caused a deterioration in water quality. Beneficial actions include those which improve water quality and the regulation of coastal development.

References:
Ballesteros, E. 1984. Els estatges supralitoral i mediolitoral de les Illes Medes. In: Els sistemes naturals de les Illes Medes (eds. J. Ros, I. Olivella & J.M. Gili). Arxius Secció Ciències, 73: 647-659. IEC. Barcelona.
Ballesteros, E. 1992. Els vegetals i la zonació litoral: espècies, comunitats i factors que influeixen en la seva distribució. Arxius Secció Ciències, 101. Institut d'Estudis Catalans. Barcelona. 616 pp.
Ballesteros, E., S. Mariani, M. E. Cefalì, M. Terradas & E. Chappuis. 2014. Manual dels hàbitats litorals a Catalunya. Generalitat de Catalunya. Departament de Territori i Sostenibilitat, Barcelona. 251 pp.
EEA, 1999. State and pressures of the marine and coastal Mediterranean environment. ISBN: 92-9167-187-8. 43pp.
Feldmann, J. 1937. Recherches sur la végétation marine de la Méditerranée: la côte des Albères. Revue Algologique, 10: 1-339.
Pinedo, S. et al. 2007. Rocky-shore communities as indicators of water quality: A case study in the Northwestern Mediterranean. Marine Pollution Bulletin, 55,126-135.
Pérès, J.M. & J. Picard. 1964. Nouveau manuel de bionomie benthique de la Mer Méditerranée. Recueil des Travaux Statione Marine d’Endoume 31 (47): 3-137.
Rodríguez-Prieto, C., E. Ballesteros, F. Boisset & J. Afonso-Carrillo. 2013. Guía de las macroalgas y fanerógamas marinas del Mediterráneo Occidental. Omega, Barcelona. 656 pp.
Templado, J., E. Ballesteros, I. Galparsoro, A. Borja, A. Serrano, L. Marín & A. Brito. 2012. Guía interpretativa: Inventario español de hábitats marinos. Inventario español de hábitats y especies marinos. Ministerio de Agricultura, Alimentación y Medio Ambiente. 229 pp.
UNEP/MAP, 2012. State of the Mediterranean Marine and Coastal Environment, UNEP/MAP – Barcelona Convention, Athens.

Criterion A Text:
Expert opinion is that this habitat has been decreasing overall but there is insufficient information to determine the percentage. This habitat has therefore been assessed as Data Deficient under criterion A for both the EU 28 and EU 28+.

Criterion B Text:
This habitat has a large natural range in the Eastern and Western Mediterranean. It is considered likely to have a continuing decline in quantity but this cannot be quantified. As EOO >50,000km2 and AOO >50, this exceeds the thresholds for a threatened category on the basis of restricted geographic distribution. The distribution of the habitat is such that the identified threats are unlikely to affect all localities at once. This habitat has therefore been assessed as Least Concern under criteria B for the EU 28 and under criteria B1c, B2c and B3 for the EU 28+ and Data Deficient for all other criteria.

Criterion C/D Text:
Increasing urbanization of the Mediterranean coast and poor water quality are considered likely to have had a moderate impact on the biotic and abiotic quality of this habitat in the recent past. This is likely to continue but lack of studies and data mean that the scale of such changes cannot be quantified. This habitat has therefore been assessed as Data Deficient under criteria C/D1.

Synthesis:
This is a widespread habitat in the Mediterranean Sea, however there is very little information on its detailed distribution. Expert opinion is that it has suffered some declines in extent and this is likely to continue as the pressures and threats remain although past and future reductions in quantity and quality cannot be quantified. The habitat has a large EOO and AOO, and its distribution is such that the identified threats are unlikely to affect all localities at once. It therefore qualifies as Least Concern under Criterion B but the overall assessment is Data Deficient both at the EU 28 and the EU 28+ levels because of the lack of information on its trends in quantity and quality.

Contributors:
Mariani S., Ballesteros E., Cefalì M. E.


Habitat Type Name:
8 Sparse or absent epifaunal communities on Baltic infralittoral rock and mixed substrata (predominantly hard)

Habitat Description:
This habitat is distributed on Baltic bottoms in the photic zone with at least 90% coverage of rock, boulders or stones of more than 63 mm in diameter but this habitat type also occurs on mixed (predominantly hard) substrates where the percentage of rock is lower than 90% according to the HELCOM Hub classification. Less than 10% of the seabed is covered by perennial vegetation or attached epifauna. In some cases no epibenthic vegetation or macrofauna are present. Six associated biotopes have been identified. These are on rock and mixed (predominantly hard substrates) variously dominated (at least 50% of the biomass) by epibenthic macrocommunity and microphytobenthic organisms and grazing snails or with no macrocommunity The sub-biotope Baltic photic rock and boulders characterized by sparse epibenthic macrocommunity (AA.A2T) only occurs in the Gulf of Bothnia, Gulf of Finland and Gulf of Riga and the sub-biotope Baltic photic rock and boulders characterized by microphytobenthic organisms and grazing snails (AA.A2W) only occurs in the Gulf of Bothnia and Gulf of Finland.
Indicators of quality:
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. Diversity, abundance and biomass of associated fauna may be indicators of quality.
Characteristic species:  
For sparse epibenthic communities Mytilus spp., Bryozoa, Balanidae, Bryozoa, Porifera, Hydrozoa; for communities characterized by microphytobenthic organisms and grazing snails Snails, e.g. Hydrobia spp., Potamopyrgus antipodarum, Theodoxus fluviatilis, Bithynia spp., Radix spp. Where there are no macrocommunities, by meiofauna and bacteria.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A3.4 Baltic exposed infralittoral rock, A3.5 Baltic moderately exposed infralittoral rock, A3.6 Baltic sheltered infralittoral rock.
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1160 Large shallow inlets and bays
1170 Reefs
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral rock & biogenic reef
Shallow sublittoral mixed sediment
 
EUSeaMap:
Shallow photic rock or biogenic reef
Shallow coarse or mixed sediments
 
IUCN:
9.2 Subtidal rock and rocky reefs
9.3. Subtidal Loose Rock/Pebble/Gravel
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.A2T Baltic photic rock and boulders characterized by sparse epibenthic macrocommunity
AA.A2W Baltic photic rock and boulders characterized by microphytobenthic organisms and grazing snails
AA.A4U Baltic photic rock and boulders characterized by no macrocommunity
AA.M2T Baltic photic mixed substrate characterized by sparse epibenthic macrocommunity
AA.M2W Baltic photic mixed substrate characterized by microphytobenthic organisms and grazing snails
AA.M4U Baltic photic mixed substrate characterized by no macrocommunity

Justification Outstanding Example of Biogeographical Region:
This habitat is typical of Baltic Sea areas of low salinity areas where the seabed is predominantly hard (rock and mixed substrates).

Trends in Quantity:
This habitat is common throughout the Baltic although some of the associated biotopes have a more restricted distribution. e.g. AA.A2W Baltic photic rock and boulders characterized by microphytobenthic organisms and grazing snails only occurs in the Gulf of Bothnia and Gulf of Finland. There is insufficient information to determine any trends in quantity of this habitat over the last 50 years. Some of the associated biotopes may increase in extent in the future due to changes in salinity, but overall, the trends have not been predicted.

Trends in Quality:
There are no established criteria on which to base a quality assessment and insufficient information to determine if there have been any recent trends in the quality of this habitat.

Pressures and Threats:
No pressure and threats have been identified specifically for this habitat.

Conservation and Management:
No conservation and management measures have been identified specifically for this habitat.

Conservation Status:
Annex 1:
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1160: VU C1 
1650: VU C1 
1170: VU C1 
HELCOM (2013) assessed six sub-habitats AA.A2T, AA.A2W

Summary:
This habitat is characterized by sparse or absent epifaunal communities. It is quite common along large parts of the Finnish, Swedish and Estonian shorelines (at least), and typical for areas with hard bottom where algae growth is limited by either overall turbidity and/or salinity, or by their fluctuations. It is found in all Baltic sub-basins, although some sub-habitats have a more limited distribution. Pressures, threats, and conservation and management measures have not been identified specifically for this habitat type.

References:
HELCOM, 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Avellan, L. (Ed). Helsinki, Finland.
Martin, G., Kotta, J., Moller, T. and Herkul, K. 2013. Spatial distribution of marine benthic habitats in the Estonia coastal sea, North-eastern Baltic sea. Estonian Journal of Ecology 62(3): 165-191.

Criterion A Text:
The area covered by this habitat is not known and there are no quantitative data on trends in quantity but expert opinion is that there has been less than a 25% decline over the last 50 years. This habitat has therefore been assessed as Least Concern under Criteria A.

Criterion B Text:
There is insufficient information on which to determine a baseline or trends in quantity and quality of this habitat at the present time although there is some country specific data e.g. a minimum area estimate of 184 km2 from surveys of six areas investigated off the coast of Estonia between 2005-8. Nevertheless, as patches of this habitat are widespread and common, being present in all the Baltic Sea sub-basins, EOO exceeds 50,000 km2 and AOO >50. It has been therefore assessed as Least Concern under Criteria B.

Synthesis:
There are no quantitative data on extent and area of the habitat but it is widespread and common. Expert opinion is that the extent is believed to have changed by less than 25% over the past 50 years but the lack of quantitative data on extent, quality and trends over time means that accurate calculations of EOO and AOO are not possible at the present time. This Red List assessment has therefore been based on expert opinion.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion HELCOM (2013) assessed six relevant Baltic sub-habitats (AA.A2T, AA.A2W, AA.A4U, AA.M2T, AA.M2W, AA.M4U) as Least Concern (A1). With no additional information on changes in extent or quality of this habitat, a known occurrence in all the Baltic Sea sub-basins, and less than a 25% decline in quantity over the last 50 years, current expert opinion is that this habitat should be assessed as Least Concern for the EU 28 and EU 28+.


Habitat Type Name:
9 Communities on Baltic infralittoral clay and other hard substrata

Habitat Description:
This is a Baltic Sea benthic habitat in the photic zone with at least 90% coverage of hard clay, marlstone rock, ferromanganese concretions and/or peat according to the HELCOM HUB classification. Sessile/semi-sessile epibenthic bivalves cover of at least 10% of the seabed and no perennial attached erect group has more than 10% coverage. In some cases macrovegetation or macrofauna may be absent. The habitat is typically encountered in high energy exposure areas. 
Seven associated biotopes have been identified. Four of these are associated with areas of hard clay and may be dominated (at least 50% of the biomass) by Mytilids (Mytilus spp., Modiolus modiolus), have a mixed epibenthic macrocommunity, a sparse epibenthic macrocommunity or have no dominant macrocommunity (AA.B1E1,  AA.B1V, AA.B2T and AA.B4U). The marlstone rock habitat  'AA.C: Baltic photic marl' is only present in the Baltic proper, Belt Sea and the Sound and  'AA.F: Baltic photic ferromanganese concretion bottoms' which is typically found below 10m occurs in Baltic proper, Gulf of Bothnia, Gulf of Finland, Gulf of Riga. 'AA.G: Baltic photic peat bottoms' which occurs in the Baltic proper and Belt Sea, has developed where marine erosion processes along the German and Danish coastline have laid these subfossil substrates bare. It is found salinity ranges between 7 and 18 psu, at all exposure classes and at depths from 0-20m. Knowledge about the latter biotope is scarce but the surface can be covered by filamentous annual algae and single juvenile Fucus spp. or Chorda spp. specimens. Normally peat bottom lacks epibenthic communities and only some specialised burrowing bivalves like Barnea candida or Zirfaea crispata may penetrate into the peat.
Indicators of quality;
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time.
There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. Diversity, abundance and biomass of the dominate species and associated fauna are potential indicators of quality of this habitat.
Characteristic species: 
Mytilus spp., and Modiolus modiolus in hard clay dominated areas. Barnea candida, Zirfaea crispata, and macrophytes on peat dominated areas.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A3.4 Baltic exposed infralittoral rock, A3.5 Baltic moderately exposed infralittoral rock and A3.6 Baltic sheltered infralittoral rock .
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1160 Large shallow inlets and bays
1170 Reefs
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral rock and biogenic reef
 
EUSeaMap:
Shallow photic rock or biogenic reef
 
IUCN:
9.2 Subtidal rock and rocky reefs
 
Other relationships:
Level 6 of the HELCOM HUB classification (2013): 
AA.B1E1 Baltic photic hard clay dominated by Mytilidae
AA.B1V Baltic photic hard clay characterized by mixed epibenthic macrocommunity
AA.B2T Baltic photic hard clay characterized by sparse epibenthic macrocommunity
AA.B4U Baltic photic hard clay characterized by no macrocommunity
Level 3 of the HELCOM HUB classification (2013): 
AA.C: Baltic photic marl (marlstone rock) only present in the Baltic proper, Belt Sea and the Sound
AA.F: Baltic photic ferromanganese concretion bottoms
AA.G: Baltic photic peat bottom

Justification Outstanding Example of Biogeographical Region:
One of the associated biotopes, hard clay with epibenthic bivalves, typically Mytilus spp. or Modiolus modiolus, may be characateristic of the Baltic Sea, but the other types (marlstone rock, ferromanganese concretions and peat) do occur in other regional seas.

Map Description:
There are insufficient data to provide a comprehensive and accurate map of the distribution of this habitat. This map has therefore been generated using the modelled data available on EMODnet for EUNIS level 3 habitats in the Baltic Sea (EMODnet, 2010). This means it indicates potential areas in which this habitat may occur, not the actual distribution of this EUNIS level 4 habitat. EOO and AOO cannot be calculated at the present time, although the habitat is known to occur in all the Baltic sub-basins.

Trends in Quantity:
There is a lack of quantitative data on the area covered by this habitat but some estimates have been made on the basis of modelling work (e.g. an area estimate for photic clay in the Baltic of 3,557 km2). All the associated biotopes are considered to have declined to some extent over the last 50 years (more than 25% in the case of the peat biotopes and in the case of hard clay approximately 10% in some areas of the Belt Sea and southern Baltic Proper).

Trends in Quality:
There is a lack of quantitative data on which to determine any trends in quality of this habitat over the last 50 years.

% of Distribution of the Habitat Type within the EU 28:
There are some differences in distribution of the associated biotopes. For example modelling suggests that around 70% of the hard clay biotope is hosted by EU 28 in the Baltic while distribution records show all the peat biotope is hosted by EU 28. A minimum estimate is therefore that 70% of this habitat is hosted by EU 28. Similar habitats do occur in other European regional seas.

Justification of Small Range/Regression:
The associated peat biotope is spatially very restricted but overall this habitat is widely distributed occurring in all the Baltic sub-basins therefore with an estimated EOO of >50,000 km2.

Pressures and Threats:
Coastal and offshore construction works which increase the suspended sediment load in the water column can smother benthic communities associated with this habitat. Similar effects may result from eutrophication (through increase in N, P and organic matter loads). Dredging can cause more direct damage and the development of an industry for the extraction of ferromanganese concretions from the seabed is a possible future threat.

Conservation and Management:
Restoring/improving water quality and establishing protected areas can benefit this habitat as can introducing controls on activities such as bottom trawling, sand, gravel and mineral extraction which cause direct damage to the substrate and the associated communities.

Conservation Status:
Annex 1:
1160: MBAL U2
1650: MBAL U2
1170: MBAL U1
 
HELCOM (2013) assessments:
1160 (VU,C1) 
1170 (VU,C1) 
1650 (VU,C1)
 
HELCOM (2013) assessed three of seven relevant Ba

Capacity to Recover its Typical Character and Functionality?:
Not where the underlying substrate (peat, marlstone rock, ferromanganese concretions) have been removed, however this habitat is not well studied therefore capacity to recover is largely unknown.

Summary:
This habitat is typified by epibenthic communities in the photic zone, including those created by mussels, that occur on hard clay, marlstone rock, ferromanganese concretions and peat. It occurs in all the Baltic Sea sub-basins but the distribution and abundance of the associated biotopes varies. Hard clay is the most widespread whereas submerged peat, formed some 8,000 years ago as sea levels rose, is the rarest and only reported from the southern Baltic off the coasts of Germany and Denmark. Areas where the seabed is comprised of ferromanganese concretions do not occur in the Belt Sea while areas of marlstone rock occur in the Baltic Proper, Belt Sea and The Sound. Activities causing physical disturbance to bottom sediments (bottom trawling, construction work, sand and gravel extraction, mineral extraction and coastal defence works), are both current and future threats to this habitat. Restoring/improving water quality and introducing controls on damaging activities, including regulation in protected areas would be beneficial.

References:
HELCOM, 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Avellan, L. (Ed). Helsinki, Finland.
Stresemann, E., Hannemann, H.-J., Klausnitzer, B. Senglaub, K., 1992. Exkursionsfauna von Deutschland. Band 1, Wirbellose (ohne Insekten). Stresemann, E., Deckert, K., Gruner, H-E., Hannemann, H-J., (Eds). Berlin, Germany.
Leipe, T., Moros, M, Tauber, F., 2011. Die Geschichte der Ostsee. IOW, Leibniz Institute for Baltic Sea Research, Warnemünde. Available at: http://www.io-warnemuende.de/geschichte-der-ostsee-2489.html. (Accessed: 16/07/2015).
Al-Hamdani, Z. & Reker, J., 2007. Towards marine landscapes in the Baltic Sea BALANCE interim Report10. Available at: http://balance-eu.org/xpdf/balance-interim-report-no-10.pdf. (Accessed: 16/07/2015).

Criterion A Text:
All the biotopes associated with this habitat are considered to have declined to some extent over the last 50 years. Expert opinion is that the overall decline has been between 25-30% therefore this habitat has been assessed as Near Threatened under Criteria A.

Criterion B Text:
Present in all the Baltic Sea sub-basins therefore EOO exceeds 50,000 km2. Accurate calculation of EOO and AOO is not possible at the present time therefore this habitat has been assessed as Data Deficient under criteria B.

Synthesis:
This habitat is present in all sub-basins of the Baltic Sea and therefore EOO exceeds 50,000 km2. There is a lack of data on quality and extent of this habitat although there has been an estimate of decline of the peat biotope of more than 25% over the last 50 years and overall a significant decline (>25%) over the last 50 years. The lack of quantitative data on extent, quality and trends over time means that accurate calculations of EOO and AOO are not possible at the present time. This Red List assessment has therefore been based on expert opinion.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed three relevant associated biotopes (AA.B1E1, AA.C and AA.F) as Least Concern (A1), Baltic peat bottoms (AA.G) (which is rare and restricted to a comparably small area of the Baltic) was assessed as Vulnerable (B2b) and three other biotopes were not evaluated (AA.B1V, AA.B2T and AA.B4U).  All the associated biotopes are considered to have declined to some extent over the last 50 years therefore expert opinion is that overall the habitat is Near Threatened for the EU 28 and EU 28+.

Sub-habitats in Need of Examination:
AA.G Baltic photic peat bottoms because of the rarity of the substrate “peat bottom” and the spatial restriction to a specific and comparably small area of the Baltic. AOO of this habitat is less than 50 as the environmental conditions (sub


Habitat Type Name:
11 Perennial algal communities (excluding kelp) on Baltic infralittoral coarse sediment

Habitat Description:
This habitat is distributed on Baltic bottomsin the photic zone with at least 90% coverage of coarse sediment according to the HELCOM HUB classification.  Perennial attached algae such as Fucus spp., or perennial red algae cover at least 10% of the seabed and more than other perennial attached erect groups.  It is most common in areas moderately exposed to wave action and in depths of up to 10 m. 
Four associated biotopes with different dominant species of algae and some differences in depth and salnity preferences, resulting in variations in their geographical occurrence in the Baltic Sea have been described by HELCOM. These are: ‘Baltic photic coarse sediment dominated by Fucus spp.’ (AA.I1C1) such as Fucus radicans, F. serratus or F. vesiculosus: ‘Baltic photic coarse sediment dominated by perennial non-filamentous corticated red algae’ (AA.I1C2) such as Furcellaria lumbricalis; ‘Baltic photic coarse sediment dominated by perennial foliose red algae’ (AA.I1C3) such as Coccotylus spp., Phyllophora spp. and Delesseria spp. and  ‘Baltic photic coarse sediment dominated by perennial filamentous algae’ (AA.I1C5) such as Polysiphonia spp, Aegagrophila linnaei, Cladophora rupestris. 
Indicators of quality:
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. The lower depth limit of algae, especially Fucus spp. where applicable, and the amount of epiphytic algae are potential indicators of quality of this habitat.
Characteristic species: 
Fucus spp., Furcellaria lumbricalis, Coccotylus truncatus, Phyllophora spp., Deleseria sanguinea, Polysiphonia spp., Cladophora rupestris, Sphacelaria spp.

Classification:
EUNIS:
The closest corresponsence in EUNIS (2004) level 4 is A5.11 Infralittoral coarse sediment in low or reduced salinity
 
Annex 1: 
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1110 Sandbanks slightly covered by seawater
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral coarse sediment
Shallow sublittoral mixed sediment
 
EUSeaMap:
Shallow coarse or mixed sediments
 
IUCN:
9.3 Subtidal loose rock/pebble/gravel
 
Other relationships:
This habitat has four sub-habitats on HUB level 6;
AA.I1C1 Baltic photic coarse sediment dominated by Fucus spp 
AA.I1C2 Baltic photic coarse sediment dominated by perennial non-filamentous corticated red algae
AA.I1C3 Baltic photic coarse sediment dominated by perennial foliose red algae
AA.I1C5 Baltic photic coarse sediment dominated by perennial filamentous algae

Justification Outstanding Example of Biogeographical Region:
It is unknown whether this habitat presents an outstanding example of the typicial characteristics of the Baltic region.

Trends in Quantity:
The habitat occurs in all the Baltic Sea sub-basins although some of the associated biotopes have a more limited distribution. Significant changes (up to 50% in places) most particularly in the depth distribution of this habitat, have been reported over the last 60 years due to reduction in Secchi depth. For example in Germany it occurred historically on stony bottoms down to 10 m but is currently never found deeper than 5-6 m. On a whole Baltic Sea scale the loss is estimated to be have been less than 25%. There are no quantitative data on historic changes and a small further reduction of extent is predicted for the coming 50 years.

Trends in Quality:
Significant changes, most particularly in the depth distribution of this habitat, have been reported over the last 60 years. For example in Germany it occurred historically on stony bottoms down to 10 m but is currently never found deeper than 5-6 m. Currently it is limited to narrow band along most of the German coast except some of the highly eutrophicated inner parts of bays and lagoons such as Schlei Fjord and Dars-Singst Bodden Chain. A continuing decline is predicted if water quality does not improve especially when combined with climate change effects, such as reductions in salinity, as this will reduce the zone for suitable growth. For exampleif trends in temperature, total phosphorus concentration and chlorophyll a, continue, water quality in Bothnian Sea is predicted to deteriorate within 2-3 decades and reach levels that may lead to major losses of F. vesiculosis.

% of Distribution of the Habitat Type within the EU 28:
This habitat occurs in the EU 28+ (Russia). The percentage hosted by EU 28 would be less than 100% but
there is insufficient information to establish the proportion.

Justification of Restricted Area:
This habitat occurs in all the Baltic Sea sub-basins so does not have a small natural range

Pressures and Threats:
Decreased light levels or increased epiphyte growth as a result of eutrophication (nutrient enrichment) are believed to be the main causes for the changes in macroalgae communities in the last 50 years. Eutrophication has many negative effects on macrophytes. Increased nutrient levels stimulate the growth of phytoplankton, which increases the concentration of particles in water and reduces the penetration of light within the water column. As nutrients are available in sufficient amounts for longer times throughout the year, phytoplankton blooms also last longer and occur more often during the season. This shortens the optimal growth periods for macrophytes. The reduced light at the bottom causes a decline in the vertical distribution of vegetation communities and a reduction in the overall amount of plants. Increased nutrient levels also stimulate the growth of opportunistic macrophytes. Their small size with fine, highly branched filamentous habit give a high surface to volume ratio and therefore a high rate of nutrient uptake. This enables opportunistic macrophytes extremely high growth rates if abiotic conditions (light, temperature) are also favourable. The effect of eutrophication has been most apparent as a reduced width of the depth zone occupied by the perennial algae.
Activities which increase turbidity or remove substrate, such as offshore construction and stone fishing, are additional known pressures as is localized pollution, for example in the Stockholm archipelago, Tallinn Bay and Gulf of Riga. Changes in sea temperature, ice cover/scour and salinity associated with climate change will add to these pressures and can be expected to change the species composition in the habitat. For example although F.lumbricalis is known for its wide tolerance range for salinity, sexual reproduction is curtailed below 7psu where regeneration occurs via asexual reproduction. This can reduce genetic diversity and therefore make populations vulnerable to sudden environmental changes. Also as the salinity declines, a larger part of the shallow benthic primary production on hard bottom will be taken over by species tolerating low salinities, such as green algal species like gut weed (Ulva intestinalis) and Cladophora spp.

Conservation and Management:
Improvements in water quality (reduction of nutrient inputs) are considered to have been a major factor in the recovery of the perennial macroalgal habitat by improving light penetration and reducing the scope for rapid and blanketing smothering of the canopy forming species by ephiphytic annual algae. Controls on coastal and offshore constructions to avoid increasing turbidity and direct removal or damage to the habitat are also important.

Conservation Status:
Annex 1:
1110: MBAL U1
1160: MBAL U2
1170: MBAL U1
1650: MBAL U2
 
HELCOM (2013) assessments:
1110: VU C1
1160: VU C1
1170: VU C1
1650: VU C1 
HELCOM (2013) has assessed all fo

Summary:
This habitat occurs in all the Baltic Sea sub basins although some of the associated biotopes have a more limited distribution.  Fucus spp. and Furcellaria lumbricalis are the characteristic species creating a canopy and these perennial algal communities can form a dense belt in the shallow sublittoral,  The algae provide a habitat for many epiphytic and epibenthic species making this one of the most species-rich habitats in the Baltic.  
Eutrophication is one of the principal causes of the changes in macroalgal vegetation in coastal waters of the Baltic. Increasing nutrient levels (N, P, organic matter) can lead to shading effects through increase in turbidity and epiphphytic growth on macroalgae. There may also be a change in the dominant species, for example the kelp Saccharina latissima which is adapted to lower light levels can move upwards and out-compete Fucus. Improvements in water quality (reduction of nutrient inputs) are considered to have been a major factor in the recovery of the perennial macroalgal habitat by improving light penetration and reducing the scope for rapid and blanketing smothering of the canopy forming species by ephiphytic annual algae. Controls on coastal and offshore construction to avoid increasing turbidity and direct removal or damage to the habitat are also important conservation measures.

References:
Dahl, K., Josefson, A.B., Göke, C., et al. 2013. Climate Change Impacts on Marine Biodiversity and Habitats in the Baltic Sea - and Possible Human Adaptations. In: Krarup Leth, O., Dahl, K., Peltonen, H., Krämer, I., Kule, L. (Eds.). Sectoral Impact Assessments for the Baltic Sea Region - Climate Change Impacts on Biodiversity, Fisheries, Coastal Infrastructure and Tourism. Coastline Reports (21), pp. 1-34. EUCC - The Coastal Union Germany, Rostock, 2013.
Gic-Grusza, C., Kryla-Straszewska, K., UrbaÅ„ski, J., Warzocha, J. and WÄ™stawski, J.M. 2009. Atlas of Polish marine area bottom habitats. Environmental valorization of marine habitats. Gic-Grusza, C., Kryla-Straszewska, K., UrbaÅ„ski, J., Warzocha, J. and WÄ™stawski, J.M. (Eds). Gdynia, Poland.
HELCOM, 2013. Fucus serratus. Species Information Sheet. Available at: http://helcom.fi/Red%20List%20Species%20Information%20Sheet/HELCOM%20Red%20List%20Fucus%20serratus.pdf. (Accesssed: 16/07/2015).
HELCOM, 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Avellan, L. (Ed). Helsinki, Finland.
Plinski and Florczyk 1993. Changes in species composition of the genus Gammarus Fabr.in Puck Bay. Oceanologia 42(1): 71-87.
Vogt, H. and Schramm, W. 1991. Conspicuous decline of Fucus in Kiel Bay (Western Baltic): what are the causes? Marine Ecology Progress Series 69: 189-194.

Criterion A Text:
There have been significant declines in the extent of this habitat (up to 50% in places) as well as in the depth zone occupied but there has also been some recovery, so overall this habitat is not considered to have declined by more than 25%. There has been no estimate of future trends in quantity. A continuing decline is predicted if water quality does not improve especially when combined with climate change effects, such as reductions in salinity, as this will reduce the zone for suitable growth. This habitat has therefore been assessed as Least Concern under Criteria A for the EU 28 and EU 28+.

Criterion B Text:
Expert opinion is that although there are shortcomings with the data used to calculate EOO and AOO, because this habitat is known to be present in all the Baltic Sea sub-basins, does not have a restricted geographic distribution, and the associated threats are not limited to a few locations it should be assessed as Least Concern under Criteria B for the EU 28 and EU 28+.

Synthesis:
Modelling and mapping studies provide information on the location and extent of the habitat in some areas (e.g. Lithuania and Poland) but there is a lack of quantitative data on the full extent of this habitat in the Baltic Sea. Significant changes most particularly in its depth distribution, but also in quality have been reported over the last 60 years but not quantified.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed the four relevant Baltic biotopes (AA.I1C1, AA.I1C2, AA.I1C3, AA.I1C5) to be Least Concern (A1). With no additional information on changes in extent or quality of this habitat, a wide geographical distribution in the Baltic and less than a 25% decline in quantity over the last 50 years, the current expert opinion is that this habitat should be assessed as Least Concern for the EU 28 and EU 28+.


Habitat Type Name:
12 Aquatic moss communities on Baltic infralittoral coarse sediment

Habitat Description:
This habitat occurs on Baltic bottoms in the photic zone where the seabed substrate is at least 90% coarse sediment according to the HELCOM HUB classification.  Aquatic moss covers at least 10% of the seabed and more than any other perennial attached erect groups. In some places the mosses form extensive underwater meadows which provide shelter and food for benthic animals. This habitat occurs where salinity is typically  <5 psu and in all exposure ranges although more common in areas exposed to wave action. It occupies the photic zone typically between 1 to 7 meters.
Indicators of quality: 
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time.
There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. The depth zone occupied and amount of epiphytic ephemeral filamentous algae are potential indicators of quality of this habitat.
Characteristic species: 
Fontinalis spp. Fissidens fontanus, Platyhypnidium riparioides.

Classification:
EUNIS:
The closest corresponsence in EUNIS (2004) level 4 is A5.11 Infralittoral coarse sediment in low or reduced salinity
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES: 
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:  
Shallow sublittoral coarse sediment
 
EUSeaMap:
Shallow coarse or mixed sediments
 
IUCN
9.3 Subtidal Loose Rock/Pebble/Gravel
 
Other relationships
Level 5 of the HELCOM HUB classification (2013).
AA.I1D: Baltic photic coarse sediment characterized by aquatic moss

Justification Outstanding Example of Biogeographical Region:
Aquatic moss habitats typically occur in freshwater. The low salinity conditions in the northern Baltic have enabled them to become established in coastal waters.

Trends in Quantity:
There is insufficient information on which to assess the current quantity of this habitat or any historical trends. No future trends have been estimated.

Trends in Quality:
There is insufficient information on which to assess the current quality of this habitat or any historical trends. No future trends have been estimated.

% of Distribution of the Habitat Type within the EU 28:
Defined as a Baltic habitat therefore 100% occurs in the Baltic Sea. Unknown what percentage is hosted by Member States in the Baltic.

Justification of Small Range/Regression:
It is unknown whether this habitat has a small natural range following regression.

Justification of Restricted Area:
It is unknown whether this habitat has a small natural range by reason on its intrinsically restricted area.

Pressures and Threats:
There is limited information on pressures and threats specifically relating to this habitat but they could be expected to include poor water quality including nutrient enrichment (N, P and organic matter) and sedimentation which would reduce light levels, encourage the growth of epiphytes and potentially smother the aquatic mosses which are the characteristic species of this habitat.

Conservation Status:
Annex 1:
1160: MBAL U2
1650: MBAL U2
 
Status of Annex 1 types in Baltic as assessed by HELCOM (2013)
1160 (VU,C1)
1650 VU (C1)
HELCOM has assessed this habitat (AA.I1D) as LC (A1)

Capacity to Recover its Typical Character and Functionality?:
Unknown. There is no information available in order to estimate the recovery capacity of this habitat type.

Summary:
Aquatic moss communities on Baltic infralittoral coarse sediment substrates may form extensive underwater meadows in sheltered waters. Fontinalis spp. penetrate into the southernmost part of the Gulf of Bothnia (Oregrund Archipelago) and are common in the Tvarminne area while Drepanocladus spp. are reported from the Gulf of Bothnia and Gulf of Finland. Although there is some species distribution information there are no quantitative data on the geographic extent of this habitat in the Baltic or changes in quality in recent or historic periods of time.
This habitat has not been extensively studied in the Baltic (compared to freshwater equivalents) but is believed to provide shelter and food for benthic animals as well as suitable spawning locations for some fish. The pressures and threats to this habitat are likely to be associated with decline in water quality, sedimentation, and physical damage. There is limited information on conservation and management measures specifically relating to this habitat but they could be expected to include those which reduce the risks of eutrophication and increase water clarity.

References:
HELCOM, 2013. Checklist of Baltic Sea Macro-species. Kontula, T. and Haldin, J., (Eds). Helsinki, Finland. 
HELCOM, 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Avellan, L. (Ed). Helsinki, Finland.
Kautsky, H., Plantman, P. & Borgiel, M., 1999. Quantitative distribution of aquatic plant and animal communities in the Forsmark-area. Svensk Kärnbränslehantering AB. SKB Rapport R-99-69. Stockholm, Sweden.
Segestråle, S.G. 1957. Treatise on Marine Ecology and Paleoecology. Geological Society of America 67(1): 751-800 Memoir.

Criterion A Text:
There are no quantitative data on trends in the area covered by this habitat type in the Baltic. Expert opinion is that there has been less than a 25% decline in the last 50 years. This habitat has therefore been assessed as Least Concern under Criteria A for EU 28 and EU 28+..

Criterion B Text:
Experts consider there to be insufficient data on which to calculated EOO or AOO. This habitat is therefore assessed as Data Deficient under Criteria B.

Synthesis:
The presence of this habitat type in the Baltic is well established. The geographical areas in which it occurs are known in general terms (the Gulf of Bothnia and Gulf of Finland in areas of low salinity) but there is a lack of quantitative data on extent and quality. The current Red List assessment has therefore been based on expert opinion.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed this habitat (AA.I1D ) to be Least Concern (A1). With no additional information on changes in extent or quality of this habitat, and based on an esimate of less than a 25% decline in quantity over the last 50 years, current expert opinion is that this habitat should be assessed as Least Concern for the EU 28 and EU 28+.


Habitat Type Name:
13 Stable aggregations of unattached perennial vegetation on Baltic infralittoral coarse sediment

Habitat Description:
This habitat is distributed on Baltic bottoms in the photic zone with at least 90% coverage of coarse sediment. Coarse sediment has less than 20% of mud/silt/clay fraction (<63 μm), and the proportion of gravel and pebbles (grain size 2–63 mm) exceeds 30% of the combined gravel and sand fraction according to the HELCOM HUB classification. Stable aggregations of unattached perennial vegetation cover at least 10%, while perennial attached erect groups or Mytilus cover less than 10% of the bottom. The habitat is rare but can be found in the photic zone of most of the Baltic Sea area where the salinity is <10 or 5 psu (depending on the area), the exposure is moderate to sheltered, and the seabed is level over wide areas. 
Three associated biotopes with different dominant species of vegetation (at least 50% of the biovolume of the unattached perennial vegetation - Fucus spp. (typical or dwarf form) and Furcellaria lumbricalis) have been identified. ‘Baltic photic coarse sediment dominated by stable aggregations of unattached Fucus spp. (typical form)’ (AA.I1Q1) and ‘Baltic photic coarse sediment dominated by stable aggregations of unattached Furcellaria lumbricalis’ (AA.I1Q3) are encountered at 0.5 to 5 meters depth. Unattached Furcellaria lumbricalis may occur in specific, ball-shaped morphology adapted to soft bottom conditions, historically described as Furcellaria cf.aegagropila. ‘Baltic photic coarse sediment dominated by stable aggregations of unattached Fucus spp. (dwarf form)’ (AA.I1Q2) forms a characteristic biotope of shallow bays and lagoons between 0.25 and 2.5 m. This specific morphology of the Fucus spp. dwarf form lacks bladders and holdfasts; it is regularly dichotomous branched with branches of similar length resulting in a fan-shaped appearance of the thalli. The single plants can be loosely anchored in the sediment with its lower, dark brownish parts. The thalli are very fragile, break very easily into pieces and thus generate new thalli. Under more exposed conditions plants form a ball-shaped form, able to roll over the sea bottom. The Fucus dwarf forms coexist with attached F. vesiculosus, unattached Furcellaria lumbricalis, higher plants like Ruppia spp., Zannichellia palustris, Stuckenia pectinatus (formerly known as Potamogeton pectinatus), Zostera spp. and several Charophytes. The biotope exists in lower mesohaline salinities (7–10 psu) and moderately exposed to very sheltered conditions. The unattached thalli can cover the sediment up to about 10 cm height and thus form a three-dimensional habitat comparable to the interstitial space in coarse sediments. Epifauna is seldom attached to the Fucus dwarf form, but in between the loose lying thalli mobile gastropods, amphipods and insects look for shelter and food. However, if abundances of the unattached form are very high, the sediment below becomes deoxygenated and the associated infauna below the Fucus layer may die. Presently the dwarf form biotope is only known to occur in Sweden and Germany. In Germany it exists only in very few coastal lagoons with low to moderate eutrophication pressures and salinities of around 7–10 psu.
Indicators of quality:  
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time.
There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. Density of unattached Fucus spp. (typical and dwarf forms), the lower limit of the Furcellaria belt, the amount of epiphytic algae, and density of Furcellaria are potential indicators of quality of this habitat.
Characteristic species: 
Fucus spp., Furcellaria lumbricalis  with morphologically typical forms and specific, ball-shaped morphologies

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.11 Infralittoral coarse sediment in low or reduced salinity  and A5.52 Kelp and seaweed communities on sublittoral sediment. 
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1130 Estuaries
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral coarse sediment
Shallow sublittoral mixed sediment
 
EUSeaMap: 
Shallow coarse or mixed sediments
 
IUCN:
9.3 Sublittoral Loose Rock/Pebble/Gravel
9.7 Macroalgal/Kelp
9.10 Estuaries
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013):
AA.I1Q Baltic photic coarse sediment characterized by stable aggregations of unattached perennial algae.
 
 
 
This habitat has three biotopes at HUB level 6;
AA.I1Q1 Baltic photic coarse sediment dominated by stable aggregations of unattached Fucus spp. (typical form)
AA.I1Q2 Baltic photic coarse sediment dominated by stable aggregations of unattached Fucus spp. (dwarf form)  (This sub-habitat has been classified as endangered (EN; A1) in the HELCOM Red List Assessment in 2013).
AA I1Q3 ‘Baltic photic coarse sediment dominated by stable aggregations of unattached Furcellaria lumbricalis’ .

Justification Outstanding Example of Biogeographical Region:
The typical species may be found in other regional seas but the unattached forms, especially the ball-shaped morphologies of Fucus and Furcellaria that are characteristic of this habitat, are unique to the Baltic Sea.

Map Description:
There are insufficient data to provide a comprehensive and accurate map of the distribution of this habitat. This map has therefore been generated using the modelled data available on EMODnet for EUNIS level 3 habitats in the Baltic Sea (EMODnet, 2010) supplemented with expert input. This means it indicates potential areas in which this habitat may occur, not the actual distribution of this EUNIS level 4 habitat. EOO and AOO cannot be calculated at the present time, although the habitat is known to occur in all the Baltic Sea regions.

Trends in Quantity:
This habitat is present in all the Baltic Sea sub-basins. There are distribution records for the characteristic species (Fucus spp and Furcellaria lumbricalis) and an area estimate for the dwarf form biotope on all substrates (minimum 7.5km2) however it may not be present on coarse sediments. There is incomplete quantitative data on the area and extent of the entire habitat. The associated biotopes have differing distributions. For example areas characterized by unattached Furcellaria lumbricalis can be found in the Estonian west coast, Belt Sea and the German part of the southern Baltic Proper. Areas characterized by Fucus spp. (typical form) can be found in northern Bothnian Sea. Fucus spp. (dwarf form) can only be found in the southern Baltic Proper off the German coast and may not occur on coarse sediments.
The biotope dominated by stable aggregations of unattached Fucus spp. (dwarf form) is estimated to have reduced in extent by more 50% over the past 50 years. Similar pressures appear to have led to a reduction in extent of the other associated biotopes (e.g. Furcellaria in Puck Bay) they but there is insufficient quantifiable data on which to make an assessment. Historical trends are unknown and it can be expected that the potential area of occurrence will be reduced in the future due to eutrophication and climate change.

Trends in Quality:
One of the associated biotopes AA.I1Q2 ‘Baltic photic coarse sediment dominated by stable aggregations of unattached Fucus spp. (dwarf form)’ has shown a severe decline in quality over 20% of its area. There is insufficient information on which to determine quality of the other three associated biotopes or of past or future trends in quality of this habitat.

% of Distribution of the Habitat Type within the EU 28:
This habitat probably occurs in the EU 28+ (Russia). The percentage hosted by EU 28 is therefore less than 100% but there is insufficient information to establish the proportion.

Justification of Small Range/Regression:
The sub-habitat AA.I1Q2 ‘Baltic photic coarse sediment dominated by stable aggregations of unattached Fucus spp. (dwarf form)’ has a small range following regression. All other sub-habitats are not believed to have regressed a

Justification of Restricted Area:
This habitat occurs in all the Baltic Sea sub-basins and therefore does not have a small natural range.

Pressures and Threats:
Past and current threats to this habitat are associated with eutrophication (increase in N, P and organic matter), contaminant pollution and the introduction of toxic substances into the marine environment. There has also been some commercial exploitation of the unattached macroalgae in Poland and there is still commercial exploitation on going for the Furcellaria sub-biotope in Estonia.
Observed declines of the spatial distribution of the unattached Fucus spp. dwarf form biotope are mainly caused by increased eutrophication and its connected impacts/threats. Decreased light penetration depth, massive growth of filamentous algae and increased sedimentation/siltation cause massive alterations in the habitat conditions of sheltered coastal zones. The enclosed characteristic of bays and lagoons intensify the eutrophication impacts. Coastal constructions (ditching, deepening of harbour access channels, leisure facilities) and increased tourism has led to a further degradation of the biotope. The threat level is particularly high in the Western and Southern Baltic Sea. In the future climate change (increasing exposure levels, temperatures) or increasing aquaculture in bays may add to the pressures on this habitat.

Conservation and Management:
Combatting local sources of eutrophication (mainly agriculture) as well as conservation measures, such as restrictions on coastal constructions and dredging, in shallow coastal lagoons and archipelago areas can prevent damage and loss of this habitat.

Conservation Status:
Annex 1:
1130: MATL U2, MBAL U2, MBLS U1, MMED U2
1160: MATL U2, MBAL U2, MBLS U1, MMAC FV, MMED XX
1650: MBAL U2
 
HELCOM (2013) assessments:
1130 CR, C1
1160: VU C1 
1650: VU C1

Capacity to Recover its Typical Character and Functionality?:
The characteristic species Fucus vesiculosus and Furcellaria lumbricalis have a natural reproductive cycle of 1-2 years, but they take several years to reach full size. If the environmental conditions are favourable and there is a seed population available, the habitat can recover in the time from few years to a decade.

Summary:
This habitat occurs in all the sub-basins of the Baltic Sea but is more typically found in moderately exposed to sheltered areas. The unattached forms of perennial vegetation can coexist with attached forms and the characteristic rooted vegetation of bays, estuaries and lagoons. These algae provide shelter and surface for attachment of invertebrates. However, if abundances of the unattached form are very high the sediment below may become deoxygenated and the associated infauna may die.
Declines have been observed in the spatial distribution of the unattached Fucus spp. dwarf form biotopes and this is believed to be mainly caused by increased eutrophication and its connected impacts/threats. Decreased light penetration depth, massive growth of filamentous algae and increased sedimentation/siltation cause massive alterations in the habitat conditions of sheltered coastal zones. The enclosed characteristic of bays and lagoons intensify the eutrophication impacts. Coastal construction (ditching, deepening of harbour access channels), leisure facilities and increased tourism has led to a further degradation of the habitat. The threat level is particularly high in the Western and Southern Baltic Sea.
In the future, climate change (increasing exposure levels, temperatures) or increasing aquaculture in bays may cause additional threats. Combatting local sources of eutrophication (mainly from agriculture) as well as conservation measures, such as restrictions on coastal construction and dredging in shallow coastal lagoons and archipelago areas can prevent damage and loss of this habitat.

References:
Bauch, R. 1954. Biologisch-ökologische Studien an der Gattung Fucus. I. Populationsdynamik der Fucusformen von hiddensee. Flora 142, 1-24: 1-24.
HELCOM, 2009. Biodiversity in the Baltic Sea. An integrated thematic assessment on biodiversity and nature conservation in the Baltic Sea. Zweifel, U.L. and Laamanen, M. (Eds). Helsinki, Finland.
HELCOM, 2013. HELCOM Red List Biotope information sheets Available at: http://www.helcom.fi/Documents/Ministerial2013/Associated%20documents/Background/HELCOM%20Red%20List%20Biotope%20Information%20Sheets%20(BIS).pdf. (Accessed: 16/07/2015).
Institute of Oceanography, University of GdaÅ„sk et al. 2009. Atlas of Polish marine area bottom habitats. Environmental valorization of marine habtiatsBroker-Innowacji, Gdynia.
Kersen, P. and Martin, G. 2007. Annual biomass loss of the loose-lying red algae community via macroalgal beach casats in the Väinameri area, NE. Baltic Sea. Proceedings of the Estonian Academy of Science: Biology, Ecology 56(4): 278-289.
Martin, G., Kukk, E., Kukk, H. and Kotta, 2004. Historical review of the literature on the phytobenthic investigations in the Gulf of Riga. Proceedings of the Estonian Academy of Sciences: Biology and Ecology 53(4): 236.
Martin, G., Paalme, T. and Torn, K. 2006. Seasonality pattern of biomass accumulation in a drifting Furcellaria lumbricalis community in the waters of the West Estonian Archipelago, Baltic Sea. Journal of Applied Phycology 18(3-5): 557-563.
Ojaveer, H. 1999. Exploitation of biological resources of the Baltic Sea by Estonia in 1928-1995. Limnologica 29(3): 224-226.
Olenin, S. and Daunys, D. 2004. Coastal typology based on benthic biotope and community data: The Lithuanian case study. Baltic Sea Coastline Reports 4: 65-83.
Overbeck, J. 1965. Die Meeresalgen und ihre Gesellschaften an den Küsten der Insel Hiddensee (Ostsee). Botanical Marina. Vol VIII, Fasc. 2-4: 218-233.
Segestråle, S.G. 1957. Chapter 24. Baltic Sea. Geological Society of America 67(1): 751-800.

Criterion A Text:
Some localised loss has been reported (e.g. Puck Bay, Poland) particularly for the dwarf form of unattached Fucus spp. Although information about the unattached Fucus dwarf form biotopes is rare, comparisons of historical records with the present distribution in German coastal lagoons give hints to a decline of >25% during the last 50 years. On the Swedish coast the decline is considerably larger but there has been some recovery. The dwarf Fucus biotope is believed to make up less than 5% of this habitat type, therefore current expert opinion is that overall reduction in quantity is less than 25%. This habitat has therefore been assessed as Least Concern under Criteria A for the EU 28 and EU 28+.

Criterion B Text:
Comprehensive quantitative data on the extent and area covered by this habitat is not available but there are some relevant records such as quotas and landings from the commercial collection of unattached seaweed in Estonia, and modelling studies from the Asko area of Sweden. Some localised loss has been reported (e.g. Puck Bay, Poland) particularly for the dwarf form of unattached Fucus spp. As the habitat is present in all Baltic Sea basins the EOO exceeds 50,000km2 . Although some potential trends have been identified, there is also a lack of information on which to base any estimation of future trends in geographical distribution or threatening processes. Experts therefore consider this habitat to be Data Deficient under Criteria B.

Synthesis:
The presence of this habitat type in the Baltic Sea is well established and it is known to occur in all the sub-basins although favouring sheltered areas. Information is also available on the distribution of the characteristic species (Fucus and Furcellaria). One of the associated biotopes, the unattached Fucus dwarf form biotope is rare, and comparisons of historical records with the present distribution in German coastal lagoons give hints to a decline of >25% during the last 50 years. On the Swedish coast the decline is considerably greater.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed the unattached dwarf form of Fucus (AA.I1Q2) as Endangered (A1). The other associated biotopes (AA.I1Q1 and AA.I1Q3) were assessed as Least Concern (A1). The dwarf form may not be present on coarse sediments or is very rare. With no additional information on changes in extent or quality of this habitat, its known occurrence in all the Baltic Sea subbasins, and less than a 25% decline in quantity over the last 50 years, current expert opinion is that this habitat should be assessed as Least Concern for the EU 28 and EU 28+.

Sub-habitats in Need of Examination:
HELCOM (2013) assessed Baltic photic coarse sediment dominated by stable aggregations of unattached Fucus spp. (dwarf form) (AA.I1Q2) as Endangered (A1). This biotope requires further examination including confirmation on whether the dwar


Habitat Type Name:
16 Emergent vegetation communities on Baltic infralittoral coarse sediment

Habitat Description:
This is a Baltic Sea benthic habitat in the photic zone where at least 90% of the substrate is coarse sediment according to the HELCOM HUB classification. It is found across all salinity ranges in the Baltic and in areas where there is low to moderate exposure to wave action typically to depths of about 2 meters. The associated communities of sedges and/or reeds are more typically found in areas of soft sediment. Their presence on coarse sediment may indicate that siltation is already taking place and that the establishment of sedges and reeds will increase the rate of siltation, changing the substrate to finer sediments over time. 
Two associated biotopes with different dominant plant species have been identified. The common reed (Phragmites australis) forms the charactersitic biotope in water depths of up to 2m and in moderately exposed conditions, where as sedges such as Schoenoplectus spp, Bolbaschoenus maritimus are generally in more sheltered and shallower waters.  Nutrient levels play a part in affecting the balance between the two biotopes with reed dominated areas favoured by conditions of eutrophication. 
Indicators of quality: 
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. The overall quality and continued occurrence of this habitat is, however, largely dependent on the presence of the emergent plant species which create the biogenic structural complexity on which the characteristic associated communities depend. The density and the maintenance of a viable population of these species is a key indicator of habitat quality, together with thevisual evidence of presence or absence of physical damage. In the case of this habitat the situation is further complicated because the reed dominated biotope is favoured by the deterioration of the sedge dominated biotope under conditions of eutrophication.
Characteristic species:
Phragmites australis, Schoenoplectus spp, Bolbaschoenus maritimus may be in areas of coarse sediment but are likely to be embedded in the patches of finer sediment.

Classification:
EUNIS: 
The closest correspondence in EUNIS (2004) level 4 is A5.54 Angiosperm communities in reduced salinity
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1130 Estuaries
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES: 
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral coarse sediment
Shallow sublittoral mixed sediment
 
EUSeaMap:
Shallow coarse or mixed sediments
 
IUCN: 
9.3 Subtidal loose rock/pebble/gravel
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.I1A–Baltic photic coarse sediment characterized by emergent vegetation This habitat has two sub-habitats on HUB level 6; ‘Baltic photic coarse sediment dominated by common reed (Phragmites australis)’ (AA.I1A1) ‘Baltic photic coarse sediment dominated by sedges (Cyperaceae)’ (AA.I1A2)

Justification Outstanding Example of Biogeographical Region:
Sedges as a dominant emergent vegetation along seashores are typical and characteristic of the Baltic Sea. Reeds are one of the most commonly widespread plants on the globe, and are commonly found along shorelines in sheltered bays and estuaries in brackish water all over world including the Baltic.  The combined habitat is not a typical characteristic for the Baltic.

Trends in Quantity:
This habitat is present in all sub-basins of the Baltic Sea and there are distribution maps for the characteristic species (e.g. Phragmites). It has increased in extent over the last 50 years due to anthropogenic eutrophication and changes in land use (less coastal pastures, less reed cutting). There also appears to have been a changing balance between the associated biotopes with sedge dominated communities declining and reed dominated communities increasing, most likely in response to eutrophication. There are no historical data on which to make an accurate trend assessment. No estimates have been made of possible future trends.
In Estonia, for example there was expansive reed growth from 1950s to end of 1970s whereas in the last few decades growth rates reduced or even ceased. This is believed to be associated with increased storminess resulting in increase of average sea level which has limited the suitable growth zones for the reed weakened by eutrophication.

Trends in Quality:
In the case of the sedge dominated biotopes some loss in density/biomass may be occuring but there are no monitoring data to confirm this. The overall trend in quality of this habitat is considered stable.

% of Distribution of the Habitat Type within the EU 28:
This habitat occurs in the EU28+ (Russia). The percentage hosted by EU28 is therefore less than 100% but there is insufficient information to establish the proportion.

Pressures and Threats:
The expansion of reed belts has been accelerated by anthropogenic eutrophication, postglacial land upheaval and the lack of grazing on coastal meadows and attached shallow water areas, while pollution associated with drainage from farming and forestry, and other sources (like traffic and industry) are threats and deterioration factors. Other pressures arise from shipping, and the construction or enlargement of harbours and marinas in sheltered areas. Changes in the water flow due to hydro-technical constructions, such as dams, cascades and river bank control, may also have adverse effects downstream. Other threats can be caused by introduction of non-indigenous, invasive species, unsustainable fisheries and tourism as well as oil spills and construction of breakwaters.
In the future climate change is likely to be a threat. Distribution of reed beds is controlled by mean sea-level variation superimposed on a background of postglacial isostatic uplift. Reduced growth in the reed beds in Estonia over last decades has probably been caused by increased storminess resulting in increase of average sea level. This is believed to have limited the suitable growth zones for the reed weakened by eutrophication.

Conservation Status:
Annex 1:
1130: MBAL U2
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1130 CR C1
1150 EN, C1
1160 VU C1
1650 VU C1 
HELCOM (2013) have assessed the associated bio

Summary:
The presence of this habitat type in the Baltic Sea is well known and it is present in sheltered areas in all the sub-basins. The characteristic species are reeds or sedges with dominance being determined by factors such as sediment type, exposure and nutrient levels. It may not be particularly common as reed and sedge habitats are more typical on softer sediments. The habitat can support a high biodiversity, for example by providing nesting areas for birds, and shelter and spawning grounds for fish, although reeds in particular can also out compete and shade other plant species (including sedges) decreasing local biodiversity. 
The expansion of reed belts has been accelerated by anthropogenic eutrophication, postglacial land upheaval and the lack of grazing on coastal meadows and attached shallow water areas, while pollution associated with drainage from farming and forestry, and other sources (like traffic and industry) are threats and deterioration factors. Other pressures arise from shipping, and the construction or enlargement of harbours and marinas in sheltered areas. Changes in the water flow due to hydrotechnical constructions, such as dams, cascades and river bank control, may also have adverse effects downstream. 
In some areas, there is an active programme of reed removal to encourage re-establishement of the sedge dominated biotopes. Improvements in water quality are also beneficial although it should be noted that whereas increased eutrophication leads to reed replacing sedges, a later decrease in eutrophication does not necessarily facilitate a process where sedges come back.

References:
HELCOM. 2009. Biodiversity in the Baltic Sea. An integrated thematic assessment on biodiversity and nature conservation in the Baltic Sea. Baltic Sea Environment Proceedings No.116B
HELCOM. 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Baltic Sea Environment Proceedings 138 Helsinki Commission
Meriste, M., Kirsimäe, K & Freiberg, L. 2012. Relative sea-level changes at shallow coasts inferred from reed bed distribution over the last 50 years in Matsalu Bay, the Baltic SeaJournal of Coastal Research 28(1): 01-Oct

Criterion A Text:
There have been different trends in the extent of this habitat depending on which of the associated biotopes is considered. Sedges have declined, quite significantly in some areas, possibly due to the expansion of, and competition with reed. The latter benefits from the nutrient enrichment associated with eutrophication. As a consequence sedges, former considered ecologically typical of sheltered areas in the Baltic are being replaced  by another biotope due to a deterioration of the environment (i.e. eutrophication),
Overall this habitat is believed to have been stable or possibly increased in extent over the last 50 years. It has therefore been assessed as Least Concern under Criteria A for the EU 28 and EU 28+.

Criterion B Text:
This habitat has a large natural range in the Baltic Sea with EOO >50,000 km2 but it is possible that it is not particularly common as reed and sedge habitats are more typically found on softer sediments. Future trends have not been estimated.  This habitat has therefore been assessed as Data Deficient under criterion B.

Synthesis:
Increases in extent have been evident in this habitat in the last 50 years, though this is mainly due to the increase of reed (Phragmites australis) while at the same time sedges have decreased, most likely a response to eutrophication favouring the former.  In the case of the sedge dominated biotopes some loss in density/biomass may be occuring but there are no monitoring data to confirm this.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed AA.I1A1 and AA.I1A2 as Least Concern (A1). Expert opinion is that this habitat is either stable or has increased in extent over the last 50 years and therefore should be assessed as Least Concern for both the EU 28 and EU 28+.

Sub-habitats in Need of Examination:
AA.I1A2 Baltic photic coarse sediment dominated by sedges (Cyperaceae).


Habitat Type Name:
17 Unvegetated epifaunal communities on Baltic infralittoral coarse sediment

Habitat Description:
This is a Baltic Sea benthic habitat in the photic zone where at least 90% of the substrate is coarse sediment according to the HELCOM HUB classification.  Three associated biotopes have been identified. ‘Baltic photic coarse sediment dominated by Mytilidae’ (AA.I1E1) is encountered in salinities higher than 5 psu, and is identified by a large representation of Mytilidae, at least 50% of the biomass among the epibenthic bivalves, and covering at least 10% of the seabed. The other two biotopes are 'Baltic photic coarse sediment characterized by mixed epibenthic macrocommunity' (AA.I1V) and 'Baltic photic coarse sediment dominated by microphytobenthic organisms and grazing snails' (AA.12W) where the benthic organisms or grazing snails (e.g. Hydrobiidae, Theodoxus spp, Bithynia spp, Radix spp) constitute at least 50% of the biomass or volume.
Indicators of quality:
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. 
Characteristic species:
Mytilus spp., Hediste diversicolor, Hydrobiidae, Theodoxus spp, Bithynia spp, Radix spp.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.11 Infralittoral coarse sediment in low or reduced salinity 
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1110 Sandbanks slightly covered all the time
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral coarse sediment
Shallow sublittoral mixed sediment
 
EUSeaMap:
Shallow coarse or mixed sediments
 
IUCN:
9.3. Subtidal loose rock/pebble/ gravel
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.I1V: Baltic photic coarse sediment characterised by mixed epibenthic macrocommunity
AA.12W: Baltic photic coarse sediment dominated by microphytobenthic organisms and grazing snails
Level 6 of the HELCOM HUB classification (2013): 
AA.I1E1: Baltic photic coarse sediment dominated by Mytiidae

Justification Outstanding Example of Biogeographical Region:
Although one of the three associated biotopes is typical of the Bothnian Bay, overall this habitat is not considered to be an outstanding example of typical characteristics of the Baltic Sea in general.

Trends in Quantity:
This habitat is common throughout the Baltic Sea occurring in all the sub-basins although some of the associated biotopes have a more limited distribution. The extent of the habitat is considered to have been stable over the last 50 years but there are no quantitative historic data. Some of the associated biotopes may increase in extent in the future in response to reductions in salinity associated with climate change.

Trends in Quality:
There are no quantitative data to determine trends in quality however current quality is believed to be good and unlikely to decrease in the future.

% of Distribution of the Habitat Type within the EU 28:
This habitat occurs in the EU 28+ (Russia). The percentage hosted by EU 28 is therefore less than 100% but there is insufficient information to establish the proportion. Similar habitats do occur in other European Regional Seas.

Pressures and Threats:
No specific pressures and threats have been identified for this habitat type.

Conservation and Management:
No specific conservation and management measures have been identified for this habitat type.

Conservation Status:
Annex 1:
1110: MBAL U1
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1110 VU C1 
1160 VU C1 
1650 VU C1 
HELCOM (2013) assessed two associated biotopes&

Summary:
This habitat occurs in all the Baltic Sea sub-basins although some of the associated biotopes have a more limited distribution. It is a benthic habitat in the photic zone where the predominate substrate is coarse sediment. The substrate may be dominated by bivalves (Mytilidae), by a mixed epibenthic macrocommunity, or by microphytobenthic organisms and grazing snails' e.g. Hydrobiidae, Theodoxus spp, Bithynia spp, Radix spp). There is no specific information on pressures, threats, conservation and management measures for this habitat.

References:
Gic-Grusza, C., Kryla-Straszewska, K., UrbaÅ„ski, J., Warzocha, J., & WÄ™stawski, J.M. (Eds) 2009 Atlas of Polish marine area bottom habitats. Environmental valorization of marine habitats. Institute of Oceanology, Polish Academy of Sciences.
HELCOM, 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Avellan, L. (Ed). Helsinki, Finland.
Olenin, S. & Daunys, D. 2004 Coastal typology based on benthic biotope and community data:The Lithuanian case study.Coastline Reports 465-83.
Wlodarska-Kowalczuk, Weslawski, J.M., Warzocha, J. & Janas, U. 2010. Habitat loss and possible effects on local species richness in a species-poor system: a case study of southern Baltic Sea macrofauna. Biodivers Conserv 19: 3991-4001.

Criterion A Text:
There is a lack of quantative data on the extent of this habitat but expert opinion is that it is likely to have been stable over the last 50 years. In the future some of the associated biotopes may increase in extent as a result of reductions in salinity associated with climate change. This habitat has therefore been assessed as Least Concern under criterion A for both the EU 28 and EU 28+.

Criterion B Text:
This habitat is present in all the Baltic sub-basins, therefore EOO exceeds 50,000km2 however with no quantitative data on habitat extent or area, accurate calculation of EOO or AOO is not possible at the present time. There is uncertainty over future trends. This habitat has therefore been assessed as Data Deficient under criterion B.

Synthesis:
This habitat is present in all sub-basins of the Baltic Sea and therefore the EOO exceeds 50,000km2. There is a lack of quantitative data on overall trends in quantity or quality but expert opinion is that the habitat is considered to be stable. Changes may occur in the future as a result of variations in salinity but the scale of any likely effect is unknown. 
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed two relevant Baltic biotopes (AA.I1E1 and AA.I2W) as Least Concern (A1). AA.I1V was not evaluated. With no additional information on changes in extent or quality of this habitat and its relatively widespread distribution, the current expert opinion is an assessment of Least Concern for both the EU 28 and EU 28+.


Habitat Type Name:
18 Infaunal communities of Baltic infralittoral coarse sediment

Habitat Description:
This is a Baltic Sea benthic habitat in the photic zone where at least 90% of the substrate is coarse sediment according to the HELCOM HUB classification. No macrovegetation or epibenthic macrofauna is present however infaunal bivalves/polychaetes/crustaceans/echinoderms or insects may dominate, comprising at least 50% of the biomass. It is encountered in areas of high energy associated with currents or wave action. Five associated biotopes have been identified but not all occur in all the sub-basins. For example  ‘Baltic photic coarse sediment characterised by infaunal bivalve species’ (AA.I3L), has only been reported in the Baltic Proper, The Belt Sea and The Sound. Where the substrate is well sorted with medium to coarse sand, gravel or small shell fragments, often building small patches inside finer sediments, the large variety of interstitial space, may be inhabited by species of specialised fauna, such the polychaetes Ophelia limacina, O. rathkei and Travisia forbesii. In areas of poorly sorted substrate there may be a higher species diversity with none of the characateristic species clearly dominant but including bivalves such as Macoma calcarea, Mya truncata, Astarte spp., and Spisula spp.
Indicators of quality:
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitatmay face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. Diversity, abundance and biomass of the dominant species and associated fauna are potential indicators of quality of this habitat.
Characteristic species:
Depending on the particular associated biotope these include  Macoma calcarea, Mya truncata, Astarte spp., Spisula spp.  Ophelia limacina, Travisia forbesii, Tanaissus spp. and Streptosyllis spp. the sand digger shrimp (Bathyporeia pilosa), the echinoderms  Amphiura spp, Ophiura spp., Brissopsis lyrifera, Echinocardium spp. and infaunal insect larvae (Chironomidae).

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.11 Infralittoral coarse sediment in low or reduced salinity.
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1110 Sandbanks slightly covered all the time
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral coarse sediment
Shallow sublittoral mixed sediment
 
EUSeaMap:
Shallow coarse or mixed sediments
 
IUCN:
9.3 Subtidal Loose Rock/Pebble/Gravel
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.I3L Baltic photic coarse sediment characterized by infaunal bivalves, this habitat has two sub-habitats on HUB level 6; ‘Baltic photic coarse sediment dominated by multiple infaunal bivalve species: Macoma calcarea, Mya truncata, Astarte spp., Spisula spp.’ (AA.I3L10) and ‘Baltic photic coarse sediment dominated by multiple infaunal polychaete species including Ophelia spp.’ (AA.I3L11).
AA.I3M Baltic photic coarse sediment characterized by infaunal polychaetes
AA.I3N Baltic photic coarse sediment characterized by infaunal crustaceans
AA.I3O Baltic photic coarse sediment characterized by infaunal echinoderms
AA.I3P Baltic photic coarse sediment characterized by infaunal insect larvae

Justification Outstanding Example of Biogeographical Region:
It is unknown whether this habitat presents outstanding typical characteristics of the Baltic region.

Trends in Quantity:
This habitat occurs in all Baltic Sea sub-basins although some of the associated biotopes have a more limited distribution. For example, Baltic photic coarse sediment dominated by infauna, only occurs in Western most areas such as the Belt Sea and the Sound, and Baltic photic coarse sediment dominated by infaunal polychaetes Ophelia is only found in the southern parts of the Belt Sea and Baltic Proper. There have been some declines in extent of this habitat, estimated to be more than 25% in the case of two of the associated biotopes and at least 10% in a third associated biotope. There was insufficient data to determine trends in the three other associated biotopes and overall no historic quantitative data or estimates of future trends.

Trends in Quality:
The quality of this habitat has shown moderate to severe reductions (10-15%) in past 50 years. Further reduction of around 10% has been estimated for at least two of the three associated biotopes which were assessed by HELCOM (2013).

Pressures and Threats:
Eutrophication, construction including oil and gas exploration and exploitation, bottom trawling, mining and quarrying and contaminant pollution have been identified as pressures and threats. For example, biotopes dominated by infaunal bivalves are threatened by oxygen deficiency caused by eutrophication. Eutrophication can also lead to an increased growth rate in algae which in turn increases organic load which threatens this habitat. An additional threat is siltation which can be caused by various construction activities. Where the habitat is close to land, increased siltation may be traced back to changes in land use such as run-off from intensively farmed areas. Coarse sediments dominated by infaunal polychaetes are mainly threatened by bottom trawling, oil and gas exploration and dredging.

Conservation and Management:
Restrictions or prohibition of bottom trawling and sediment extraction will protect this habitat along with activities that can improve oxygen conditions, for example by reducing the risk of eutrophication. A Baltic Sea wide biotope inventory and threat assessment would be a useful tool to guide conservation and management.

Conservation Status:
Annex 1:
1110: MBAL U1
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1110 VU C1 
1160 VU C1 
1650 VU C1 
HELCOM (2013) assessed two associated biotopes

Summary:
This habitat occurs in all the Baltic Sea sub-basins although some of the associated biotopes have a more limited distribution. It is a benthic habitat in the photic zone where the predominate substrate is coarse sediment. No macrovegetation or epibenthic macrofauna is present however infaunal bivalves/polychaetes/crustaceans/echinoderms or insects may dominate. The pressures and threats include eutrophication (increased N, P and organic matter), sedimentation and siltation caused by offshore and coastal constructions, and localised pollution. Direct damage may also result from activities that disturb the seabed such as demersal fisheries. Proposed conservation measures include establishing protected areas where damaging activities are restricted or prohibited and managing activities elsewhere.

References:
HELCOM. Available at: http://www.helcom.fi/environment2/biodiv/endangered/Invertebrates/en_GB/Mya_truncata/ (Accessed:05/07/15).
HELCOM. Available at http://www.helcom.fi/environment2/biodiv/endangered/Biotopes/en_GB/Gravel_bottoms_Ophelia/ (Accessed:05/07/15).
Krause, J. Ch. 2000. Der Einfluss von Sand- und Kiesabbau auf bestandsgefährdete Makrofauna-Populationen in der südlichen Ostsee. PhD thesis University of Rostock.
Moen, F.E. and Svensen, E. 2004. Marine fish and invertebrates of Northern Europe. KOM, Kristiansund. 608pp.
Schiewer, U. 2008. Ecology of Baltic Coastal Waters. p. 12. Springer, Berlin, Germany.
Trutschelt, K. and Samtleben, C. 1988. Shell growth of Astarte elliptica (Bivalvia) from Kiel Bay (Western Baltic Sea). Marine Ecology progress Series 42: 155–162.
Zettler, M. 2002. Ecological and morphological features of the bivalve Astarte borealis (Schumacher 1817) in the Baltic Sea near its geographical range. Journal of Shellfish Research 21: 33–40.

Criterion A Text:
There have been reductions in quantity of more than 25% for two of the three associated biotopes that were assessed by HELCOM (2013). Expert opinion is that there has been an overall reduction in quanity of this habitat by >25% in the last 50 years. This habitat has therefore been assessed as Near Threatened under Criterion A for both the EU 28 and EU 28+.

Criterion B Text:
This habitat is present in all the Baltic Sea sub-basins therefore EOO exceeds 50,000 km2 however with no quantitative data on habitat extent or area, accurate calculation of EOO or AOO is not possible at the present time. Future trends have not been predicted. This habitat has therefore been assessed as Data Deficient under criterion B.

Criterion C/D Text:
The quality of this habitat is believed to have shown moderate to severe reductions (10-15% of extent) in past 50 years. Further reduction of around 10% has been estimated for at least two of the three associated biotopes which were assessed by HELCOM (2013). This does not exceed the threshold for threatened status on the basis of decline in quality. This habitat has therefore been assessed as Least Concern under criteria C/D.

Synthesis:
There have been some declines in extent of this habitat, estimated to be more than 25% over the last 50 years in the case of the associated biotopes dominated by infaunal bivalves and polychaetes and at least 10% in a third associated biotope. Moderate to severe reductions of between10-15% of the habitat is also believed to have occurred in a similar period. The lack of quantitative data on extent, quality and trends over time means that accurate calculations of EOO and AOO are not possible at the present time. This Red List assessment has therefore been based on expert opinion.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed two relevant Baltic biotopes (AA.I3L10 and AA.I3L11) as Near Threatened (A1). A third biotope AA.I3N3 was assessed as Least Concern (A1). The remaining three AA.I3N, AA.I3O and AA.I3P were not evaluated There is no additional data or information to update the assessment outcome past the HELCOM 2013 assessment. Given that there have been declines of more than 25% for much of this habitat, current expert opinion is therefore an assessment of Near Threatened for both the EU 28 and EU 28+.

Sub-habitats in Need of Examination:
AA.I3L10 Baltic photic coarse sediment dominated by multiple infaunal bivalve species Macoma calcarea, Mya truncata, Astarte spp., Spisula spp.
AA.I2L11 Baltic photic coarse sediment dominated by multiple infaunal polychaetes sp


Habitat Type Name:
22 Sparse or no communities on Baltic infralittoral shell gravel

Habitat Description:
This benthic Baltic Sea habitat occurs in the photic zone with at least 90% coverage of shell gravel according to the HELCOM HUB classification. Epibenthic macrovegetation or macrofauna does not occur. The habitat is most often encountered in high energy exposure areas and therefore believed to be limited to the Baltic Proper, Belt Sea and The Sound.
Indicators of quality:
Unknown
Characteristic species:
Unknown

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.11 Infralittoral coarse sediment in low or reduced salinity
 
Annex 1:  
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1110 Sandbanks slightly covered all the time
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral coarse sediment
Shallow sublittoral mixed sediment
 
EUSeaMap:
Shallow coarse or mixed sediments
 
IUCN:
9.3 Subtidal loose rock/pebble/gravel
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013).
AA.E4U  Sparse or no  communities on Baltic infralittoral shell gravel

Trends in Quantity:
There is insufficient information on baseline conditions or changes over the last 50 years to determine any trends in quantity.

Trends in Quality:
There is insufficient information on baseline conditions or changes over the last 50 years to determine any trends in quality.

Justification of Small Range/Regression:
It is unknown whether this habitat has a small natural range following regression

Justification of Restricted Area:
It is unknown whether this habitat has a small range by reason of its intrinsically restricted area.

Pressures and Threats:
No pressures and threats have been identified for this specific habitat.

Conservation and Management:
No conservation and management measures have been identified for specifically for this habitat.

Conservation Status:
Annex 1:
1110: MBAL U1
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1110 VU C1 
1160 VU C1 
1650 VU C1 
This habitat was not evaluated by HELCOM in the

Summary:
This habitat, characterized as sparse or no communities on infralittoral shell gravel is poorly studied. Threats and pressures are unknown at present and no conservation or management measures have been identified specifically for this habitat.  This habitat was not evaluated by HELCOM in the 2013 Red List of Habitat Assessment because of insufficient data.

Criterion A Text:
Experts considered there to be insufficient data on which to assess criteria A. This habitat has therefore been assessed as Data Deficient under criterion A.

Criterion B Text:
Experts considered there to be insufficient data on which to assess criteria B. This habitat has therefore been assessed as Data Deficient under criterion B.

Synthesis:
This habitat, characterised as sparse or no communities on infralittoral shell gravel is poorly studied.  It was not evaluated by HELCOM in the 2013 Red List of Habitat Assessment. Due to a lack of information on which to base a quantitative assessment or to make an assessment based on expert opinion this habitat is considered to be Data Deficient.


Habitat Type Name:
20 Unvegetated communities on Baltic infralittoral shell gravel

Habitat Description:
This Baltic Sea benthic habitat occurs on with at least 90% coverage of shell gravel according to the HELCOM HUB classification.  Four biotopes and two sub-biotopes have been associated with this habitat. The sub-biotope 'Baltic photic shell gravel dominated by Mytilidae’ (AA.E1E1),  sessile/semi-sessile epibenthic bivalves cover at least 10% of the seabed and more than other perennial attached erect groups. This biotope is identified by a large representation of Mytilidae, at least 50% of the biomass among the epibenthic bivalves and often encountered in high energy exposure areas. It has been reported from the Baltic proper and Belt Sea. 'Baltic photic shell gravel dominated by vase tunicate (Ciona intestinalis) (AA.E1F1) is ony reported from the Belt Sea and occurs in areas where the bottom consists largely of mollusc shells or small shell fragments, often constituting small patches inside other sediments. Due to the combination of the extended interstitial space and the presence of biotic hard substrates, it is inhabited by a unique combination of endobenthic and epibenthic species, such as the vase tunicate (Ciona intestinalis). The biotopes 'Baltic photic shell gravel characterized by sparse or  by mixed epibenthic macrocommunities (AA.E2T and AA.E1V)' are characterised by a low (0-10%) coverage of macroscopic vegetation or sessile macroscopic epifauna and most often encountered in high energy exposure areas.
Indicators of Quality:
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis.
Characteristic species: 
Mytilus spp., Modiolus modiolus, Ciona intestinalis.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.41 Sublittoral mixed sediment in low or reduced salinity 
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1110 Sandbanks slightly covered with seawater all the time
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:  
Shallow sublittoral coarse sediment
Shallow sublittoral mixed sediment
 
EUSeaMap:
Shallow coarse or mixed sediments
 
IUCN:
9.3. Subtidal loose rock/pebble/ gravel
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013).
AA.E1E Baltic shell gravel characterized by epibenthic bivalves
AA.E1F Baltic photic shell gravel characterized by epibenthic chordates
AA.E1V Baltic photic shell gravel characterized by mixed eipbenthic macrocommunity
AA.E2T Baltic photic shell gravel characterized by sparse epibenthic macrocommunity
Level 6 of the HELCOM HUB classification (2013).
AA.E1E1: Baltic photic shell gravel dominated by Mytiidae
AA.E1F1: Baltic photic shell gravel dominated by vase tunicate (Ciona intestinalis).

Trends in Quantity:
This habitat is limited in its occurrence in the Baltic Sea, confined to the Belt Sea and the Baltic Proper. One associated biotope (Baltic photic shell gravel dominated by vase tunicates) is considered rare and restricted to small patches. There have been reductions in extent of this habitat due to increased siltation and bottom trawling but a lack of quantitative historical data.

Trends in Quality:
There is a lack of information on which to determine any trends in quality of this habitat.

% of Distribution of the Habitat Type within the EU 28:
This habitat is believed to be limited to the EU 28 in the Baltic.

Justification of Small Range/Regression:
One of the associated biotopes (Baltic photic shell gravel dominated by vase tunicates AA.E1F1) is considered to be rare, limited to small patches and have a restricted distribution.

Justification of Restricted Area:
One of the associated biotopes (Baltic photic shell gravel dominated by vase tunicates AA.E1F1) is considered to be rare, limited to small patches and have a restricted distribution.

Pressures and Threats:
The current threats to this habitat are from eutrophication, contaminant pollution, bottom trawling, oil and gas exploration, sand and gravel extraction and climate change. Of these, oxygen depletion and increased siltation caused by eutrophication are considered to be the main threats. In addition, bottom trawling threatens the physical integrity of the habitat.
Since the habitat consist of an organic substrate, produced by bivalves, the state and distribution of the substrate-producing bivalve species affect the habitat directly. Predicted ocean acidification caused by increasing atmospheric CO2 is a potential future threat, both to the occurrence and durability of the habitat and to the substrate-producing species.  Acidification may affect the shell gravel substrate severely as the natural degradation process of the calcium carbonate shells may accelerate if the waters become more acidic resulting in a more restricted distribution of this habitat in the future. Additional threats are hazardous substances introduced to the Baltic, pollution from offshore installations and sand and gravel extraction, although the impacts of these are currently considered to be smaller than those associated with eutrophication.

Conservation and Management:
To conserve this habitat, its distribution should be mapped in order to better understand its environmental requirements. Where it occurs, it should be protected and bottom trawling prohibited. Further eutrophication should be stopped or reversed to improve the oxygen conditions and reduce overgrowth for example of annual brown algae on vase tunicates.

Conservation Status:
Annex 1:
1110: MBAL U1
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1110 VU C1
1160 VU C1 
1650 VU C1 
HELCOM (2013) assessed (AA.E1E1: Baltic photic shell

Summary:
This habitat is limited in its distribution and is not found in all the Baltic Sea sub-basins as the shell gravel substrate is relatively rare. The associated species are vulnerable to direct disturbance, for example as a result of the removal of substrate, but also to indirect effects such as through eutrophication, siltation and in the future increasing acidity of the oceans which is predicted as a response to climate change. Conservation measures include protected areas within which activities that directly damage the shell gravel substrate are restricted or prohibited, and improvements in water quality.

References:
Dybern, B. 1967. The distribution and salinity tolerance of Ciona intestinalis (L.) F. typica with special reference to the waters around Southern Scandinavia. Ophelia 4(2): 207–226. DOI: 10.1080/00785326.1967.10409621
HELCOM. 1998. Red List of Marine and Coastal Biotopes and Biotope Complexes of the Baltic Sea, Belt Sea and Kattegat - Including a comprehensive description and classification system for all Baltic Marine and Coastal Biotopes. Baltic Sea Environment Proceedings No. 75. Helsinki Commission, Helsinki. 115 pp. Available at: http://www.helcom.fi/stc/files/Publications/Proceedings/bsep75.pdf (viewed 28 May 2013)
HELCOM 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Baltic Sea Environmental Proceedings No. 138
Moen, E. and Svensen, E. 2009. Djurliv i havet, Nordeuropeisk marin fauna. Nordstedst. 768 pp.
Petersen, J. and Svane, I. 2002. Larval dispersal in the ascidian Ciona intestinalis (L.). Evidence for a closed population. Journal of Experimental Marine Biology and Ecology 186: 89–102.
Petersen, J. and Riisgård, H.U. 1992. Filtration capacity of the ascidian Ciona intestinalis and its grazing impact in a shallow fjord. Marine Ecology Progress Series 88: 9–17.

Criterion A Text:
This habitat is only present in the EU 28. There is no quantitative information on reduction in quantity for this habitat, although the HELCOM (2013) assessement indicated a decline of between 30-50% of one of the three associated biotopes.  Expert opinion is that an overall decline of more than 25% of this habitat in recent years and over the next 50 years (linked to ocean acidification, eutrophication and activities which directly disturb the seabed) is possible. This habitat has therefore been assessed as Near Threatened under Criteria A.

Criterion B Text:
There is insufficient information to determine the EOO and AOO for this habitat. One of the associated biotopes has a restricted distribution and has suffered some decline in spatial extent and quality. Threatening processes are believed likely to cause continuing declines within the next 20 years although this cannot be quantified. This habitat has been assessed as Data Deficient under Criteria B.

Criterion C/D Text:
One of the associated biotopes has suffered some decline in abiotic environmental quality although it is not possible to quantify this. Experts consider there to be insufficient data on which to assess criteria C/D.

Synthesis:
This habitat is only present in the EU 28. The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion.  HELCOM (2013) assessed the associated biotope AA.E1E1 as Least Concern (A1) and biotope AA.E1F1 as Vulnerable (B1A[ii]). 
There is a lack of quantitative data on baseline conditions and trends in quantity and quality of this habitat but declines of between 30-50% have been reported for one of the associated biotopes. Because of an estimated overall decline of 25% and likely future declines (linked to ocean acidification, eutrophication and activities which directly disturb the seabed) this habitat has been assessed as Near Threatened for both the EU 28 and EU 28+.

Sub-habitats in Need of Examination:
AA.E1F1 Baltic photic shell gravel dominated by vase tunicate (Ciona intestinalis).


Habitat Type Name:
21 Infaunal communities on Baltic infralittoral shell gravel

Habitat Description:
This is a Baltic Sea benthic habitat in the photic zone where at least 90% of the substrate is shell gravel according to the HELCOM HUB classification. The shell gravel fragments are coarse and well-sorted. This habitat is most often encountered in high energy exposure areas and is only found in the southern parts of the Baltic. Whilst macroscopic infauna are present, there is typically no macrovegetation or epibenthic macrofauna.  Two associated biotopes have been identified: 'Baltic photic shell gravel characterised by mixed infaunal macrocommunity in coarse and well-sorted shells and shell fragments' (AA.E3X) and 'Baltic photic shell gravel characterized by mixed infaunal macrocommunity in fine sand-like shell fragments' (AA.E3Y). The benthic macroinfauna species vary as the interstitial spaces are smaller in the latter sand-like shell gravel substrate, enabling burrowing polychaetes and amphipods to build tunnels using the small grains. 
Indicators of quality:
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis.
Characteristic species:
Insufficiently studied to list at the present time.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.11 Infralittoral coarse sediment in low or reduced salinity.
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1110 Sandbanks slightly covered all the time
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral coarse sediment
Shallow sublittoral mixed sediment
 
EUSeaMap:
Shallow coarse or mixed sediments
 
IUCN:
9.3 Subtidal loose rock/pebble/gravel
 
Other relationships:
This habitat has two sub-habitats on HUB level 6; ‘AA.E3X Baltic photic shell gravel characterised by mixed infaunal macrocommunity in coarse and well-sorted shells and shell fragments' and 'AA.E3Y: Baltic photic shell gravel characterised by mixed infaunal macrocommunity in fine sand-like shell fragments'

Map Description:
There are insufficient data to provide a comprehensive and accurate map of the distribution of this habitat. This map has been generated using presence in 100 x 100km grid squares indicated by HELCOM  converted to 10 x 10 km cells and therefore shows a maximum potential AOO and EOO based on current knowledge.

Comment EU28:
Based on presence in 100 x 100km grid squares therefore maximum potential EOO and AOO

Trends in Quantity:
This habitat is reported to have declined in the last 50 years due to degradation of water quality caused by pollution but there is a lack of quantitative data. There is insufficient information to identify any historical trends and no future trends have been estimated.

% of Distribution of the Habitat Type within the EU 28:
All of the current known distribution is hosted by EU 28 (Germany). A similar habitat is known to be present in the Kattegat and therefore in the North East Atlantic regional sea.

Justification of Small Range/Regression:
At the present time only a few small patches of this habitat have been recorded and it is believed to have declined in extent over the last 50 years although there is a lack of quantative data.

Justification of Restricted Area:
Only a few small patches of this habitat have been recorded. These are in German waters in the Belt Sea.

Pressures and Threats:
Eutrophication (increase in N, P and organic matter), pollution and ocean acidification, predicted as a result of climate change, are the main threats to this habitat. Eutrophication affects the sand-like shell gravel habitat adversely by increasing the organic load with some of the sand-like gravel patches at risk of being covered by overgrowth of algae. Localised  oxygen depletion may also result. Ocean acidification is assumed to increase the dissolving rate of the calcium carbonate in the mollusc shells which are the principal substrate of this habitat. However, it is unclear how the process will affect the sand-like shell gravel. Due to higher acidity, shell gravel may be ground down to a sand-like substrate at increasing rates possibly making the sand-like shell gravel more common. Alternatively the increased acidity may increase the dissolving rate of the grains thus decreasing the amount of sand-like shell gravel.

Conservation and Management:
The extent and occurrence of the habitat needs to be mapped in more detail to establish whether it exists outside the German Exclusive Economic Zone. Measures to improve water quality are likely to benefit this habitat.

Conservation Status:
Annex 1:
1110: MBAL U1
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1110 VU C1
1160 VU C1
1650 VU C1
HELCOM (2013) assessed the associated biotope AA.E3Y Baltic photi

Summary:
This benthic habitat is currently only known in a few small patches in the German waters of the Baltic Sea. Whilst macroscopic infauna are present, there is typically no macrovegetation or epibenthic macrofauna.  The benthic macroinfauna species vary depending on the coarseness of the shell gravel. For example where the interstitial spaces are small, burrowing polychaetes and amphipods build tunnels using the small grains. 
Eutrophication affects the sand-like shell gravel biotope adversely by increasing the organic loading. This can lead to local oxygen depletion and some of the sand-like shell gravel patches may also become covered by overgrowth of algae. Effects associated with climate change are likely to be an additional pressure. Ocean acidification as a result of increase in atmospheric CO2 is assumed to increase the rate by which calcium carbonate of mollusc shells dissolve but it is unclear how this might affect the sand-like shell gravel. More detailed mapping of the extent of the habitat, and investigation into potential effects of climate change is required. Other beneficial management activities include improvements in water quality and limiting or prohibiting activities which damage the seabed.

References:
HELCOM, 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Avellan, L. (Ed). Helsinki, Finland.
HELCOM, 2013. Biotope Information Sheet. Available at: http://helcom.fi/Red%20List%20of%20biotopes%20habitats%20and%20biotope%20complexe/HELCOM%20Red%20List%20AA.E3Y,%20AB.E3Y.pdf (Accessed: 16/07/2015).

Criterion A Text:
This habitat has a restricted distribution in the Baltic Sea, currently only reported within the German EEZ. There is a lack of quantitative data on changes in quantity of this habitat. There has been some decline in extent but it is believed to be less than 25% over the last 50 years. No estimates have been made on possible future trends in quantity. This habitat has been assessed as Least Concern under criterion A.

Criterion B Text:
This habitat has a restricted distribution in the Baltic Sea, currently only reported within the German EEZ. It is believed to have declined in extent although by less than 25% in the last 50 years. Because of an expected continuing decline in abiotic environmental quality and because it only appears to be present in very few locations this habitat fulfills criteria B1a(ii) and B3, and it has therefore been assessed as Endangered under criterion B. 
It is important to note some shortcomings with the EOO and AOO calculations. The data used to calculate EOO and AOO was based on HELCOM mapping in 100 x 100 cells of only one of the two associated biotopes. The full extent and area covered by the habitat could therefore be greater. Equally relevant is that fact that HELCOM information has been converted to 10 x 10 km cells to derive AOO. As the habitat may not occur in all the cells mapped this figure could be an over estimate. The confidence of this assessment has therefore been given as low.

Criterion C/D Text:
This habitat has a restricted distribution in the Baltic Sea, currently only reported within the German EEZ. Experts considered there to have been some decline in quality of this habitat over the last 50 years but insufficient data on which to assess criteria C/D.

Criterion E Text:
This habitat has a restricted distribution in the Baltic Sea, currently only reported within the German EEZ. There is no quantitative analysis available to estimate the probability of collapse of this habitat type.

Synthesis:
The habitat has a restricted distribution in the Baltic, currently only reported within the German EEZ. It is believed to have declined in extent, although by less than 25% in the last 50 years, due to degradation of the environmental quality caused by pollution. Current information suggests that the maximum area may be around 2,000 km2, based on presence in 100 x 100 km grid squares mapped by HELCOM. 
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed the associated biotope AA.E3Y Baltic photic shell gravel characterised by mixed infaunal macrocommunity in fine sand-like shell fragments as Near Threatened (B1a(ii). The other associated biotope (AA.E3X) was not evaluated.
Expert opinion is that this habitat should be assessed as Endangered (B1aii, B3) for both the EU 28and EU 28+. This is because of the relatively restricted distribution of the shell gravel habitat combined with past and predicted future decline in abiotic environmental quality. It is important to note some shortcomings with the EOO and AOO calculations. The data used to calculate EOO and AOO was based on HELCOM mapping in 100 x 100 km2 cells of only one of the two associated biotopes. The full extent and area covered by the habitat could therefore be greater. Equally relevant is that HELCOM information has been converted to 10 x 10 km cells to derive AOO. As the habitat may not occur in all the cells mapped this figure could be an over estimate. The confidence in this assessment is therefore given as Low.

Sub-habitats in Need of Examination:
AA.E3Y Baltic photic shell gravel characterised by mixed infaunal macrocommunity in fine sand-like shell fragments.


Habitat Type Name:
19 Sparse or no macrofaunal community on infralittoral coarse sediment

Habitat Description:
This Baltic Sea benthic habitat occurs in the photic zone with at least 90% coverage of coarse sediment according to the HELCOM HUB classification. Sessile/semi-sessile epifauna and flora is present but covers less than 10%. The habitat is encountered in high energy exposure areas whre the topmost level is mixed by wave action. Two associated biotopes have been identified ‘Baltic photic coarse sediment characterized by sparse epibenthic macrocommunity (AA.I2T) and Baltic photic coarse sediment characterized by no macrocommunity (AA.I4U)
Indicators of quality:
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed
indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis.
Characteristic species: 
Mytilus spp, Hydroids, Amphibalanus improvisus

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.41 Sublittoral mixed sediment in low or reduced salinity 
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1110 Sandbanks slightly covered all the time
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral coarse sediment
Shallow sublittoral mixed sediment
 
EUSeaMap:
Shallow coarse or mixed sediments
 
IUCN:
9.3 Subtidal Loose Rock/Pebble/Gravel
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.I2T Baltic photic coarse sediment characterized by sparse epibenthic macrocommunity
AA.I4U Baltic photic coarse sediment characterized by no macrocommunity

Justification Outstanding Example of Biogeographical Region:
Gravel (or coarse substrate) in high energy areas also exist in other parts of the world, and it is not uncommon that the flora and/or sessile fauna is sparse. This is due to the challenge of colonizing a substrate where the topmost layer is “continuously” moving, with an abrasive effect on organic structures.

Trends in Quantity:
This habitat is present in all Baltic Sea sub-basins. There is a lack of quantitative data on trends but extent is considered to have been stable over the last 50 years and expert opinion is that this is likely to remain so in the near future.

Trends in Quality:
There is insufficient information on which to determine any trends in quality of this habitat over the last 50 years.

Pressures and Threats:
No information on pressure and threats specific to this habitat have been identified.

Conservation Status:
Annex 1:
1110: MBAL U1
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1110 VU C1 
1160 VU C1 
1650 VU C1 
HELCOM (2013) assessed the two associated biotopes A

Summary:
This habitat occurs in all the Baltic Sea sub-basins, particularly in high energy exposure areas. There is a lack of quantitative data on pressure and threats as well as on distribution, extent and quality. No conservation or management measures have been identified specifically for this habitat.

References:
HELCOM, 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes.  Helsinki Commission. 138.

Criterion A Text:
There is a lack of quantitative data on changes in quantity of this habitat but it is believed to have been stable over the last 50 years. This habitat has been assessed as Least Concern under Criteria A for both the EU 28 and EU 28+.

Criterion B Text:
This habitat isp resent in all the Baltic Sea sub-basins therefore EOO exceeds 50,000km2 however with no quantitative data on habitat extent, area, potential future trends and associated threats it is assessed as Data Deficient under Criteria B.

Criterion C/D Text:
Experts consider there to be insufficient data on which to assess criteria C/D

Synthesis:
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion.
HELCOM (2013) assessed two relevant Baltic biotopes (AA.I2T and AA.I4U) as Least Concern (A1).  The extent and area of this habitat is believed to have been stable over the last 50 years and no change is expected in the near future. Current expert opinion is an assessment for this habitat as Least Concern for both the EU 28 and EU 28+.


Habitat Type Name:
23 Emergent vegetation communities on Baltic infralittoral mixed substrata (predominantly soft)

Habitat Description:
This is a Baltic Sea benthic habitat in the photic zone where at least 10%, but less than 90% of the substrate is a mix of hard and soft substrata.  Emergent vegetation covers at least 10% of the seabed and exceeds that of other perennial attached erect groups. The habitat occurs in areas of low to moderate exposure to wave action, typically to depths of about 2 meters. 
Two associated biotopes with different dominant plant species have been identified. The common reed (Phragmites australis) forms the characteristic biotope in water depths of up to 2m and in moderately exposed conditions, whereas sedges such as Schoenoplectus spp, and Bolbaschoenus maritimus are generally present in more sheltered and shallower waters in areas of low to moderate salinity. Nutrient levels play a part in affecting the balance between the two biotopes with reed dominated areas favoured by conditions of eutrophication.
Indicators of quality: 
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time.
There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. The overall quality and continued occurrence of this habitat is, however, largely dependent on the presence of the emergent plant species which create the biogenic structural complexity on which the characteristic associated communities depend. The density and the maintenance of a viable population of these species is a key indicator of habitat quality, together with the visual evidence of presence or absence of physical damage. In the case of this habitat the situation is further complicated because the reed dominated biotope is favoured by the deterioration of the sedge dominated biotope under conditions of eutrophication.
Characteristic species: 
Phragmites australis, Schoenoplectus spp., Bolbaschoenus maritimus.

Classification:
EUNIS: 
The closest correspondence in EUNIS (2004) level 4 is A5.54 Angiosperm communities in reduced salinity.
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1130 Estuaries
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral sand
Shallow sublittoral mud
Shallow sublittoral mixed sediment
 
EUSeaMap:
Shallow sands
Shallow muds
Shallow coarse or mixed sediments
 
IUCN:
9.3 Subtidal loose rock/pebble/gravel
9.5 Subtidal sandy-mud
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.M1A Baltic photic mixed substrate characterized by emergent vegetation. This habitat has two sub-habitats on HUB level 6; ‘Baltic photic mixed substrate dominated by common reed (Phragmites australis)’ (AA.M1A1) ‘Baltic photic mixed substrate dominated by sedges (Cyperaceae)’ (AA.M1A2).

Map Description:
There are insufficient data to provide a comprehensive amd accurate map of the distribution of this habitat. This map has therefore been generated using the modelled data available on EMODnet for EUNIS level 3 habitats in the Baltic Sea (EMODnet, 2010). This means it indicates potential areas in which this habitat may occur, not the actual distribution of this EUNIS level 4 habitat. EOO and AOO cannot be calculated at the present time, although the habitat is known to occur in all the Baltic Sea sub-basins.

Trends in Quantity:
This habitat is present in all sub-basins of the Baltic Sea and there are distribution maps for the characteristic species (e.g. Phragmites). It has increased in extent over the last 50 years due to anthropogenic eutrophication and changes in land use (less coastal pastures, less reed cutting). There also appears to have been a changing balance between the associated biotopes with sedge dominated communities declining and reed dominated communities increasing, most likely in response to eutrophication. There are some exceptions. In Estonia, for example there was expansive reed growth from 1950s to end of 1970s whereas in the last few decades growth rates reduced or even ceased. This is believed to be associated with increased storminess resulting in increase of average sea level which has limited the suitable growth zones for the reed weakened by eutrophication.
The quantity of this habitat is expected increase  in the future in the whole Baltic Sea.

Pressures and Threats:
The expansion of reed belts has been accelerated by anthropogenic eutrophication, postglacial land upheaval and the lack of grazing on coastal meadows and attached shallow water areas, while pollution associated with drainage from farming and forestry, and other sources (like traffic and industry) are threats and deterioration factors.. Other pressures arise from shipping, and the construction or enlargement of harbours and marinas in sheltered areas. Changes in the water flow due to hydrotechnical constructions, such as dams, cascades and river bank control, may also have adverse effects downstream. Other threats can be caused by introduction of non-indigenous, invasive species, unsustainable fisheries and tourism as well as oil spills and construction of breakwaters.
The environmental conditions in river mouths depend highly on inflows from local point sources as well as from the whole catchment area. They are therefore closely related to human activities on land. The maximum growth depth of Phragmites (limited by oxygen transportation to the roots) is around 2m therefore sea level rise may lead to changes in extent and shifts in distribution. Some of these activities described above may increase the extent of the habitat or change the relatively dominance of reeds or sedges. For example, dredging of the tributary rivers of the Kasari delta, Estonia, in the 1920s–1930s caused a rapid seaward colonisation of the reed bed along the dredged channels by the dispersal and reburial of fragmented rhizomes at the channel banks and on the shallow sea bottom of Matsalu Bay.

Conservation Status:
Annex 1:
1130: MBAL U2
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1130 CR C1 
1160 VU C1 
1650 VU C1 
HELCOM (2013) have assessed associated biotopes

Summary:
The presence of this habitat in the Baltic Sea is well known from sheltered areas in all the sub-basins. The characteristic species are reeds or sedges with dominance being determined by factors such as sediment type, exposure and nutrient levels. The habitat can support a high biodiversity, for example by providing nesting areas for birds, and shelter and spawning grounds for fish, although reeds in particular can also out compete and shade other plant species (including sedges) decreasing local biodiversity.
The expansion of reed belts has been accelerated by anthropogenic eutrophication, postglacial land upheaval and the lack of grazing on coastal meadows and attached shallow water areas, while pollution associated with drainage from farming and forestry, and other sources (like traffic and industry) are threats and deterioration factors. Other pressures arise from shipping, and the construction or enlargement of harbours and marinas in sheltered areas. Changes in the water flow due to hydrotechnical
constructions, such as dams, cascades and river bank control, may also have adverse effects downstream.
In some areas, there is an active programme of reed removal to encourage re-establishement of the sedge dominated biotopes. Improvements in water quality are also beneficial although it should be noted that whereas increased eutrophication leads to reed replacing sedges, a later decrease in eutrophication does not necessarily facilitate a process where sedges come back.

Criterion A Text:
There have been different trends in the extent of this habitat depending on which of the associated biotopes is considered. Sedges have declined, quite significantly in some areas, possibly due to the expansion of, and competition with reed. The latter benefits from the nutrient enrichment associated with eutrophication. As a consequence sedges, former considered ecologically typical of sheltered areas in the Baltic are being replaced by another biotope due to a deterioration of the environment (i.e. eutrophication).
Overall this habitat is believed to have been stable or possibly increased in extent over the last 50 years. It has therefore been assessed as Least Concern under Criteria A for the EU 28 and EU 28+.

Criterion B Text:
This habitat has a large natural range in the Baltic Sea with EOO >50,000 km2 but it is possible that it is not particularly common as reed and sedge habitats are more typically found on softer sediments. Future trends have not been estimated. This habitat has therefore been assessed as Data Deficient under criterion B.

Synthesis:
Increases in extent have been evident in this habitat in the last 50 years, though this is mainly due to the increase of reed (Phragmites australis) while at the same time sedges have decreased, most likely a response to eutrophication favouring the former. In the case of the sedge dominated biotopes some loss in density/biomass may be occuring but there are no monitoring data to confirm this.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed AA.M1A1 and AA.M1A2 as Least Concern (A1). The overall assessment for this habitat type, based on expert opinion is Least Concern for both the EU 28 and EU 28+.

Sub-habitats in Need of Examination:
‘Baltic photic mixed substrate dominated by sedges (Cyperaceae)’ (AA.M1A2).


Habitat Type Name:
24 Submerged rooted plant communities on Baltic infralittoral mixed substrata (predominantly soft)

Habitat Description:
This benthic Baltic Sea habitat occurs in the photic zone with more than 10%, but less than 90% coverage of  hard and soft substrata according to the HELCOM HUB classification. Coverage of submerged rooted plants which also includes plants with rhizoids (i.e. Charales) cover at least 10% of the seabed, and more than other perennial attached erect groups. Mixed sediments covered by rooted plants are mainly distributed in moderate exposure levels but may also occur in sheltered conditions. The habitat covers the full salinity range of the Baltic Sea and is distributed from the Belt Sea up to the northern part of Bothnian Bay. Depending on the salinity and depth the dominant species (>50% of the biovolume), defining the associated biotope type, varies. 
’Baltic photic mixed substrate dominated by pondweed (Potamogeton perfoliatus and/or Stuckenia pectinata)’ (AA.M1B1) is found between 0.2-4 m depth in sheltered sites with up to 6 psu.  ‘Baltic photic mixed substrate dominated by watermilfoil (Myriophyllumspicatum and/or Myriophyllum sibiricum)’ (AA.M1B3) has a similar distribution but a more narrow depth range (0.2-2 m).  ’Baltic photic mixed substrate dominated by Charales’ is found in a wider range of salinity (2-15), depth (0.2-7 m) and wave exposure (low to moderate) (AA.M1B4).  ’Baltic photic mixed substrate dominated by Zannichellia spp. and/or Ruppia spp. and/or Zostera noltii’ is found at 0-4 m depth throughout the salinity gradient of the Baltic Sea and in low to moderate exposure (AA.M1B2).  ’Baltic photic mixed substrate dominated by common eelgrass (Zostera marina)’ (AA.M1B7) differs most strongly from the other sub-biotopes in distribution, occurring mainly at moderate exposure and in salinities of 5 psu or higher. It is typically found deeper than the other associated biotopes (1-6 m) and often marks the lower depth limit distribution of soft bottom vegetation. This biotope is absent from areas with low salinity in the inner part of Gulf of Finland and Gulf of Bothnia.
Indicators of quality: 
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change overtime. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. 
The vertical depth limit of submerged rooted plants is used in several countries as a Water Framework Directive parameter for assessing ecological status. The overall quality and continued occurrence of this habitat is, however, largely dependent on the presence of the rooted plant species which create the biogenic structural complexity on which the characteristic associated communities depend. The density and the maintenance of a viable population of these species is a key indicator of habitat quality, together with the visual evidence of presence or absence of physical damage.
Characteristic species: 
Stuckenia pectinata, Potamogeton perfoliatus,Zostera marina, , Z. noltei, Ruppia cirrhosa, R. maritima, Zanichellia palustris, Myriophyllum spicatum, Chara baltica.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.53 Sublittoral seagrass beds and A5.54 Angiosperm communities in reduced salinity.
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1110 Sandbanks slightly covered by seawater
1130 Estuaries
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral sand
Shallow sublittoral coarse sediment
Shallow sublittoral mixed sediment
 
EUSeaMap:
Shallow sands
Shallow coarse or mixed sediments
 
IUCN:
9.3 Subtidal Loose Rock/Pebble/Gravel)
9.4 Subtidal Sandy
9.9 Seagrass
9.10 Estuaries
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.M1B Baltic photic mixed substrate characterized by submerged rooted plants
This habitat has five sub-habitats on HUB level 6;
AA.M1B1 ’Baltic photic mixed substrate dominated by pondweed (Potamogeton perfoliatus and/or Stuckenia pectinata)’
AA.M1B2 ’Baltic photic mixed substrate dominated by Zannichellia spp. and/or Ruppia spp. and/or Zostera noltii’
AA.M1B3 Baltic photic mixed substrate dominated by watermilfoil (Myriophyllum spicatum and/or Myriophyllum sibiricum)’
AA.M1B4 ’Baltic photic mixed substrate dominated by Charales’ 
AA.M1B7 ’Baltic photic mixed substrate dominated by common eelgrass (Zostera marina)’

Justification Outstanding Example of Biogeographical Region:
This habitat is common on photic mixed substrate in the entire Baltic Sea. Most of the associated biotopes have a very typical and characteristic species composition for the Baltic Sea, dominated by species with freshwater origin.

Map Description:
There are insufficient data to provide a comprehensive and accurate map of the distribution of this habitat. This map has therefore been generated using the modelled data available on EMODnet for EUNIS level 3 habitats in the Baltic Sea (EMODnet, 2010) and supplemented with expert input. This means it indicates potential areas in which this habitat may occur, not the actual distribution of this EUNIS level 4 habitat.

Trends in Quantity:
This habitat is common in along the coastline in all the Baltic Sea sub-basins as are most of the associated biotopes although AA.M1B7 ’Baltic photic mixed substrate dominated by common eelgrass (Zostera marina)’ is absent from areas with low salinity in the Gulf of Finland and Gulf of Bothnia. Reduction in depth distribution for Zostera marina from 10 m to currently 4-6 m resulted in area reduction (since 1930s) to about 25-50 % along the German and Danish coastline but to varying extents in the different Baltic Sea regions. The associated biotope AA.M1B4 ’Baltic photic mixed substrate dominated by Charales’ has declined by >25% during the last 50 years. The decline has been to varying extent in different Baltic Sea regions with the strongest decline occurred again in the Western and Southern Baltic Sea. In some bays and lagoons conditions have changed so intensively that the habitat has disappeared completely. The remaining associated biotopes are believed to have declined less than 25% during the last 50 years. Detailed historical area data are only available for some areas/countries. Some of the associated biotopes are considered likely to decline in the future (e.g. by more than 20% for those dominated by Charales).

Trends in Quality:
The quality of the biotope has declined during the past 50 years and historic times, at least in some areas and biotopes, such as those dominated by charophytes around the Hanko peninsula (Finland) and the German Bodden and Haffe, but there is insufficient data on large scale to assess any overall trend in quality.

% of Distribution of the Habitat Type within the EU 28:
This habitat occurs in the EU 28+ (Russia). The percentage hosted by EU 28 is therefore less than 100% but there is insufficient information to establish the proportion.Submerged rooted plant communities on infralittoral mixed substrata do occur in other European regional seas.

Pressures and Threats:
Eutrophication, epidemics (wasting disease), bottom trawling, water traffic, construction, sand extraction, dredging, dumping, aquaculture, coastal works and localised damage from mooring have all been identified as past and current threats. These are also likely to be threats in the future along with climate change.
Observed declines of the spatial distribution of the biotope AA.M1B4 ’Baltic photic mixed substrate dominated by Charales’ are mainly caused by increased eutrophication and connected effects. Decreasing light penetration depth, massive growth of ephemeral algae and increased siltation rates cause massive alterations in the biotopes of sheltered coastal areas. The enclosed characteristic of bays and lagoons intensify the eutrophication impacts. Coastal constructions (e.g. dredging for deepening of harbour access channels, ditching and construction of leisure facilities) and increased tourism has led to a further degradation of the biotope. The threat level is particularly high in the Western and Southern Baltic Sea. In the future climate change (increasing exposure levels, temperatures) or increasing aquaculture in bays may cause additional threats.
The main causes of the observed declines of the spatial distribution of the AA.M1B7 ’Baltic photic mixed substrate dominated by common eelgrass (Zostera marina)’ are (1) the “wasting disease” that caused about 90% of the North European stock to disappear in the 1930 and also affected the Zostera beds in Danish and German waters and (2) eutrophication of the Baltic Sea that has resulted in significant decline of eelgrass meadows in mainly Danish, German, Swedish and Polish coastal areas. Eutrophication has decreased the depth where Zostera dominated biotopes can receive enough light and may in addition cause a shift from eelgrass meadows to communities dominated by fast-growing macro-algae. Climate change is predicted to lower the salinity level in the northern parts of the Baltic Sea due to an increase of precipitation, which may threaten Zostera marina in the northernmost areas where it currently exists on the limits of its salinity tolerance.

Conservation and Management:
All actions to reduce eutrophication of the Baltic Sea are important for the conservation of this habitat. For the biotopes that mainly occurs in bays with limited water exchange with the open ocean (e.g. AA.M1B4 ’Baltic photic mixed substrate dominated by Charales’), combating local sources of eutrophication is essential. Conservation measures such as area protection and restrictions on coastal constructions and dredging in shallow coastal lagoons and archipelago areas are also important.

Conservation Status:
Annex 1:
1110: MBAL U1
1130: MBAL U2
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments: 1110 (VU,C1) 1130 (CR,C1) 1160 (VU,C1), and 1650 (VU,C1) HELCOM (2013) have assessed biotopes AA.M1B4 and AA.M1B7 as

Capacity to Recover its Typical Character and Functionality?:
In areas where the habitat is dominated by common eelgrass (Zostera marina)’ it can be slow to recover after strong decline (taking more than 20 yrs). Intervention (transplantation) may speed up the recovery but transplantation experiments have had limited success to date. Regeneration from root systems is slow and recovery of entire beds, with characteristic structure and associated species could take many years. 
In the northern Baltic low salinity means that any expansion takes place vegetatively. Zostera plants are believed to be from the same genotype, estimated to be between 800-1600 years old. Clonal growth and low genetic diversity may reduce the acclimation capacity and survival of the species in rapidly changing environmental conditions. Where other species dominate natural recovery can probably occur within 10 years.

Summary:
This habitat occurs in all Baltic sub-basins in the shallow waters of the photic zone. Distribution of the associated biotopes depends on the dominant species and is influenced mainly by salinity and exposure Zostera noltei, for example, is not found east of the Darss Sill in the Arkona basin, while Potamogeton perfoliatus occurs mostly in the northern part of the Bothnian Bay, and Chara horrida in the central Baltic and Archipelago Sea. The submerged rooted plant communities (higher plats and charophytes) provide structure for the benthic environment and associated communities on the underlying sediment. The best studied biotopes are those dominated by seagrass, brackish water angiosperms and charophytes
Eutrophication (increasing N, P and organic matter) has both direct and indirect negative impacts, for example by reducing light penetration through the water column and therefore the depth penetration of submerged species, increased sedimentation which can prevent settlement and excess of nutrients which often favours opportunistic species with short life cycles and rapid development over perennial species with lower productivity, causing a shift in the community composition. Climate change may also result in a shift in the dominant species due to predicted associated changes in salinity. All actions to reduce eutrophication of the Baltic Sea are important for the conservation of this habitat as are area protection and restrictions on coastal construction and dredging.

References:
Baden, S.P., Boström, C. 2001. The leaf canopy of seagrass beds: faunal community structure and function in a salinity gradient along the Swedish coast. In: Reise, K. (ed.), Ecological comparisons of sedimentary shores, Ecological Studies 151, Springer-Verlag, Berlin, pp. 213-236.
Baden, S.P., Loo, L.-O., Pihl, L., Rosenberg, L. 1990. Effects of eutrophication on benthic communities including fish: Swedish west coast. Ambio 19: 113-122.
Berg Ch., Dengler J., Abdank A., Isermann M. 2004. Die Pflanzengesellschaften Mecklenburg-Vorpommerns und ihre Gefährdung – Textband. Weissdorn-Verlag, Jena: 94–98.
Berglund, J., Mattila, J., Rönnberg, O., Heikkilä, J., Bonsdorff, E. 2003. Seasonal and inter-annual variation in occurrence and biomass of rooted macrophytes and drift algae in shallow bays. Estuarine, Coastal and Shelf Science 56(5–6): 1667–1175.
Blindow, I. (2000): Distribution of charophytes along the swedish coast in relation to salinity and eutrophication. Internat. Rev. Hydrobiol. 85 (5–6): 707–717
Borum, J., Duarte, C.M., Krause-Jensen, D., Greve T.M. (eds). 2004. European seagrasses: an introduction to monitoring and management. The M&MS project. 95 pp. Available at: http://www.seagrasses.org/handbook/european_seagrasses_low.pdf (Accessed: 29/10/2015).
Boström, C. 2001. Ecology of Seagrass Meadows in the Baltic Sea. Environmental and Marine Biology, Department of Biology, Åbo Akademi University, Åbo, Finland. 47 pp.
Boström, C., Bonsdorff, E. 1997. Community structure and spatial variation of benthic invertebrates associated with Zostera marina (L) beds in the northern Baltic Sea. Journal Of Sea Research 37(1-2): 153–166.
Boström, C., Baden, S.P., Krause-Jensen, D. 2003. The seagrasses of Scandinavia and the Baltic Sea. In: Green, E. P. & Short, F.T. (eds). World Atlas of Seagrasses. University of California Press. pp. 27-37.
Boström, C., Bondsorff, E., Kangas, P. Norkko, A. 2002. Long-term changes of a brackish water eelgrass (Zostera marina L.) community indicate effects of coastal eutrophication. Est. Coast. Shlef Sci. 55: 795-804.
Dahl, K., Josefson, A.B., Göke, C., et al. 2013. . Climate Change Impacts on Marine Biodiversity and Habitats in the Baltic Sea - and Possible Human Adaptations. In: Krarup Leth, O., Dahl, K., Peltonen, H., Krämer, I., Kule, L.(eds.). Sectoral Impact Assessments for the Baltic Sea Region - Climate Change Impacts on Biodiversity, Fisheries, Coastal Infrastructure and Tourism. Coastline Reports (21), pp. 1-34. EUCC - The Coastal Union Germany, Rostock, 2013.
den Hartog, C. 1970. The seagrasses of the world. Verh K Ned Ak Wet Adf. North-Holland, Amsterdam 59: 1-275.
Hauxwell, J., Cebrian, J., Furlong, C., Valiela, I. 2000. Macroalgal canopies contribute to eelgrass (Zostera marina) decline in temperate estuarine ecosystems. Ecology 82: 1007-1022.
HELCOM. 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Baltic Sea Environment Proceedings 138 Helsinki Commisison.
Kruk-Dowgiallo, L. 1996. The role of filamentous brown algae in the degradation of the underwater meadows the Gulf of Gdansk. Oceanological Studies XXV (1-2): 125-135.
Lundberg,C. 2005. Eutrophication in the Baltic Sea – from area-specific biological effects to interdisciplinary consequences. Environmental and Marine Biology. Department of Biology. Åbo Akademi University, Åbo Finland 166 pp
McGlathery, K.J. 2001. Macroalgal blooms contribute to the decline of seagrass in nutrient-enriched coastal waters. J. Phycol. 37: 453-456.
Mäkinen, A., Tallberg, P., Anttila, S., Boström, C., Boström, M., Bäck, S., Ekebom, J., Flinkman, J., Henricson, C., Koistinen, M., Korpinen, P., Kotilainen, A., Laine, A., Lax, H.-G., Leskinen, E., Munsterhjelm, R., Norkko, A., Nyman, M., O’Brien, K., Oulasvirta, P., Ruuskanen, A., Vahteri, P. & Westerbom, M. 2008. Itämeren vedenalaiset luontotyypit. In: Raunio, A. Schulman, A. & Kontula, T. (eds). 2008. Suomen luontotyyppien uhanalaisuus − Osa II: Luontotyyppien kuvaukset. Finnish Environment Institute, Helsinki. Suomen ympäristö 8/2008. 572 p.
Möller, T. 2008. Zostera marina (LINNAEUS 1753), Eelgrass (Angiospermophyta). HELCOM Species Fact Sheet: http://www.helcom.fi/environment2/biodiv/endangered/Vascular_plants/en_GB/Zostera_marina/
OSPAR 2008. OSPAR List of Threatened and/or Declining Species and Habitats.
Pihl, L., Isaksson, I., Wennhage, H. Moksnes, P.-O. 1995. Recent increase of filamentous algae in shallow Swedish bays: effects on the community structure of epibenthic fauna and flora. Neth. J. Aquatic Ecol. 29: 349-358.
Schiewer, U. 2002. Recent changes in northern German lagoons with special reference to eutrophication. In: Schernewski, G. & U. Schiewer (eds.), Baltic coastal ecosystems, structure, function and coastal zone management. Central and Eastern European Development Studies, Springer Verlag, Berlin, pp. 19-30.
Schubert, H. & I. Blindow (eds.) 2003. Charophytes of the Baltic Sea. The Baltic Marine Biologists Publication, No. 19: 326 S.
Schubert, H.; Blümel, C.; Eggert, A.; Rieling, T.; Schubert, M. & U. Selig. 2003. Entwicklung von leitbildorientierten Bewertungsgrundlagen für innere Küstengewässer der deutschen Ostseeküste nach der EU-WRRL. Forschungsbericht zum BMBF Projekt ELBO. FKZ 0330014: 1-109.
Tolstoy , A., Österlund, K. 2003. Alger vis Sveriges östersjökust – en fotoflora. ArtDatabanken, SLU. Almqvist & Wiksell Tryckeri, Uppsala. 282 pp.
Torn, K., Martin, G., Kukk, H., Trei, T. 2004. Distribution of charophytes along the Swedish coast in relation to salinity and eutrophication. Scientia Marina 68: 129-136.

Criterion A Text:
There are quantiative data for changes in this habitat in some parts of its range in the Baltic Sea and for some of the sub-habitats. Expert opinion is that overall this is probably more than 25% in the last 50 years. This habitat has therefore been assessed as Near Threatened under criterion A. for both the EU 28 and EU 28+.

Criterion B Text:
This habitat has a large natural range in the Baltic Sea extending from the Danish coast in the west to the Bothnian Bay in the north-east. EOO >50,000 km2 and AOO >50 and it is not limited to a few locations, however the precise extent of this habitat over the last 50 years is unknown. This habitat has been assessed as Least Concern under Criteria B for both the EU 28 and EU 28+.

Criterion C/D Text:
There have been declines in the quality of some of the associated biotopes in some areas e.g. Charophytes and Zostera marina, however experts consider there to be insufficient data on which to make an overall assessment of criteria C/D.

Synthesis:
The best studied biotopes are those dominated by seagrass, brackish water angiosperms and charophytes and for most of them there have been declines in extent. Zostera marina and several species of Charales are on the HELCOM Red List of threatened species. Deeper water eelgrass meadows are at risk of disappearing in the future if there is continued reduction in light levels (e.g. due to eutrophication, sediment disturbance).
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed AA.M1B1, AA.M1B2 and AA.M1B3 as Least Concern (A1) and AA.M1B4 and AA.M1B7 as Near Threatened (A1). The overall assessment for this habitat type based on expert opinion is Near Threatened for both the EU 28 and EU 28+ because of the reduction in quantity of this habitat over the last 50 years.

Sub-habitats in Need of Examination:
AA.M1B4 Baltic photic mixed sediment dominated by Charales
AA.M1B7 Baltic photic mixed sediment dominated by common eelgrass (Zostera marina)


Habitat Type Name:
25 Unvegetated Baltic infralittoral mixed sediment (hard and soft) with sparse or no macrofaunal community

Habitat Description:
This benthic Baltic Sea habitat occurs in the photic zone with a mix of more than 10%, but less than 90% coverage of either hard and soft substrata according to the HELCOM HUB classification. Typical examples include singular rocks or boulders/stones extending above the soft substrata as well as soft substrata aggregation between abundant rocks and stones/boulders. The amount of soft substrata is affected by energy, both in the lateral and horizontal dimension, leading to a typically continuous small-scale variation in substrate composition. Sessile/semi-sessile macroscopic epibenthic fauna and flora is present where there is a sparse macrofaunal community (less than 10% coverage). In these situations microphytobenthic organisms and grazing snails (e.g. Hydrobiidae, Theodoxus, Bithynia, Radix) dominate constituting 50% in biomass or volume. Elsewhere there may be no macrovegetation present and neither macroepifauna or macro infauna. 
Indicators of quality:
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time.
There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis.
Characteristic species:  
Hydrobiidae, Theodoxus, Bithynia, Radix where there is sparse macrofauna. Meiofauna and bacteria where is there is macrofaunal community.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.41 Sublittoral mixed sediment in low or reduced salinity
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1110 Sandbanks slightly covered all the time
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD: 
Shallow sublittoral rock & biogenic reef
Shallow sublittoral coarse sediment
Shallow sublittoral mixed sediment
Shallow sublittoral sand
Shallow sublittoral mud
 
EUSeaMap:
Shallow photic rock or biogenic reef
Shallow coarse or mixed sediments
Shallow sand
Shallow mud
 
IUCN:
9.2 Subtidal rock and rocky reefs
9.3 Subtidal loose rock/pebble/gravel
9.5 Subtidal sandy-mud
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.M2W Baltic photic mixed substrate characterized by microphytobenthic organisms and grazing snails.
AA.M2T Baltic photic mixed substrate characterized by sparse epibenthic macrocommunity.
AA.M4U Baltic photic mixed substrate characterized by no macrocommunity.

Justification Outstanding Example of Biogeographical Region:
Overall, this habitat is not considered an outstanding example of Baltic habitat. However, the associated biotope AA.M2W Baltic photic mixed substrate characterised by microphytobenthic organisms and grazing snails is typical for the Baltic reflecting the combined effects of low salinity, mixed substrate and low energy exposure.

Trends in Quantity:
This habitat is common throughout the Baltic and the quantity is considered to have been stable over the last 50 years. There are no quantitative historic data and no estimates of future trends although future land uplift and turbidity changes/fluctuations can affect the distribution between this habitat and the corresponding circalittoral habitat.

Trends in Quality:
From the limited information available, the current habitat condition is considered to be good. There is no information on trends in quality. In the future land uplift and turbidity changes/fluctuations may affect the distribution between this habitat and the corresponding circalittoral habitat.

Justification of Small Range/Regression:
The trend is stable and the habitat has a large natural range in the Baltic Sea.

Justification of Restricted Area:
This habitat has a large natural range in the Baltic Sea.

Conservation Status:
Annex 1:
1110: MBAL U1
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1110 VU C1 
1160 VU C1 
1650 VU C1 
HELCOM (2013) assessed all three associate

Summary:
This habitat occurs in all the sub-basins of the Baltic Sea and the extent is considered to have been stable over the last 50 years. Future changes in sea level/land uplift may affect the natural extent and quality of this habitat. There is no specific information on pressures, threats, conservation and management measures for this habitat nor any quantitative data on possible future changes in distribution, extent and quality.

Criterion A Text:
Expert opinion is that overall, the extent of this habitat has been stable over the last 50 years. It has therefore been assessed as Least Concern under criterion A for both the EU 28 and EU 28+.

Criterion B Text:
This habitat is present in all Baltic Sea sub-basins therefore EOO exceeds 50,000km2  however with no quantitative data on habitat extent or area, accurate calculation of EOO or AOO is not possible at the present time. This habitat is therefore Data Deficient under criterion B.

Synthesis:
This habitat is known to have a widespread distribution in the Baltic Sea.The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed three relevant Baltic biotopes (AA.M2W, AA.M2T and AA.M4U) as Least Concern (A1). Current expert opinion is that because of the widespread distribution of this habitat in the Baltic Sea and no significant decline over the last 50 years it can be assessed as Least Concern for both the EU 28 and EU 28+.


Habitat Type Name:
30 Epibenthic macrocommunity on Baltic infralittoral sand

Habitat Description:
This is a Baltic Sea benthic habitat in the photic zone where at least 90% of the substrate is sand according to the HELCOM HUB classification. No perennial attached vegetation is present but perennial unattached algae or annual algae may occur and cover more than 10% of the substrate. The habitat could occur across all salinity regimes in the Baltic and in areas moderately exposed to currents or wave action. 
Indicators of quality:
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis.
Characteristic species:
Insufficiently studied to list characteristic species at the present time.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.21 Sublittoral sand in low or reduced salinity.
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1110 Sandbanks slightly covered all the time
1130 Estuaries
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD: 
Shallow sublittoral sand
 
EUSeaMap:
Shallow sands
 
IUCN:
9.4 Subtidal Sandy
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.J1V Baltic photic sand characterised by mixed epibenthic macrocommunity.

% of Distribution of the Habitat Type within the EU 28:
This habitat is believed to  be present in the EU 28+ (Russia) however the percentage is unknown.

Justification of Restricted Area:
It is unknown whether this habitat has a small natural range by reason of its intrinsically restricted area.

Pressures and Threats:
No pressures and threats have been specifically identified for this habitat.

Conservation and Management:
No specific conservation and management measures have been identified for this habitat.

Summary:
This habitat is poorly study. It is a benthic habitat in the photic zone where the predominant substrate is sand, characterised by epibenthic communities on Baltic infralittoral sand. Although no perennial attached vegetation is present, perennial unattached algae or annual algae may occur. Threats and pressures are unknown at present and no conservation or management measures have been specifically identified for this habitat.

Criterion A Text:
Experts considered there to be insufficient data on which to assess Criterion A.

Criterion B Text:
Lack of data means that EOO or AOO cannot be calculated or estimated at the present time although as the habitat is considered likely to be present in all the Baltic Sea sub-basins the EOO may exceed 50,000km2.

Synthesis:
This habitat was not evaluated by HELCOM in the 2013 Red List Habitat Assessments. There remains insufficient information to make an assessment therefore it is considered to be  Data Deficient for both the EU 28 and EU 28+ at the present time.


Habitat Type Name:
45 Epifaunal communities on Baltic upper circalittoral coarse sediment and shell gravel

Habitat Description:
This is a Baltic Sea benthic habitat in the aphotic zone where at least 90% of the substrate is coarse sediment or shell gravel according to the HELCOM HUB classification. Sessile/semi-sessile epibenthic bivalves/epibenthic chordates cover at least 10% of the seabed and more than other perennial attached erect groups. The habitat typically occurs below 20m and is mostly encountered in high energy exposure areas. In offshore areas shell gravel bottoms are mainly found permanently at the same location whereas closer inshore they are more likely to shift dynamically from one location to another.
Six associated biotopes have been described; ‘Baltic aphotic shell gravel dominated by epibenthic bivalves (AB.E1E) where there is one sub-habitat with a large representation (at least 50% of the biomass) of Mytilidae’ (AB.E1E1) and ‘Baltic photic shell gravel characterised by epibenthic chordates (AB.E1F) with a sub-habitat dominated by vase tunicate (Ciona intestinalis) (AB.E1F1)'. The latter, which is only, present in the Belt Sea, occurs in areas where the bottom consists largely of mollusc shells or small shell fragments, often in small patches along with other sediments. Due to the combination of the extended interstitial space and the presence of biotic hard substrates, it is inhabited by a unique combination of endobenthic and epibenthic species, such as the vase tunicate (Ciona intestinalis). In these habitats coverage of epibenthic chordates is at least 10% of the sea floor, of which vase tunicate (Ciona intestinalis), which is largely annual in the Baltic, often constitutes at least 50% of the biomass. The tunicates might be overgrown by Ectocarpus spp. or Desmarestia spp. during summer in the photic zone. 
There are also associated aphotic shell gravel and coarse sediment biotopes characterised by mixed epibenthic communities (AB.I1V & AB.E1V) by epibenthic bivalves (AB.I1E) and shell gravel characterisied by a sparse epibenthic macrocommunities (AB.E2T).
 
Indicators of quality: 
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. Diversity, abundance and biomass of the dominant. species and associated fauna are potential indicators of quality of this habitat
Characteristic species:  
Mytilus spp., Modiolus modiolus, Ciona intestinalis, Hediste diversicolor

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.11 Infralittoral coarse sediment in low or reduced salinity.
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1110 Sandbanks slightly covered all the time
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral coarse sediment
Shallow sublittoral mixed sediment
 
EUSeaMap: 
Shallow coarse or mixed sediments
 
IUCN:
9.3 Subtidal Loose Rock/Pebble/Gravel
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AB.E1E–Baltic aphotic shell gravel characterized by epibenthic bivalves. This habitat has one sub-habitat on HUB level 6; ‘Baltic aphotic shell gravel dominated by Mytilidae’ (AB.E1E1).
AB.E1F–Baltic aphotic shell gravel characterized by epibenthic chordates. This habitat has one sub-habitat on HUB level 6; Baltic photic shell gravel dominated by vase tunicate (Ciona intestinalis) (AB.E1F1).
AB.E1V–Baltic aphotic shell gravel characterized by mixed epibenthic macrocommunity.
AB.E2T–Baltic aphotic shell gravel characterized by sparse epibenthic macrocommunity
AB.I1E–Baltic aphotic coarse sediment characterized by epibenthic bivalves One sub-biotope has been identified: ‘Baltic aphotic coarse sediment dominated by Mytilidae’ (AB.I1E1).
AB.I1V–Baltic aphotic coarse sediment characterized by mixed epibenthic macrocommunity.
 
OSPAR list of threatened biotopes: Modiolus modiolus beds. The habitat occurs in the OSPAR Region II (including Kattegat) and is listed threatened and/or declining in this region.

Justification Outstanding Example of Biogeographical Region:
One of the associated biotopes Baltic aphotic shell gravel dominated by Mytilidae is considered a special habitat in the Baltic Sea. It is currently not possible to determine if the other associated biotopes or whether the habitat is typical of the Baltic.

Trends in Quantity:
Overall the extent of this habitat is unknown. Some biotopes are considered to have been stable over the last 50 years (aphotic shell gravel dominated by Mytilidae) and others (aphotic shell gravel dominated by vase tunicate) to have reduced in quantity by more than 25%.

Trends in Quality:
There is insufficient information on the quality of this habitat at the present time or over the last 50 years to reach a view on potential trends in quality.

% of Distribution of the Habitat Type within the EU 28:
Overall unknown, although one associated biotope (shell gavel dominated by the vase tunicate) only occurs in areas hosted by EU 28.

Justification of Small Range/Regression:
At least one of the associated biotopes (shell gravel dominated by vase tunicate) is believed to have a small natural range (<50,000km2) and reduced in distribution. Overall this habitat does not have a small natural range and current tre

Justification of Restricted Area:
This habitat does not have a small natural range.

Pressures and Threats:
Oxygen depletion and increased siltation caused by eutrophication are believed to be main pressures on this habitat. Bottom trawling also threatens the physical integrity of the habitat. The predicted ocean acidification caused by the increasing atmospheric CO2 is a potential future threat as the natural degradation process of the calcium-carbonate shell gravel may accelerate if the water becomes more acidic. Additional threats are the effects of hazardous substances on the associated communities introduced to the Baltic Sea via pollution, and physical disturbance of the seabed associated with offshore installations and sand or gravel extraction. The effects of these are however assumed to be smaller than that posed by eutrophication.

Conservation and Management:
The distribution of this habitat should be mapped to gain better understanding of its environmental requirements. The area where the biotopes associated with shell gravel occur should be protected by prohibiting bottom trawling and other seabed disturbing activities. The oxygen conditions of the habitat need to be improved by reducing activities which lead to eutrophication.

Conservation Status:
Annex 1:
1110: MBAL U1
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1110 VU C1 
1160 VU C1 
1650 VU C1 
HELCOM (2013) assessed biotopes AB.E1E1 and AB.

Summary:
This is a Baltic Sea benthic habitat in the aphotic zone where at least 90% of the substrate is shell gravel or coarse sediment.  The habitat typically occurs below 20m and is mostly encountered in high energy exposure areas. In offshore areas shell gravel bottoms are mainly found permanently at the same location whereas closer inshore they are more likely to shift dynamically from one location to another. Areas of shell gravel dominated by Mytilidae are restricted to the Baltic Proper and the Belt Sea and areas dominated by the vase tunicate (Ciona intestinalis) have only been reported from the Belt Sea.  Sessile/semi-sessile epibenthic bivalves/epibenthic chordates cover at least 10% of the seabed and more than other perennial attached erect groups.
Oxygen depletion and increased siltation caused by eutrophication are believed to be main pressures on this habitat while bottom trawling threatens the physical integrity of the habitat. The predicted ocean acidification caused by the increasing atmospheric CO2 is a potential future threat as the natural degradation process of the calcium-carbonate shell gravel may accelerate. Additional threats are the effects of hazardous substances on the associated communities, and physical disturbance of the seabed associated with offshore installations and sand or gravel extraction. Improved mapping of the distribution of this habitat is needed to improve understanding of its environmental requirements. The area where the biotopes associated with shell gravel occur should be protected by prohibiting bottom trawling and other seabed disturbing activities. The oxygen conditions of the habitat need to be improved by reducing activities which lead to eutrophication.

References:
HELCOM. 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Baltic Sea Environmental Proceedings No. 138.
Dybern, B. 1967. The distribution and salinity tolerance of Ciona intestinalis (L.) F. typica with special reference to the waters around Southern Scandinavia. Ophelia 4(2): 207–226. DOI: 10.1080/00785326.1967.10409621
HELCOM. 1998. Red List of Marine and Coastal Biotopes and Biotope Complexes of the Baltic Sea, Belt Sea and Kattegat - Including a comprehensive description and classification system for all Baltic Marine and Coastal Biotopes. Baltic Sea Environment Proceedings No. 75. Helsinki Commission, Helsinki. 115 pp.
Moen, E., Svensen, E. 2009. Djurliv i havet, Nordeuropeisk marin fauna. Nordstedst. 768 pp.
Petersen, J., Svane, I. 2002. Larval dispersal in the ascidian Ciona intestinalis (L.). Evidence for a closed population. Journal of Experimental Marine Biology and Ecology 186: 89–102.
Petersen, J., Riisgård, H.U. 1992. Filtration capacity of the ascidian Ciona intestinalis and its grazing impact in a shallow fjord. Marine Ecology Progress Series 88: 9–17.

Criterion A Text:
There is considered to have been a decline in extent of more than 25% one of the six associated biotopes. Two others were also considered to have declined, but by less than 25% and three were not evaluated in the HELCOM (2013) red list assessment. This habitat has therefore been assessed as Near Threatened under criterion for both the EU 28 and EU 28+.

Criterion B Text:
Present in all the Baltic sea basins therefore EOO exceeds 50,000km2 however with no quantitative data on habitat extent or area, accurate calculation of EOO or AOO is not possible at the present time. This habitat has therefore been assessed as Data Deficient under criterion B.

Synthesis:
The overall extent of this habitat is unknown although some biotopes are considered to have been stable over the last 50 years (aphotic shell gravel dominated by Mytilidae) and others (aphotic shell gravel dominated by vase tunicate) to have reduced in quantity by more than 25%. There is insufficient information on the quality of this habitat at the present time or over the last 50 years to reach a view on potential trends in quality.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed biotopes AB.E1E1 and AB.I1E1 as Least Concern (A1). Biotope AB.E1F1 was assessed as Vulnerable (B1aii) . Three biotopes (AB.E1V, AB.E2T and AB.I1V) were not evaluated. There is no quantitative data on the decline of the associated biotopes but given the past and predicted future pressures, most specifically where the substrate is comprised of shell gravel, expert opinion is that this habitat should be assessed as Near Threatened (A1) for both the EU 28 and EU 28+.

Sub-habitats in Need of Examination:
AB.E1F1 Baltic aphotic shell gravel dominated by vase tunciate (Ciona intestinalis)


Habitat Type Name:
32 Infaunal communities in Baltic infralittoral sand not dominated by bivalves

Habitat Description:
This is a Baltic Sea benthic habitat in the photic zone where at least 90% of the substrate is sand according to the HELCOM HUB classification. There is a lack of macrovegetation or epibenthic macrofauna but crustaceans, polychaetes and insect larvae may dominate the infauna. The habitat is present in areas of high energy associated with wave action or currents.
Where polychaetes dominate the infauna two associated biotopes with different dominant species of polychaetes (at least 50% of the biomass of the infaunal polychaetes) can be identified. ‘Baltic photic sand dominated by lugworms (Arenicola marina)’ (AA.J3M2) usually at a depth of 1 – 5 meters, in high exposure and in salinities over 10 psu. It is distributed in only in the western Baltic Sea, in the Sound and the Belt Sea. ‘Baltic photic sand dominated by multiple infaunal polychaete species: Pygiospio elegans, Marenzelleria spp. and Hediste diversicolor’ (AA.J3M4) distributed in the whole Baltic Sea. Where crustaceans dominate the infauna one associated biotope has been identified: ‘Baltic photic sand dominated by sand digger shrimp (Bathyporeia pilosa)’ (AA.J3N3). Depth of this biotope is typically from 1 to 10 meters, and it is encountered in areas of moderate to high wave exposure with salinity over 4 psu. Another biotope ‘Baltic photic sand dominated by midge larvae (Chironomidae)’ (AA.J3P1) is identified by a large representation of Midge larvae (Chironomidae).
Indicators of quality: 
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time.
There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. Diversity, abundance and biomass of fauna are potential indicators of quality.
Characteristic species: 
Arenicola marina with Mya arenaria and Cerastoderma sp.; where mixed polychaetes dominate, Pygospio elegans, Marenzelleria spp., Hediste diversicolor, Ophelia spp. and Travisia forbesii; where crustaceans dominate Monoporeia affinis; and where insect larvae dominate Chironomid larvae.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.21 Sublittoral sand in low or reduced salinity.
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1110 Sandbanks slightly covered all the time
1130 Estuaries
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral sand
 
EUSeaMap:
Shallow sands
 
IUCN:
9.4 Subtidal Sandy
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.J3M Baltic photic sand characterised by infaunal polychaetes This habitat has two biotopes on HUB level 6; ‘Baltic photic sand dominated by lugworms (Arenicola marina)’ (AA.J3M2) and ‘Baltic photic sand dominated by multiple infaunal polychaete species: Pygiospio elegans, Marenzelleria spp. and Hediste diversicolor’ (AA.J3M4)
AA.J3N Baltic photic sand characterised by infaunal crustacea. This habitat has one biotope on HUB level 6; ‘Baltic photic sand dominated by sand digger shrimp (Bathyporeia pilosa)’ (AA.J3N3).
AA.J3P Baltic photic sand characterised by infaunal insect larvae This habitat has one biotope on HUB level 6; ‘Baltic photic sand dominated by midge larvae (Chironomidae)’ (AA.J3P1).

Justification Outstanding Example of Biogeographical Region:
Not overall but the biotope dominated by midge larvae (Chironomidae) is typical of the Bothnain Bay and important in large lagoons in the southern parts of the Baltic.

Trends in Quantity:
There have been different trends in the different associated biotopes. AA.J3N3 (dominated by the sand digger shrimp (Bathyporeia pilosa) is estimated to have declined by around 10% in the past 50 years, areas dominated by midge larvae (AA.J3N3) are considered to have been stable, and areas where the infauna are dominated by polychaetes (AA.J3 M2 and AA.J3M4) are considered to be increasing. Expert opinion is that the overall condition of the habitat is most likely to be stable. There are no detailed historic data and no estimates available on future trends in quantity.

Trends in Quality:
Overall habitat quality is considered to be generally good although there have been declines in quality in areas where the infauna is dominated by the sand digger shrimp (an estimated reduction of 10% over the past 50 years). Overall quality is considered to have been stable over the past 50 years.

Pressures and Threats:
No pressures and threats specific to this habitat type have been identified at the present time.

Conservation and Management:
No conservation and management measures have been identified specifically for this habitat type at the present time.

Summary:
This habitat occurs in shallow areas in all the Baltic sub-basins although some of the associated biotopes have a more limited distribution.  It is a benthic habitat in the photic zone where at least 90% of the substrate is sand. There is a lack of macrovegetation or epibenthic macrofauna but crustaceans, polychaetes and insect larvae may dominate the infauna. The habitat is present in areas of high energy associated with wave action or currents. No pressures and threats specific to this habitat, nor any specific conservation or management measures have been identified at the present time.

References:
Gic-Grusza, C., Kryla-Straszewska, K., UrbaÅ„ski, J., Warzocha, J., & WÄ™stawski, J.M., 2009. Atlas of Polish marine area bottom habitats. Environmental valorization of marine habitats. Gic-Grusza, C., Kryla-Straszewska, K., UrbaÅ„ski, J., Warzocha, J., & WÄ™stawski, J.M. (Eds), Gdynia, Poland.
HELCOM, 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Avellan, L. (Ed). Helsinki, Finland.

Criterion A Text:
One of the associated biotopes (where the infauna is dominated by the sand digger shrimp, Bathyporeia pilosa) is estimated to have declined by 10% in the last 50 years. The other associated biotopes have either been stable or increased. Expert opinion is that overall this habitat has been stable over the last 50 years. This habitat is therefore assessed as Least Concern under criterion A for both the EU 28 and EU 28+.

Criterion B Text:
This habitat is present in all Baltic Sea basins therefore EOO exceeds 50,000km2 however with no quantitative data on habitat extent or area, accurate calculation of EOO or AOO is not possible at the present time. This habitat has therefore been assessed as Data Deficient under criterion B.

Synthesis:
There is a lack of quantitative data on current status and changes in extent and quality for the entire Baltic over the last 50 years although there are modelled data predicting distribution in some regions (e.g. Poland). One of the biotopes (where the infauna is dominated by the sand digger shrimp, Bathyporeia pilosa) is estimated to have declined by 10% over that time. The other biotopes have either been stable or increased.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed the four associated biotopes as Least Concern (A1). With no additional data on changes in extent or quality of this habitat the current expert opinion is an assessment of Least Concern for both the EU 28 and EU 28+.

Sub-habitats in Need of Examination:
AA.J3N3 Baltic photic sand dominated by sand digger shrimp (Bathyporeia pilosa).


Habitat Type Name:
33 Sparse or no macrofauna communities on Baltic infralittoral sand

Habitat Description:
This Baltic Sea benthic habitat occurs in the photic zone with at least 90% coverage of sand according to the HELCOM HUB classification. The substrate may be mobile and any macro or microvegetation, if present, is sparse. Macrofauna, eipfauna and infauna in this habitat are also sparse and it supports a low species diversity.  
Indicators of quality:
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change overtime. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis.
Characteristic species;
Low species diversity but may include burrowing infauna such as  Marenzelleria viridis, Pygospio elegans, Macoma baltica or actively swimming nectobenthic forms such as Bathyporeia pilosa and Crangon crangon.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.21 Sublittoral sand in low or reduced salinity.
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1110 Sandbanks slightly covered all the time
1130 Estuaries
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES: 
Marine - Marine inlets and transitional waters
Marine – Coastal
 
MSFD:
Shallow sublittoral sand
 
EUSeaMap:
Shallow sands
 
IUCN:
9.4 Subtidal Sandy
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.J4U: Baltic photic sand characterized by no macrocommunity.

Justification Outstanding Example of Biogeographical Region:
Photic sand with sparse or no macrofauna exist in other places around the world.

Trends in Quantity:
This habitat is fairly common in the Baltic Sea with a clear emphasis on the northern parts of the Bothnian Bay where low salinity limits the amount of colonizing macrospecies. The quantity is believed to have been stable over the last 50 years although slight regional changes have occurred. There are no quantitative data on historic changes and no estimates of future change in quantity.

Trends in Quality:
The current condition of this habitat is generally good.
In the Bothnian Bay natural continual change into other biotopes (defined by vegetation cover) occur due to the combination of land uplift and siltation/sedimentation. Land uplift and turbidity change/fluctuation also affects the distribution between this habitat and the corresponding circalittoral habitat.

Pressures and Threats:
Eutrophication (increased N, P and organic matter) leading to increased water turbidity will affect the boundary between this habitat and its circalittoral counterpart by changing the bottom conditions from photic to aphotic. Correspondingly the photic habitat will increase if turbidity improves. In the northern parts of the Baltic this effect could be quite dramatic due to the general shallowness of the seafloor.

Summary:
This habitat occurs in all sub-basins in the Baltic. There is some information on extent in particular locations (e.g. a minimum of 3,296km2 in six survey areas off the coast of Estonia), but no overall quantitative information on changes in quality or quantity. The main factor affecting the quantity is the photic/aphotic boundary which is affected by water quality (turbidity), which in turn is affected by eutrophication (increases in N, P and organic matter). No conservation measures have been identified specifically for this habitat.

References:
HELCOM 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Baltic Sea Environmental Proceedings No. 138.
Martin, G., Kotta, J., Möller, T. and Herkül, K. 2013. Spatial distribution of marine benthic habitats in the Estonian coastal sea, northeastern Baltic Sea. Estonian Journal of Ecology 62(3): 165-191.
Olenin, S. and Daunys, D. 2004. Coastal typology based on benthic biotope and community data: The Lithuanian case study. Coastline Reports 4. 65-83.

Criterion A Text:
The quantity of this habitat is believed to have been stable over the last 50 years. This habitat has therefore been assessed as Least Concern under criterion A for both the EU 28 and EU 28+.

Criterion B Text:
A lack of a comprehensive of quantitative data on the area covered by this habitat in the Baltic means that precise figures for EOO and AOO could not be calculated however as it is present in all Baltic Sea sub basins the EOO is likely to exceed 50,000km2. This habitat has therefore been assessed as Data Deficient under criterion B for both the EU 28 and EU 28+.

Synthesis:
The presence of this habitat type in the Baltic Sea is well known and it occurs in all the sub-basins. The quantity and quality of this habitat is considered to have been stable over the last 50 years and no change is expected in the near future. The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed this habitat as Least Concern (A1). No additional information is available, therefore the current expert opinion is an assessment of Least Concern for both the EU 28 and EU 28+.


Habitat Type Name:
35 Annual algal communities on Baltic infralittoral muddy sediment

Habitat Description:
This Baltic Sea benthic habitat is occurs in the photic zone with at least 90% coverage of muddy sediment according to the HELCOM HUB classification. Annual algae cover at least 10% of the seabed, while all other epibenthic biotic structures like rooted plants, unattached perennial algae or blue mussels cover less than 10%. The habitat covers the full salinity range of the Baltic Sea and is common in sheltered, very shallow areas.  One associated biotope has been identified: ‘Baltic photic muddy sediment dominated by Vaucheria spp.’ (AA.H1S3). This is encountered most of the Baltic Sea with the exception of the more saline western parts (the Belt Sea and The Sound) and is identified by a large representation of Vaucheria spp., which constitutes at least 50% of the biovolume of the annual algae. It forms dense mats in bays with soft sediment, requires a salinity below 7 psu and is found at up to 7 meters depth.
Indicators of quality: 
The ratio of annual to perennial epibenthic components is used in several countries to describe habitat quality. As such the area of the habitat itself or the biomass of the corresponding species is used as an indicator for quality.In this particular case the lowest area or biomass is a sign of high quality as only in very high exposure levels should annual algae dominate. In all other circumstances perennials (Fucus) should dominate except where there is a low salinity (below 3 psu) as perennial algae growth does not generally occur under such conditions.
Characteristic species: 
Vaucheria spp.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.31 Sublittoral mud in low or reduced salinity or A5.52 Kelp and seaweed communities on sublittoral sediment.
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1130 Estuaries
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral mud
 
EUSeaMap:
Shallow muds
 
IUCN:
9.6 Subtidal muddy
9.10 Estuaries
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.H1S Baltic photic muddy sediment characterized by annual algae This habitat has one associated biotope on HUB level 6; ‘Baltic photic muddy sediment dominated by Vaucheria spp. (AA.H1S3).

Justification Outstanding Example of Biogeographical Region:
Biotopes dominated by annual algae are found in all regional seas, although the characteristic species may vary between regions. In the Baltic Sea annual algae represent a more or less reduced marine flora.

Trends in Quantity:
This habitat is present in in nearly all sub-basins of the Baltic Sea: the Baltic Proper, Gulf of Bothnia, Gulf of Finland, Gulf of Riga and in coastal lagoons or estuaries of the Belt Sea with the respective low salinity values. No recent or historic decrease in quantity is believed to have occurred. Expected increase of around 15% over the next 50 years in the Quark and Bothnian Bay has been predicted. No information on other areas.

Trends in Quality:
Some decline in quality has been estimated such as 20% of the area in the Quark and Bothnian Bay over the past 50 years. There are no data related to trends in quality in other areas.

% of Distribution of the Habitat Type within the EU 28:
Unknown (no data available on whether it occurs in Russia).

Justification of Small Range/Regression:
This habitat is present in in nearly all sub-basins of the Baltic Sea so does not have a small natural range.

Justification of Restricted Area:
This habitat is present in in nearly all sub-basins of the Baltic Sea so does not have a small natural range.

Pressures and Threats:
No pressures and threats specific to this habitat type have been idenfied.

Conservation Status:
Annex 1:
1130: MBAL U2
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1130 CR C1 
1160 VU C1
1650 VU C1 
HELCOM (2013) have assessed this habitat as LC(A1).</

Capacity to Recover its Typical Character and Functionality?:
As the dominant species of this biotope are annual species, often known as opportunists with short life cycles, recovery can be very fast (1-2 years) even after strong declines.

Summary:
This habitat, occurs in most the Baltic Sea sub-basins. It is characterized by annual algal communities on infralittoral muddy sediment. Threats and pressures are unknown at present and no specific conservation or management measures have been identified.

References:
HELCOM, 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Avellan, L. (Ed). Helsinki, Finland.
HELCOM. 2013. HELCOM Red List Biotope information sheets (BIS)http://www.helcom.fi/Documents/Ministerial2013/Associated%20documents/Background/HELCOM%20Red%20List%20Biotope%20Information%20Sheets%20(BIS).pdf
Kersen, P. 2012. First findings of the benthic macroalgae Vaucheria cf.dichotoma (Xanthophyceae) and Puncaria tenuissima (Phaeophyceae) in Estonian coastal waters. Estonian Journal of Ecology 2: 135-147

Criterion A Text:
This habitat is not considered to have declined in extent over the last 50 years although there is an absence of quantitative data. It has been assessed as Least Concern under Criteria A for both the EU 28 and EU 28+.

Criterion B Text:
This habitat has a large natural range in the Baltic Sea extending from the German estuaries  in the west to the Bothnian Bay in the north-east. EOO >50,000 km2 and AOO >50. There is a lack of data on its precise location. This habitat has therefore been assessed as Data Deficient under criterion B for both the EU 28 and EU 28+.

Criterion C/D Text:
Expert opinion is that there are insufficient data on which to undertake a quantitative assessment of criterion C/D.

Synthesis:
There is a lack of data on the extent, quantity and quality of this habitat but expert opinion is that it is unlikely to have declined in extent over the last 50 years.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. This habitat was evaluated by HELCOM in the 2013 Red List of Habitat Assessment as Least Concern (A1). With no further baseline information or data on changes in extent or quality, the current expert opinion is an assessment of Least Concern for both the EU 28 and EU 28+.


Habitat Type Name:
34 Stable aggregations of unattached perennial vegetation on Baltic infralittoral muddy sediment

Habitat Description:
This benthic Baltic Sea habitat occurs in the photic zone with at least 90% coverage of muddy sediment according to the HELCOM HUB classification. Stable aggregations of unattached perennial vegetation cover at least 10%, while perennial attached erect groups or Mytilus cover less than 10% of the bottom. The habitat is encountered in areas with salinity below 10 or 5 psu (depending on the area) and can be found in most of the Baltic Sea area, where the seabed is level over wide areas within the photic zone. The algae provide shelter and surface for attachment of invertebrates, however, if abundances of the unattached form are very high the sediment below may become deoxygenated and the associated infauna may die. The unattached forms of associated algae can coexist with attached forms and the characteristic rooted vegetation of bays, estuaries and lagoons.
Five associated biotopes have been described some of which have a more restricted distribution. These are variously dominated by unattached Fucus spp.,  Furcellaria lumbricalis, or by the dwarf form of Fucus species which coexists with attached F. vesiculosus, unattached Furcellaria lumbricalis, higher plants like Ruppia spp., Zannichellia palustris, Stuckenia pectinatus (formerly known as Potamogeton pectinatus), Zostera spp. and several charophytes. There are also biotopes dominated by stable aggregations of unattached rigid hornwort (Ceratophyllun demersum) and the unattached lake ball (Aegagropila linnaei).
Indicators of quality:
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. For this habitat the density of unattached Fucus spp. (typical  and dwarf forms), lower limit of Furcellaria belt, amount of epiphytic algae, and density of Furcellaria are potential indicators of quality.
Characteristic species: 
Fucus vesiculosus (typical and dwarf form), Furcellaria lumbricalis, Ceratophyllum demersum, Aegagropila linnaei

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.52 Kelp and seaweed communities on sublittoral sediment and A5.31 Sublittoral mud in low or reduced salinity 
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1130 Estuaries
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral mud
 
EUSeaMap:
Shallow muds
 
IUCN:
9.6 Sublittoral Muddy
9.7 Macroalgal/Kelp
9.10 Estuaries
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.H1Q Baltic photic muddy sediment characterized by stable aggregations of unattached perennial algae.
 
This habitat has five biotopes on HUB level 6;
‘Baltic photic muddy sediment dominated by stable aggregations of unattached Fucus spp. (typical form)’ (AA.H1Q1)
‘Baltic photic muddy sediment dominated by stable aggregations of unattached Fucus spp. (dwarf form)’ (AA.H1Q2).
‘Baltic photic muddy sediment dominated by stable aggregations of unattached Furcellaria lumbricalis’ (AA.H1Q3)
‘Baltic photic muddy sediment dominated by stable aggregations of unattached rigid hornwort (Ceratophyllun demersum)’ (AA.H1Q4)
‘Baltic photic muddy sediment dominated by stable aggregations of unattached lake ball (Aegagropila linnaei)’ (AA.H1Q5).

Trends in Quantity:
This habitat is present in all the Baltic Sea sub-basins although the distribution of the associated biotopes varies. For example AA.H1Q1 ‘Baltic photic muddy sediment dominated by stable aggregations of unattached Fucus spp. (typical form)’ can be found in northern Bothnian Sea. AA.H1Q2 ‘Baltic photic muddy sediment dominated by stable aggregations of unattached Fucus spp. (dwarf form)’ can only be found in the southern Baltic Proper at the German and Swedish coast. AA.H1Q3 ‘Baltic photic muddy sediment dominated by stable aggregations of unattached Furcellaria lumbricalis’ can be found in the Estonian west coast, Belt Sea and the German part of the southern Baltic Proper. AA.H1Q4 Baltic photic muddy sediment dominated by stable aggregations of unattached rigid hornwort (Ceratophyllun demersum) can be found in sheltered bays and inlets all around the Baltic Sea. AA.H1Q5 Baltic photic muddy sediment dominated by stable aggregations of unattached lake ball (Aegogrophila linnaei) can be found in sheltered bays and inlets all around the Baltic Sea.
The biotope dominated by stable aggregations of unattached Fucus spp. (dwarf form)’ is estimated to have reduced in extent by more 50% over the past 50 years. Similar pressures appear to have led to a reduction in extent of the other associated biotopes (e.g. Furcellaria in Puck Bay)  but there is insufficient quantifiable data on which to make an assessment. Historical trends are unknown and it can be expected that potential area of occurrence will be reduced in the future due to eutrophication and climate change.

Trends in Quality:
One of the associated biotopes AA.H1Q2 ‘Baltic photic muddy sediment dominated by stable aggregations of unattached Fucus spp. (dwarf form)’ has shown a severe decline in quality in 20% of the area. There is insufficient information  to determine quality changes in the habitat dominated by other species of unattached perennial vegetation.

Justification of Small Range/Regression:
Overall this habitat does not have a small range, but one of the associated biotopes (where the dwarf form of Fucus spp. is the dominant species) does have a small range following regression.

Justification of Restricted Area:
This habitat is present in all the Baltic Sea sub-basins and therefore does not have an intrinsically restricted area.

Pressures and Threats:
Past and current threats are eutrophication, contaminant pollution and the introduction of toxic substances. Observed declines of the spatial distribution of the unattached Fucus spp. dwarf form biotopes are mainly caused by increased eutrophication and its connected impacts/threats. Decreased light penetration depth, massive growth of filamentous algae and increased sedimentation/siltation cause massive alterations in the habitat conditions of sheltered coastal zones. The enclosed characteristic of bays and lagoons intensify the eutrophication impacts. Coastal construction (ditching, deepening of harbour access channels), leisure facilities and increased tourism has led to a further degradation this habitat. The threat level is particularly high in the Western and Southern Baltic Sea. There has also been some commercial exploitation of the unattached macroalgae in Poland and there is still commercial exploitation of the Furcellaria biotope in Estonia.
Future threats are climate change (increasing exposure levels and temperatures) and increasing aquaculture in bays and sheltered areas where this habitat occurs.

Conservation and Management:
Combatting local sources of eutrophication (mainly agriculture) as well as restrictions on coastal construction and dredging in and around  shallow coastal lagoons and archipelago areas can prevent decline in this habitat type.

Conservation Status:
Annex 1:
1130: MBAL U2
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1130 CR C1
1160 VU C1 
1650 VU C1 
HELCOM (2013) have assessed the associated biotopes A

Summary:
This habitat occurs in all the sub-basins of the Baltic Sea but is more typically found in sheltered areas. The algae provide shelter and surface for attachment of invertebrates, however, if abundances of the unattached form are very high the sediment below may become deoxygenated and the associated infauna may die. The unattached forms of associated algae can coexist with attached forms and the characteristic rooted vegetation of bays, estuaries and lagoons. 
Decreased light penetration depth, massive growth of filamentous algae and increased sedimentation/siltation believed to be associated with eutrophication has  led to massive alterations in the habitat conditions of sheltered coastal zones where this habitat occurs The enclosed characteristic of bays and lagoons intensify the eutrophication impacts. Coastal construction (ditching, deepening of harbour access channels, leisure facilities and increased tourism has led to a further degradation of the habitat. The threat level is particularly high in the Western and Southern Baltic Sea. In the future climate change (increasing exposure levels, temperatures) or increasing aquaculture in bays may cause additional threats. Combating local sources of eutrophication (mainly agriculture) as well as conservation measures, such as restrictions on coastal constructions and dredging, in shallow coastal lagoons and archipelago areas can prevent further decline of this habitat.

References:
Bauch, R. 1954. Biologisch-ökologische Studien an der Gattung Fucus. I. Populationsdynamik der Fucusformen von hiddensee. Flora 142, 1-24: 1-24.
HELCOM Website 1 http://helcom.fi/baltic-sea-trends/biodiversity/helcom-hub/hub/aa-h1q
HELCOM website 2 http://helcom.fi/Red%20List%20of%20biotopes%20habitats%20and%20biotope%20complexe/HELCOM%20Red%20List%20AA.H1Q2,%20AA.H1Q2.%20AA.H1Q2,%20AA.J1Q2.pdf
HELCOM 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Baltic Sea Environmental Proceedings No. 138.
Overbeck, J. 1965. Die Meeresalgen und ihre Gesellschaften an den Küsten der Insel Hiddensee (Ostsee). bot mar. Vol VIII, Fasc. 2-4: 218-233.                         
von Oertzen, J.-A. 1968. Untersuchungen über die Besiedlung der Fucusvegetation der Gewässer um Hiddensee. Z. Fischerei NF Bd. 16, 34: 253-277.

Criterion A Text:
Some localised loss has been reported (e.g. Puck Bay, Poland) particularly for the dwarf form of unattached Fucus spp. Although information about the unattached Fucus dwarf form biotopes is rare, comparisons of historical records with the present distribution in German coastal lagoons give hints to a decline of >25% during the last 50 years. On the Swedish coast the decline is considerably larger, but there has been some recovery. The dwarf Fucus biotope is believed to make up less than 5% of this habitat type, therefore current expert opinion is that overall reduction in quantity is less than 25%. This habitat has therefore been assessed as Least Concern under Criteria A for both the EU 28 and EU 28+.

Criterion B Text:
Comprehensive quantitative data on the extent and area covered by this habitat is not available but there are some relevant data such as an estimated 189km2 of the Fucus biotopes off the coast of Finland. Some localised loss has been reported (e.g. Puck Bay, Poland) particularly for the dwarf form of unattached Fucus spp. but the habitat as a whole is widely distributed, therefore EOO exceeds 50,000km2. Future trends have not been predicted. This habitat has therefore been assessed as Data Deficient under criterion B for both the EU 28 and EU 28+.

Criterion C/D Text:
The biotope AA.H1Q2 ‘Baltic photic muddy sediment dominated by stable aggregations of unattached Fucus spp. (dwarf form)’ has shown a severe decline in quality in 20% of the area but this is considered to comprise less than 5% of the habitat overall. There is a lack of information on quality changes in the habitat dominated by other species of unattached perennial vegetation therefore experts considered there to be insufficient data on which to assess criteria C/D.

Synthesis:
There have been significant declines in the biotope dominated by the typical form of Fucus which is characteristic of most of this habitat e.g. an estimated 20% decline over the past 50 years in some areas. The unattached Fucus dwarf form biotope is rare, and comparisons of historical records with the present distribution in German coastal lagoons give hints to a decline of >25% during the last 50 years. On the Swedish coast the decline is considerably larger. 
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion.  HELCOM (2013) assessed the the unattached dwarf form of Fucus (AA.H1Q2) as Endangered (A1). The other biotopes (AA.H1Q1, AA.JHQ3, AA.H1Q4 and AA.H1Q5) were assessed as Least Concern  (A1). The dwarf form is believed to constitute perhaps 1% of this habitat, consequently the overall assessment for this habitat type is Least Concern for both the EU 28 and EU 28+ because although there have been declines, taken together these are not believed to have exceeded 25% over the last 50 years.

Sub-habitats in Need of Examination:
AA.H1Q2 Baltic photic muddy dominated by stable aggregations of unattached Fucus spp. (dwarf form).


Habitat Type Name:
36 Submerged rooted plant communities on Baltic infralittoral muddy sediment

Habitat Description:
This Baltic Sea benthic habitat occurs in the photic zone with at least 90% coverage of muddy sediment according to the HELCOM  HUB classification.  The habitat covers the full salinity range of the Baltic Sea and is distributed from lagoons in the Belt Sea up to the northern part of Bothnian Bay. Muddy bottoms covered by rooted plants are mainly distributed in sheltered to very sheltered exposure conditions. In this habitat submerged rooted plants, including plants with rhizoids (i.e. Charales) cover at least 10% of the seabed and more than any other perennial attached erect groups. The charactersitic species depends on the salinity and depth.
Eight associated biotopes have been described. AA.H1B5 ’Baltic photic muddy sediment dominated by spiny naiad (Najas marina)’ has a restricted distribution at 0-1 m depth in extremely sheltered areas at low salinity (<4 psu).  AA.H1B8 ’Baltic photic muddy sediment dominated by spikerush (Eleocharis spp.)’ is also found in shallow (0-2 m depth) and sheltered areas with low salinity (<5 psu). AA.H1B1 ’Baltic photic muddy sediment dominated by pondweed (Potamogeton perfoliatus and/or Stuckenia pectinata)’ is found between 0.2-4 m depth in sheltered sites with up to 6 psu. AA.H1B3 ‘Baltic photic muddy sediment dominated by watermilfoil (Myriophyllumspicatum and/or Myriophyllumsibiricum)’ has a similar distribution but a more narrow depth range (0.2-2 m). AA.H1B6 ’Baltic photic muddy sediment dominated by Ranunculus spp.’ is also found up to 6 psu but is restricted to extremely sheltered sites. AA.H1B4 ’Baltic photic muddy sediment dominated by Charales’ is found in a wider range of salinity (2-15psu), depth (0.2-7 m) and wave exposure (low to moderate).AA.H1B2 ’Baltic photic muddy sediment dominated by Zannichellia spp. and/or Ruppia spp. and/or Zostera noltei’ is found at 0-4 m depth throughout the salinity gradient of the Baltic Sea and in low to moderate exposure. AA.H1B7 ’Baltic photic muddy sediment dominated by common eelgrass (Zostera marina)’ differs most strongly from the other associated biotopes in distribution, occurring mainly at moderate to high exposure, in salinities of 5 psu or higher and sedldom on muddy sediments. It is typically found deeper than the other associated biotopes (1-6 m) and often marks the lower depth limit distribution of soft bottom vegetation. This biotope is absent from areas with low salinity in the inner part of the Gulf of Bothnia.
Indicators of quality: 
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change overtime. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. The vertical depth limit of submerged rooted plants is used in several countries as a Water Framework Directive parameter for assessing ecological status. 
Characteristic species: 
Stuckenia pectinata, Potamogeton perfoliatus, Zostera marina, Ruppia maritima, Zanichellia palustris, Myriophyllum spicatum, Najas marina, Chara tomentosa, Chara aspera, Ranunculus peltatus subsp. baudotii, Eleocharis sp.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.31 Sublittoral mud in low or reduced salinity and A5.54 Angiosperm communities in reduced salinity
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1130 Estuaries
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral mud
 
EUSeaMap:
Shallow muds
 
IUCN:
9.6 Subtidal Muddy
9.9 Seagrass
9.10 Estuaries
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.H1B Baltic photic muddy sediment characterized by submerged rooted plants This habitat has eight associated biotopes on HUB level 6; AA.H1B1 ’Baltic photic muddy sediment dominated by pondweed (Potamogeton perfoliatus and/or Stuckenia pectinata)’ AA.H1B2 ’Baltic photic muddy sediment dominated by Zannichellia spp. and/or Ruppia spp. and/or Zostera noltii’ AA.H1B3 ‘Baltic photic muddy sediment dominated by watermilfoil (Myriophyllum spicatum and/or Myriophyllum sibiricum)’ AA.H1B4 ’Baltic photic muddy sediment dominated by Charales’ AA.H1B5 ’Baltic photic muddy sediment dominated by spiny naiad (Najas marina)’ AA.H1B6 ’Baltic photic muddy sediment dominated by Ranunculus spp.’ AA.H1B7 ’Baltic photic muddy sediment dominated by common eelgrass (Zostera marina)’ AA.H1B8 ’Baltic photic muddy sediment dominated by spikerush (Eleocharis spp.)’.

Justification Outstanding Example of Biogeographical Region:
This habitat is common on photic muddy sediment in the entire Baltic Sea. Most of the associated biotopes have a very typical and characteristic species composition for the Baltic Sea dominated by species with freshwater origin.

Comment EU28:
This habitat is present in all the Baltic sub-basins

Trends in Quantity:
This habitat is very common in bays, inlets and coastal lagoons of all sub-regions of the Baltic Sea. Most of the associated biotopes are present across the Baltic Sea coastline but AA.H1B7 ’Baltic photic muddy sediment dominated by common eelgrass (Zostera marina)’ is absent from areas with low salinity in the inner part of the Gulf of Finland and Gulf of Bothnia. There have been significant declines in the quantity of some of the associated biotopes. AA.H1B4 ’Baltic photic muddy sediment dominated by Charales’ has declined by >25% during the last 50 years. The greatest declines have been observed in the Western and Southern Baltic Sea. In some bays and lagoons conditions have changed so intensively that it has disappeared completely. The biotope dominated by spiny naiad (Najas marina)’ has also exhibited a strong decline in the highly eutrophicated areas of the Southern Baltic Sea and disappeared from some locations. A comparison of the current with the historical distribution status of Najas marina within the German Bodden areas of Mecklenburg Western Pomerania (Southern Baltic Sea) for example shows nearly total loss There are no data to support similar declines in other Baltic Sea areas but the subhabitat is largely restricted to lagoons which is an endangered biotope complex. Areas dominated by common eelgrass (Zostera marina)’ have declined >25% during the last 50 years although to varying extents in the different Baltic Sea regions, with the largest decline recorded in the Southern Baltic Sea. The remaining associated biotopes are believed to have declined by less than 25% over the last 50 years. There is a lack of comprehensive quantitative data on the historic extent of this habitat and no future trends have been estimated.

Trends in Quality:
The quality of the habitat is believed to have declined during the past 50 years, at least in some areas, but there are no comprehensive data to quantify the decline.

Justification of Small Range/Regression:
This habitat is present in all the Baltic Sea sub-basins therefore does not have a small natural range

Pressures and Threats:
Eutrophication, epidemics (wasting disease), bottom trawling, water traffic, construction, dredging, dumping, aquaculture and coastal works have all been identified as past and current threats. These are also likely to be threats in the future along with climate change. One predicted effect is a lowering of salinity in the northern parts of the Baltic Sea due to an increase of precipitation, which may threaten Zostera marina in the northernmost areas where it currently exists on the limits of its salinity tolerance.
Observed declines of the spatial distribution of the associated biotopes where Charales’ and the spiny naiad dominate are mainly caused by increased eutrophication and connected effects. Decreasing light penetration depth, massive growth of ephemeral algae and increased siltation rates cause massive alterations in the biotopes of sheltered coastal areas. The enclosed characteristic of bays and lagoons intensify the eutrophication impacts. Coastal constructions (e.g. dredging for deepening of harbour access channels, ditching and construction of leisure facilities) and increased tourism have led to a further degradation. The threat level is particularly high in the Western and Southern Baltic Sea. In the future climate change (increasing exposure levels, temperatures) or increasing aquaculture in bays may cause additional threats.
The main causes of the observed declines of the spatial distribution of the biotope dominated by common eelgrass (Zostera marina)’ are (1) the “wasting disease” that caused about 90% of the North European stock to disappear in the 1930 and also affected the Zostera beds in Danish and German waters and (2) eutrophication of the Baltic Sea that has resulted in significant decline of eelgrass meadows in mainly Danish, German, Swedish and Polish coastal areas. Eutrophication has decreased the depth where Zostera can receive enough light and may in addition cause a shift from eelgrass meadows to communities dominated by fast-growing macro-algae. Climate change is predicted to lower the salinity level in the northern parts of the Baltic Sea due to an increase of precipitation, which may threaten Zostera marina in the northernmost areas where it currently exists on the limits of its salinity tolerance.

Conservation and Management:
All actions to reduce eutrophication of the Baltic Sea are important for the conservation of this habitat. For the associated biotopes that mainly occur in bays with limited water exchange with the open ocean (those dominated by Charales’ and the spiny naiad) combating local sources of eutrophication is essential. Conservation measures are also important, such as area protection and restrictions on coastal construction and dredging in shallow regions and archipelago areas.

Conservation Status:
Annex 1:
1130: MBAL U2
1160: MATL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1130 CR C1 
1160 VU C1
1650 VU C1 
HELCOM (2013) have assessed associated biotopes

Capacity to Recover its Typical Character and Functionality?:
The biotope dominated by common eelgrass (Zostera marina)’ can be slow to recover after strong decline (taking more than 20 yrs). Intervention may speed up the recovery but transplantation experiments have had limited success to date. Regeneration from root systems is slow and recovery of entire beds, with characteristic structure and associated species will take a long time. In the northern Baltic low salinity means that any expansion takes place vegetatively. Zostera plants are believed to be from the same genotype, estimated to be between 800-1600 years old. Clonal growth and low genetic diversity may reduce the acclimation capacity and survival of the species in rapidly changing environmental conditions. For the other associated biotopes natural recovery can probably occur within 10 years.

Summary:
This habitat occurs in all Baltic sub-basins in the shallow waters of the photic zone. The submerged rooted plant communities provide structure for the benthic environment and associated communities on the underlying sediment. Distribution of the associated biotopes depends on the dominant species and is influenced mainly by salinity and exposure. Zostera noltei, for example, is not found east of the Darss Sill in the Arkona basin, while Potamogeton perfoliatus occurs mostly in the northern part of the Bothnian Bay, and Chara horrida in the central Baltic and Archipelago Sea. 
Eutrophication (increasing N, P and organic matter) has both direct and indirect negative impacts on this habitat, for example by reducing light penetration through the water column and therefore the depth penetration of submerged species. Increased sedimentation can prevent settlement and excess of nutrients often favours opportunistic species with short life cycles and rapid development over perennial species with lower productivity, causing a shift in the community composition. Climate change may also result in a shift in the dominant species due to predicted associated changes in salinity. All actions to reduce eutrophication of the Baltic Sea are important for the conservation of this habitat. Conservation measures are also important, such as area protection and restrictions on coastal construction and dredging where these are likely to have an impact on the habitat.

References:
Baden, S.P., Boström, C. 2001. The leaf canopy of seagrass beds: faunal community structure and function in a salinity gradient along the Swedish coast. In: Reise, K. (ed.), Ecological comparisons of sedimentary shores, Ecological Studies 151, Springer-Verlag, Berlin, pp. 213-236.
Baden, S.P., Loo, L.-O., Pihl, L., Rosenberg, L. 1990. Effects of eutrophication on benthic communities including fish: Swedish west coast. Ambio 19: 113-122.
Berg Ch., Dengler J., Abdank A., Isermann M. 2004. Die Pflanzengesellschaften Mecklenburg-Vorpommerns und ihre Gefährdung – Textband. Weissdorn-Verlag, Jena: 94–98.
Berglund, J., Mattila, J., Rönnberg, O., Heikkilä, J., Bonsdorff, E. 2003. Seasonal and inter-annual variation in occurrence and biomass of rooted macrophytes and drift algae in shallow bays. Estuarine, Coastal and Shelf Science 56(5–6): 1667–1175.
Blindow, I. 2000. Distribution of charophytes along the swedish coast in relation to salinity and eutrophication. Internat. Rev. Hydrobiol. 85 (5–6): 707–717.
Borum, J., Duarte, C.M., Krause-Jensen, D., Greve T.M. (eds). 2004. European seagrasses: an introduction to monitoring and management. The M&MS project. 95 pp. Available at:  http://www.seagrasses.org/handbook/european_seagrasses_low.pdf (Accessed: 29/10/2015).
Boström, C. 2001. Ecology of Seagrass Meadows in the Baltic Sea. Environmental and Marine Biology, Department of Biology, Åbo Akademi University, Åbo, Finland. 47 pp.
Boström, C., Bonsdorff, E. 1997. Community structure and spatial variation of benthic invertebrates associated with Zostera marina (L) beds in the northern Baltic Sea. Journal Of Sea Research 37(1-2): 153–166.
Boström, C., Baden, S.P., Krause-Jensen, D. 2003. The seagrasses of Scandinavia and the Baltic Sea. In: Green, E. P. & Short, F.T. (eds). World Atlas of Seagrasses. University of California Press. pp. 27-37.
Boström, C., Bondsorff, E., Kangas, P. Norkko, A. 2002. Long-term changes of a brackish water eelgrass (Zostera marina L.) community indicate effects of coastal eutrophication. Est. Coast. Shelf Sci. 55: 795-804.
Eriksson, B.K., Sandström, A., Isaeus, M. et al, 2004. Effects of boating activities on aquatic vegetation in the Stockholm archipelago, Baltic Sea. Estuarine, Coastal and Shelf Science 61(2): 339-349.
HELCOM. 1998. Red List of marine and coastal biotopes and biotopes complexes of the Baltic Sea, Belt Sea and Kattegat. Baltic Sea Environmental Proceedings No. 75. Helsinki Commission, Helsinki. 115pp.
HELCOM. 2013. Climate change in the Baltic Sea: HELCOM thematic assessment in 2013. Baltic Sea Environmental Proceedings XXX
HELCOM 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Baltic Sea Environmental Proceedings No. 138.
Holmen, M. 1987. The aquatic Adephaga (Coleptera) of Fennoscandia and Denmark. I. Gyrinidae, Haliplidae, Hygrobiidae and Noteridae. Fauna Ent. Scand. 20:1-168.
Kruk-Dowgiallo, L. 1996. The role of filamentous brown algae in the degradation of the underwater meadows the Gulf of Gdansk. Oceanological Studies XXV (1-2): 125-135.
Lundberg,C. 2005. Eutrophication in the Baltic Sea – from area-specific biological effects to interdisciplinary consequences. Environmental and Marine Biology. Department of Biology. Åbo Akademi University, Åbo Finland 166 pp
McGlathery, K.J. 2001. Macroalgal blooms contribute to the decline of seagrass in nutrient-enriched coastal waters. J. Phycol. 37: 453-456.
Mäkinen, A., Tallberg, P., Anttila, S., et al.,  2008 Itämeren vedenalaiset luontotyypit. In: Raunio, A. Schulman, A. & Kontula, T. (eds). 2008. Suomen luontotyyppien uhanalaisuus − Osa II: Luontotyyppien kuvaukset. Finnish Environment Institute, Helsinki. Suomen ympäristö 8/2008. 572 p.
OSPAR. 2008. OSPAR List of Threatened and/or Declining Species and Habitats.
Pihl, L., Isaksson, I., Wennhage, H. Moksnes, P.-O. 1995. Recent increase of filamentous algae in shallow Swedish bays: effects on the community structure of epibenthic fauna and flora. Neth. J. Aquatic Ecol. 29: 349-358.
Schiewer, U. 2002. Recent changes in northern German lagoons with special reference to eutrophication. In: Schernewski, G. & U. Schiewer (eds.), Baltic coastal ecosystems, structure, function and coastal zone management. Central and Eastern European Development Studies, Springer Verlag, Berlin, pp. 19-30.
Schubert, H. & I. Blindow (eds.) 2003. Charophytes of the Baltic Sea. The Baltic Marine Biologists Publication, No. 19: 326 S.
Schubert, H.; Blümel, C.; Eggert, A.; Rieling, T.; Schubert, M. & U. Selig 2003. Entwicklung von leitbildorientierten Bewertungsgrundlagen für innere Küstengewässer der deutschen Ostseeküste nach der EU-WRRL. Forschungsbericht zum BMBF Projekt ELBO. FKZ 0330014: 1-109.
Selig, U., Eggert, A., Schories, M., Schubert, C., Blümel, C., Schubert., H. 2007. Ecological classification of macroalgae and angiosperm communities of inner coastal waters in the southern Baltic Sea. Ecological Indicators 7(3): 665–678.
Selig, U., Schubert, M., Eggert, A., Steinhardt, T., Sagert, S., Schubert, H. 2007. The influence of sediments on soft bottom vegetation in inner coastal waters of Mecklenburg-Vorpommern (Germany). Estuarine, Coastal and Shelf Science 71(1–2): 241–249.
Tolstoy , A., Österlund, K. 2003. Alger vis Sveriges östersjökust – en fotoflora. ArtDatabanken, SLU. Almqvist & Wiksell Tryckeri, Uppsala. 282 pp.
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Criterion A Text:
Losses of some of the associated biotopes are estimated to be more than 25% and, in some cases, muddy sediments dominated by the spiny naiad, have almost totally disappeared. Expert opinion is that overall the decline in quantity over the last 50 years is likely to have been > 25%. This habitat is therefore assessed as Near Threatened under Criteria A for both the EU 28 and EU 28+.

Criterion B Text:
This habitat has a large natural range in the Baltic Sea extending from the Danish coast in the west to the Bothnian Bay in the north-east. EOO >50,000 km2 and AOO >50 and it is not limited to a few locations. Future trends have not been estimated. This habitat has therefore been assessed as Least Concern under criterion B.

Criterion C/D Text:
There have been declines in the quality of some of the associated biotopes in some areas e.g. charophytes and Zostera marina however experts consider there to be insufficient data on which to make an overall assessment of criteria C/D.

Synthesis:
The presence of this habitat type in the Baltic is well known. The best studied biotopes are those dominated by seagrass, brackish water angiosperms and charophytes. There have been significant declines (>25%) in the extent of the seagrass and Charales dominated communities in the last 50 years. Zostera marina and several species of Charales are also on the HELCOM Red List of threatened species in the Baltic.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed AA.H1B1, AA.H1B2, AA.H1B3 and AA.H1B6 as Least Concern (A1) and AA.H1B4, AA.H1B5 and AA.I1B7 as Near Threatened (A1). The overall assessment for this habitat type based on expert opinion is Near Threatened (A1) for both the EU 28 and EU 28+.

Sub-habitats in Need of Examination:
AA.H1B4 Baltic photic muddy sediment dominated by Charales
AA.H1B5 Baltic photic muddy sediment dominated by spiny naiad (Najas marina)
AA.H1B7 Baltic photic muddy sediment dominated by common eelgrass (Zostera marina<


Habitat Type Name:
37 Emergent vegetation communities on Baltic infralittoral muddy sediment

Habitat Description:
This is a Baltic Sea benthic habitat in the photic zone where at least 90% of the substrate is muddy sediment according to the HELCOM HUB classification. Emergent vegetation covers at least 10% of the seabed and exceeds that of any other perennial attached erect groups. The habitat requires a salinity of less than 6 psu for the associated communities to develop and is encountered in sheltered areas down to a depth of 2 meters.  Two associated biotopes with different dominant plant species have been identified. The common reed (Phragmites australis) forms the characteristic biotope in water depths of up to 2m and in moderately exposed conditions, whereas sedges such as Schoenoplectus spp., and Bolbaschoenus maritimus are generally present in more sheltered and shallower waters in areas of low to moderate salinity.
In the Baltic Sea, sedges form large biotopes in shallow areas typically in estuaries and inlets. It can be found in very sheltered lagoons and in some estuaries around the whole Baltic Sea, but occurs mainly in the north along the Swedish and Finnish coasts of the Bothninan Bay and Gulf of Finland.  The species diversity is usually high because of the large variety and abundance of associated fish and birds. The benthic fauna consists mainly of soft-sediment invertebrates, such as polychaetes, crustaceans, bivalves and insect larvae. These shallow sheltered areas are of high biological productivity in a brackish environment. They form important breeding, resting, and feeding sites for water birds. The muddy substrate biotope dominated by the common reed (Phragmites australis) often occurs in the immediate vicinity of the biotope dominated by sedges and the two biotopes can form a mosaic.  Nutrient levels play a part in affecting the balance between the two biotopes with reed dominated areas favoured by conditions of eutrophication.
Indicators of quality: 
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. The overall quality and continued occurrence of this habitat is, however, largely dependent on the presence of the emergent plant species which create the biogenic structural complexity on which the characteristic associated communities depend. The density and the maintenance of a viable population of these species is a key indicator of habitat quality, together with the visual evidence of presence or absence of physical damage. In the case of this habitat the situation is further complicated because the reed dominated biotope is favoured by the deterioration of the sedge dominated biotope under conditions of eutrophication.
Characteristic species: 
Phragmites australis, Schoenoplectus spp., Bolbaschoenus maritimus.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.54 Angiosperm communities in reduced salinity and A5.31 Sublittoral mud in low or reduced salinity
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1130 Estuaries
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral mud
 
EUSeaMap: 
Shallow muds
 
IUCN: 
9.5 Subtidal sandy-muddy
9.6 Subtidal muddy
 
Other relationships:
AA.H1A– Baltic photic muddy sediment characterized by emergent vegetation This habitat has two associated biotopes on HELCOM HUB level 6: ‘Baltic photic muddy sediment dominated by common reed (Phragmites australis)’ (AA.H1A1), and ‘Baltic photic muddy sediment characterized by sedges (Cyperaceae)’ (AA.H1A2).

Trends in Quantity:
The distribution of photic muddy sediment dominated by sedges (Cyperaceae) has decreased by an estimated 25-30% in the last 50 years. Phragmites dominated areas have increased since the last century. In other cases, such as Estonia, there has been considerable fluctuation with significant expansion between 1950-1970 followed by reduction. There also appears to have been a changing balance between the associated biotopes with sedge dominated communities declining and reed dominated communities increasing, most likely in response to eutrophication.
The distribution of photic muddy sediment dominated by common reed (Phragmites australis) is expected to increase by around 25% in the next 50 years. No trend estimates are available for the sedge dominated biotope but this may decrease if it is outcompeted by the reeds. Overall, the quanitity of this habitat is believed to be increasing.

Trends in Quality:
The biotope with sedges as the dominant plant has shown a severe decline in quality in 20% of the area and moderate decline in quality in 30% in the Gulf of Bothnia in the last 50 years. No data or future estimates are available for other sub-basins or for the biotope dominated by reed. The overall trend in quality of this habitat is considered stable.

% of Distribution of the Habitat Type within the EU 28:
Defined as a Baltic habitat therefore 100% occurs in the Baltic Sea. Unknown what percentage is hosted by EU Member States in the Baltic.

Justification of Small Range/Regression:
This habitat does not have a small natural range in the Baltic Sea as it occurs in all the sub-basins although less abundantly in the more saline Sound.

Justification of Restricted Area:
This habitat does not cover an intrinsically restricted area as it occurs in all the sub-basins of the Baltic Sea although less abundantly in the more saline Sound.

Pressures and Threats:
The expansion of reed belts has been accelerated by anthropogenic eutrophication, postglacial land upheaval and the lack of grazing on coastal meadows and attached shallow water areas, while pollution associated with drainage from farming and forestry, and other sources (like traffic and industry) are threats and deterioration factors. Other pressures arise from shipping, and the construction or enlargement of harbours and marinas in sheltered areas. Changes in the water flow due to hydrotechnical constructions, such as dams, cascades and river bank control, may also have adverse effects downstream. The environmental conditions in river mouths depend highly on inflows from local point sources as well as from the whole catchment area. They are therefore closely related to human activities on land.
The maximum growth depth of Phragmites (limited by oxygen transportation to the roots) is around 2m therefore sea level rise may lead to changes in extent and shifts in distribution. Some of these activities described above may increase the extent of the habitat or change the relatively dominance of reeds or sedges. For example, dredging of the tributary rivers of the Kasari delta, Estonia, in the 1920s–1930s caused a rapid seaward colonisation of the reed bed along the dredged channels by the dispersal and reburial of fragmented rhizomes at the channel banks and on the shallow sea bottom of Matsalu Bay.

Conservation and Management:
One of the main solutions to stop and reverse degradation of the estuaries is a general protection of this natural habitat type by law. Further, programmes and measures are needed to maintain or restore natural conditions along the whole course of the rivers, which e.g. allow natural erosion and temporary flooding of river banks. A drastic reduction of nutrient and pollution loads in the catchment area of rivers with estuaries would help to improve the environmental situation of the whole Baltic marine area and this habitat.
In some areas, there is an active programme of reed removal to encourage re-establishement of the sedge dominated biotopes. Improvements in water quality are also beneficial although it should be noted that whereas increased eutrophication leads to reed replacing sedges, a later decrease in eutrophication does not necessarily facilitate a process where sedges come back.

Conservation Status:
Annex 1:
1130: MBAL U2
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1130 CR C1 
1160 VU C1
1650 VU C1 
HELCOM (2013) have assessed biotope AA.H1A1 as LC(A1)

Summary:
This habitat occurs at the land-water interface in sheltered areas of all the Baltic sub-basins although less common in The Sound. It is dominated by reed or sedges with dominance is determined by factors such as sediment type, exposure and nutrient levels. The habitat can support a high biodiversity, for example by providing nesting areas for birds, and shelter and spawning grounds for fish, but reeds in particular can also out compete and shade other plant species (including sedges) decreasing local biodiversity.
The expansion of reed belts has been accelerated by anthropogenic eutrophication, postglacial land upheaval and the lack of grazing on coastal meadows and attached shallow water areas, while pollution associated with drainage from farming and forestry, and other sources (like traffic and industry) are threats and deterioration factors. Other pressures arise from shipping, and the construction or enlargement of harbours and marinas in sheltered areas. Changes in the water flow due to hydrotechnical constructions, such as dams, cascades and river bank control, may also have adverse effects downstream. The environmental conditions in river mouths depend highly on inflows from local point sources as well as from the whole catchment area. They are therefore closely related to human activities on land.
In some areas, there is an active programme of reed removal to encourage re-establishment of the sedge dominated biotopes. Improvements in water quality are also beneficial although it should be noted that whereas increased eutrophication leads to reed replacing sedges, a later decrease in eutrophication does not necessarily facilitate a process where sedges come back.

References:
Altartouri, A., Nurminen, L. & Jolma, A., 2014. Modeling the role of the close-range effect and environmental variables in the occurrence and spread of Phragmites australis in four sites on the Finnish coast of the Gulf of Finland and Archipelago Sea. Ecology and Evolution 4(7): 987-1005.
Martin, G., Kotta, J., Möller, T. & Herkül, K., 2013. Spatial distribution of marine benthic habitats in the Estonian coastal sea, northeastern Baltic Sea. Estonian Journal of Ecology 62(3): 165-191.
Meriste, M.  & Kirsimäe, K., 2015. Development of the reed bed in Matsalu wetland, Estonia:responses to neotectonic land upllift, sea level changes and human influences. Estonian Journal of Earth Sciences 64(2): 159-172.

Criterion A Text:
There have been different trends in the extent of this habitat depending on which of the associated biotopes is considered. Sedges have declined, quite significantly in some areas, possibly due to the expansion of, and competition with reed. The latter benefits from the nutrient enrichment associated with eutrophication. As a consequence sedges, former considered ecologically typical of sheltered areas in the Baltic are being replaced by another biotope due to a deterioration of the environment (i.e. eutrophication).
Overall this habitat is believed to have been stable or possibly increased in extent over the last 50 years. It has therefore been assessed as Least Concern under Criterion A for both the EU 28 and EU 28+.

Criterion B Text:
This habitat has a large natural range in the Baltic Sea with EOO >50,000 km2. A lack of a comprehensive of quantitative data on the area covered by this habitat in the Baltic means that EOO and AOO could not be calculated. This habitat has been assessed as Data Deficient under criterion B.

Synthesis:
Cycles of change have been evident in this habitat in some areas. In Matsalu Bay, Estonia, for example there was expansive growth of the reed beds in the middle of the last century followed by a decrease in the last 20 years. In the Gulf of Bothnia the habitat has steadily increased, due to the expansion of  reed (while sedges have declined).The expansion has been attributed to a combination of natural processes such as the shoreline advance due to neotectonic land uplift and human activities, both indirect and direct from dredging and eutrophication. In recent decades enlargement has stopped and there are signs of deterioration, attributed to a combination of sea level rise and an increased storminess which is believed to have inhibited reed growth and therefore resulted in decline in some areas exposed to wave action. Changes in the dominant species have also taken place with reeds being able to outcompete the sedges in less muddy areas. 
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed AA.H1A1 as Least Concern (A1) and AA.H1A2 as Near Threatened (A1). The overall assessment for this habitat type, based on expert opinion is Least Concern for both the EU 28 and EU 28+ as the area dominated by Phragmites (AA.H1A1) is large and not threatened in any way.

Sub-habitats in Need of Examination:
AA.H1A2 Baltic photic muddy sediment dominated by sedges (Cyperaceae).


Habitat Type Name:
39 Infaunal communities of Baltic infralittoral muddy sediment - bivalves

Habitat Description:
This is a Baltic Sea benthic habitat in the photic zone where at least 90% of the substrate is muddy sediment according to the HELCOM HUB classification. Sessile/semi-sessile epibenthic macrofauna are absent and infaunal bivalves dominate the biomass at depths of below approximately 20 m. It is a habitat that is present in conditions of low to moderate exposure to wave action and currents.
Three associated biotopes with different dominant species of bivalves (at least 50% of the infaunal bivalves) and slightly different distributions have been identified. ‘Baltic aphotic muddy sediment dominated by Baltic tellin (Macoma balthica)’ (AB.H3L1) is commonly found all parts of the Baltic Sea. ‘Baltic aphotic muddy sediment dominated by ocean quahog (Arctica islandica)’ (AB.H3L3) can only be found in the southwestern parts in the Belt Sea where the salinity is > 15 psu and has an optimum depth range of between 25 and 80 m. ‘Baltic aphotic muddy sediment dominated by Astarte spp.’ (AB.H3L5) is only found in areas where the near bottom water exhibits a salinity range between 10 and 15 psu, a temperature between 3 and 8oC and relatively good oxygen conditions. It is encountered in the southern and western Baltic Sea, in the southern Baltic Proper, in the Belt Sea and the Sound. As an arctic-boreal species, Astarte borealis appears in these Baltic biotopes at its southern limit.
Indicators of quality: 
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed
indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. Diversity, abundance and biomass of fauna are potential indicators of quality.
Characteristic species: 
Macoma balthica, Arctica islandica, Astarte spp.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.31 Sublittoral mud in low or reduced salinity.
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1130 Estuaries
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD: 
Shallow sublittoral mud
 
EUSeaMap: 
Shallow muds
 
IUCN: 
9.6 Subtidal muddy
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AB.H3L Baltic aphotic muddy sediment characterized by infaunal bivalves This habitat has three associated biotopes on HUB level 6; ‘Baltic aphotic muddy sediment dominated by Baltic tellin (Macoma balthica)’ (AB.H3L1) ‘Baltic aphotic muddy sediment dominated by ocean quahog (Arctica islandica)’ (AB.H3L3), and ‘Baltic aphotic muddy sediment dominated by Astarte spp.’ (AB.H3L5).

Justification Outstanding Example of Biogeographical Region:
Common and widespread especially in inner coastal waters (bays, lagoons, estuaries) of the Baltic Sea.

Map Description:
There is insufficient data to provide a comprehensive accurate map of the distribution of this habitat. This map has therefore been generated using the modelled data available on EMODnet for EUNIS level 3 habitats in the Baltic Sea (EMODnet, 2010). This means it indicates potential areas in which this habitat may occur, not the actual distribution of this EUNIS level 4 habitat. EOO and AOO cannot be calculated at the present time, although the habitat is known to occur in all the Baltic Sea sub-basins.

Trends in Quantity:
This habitat is common throughout the Baltic Sea mainly represented by areas dominated by Baltic tellin (Macoma baltica). The biotopes AA.H3L8 ‘Baltic photic muddy sediment dominated by Abra spp.’ and AA.H3L3 ‘Baltic photic muddy sediment dominated by ocean quahog (Arctica islandica)’ are only present in the Belt Sea. AA.H3L6 ‘Baltic photic muddy sediment dominated by Unionidae’ is restricted to oligohaline lagoons, bays and estuaries and the northern most part of the Bothnian Sea. The location of some of the associated biotopes has been mapped by HELCOM but there is a lack of comprehensive quantitative data on which to determine the current extent of this habitat. Infralittoral muddy sediment dominated by ocean quahog (Arctica islandica)’ or by Unionidae’ are believed to have declined by 25-30% over the last 50 years.There is insufficient information on which to determine any historical trends. No future trends have been estimated.

Trends in Quality:
In 2002 and 8-10 week period of low bottom water oxygen concentrations changed benthic faunal diversity and composition in an area of several thousand square kilometers in the southern Baltic including parts of this habitat in The Sound and Arkona Basin.
Areas of muddy sediment dominated by ocean quahog (Arctica islandica) are estimated to have shown a severe decline in quality in around 10% of the area in which it occurs.

Pressures and Threats:
Eutrophication is considered to have been the main pressure on this habitat while pressures associated with climate change are considered to be a likely future threat. In areas dominated by Arctica islandica long lasting and frequent periods of oxygen depletion have caused mortality. Due to the slow population growth rate, the recovery of declined populations is slow, and therefore communities characterised by Arctica islandica have been replaced by communities consisting of short living polychaetes., Another pressure resulting from eutrophication is increasing the particle concentration in impeding the filter-feeding of the Unionidae mussels.The alien species zebra mussel (Dreissena polymorpha) is also thought to pose threat to this habitat. It is a non-native species which was already established in the Baltic Sea in the 19th century as a result of the construction of canals in Europe. It originates from the Ponto-Caspian region and was first reported from the south-eastern Baltic lagoons and estuaries in 1825. The spread of the species is restricted by salinity and temperature as it cannot survive freezing. In the Gulf of Finland the recruitment success of new larvae is only possible during more favourable warmer years with Unionidae shells providing hard substratum for the settlement of zebra mussel juveniles. The overgrowth of Unionidae mussels by D. polymorpha impairs their filter-feeding, burrowing and movement along the sediment surface. Evidence of local Unionidae extinction due to a D. polymorhpa invasion has been found in other parts of the world (e.g. Belarus lakes, North American Great Lakes and the Mississippi River).

Conservation and Management:
All actions that reduce the level of eutrophication in the Baltic Sea will benefit this habitat.These actions include measures to reduce the diffuse run off of nutrients from agriculture and tackling point source pollution by installation of waste water treatment plants. Some consecutive years when the oxygen level remains at a good level is needed for the recruitment to be successful.

Conservation Status:
Annex 1-type:
1110: MBAL U1
1130: MBAL U2
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1110 VU C1 
1130 CR C1 
1160 VU C1 
1650 VU C1&n

Capacity to Recover its Typical Character and Functionality?:
The most threatened biotopes, those dominated by ocean quahog (Arctica islandica) and Unionidae are characterised by species with a slow growth rate and a life span >>50 years so natural recovery times to re-establish communities with mixed age populations of this species are likely to be substantial.
Adult individuals of Arctica islandica can tolerate periods of anoxia by burrowing deeper into the sediment and remaining inactive. The larvae settling on the surface and younger specimens have not got this potential. Astarte borealis is resistant to anoxic conditions, however recurring and long lasting anoxia is fatal

Summary:
This habitat occurs in all Baltic sub-basins in the shallow waters of the photic zone and is mostly characterised by dominance of the infauna by the Baltic tellin Macoma balthica. Areas dominated by ocean Quahog (Arctica islandica) and Abra spp. are only present in the Belt Sea. and photic muddy sediment dominated by Unionidae are restricted to oligohaline lagoons, bays and estuaries and the northern most part of the Bothnian Sea.  Eutrophication is considered to have been the main pressure on this habitat and pressures associated with climate change are considered to be a likely future threat. Every action to reduce the level of eutrophication in order to increase the oxygen level on the deep muddy bottoms are urgently needed. Some consecutive years when the oxygen level remains at a good level is needed for the recruitment to be successful.

References:
Conley, D.J. Carstensen, J., Ertebjerg, G. et al. 2007 Long-term changes and impacts of hypoxia in Danish coastal waters. Ecological Applications 17(5): 165-184.
Gic-Grusza, C., Kryla-Straszewska, K., UrbaÅ„ski, J., Warzocha, J., & WÄ™stawski, J.M., 2009. Atlas of Polish marine area bottom habitats. Environmental valorization of marine habitats. Gic-Grusza, C., Kryla-Straszewska, K., UrbaÅ„ski, J., Warzocha, J., & WÄ™stawski, J.M. (Eds), Gdynia, Poland.
Gogina, M., Zettler, M.L. 2010. Diversity and distribution of benthic macrofauna in the Baltic Sea: Data inventory and its use for species distribution modelling and prediction. Journal of Sea Research 64(3): 313–321.
HELCOM, 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Avellan, L. (Ed). Helsinki, Finland.
KrzymiÅ„ska, J., 2000. Bivalves in surface deposits of the Southern Baltic. Folia Malacologica 8(1): 95-100.
Morton, B. 2011. The biology and functional morphology of Arctica islandica (Bivalvia: Arcticidae): A gerontophilic living fossil. Marine Biology Research 7: 540–553.
OSPAR. 2009. OSPAR Background for Ocean quahog Arctica islandica. Biodiversity Series. http://qsr2010.ospar.org/media/assessments/Species/P00407_Ocean_quahog.pdf
Trutschelt, K., Samtleben, C. 1988. Shell growth of Astarte elliptica (Bivalvia) from Kiel Bay (Western Baltic Sea). Marine Ecology progress Series 42: 155-162.
Zettler, M. L., Bönsch, R., Gosselck, F. 2001. Distribution, abundance and some population characteristics of the ocean quahog, Arctica islandica (Linnaeus, 1767), in the  Mecklenburg Bight (Baltic Sea). Journal of Shellfish Research 20: 161– 169.
Zettler, M. 2002. Ecological and morphological features of the bivalve Astarte borealis (Schumacher 1817) in the Baltic Sea near its geographical range. Journal of Shellfish Research 21: 33-40.

Criterion A Text:
This habitat occurs in all the Baltic sub-basins. There has been a decline in quantity of some the associated biotopes dominated by the infaunal bivalve Arctica islandica and Unionidae with an estimated overall decline of >25%. This habitat has therefore been assessed as Near Threatened under Criterion A.

Criterion B Text:
This habitat occurs in all the Baltic sub-basins therefore the EOO is likely to exceed 50,000km2. HELCOM have mapped the presence of some of the associated biotopes but there is insufficient information on which to calculate area of this habitat across the Baltic or accurately calculate EOO and AOO.

Synthesis:
The presence of this habitat type in the Baltic is well established and the occurrence of some of the biotopes has been mapped, but there is a lack of comprehensive quantitative data on the area covered. There have been declines in the extent of two of the four associated biotopes with overall decline is considered to be more than 25%. There have also been some declines in quality of this habitat in the Belt Sea (more than 10% in for A.islandica dominated areas).
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed the two biotopes AA.H3L1 and AA.H3L8 as LC(A1). AA.H3L3 and AA.H3L8 were assessed as NT(A1). Given the severity of decline of some of the associated biotopes over the last 50 years, the current expert opinion is that this habitat should be assessed as Near Threatened (A1).

Sub-habitats in Need of Examination:
AA.H3L3 Baltic photic muddy sediment dominated by ocean quahog (Arctica islandica)
AA.H3L6 Baltic photic muddy sediment dominated by Unionidae

Contributors:
HELCOM RED LIST Biotope Expert Team 2013 and Baltic Sea Working Group for the European Red List of Habitats 2014 and 2015


Habitat Type Name:
40 Infaunal communities in Baltic infralittoral muddy sediment not dominated by bivalves

Habitat Description:
This Baltic Sea benthic habitat occurs in the  photic zone with at least 90% coverage of muddy sediment according to the HELCOM HUB classification. Macrovegetation and epibenthic macrofauna are typically absent and the biomass is dominated (at least 50%) by infaunal polychaetes, crustaceans, echinoderms or insect larvae. The associated biotopes occur over a range of depths, from 1m to over 100m, and  different degrees of energy exposure.
Indicators of quality: 
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change overtime. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. Diversity, abundance and biomass of fauna may be used as potential indicators of quality.
Characteristic species:  
Monoporeia affinis, Saduria entomon, Pontoporeia femorata, Corophium volutator and Apocorophium lacustre where crustaceans dominate. Where polychaetes dominate Polydora ciliata, Lagis koreni, Capitella capitata, Scoloplos (Scoloplos) armiger, Marenzelleria spp. (Marenzelleria arctia, Marenzelleria viridis, Marenzelleria neglecta); where insect larvae dominate, midge larvae (Chironomidae).

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.31 Sublittoral mud in low or reduced salinity
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1130 Estuaries
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral mud
 
EUSeaMap:
Shallow muds
 
IUCN:
9.6. Subtidal muddy
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.H3N: Baltic photic muddy sediment characterized by infaunal crustaceans
AA.H3M: Baltic photic muddy sediment characterized by infaunal polychaetes 
AA.H3O: Baltic photic muddy sediment characterized by infaunal echinoderms
AA.H3P: Baltic photic muddy sediment characterized by infaunal insect larvae
 
HUB level 6;
‘Baltic photic muddy sediment dominated by Monoporeia affinis’ (AA.H3N1)
‘Baltic photic muddy sediment dominated by mud shrimps (Corophiidae)’ (AA.H3N2)
‘Baltic photic muddy sediment dominated by Marenzelleria spp.’ (AA.H3M3)
‘Baltic photic muddy sediment dominated by various opportunistic polychaetes’ (AA.H3M5)
‘Baltic photic muddy sediment dominated by midge larvae (Chironomidae)’ (AA.H3P1).

Justification Outstanding Example of Biogeographical Region:
One of the associated biotopes dominated by various opportunistic polychaetes is typical of the Baltic however the dominant species Marenzelleria spp. is a non-native species. It has been recorded in the Baltic for at least the past century and is now considered to be an established part of various soft sediment communities.

Trends in Quantity:
There have been different trends in the different associated biotopes. Those dominated by Monoporeia affinis and by mud shrimps (Corophiidae) are believed to have decreased (but by less than 20% in the past 50 years); areas dominated by various opportunistic polychaetes and by Marenzelleria spp. are considered to have been stable, and areas where the infauna are dominated by midge larvae are considered to have increased. There are no detailed historic data and no estimates available on future trends in quantity. Expert opinion is that the overall condition of the habitat is most likely to be stable.

Trends in Quality:
There is insufficient information available on which to make an assessment of the current status and trends in quality over the last 50 years. No future estimates of quality have been made.

Pressures and Threats:
No pressures and threats have been identified specifically for this habitat at the present time.

Conservation Status:
Annex 1:
1130: MBAL U2
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1130 CR C1 
1160 VU C1 
1650 VU C1 
HELCOM (2013) have assessed all six associated

Summary:
This habitat occurs in shallow areas in all the Baltic sub-basins.  No pressures and threats specific to this habitat have been identified, nor any specific conservation management measures.

References:
Dahl, K., Josefson, A.B., Goke, C., et al, 2013. Sectoral Impact Assessments for the Baltic Sea Region - Climate Change Impacts on Biodiversity, Fisheries, Coastal Infrastructure and Tourism. Leth, K., Dahl, :eltonen, Kramer & Kule (Eds). Warnemünde, Rostock, Germany.
Gic-Grusza, C., Kryla-Straszewska, K., UrbaÅ„ski, J., Warzocha, J., & WÄ™stawski, J.M., 2009. Atlas of Polish marine area bottom habitats. Environmental valorization of marine habitats. Gic-Grusza, C., Kryla-Straszewska, K., UrbaÅ„ski, J., Warzocha, J., & WÄ™stawski, J.M. (Eds), Gdynia, Poland.
HELCOM 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Baltic Sea Environmental Proceedings No. 138.

Criterion A Text:
Two of the associated biotopes (dominated by Monoporeia affinis and by mud shrimps (Corophiidae) are believed to have decreased (but by less than 25% in the past 50 years).The other associated biotopes have either been stable or increased therefore expert opinion is that any overall decline in the quantity of the habitat is likely to have been less than 25%. It has been assessed as Least Concern under Criteria A for both the EU 28 and EU 28+.

Criterion B Text:
A lack of a comprehensive of quantitative data on the area covered by this habitat in the Baltic means that precise figures for EOO and AOO could not be calculated however as it is present in all Baltic Sea sub basins the EOO is likely to exceed 50,000km2. This habitat has therefore been assessed as Data Deficient under criteria B.

Synthesis:
There have been a variety of trends for the different biotopes associated with this habitat. Where the infauna are dominated by various opportunistic polychaetes Marenselleria, and midge larvae the biotopes are either considered to have been stable or increased over the last 50 years, whilst those dominated by the mudshrimp and Monoporeia affinis have shown some decline in both extent and quality (but believed to be less than 25%).
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessmentswere derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed all five associated biotopes as Least Concern (A1). With no additional data available the current expert opinion is that this habitat should be assessed as Least Concern for both the EU 28 and EU 28+.


Habitat Type Name:
48 Sparse or no macrofaunal community on Baltic upper circalittoral coarse sediment and shell gravel

Habitat Description:
This is a Baltic Sea benthic habitat in the upper circalittoral where at least 90% of the substrate is coarse sediment or shell gravel according to the HELCOM HUB classification. It is typically encountered in depths below 30 m in high energy exposure areas. Macrofauna, epifauna and infauna are generally sparse or absent. Where the habitat is dominated by meiofauna’ (AB.I4U1) they constitute at least 50% of the biomass.
Indicators of quality:
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly
agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values havebeen determined and applied on a location-specific basis.
Characteristic species: 
In the biotope dominated by meiofauna the main species groups present are Oligochaetes, Ostracods and Nematodes.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.11 Infralittoral coarse sediment in low or reduced salinity
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1110 Sandbanks slightly covered all the time
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine – Coastal
 
MSFD:
Shallow sublittoral coarse sediment Shelf sublittoral coarse sediment
 
EUSeaMap:
Shallow coarse or mixed sediments
 
IUCN:
9.3 Subtidal Loose Rock/Pebble/Gravel
 
Other relationships:
Level 5 of the HELCOM HUB (2013) classification: 
AB.E4U Baltic aphotic shell gravel characterised by no macrocommunity
AB.I4U: Baltic aphotic coarse sediment characterised by no macrocommunity. The latter has one biotope on HUB level 6; ‘Baltic aphotic coarse sediment dominated by meiofauna’ (AB.I4U1).

Trends in Quantity:
This habitat is present in all the sub-basins of the Baltic Sea. Although poorly studied the current trend is considered to be stable. There are no data on historic trends nor any estimates of future trends.

Trends in Quality:
No information is available for trends in quality for this habitat.

Pressures and Threats:
This habitat is poorly studied with no information on specific pressures and threats at the present time.

Conservation and Management:
No conservation or management measures have been identified specifically for this habitat.

Conservation Status:
Annex 1:
1110: MBAL U1
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1110 VU C1 
1160 VU C1 
1650 VU C1 
HELCOM (2013) assessed two biotope AB.I4U1

Summary:
This is a Baltic Sea benthic habitat in the upper circalittoral where at least 90% of the substrate is coarse sediment or shell gravel. It is present in all the Baltic Sea sub-basins, typically in depths below 30 m in high energy exposure areas. Macrofauna, epifauna and infauna are generally sparse or absent.  There is a lack of quantitative data on pressure and threats as well distribution, extent and quality. No specific pressures, threats, conservation or management measures have been identified for this habitat.

References:
HELCOM. 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Baltic Sea Environment Proceedings138 Helsinki Commission

Criterion A Text:
The area covered by this habitat is believed to have been stable over the last 50 years and there is no information on historic or future reductions. This habitat is therefore assessed as Least Concern under Criterion A for both the EU 28 and EU 28+.

Criterion B Text:
This habitat is present in all the Baltic Sea sub-basins therefore the EOO is likely to exceed 50,000 km2. The AOO is unknown. The habitat is believed to have been stable over the past 50 years, therefore there is no continuing decline in extent. Quality trends are unknown. This habitat has therefore been assessed as Data Deficient under criterion B for the EU 28 and EU 28+.

Criterion C/D Text:
Experts consider there to be insufficient data on which to make an overall assessment of criteria C/D.

Synthesis:
The habitat is believed to have been stable over the last 50 years and no change is expected in the near future.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed one relevant Baltic biotope (AB.I4U1) as Least Concern (A1). A second biotope (AB.E4U) was Not Evaluated. There is no additional data or information to update the assessment outcome past the HELCOM 2013 assessment. With no additional data available the current expert opinion is that this habitat should be assessed as Least Concern for both the EU 28 and EU 28+


Habitat Type Name:
41 Sparse or no macrofaunal communities on Baltic infralittoral muddy sediment

Habitat Description:
This is a Baltic Sea benthic habitat in the photic zone where at least 90% of the substrate is muddy sediment according to the HELCOM HUB classification. It occurs in areas where there is low to medium exposure to wave action. Macrovegetation, epifauna and infauna are generally sparse or absent however the one associated biotope described has a large representation (more than 50% of biomass) of meiofauna. This is ‘Baltic photic muddy sediment dominated by meiofauna (Oligochaeta, Ostracoda, Nematoda)’ (AA.H4U1).
The benthic meiofauna in the Baltic Sea is a diverse group of small animals including Ostracoda, Nematoda, Oligochaeta, Rotifera, Turbellaria and Copepoda living on and in the sediments. In the north-western Baltic Sea Proper, Nematoda are the most abundant group of benthic meiofauna, making up between 67–91% of the species observed in the sediment. Only nematodes are found to be common below 2 cm depth in the sediment. Meiofauna can be split into surface feeders and subsurface feeders. Sedimentation of organic matter may have an effect on the meiofaunal community, as the increased rate of sedimentation can increase the abundance of surface feeding species.
Indicators of quality:
Quality indicators have not been described for this habitat. Generally the ecology of meiofaunal communities is less well understood than that of benthic macrofauna communities. Fewer studies have been carried out and in many studies meiofauna is only stated to be present in a certain abundance. Studies looking into the environmental requirements and species interactions are rare. It is also quite rare that meiofauna is taxonomically identified to species level which is the rule in macrofauna studies. 
 
Characteristic species:
Oligochaeta, Ostracoda, Nematoda

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is to ‘Sublittoral mud in low or reduced salinity‘ (A5.31). 
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM however this habitat may occur in the following Annex 1 habitats:
1130 Estuaries
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral mud
 
EUSeaMap:
Shallow muds
 
IUCN:
9.6 Subtidal muddy
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AA.H4U: Baltic photic muddy sediment characterised by no macrocommunity This habitat has one sub-habitat on HUB level 6; ‘Baltic photic muddy sediment dominated by meiofauna (Oligochaeta, Ostracoda, Nematoda)’(AA.H4U1).

Trends in Quantity:
This habitat is present in the Baltic Proper, Gulf of Bothnia, Gulf of Finland, Gulf of Riga. It is believed to have increased in extent over the last 50 years due to anthropogenic eutrophication. There is a lack of historical data on which to make a quantitative assessment and no estimates of future change.

% of Distribution of the Habitat Type within the EU 28:
Unknown. Similar habitats may occur in other European Regional Seas.

Pressures and Threats:
No pressures or threats have been identified specifically for this habitat. Whereas eutrophication is a pressure for many habitats, nutrient enrichment is beneficial in this case and is contributing to an expansion in its range.

Conservation Status:
Annex 1:
1130: MBAL U2
1160: MBAL U2
1650: MBAL U2
HELCOM (2013) assessments: 
1130 CR C1
1160 VU C1
1650 VU C1
 HELCOM (2013) assessed this habitat as LC (A1).

Summary:
This is a benthic habitat in the photic zone where the predominant substrate is muddy sediment. It is present in the Baltic Proper, the Gulf of Riga, the Gulf of Finland, and the Gulf of Bothnia but not reported from the more exposed conditions of the Sound and the Belt Sea.  Macrovegetation, epifauna and infauna are generally sparse or absent however there may be a large representation of meiofauna. No specific threats, pressures, conservation or management measures have been identified for this habitat.

Criterion A Text:
There is a lack of quantitative data on the extent and trends in quanity of this habitat but expert opinion is that it has increased in extent over the last 50 years. This habitat has therefore been assessed as Least Concern under criterion A.

Criterion B Text:
Experts consider there to be insufficient data on which to calculated EOO or AOO .This habitat has therefore been assessed as Data Deficient under criterion B.

Synthesis:
This habitat is considered to have expanded its extent over the last 50 years due to nutrient enrichment, however, this has not been quantified. The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed this habitat as Least Concern (A1) due to the increase in extent in the last 50 years with nutrient enrichment. The current expert opinion is an assessment of Least Concern for both the EU 28 and EU 28+.


Habitat Type Name:
42 Epifaunal communities on Baltic circalittoral rock and mixed substrata (predominantly hard)

Habitat Description:
This is a Baltic Sea benthic habitat in the aphotic zone where at least 90% of the substrate is rock, boulders or stones as well as on mixed (predominantly hard) substrates where the percentage of rock is between 10-90% according to the HELCOM HUB classification. The HELCOM HUB identifies 14 different biotopes associated with the habitat. In each case the dominate species or species group (in the biotope title) constitutes at least 50% of the biomass. These are: epibenthic bivalves, chordates, cnidarians, bryozoans, crustaceans and sponges. 
Indicators of quality:
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. The amount of sediment covering the hard surfaces and the diversity, abundance and biomass of associated fauna are potential quality indicators for this habitat. 
Characteristic species: 
For mussel dominated biotopes Mytilus spp., Modiolus modiolus; for epibenthic chordate dominated biotopes - seasquirts (Ascidiaceae), such as Ciona intestinalis, Dendrodoa grossularia, Molgula spp., Corella parallellogramma, Ascidia mentula, Ascidia virginea and Ascidia obliqua; For epibenthic cnidarians dominated biotopes- Laomedea spp., Cordylophora caspia, Edwardsia spp, Metridium senile, Gonactinia prolifera, Urticina felina, Stomphia coccinea, Sagartia elegans; for epibenthic moss animal (Bryozoa) dominated habitats. Electra crustulenta, Flustra foliacea, other Bryozoa (Eucratea loricata), also sponges, sea squirts or hydrozoans; for epibenthic crustacean dominated biotopes, Balanidae, for example Amphibalanus improvises, Balanus crenatus, Semibalanus balanoides; for sponge dominated biotopes Haliclona oculata and only rarely other species such as Halichondria panicea, Halisarca dujardini and Scypha ciliata. In the northern Baltic Sea only Ephydatia fluviatilis.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A4.4 Baltic exposed circalittoral rock, A4.5 Baltic moderately exposed circalittoral rock and A4.6 Baltic sheltered circalittoral rock 
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1160 Large shallow inlets and bays
1170 Reefs
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral rock & biogenic reef
Shallow sublittoral mixed sediment
 
EUSeaMap:
Shallow aphotic rock or biogenic reef
 
IUCN:
9.2. Subtidal rock and rocky reefs
9.3. Subtidal Loose Rock/Pebble/Gravel
 
Other relationships:
Level 5 of the HELCOM HUB (2013) classification: 
AB.A1E/AB.M1E Baltic aphotic rock and boulders/mixed substrates characterised by epibenthic bivalves These biotopes have two sub-habitats on HUB level 6; ‘Baltic aphotic rock and boulders/mixed substrates dominated by Mytilidae’ (AB.A1E1/AB.M1E1).
AA.A1F/AB.M1F Baltic aphotic rock and boulders/mixed substrates characterised by epibenthic chordates These habitats have two sub-habitats on HUB level 6; ‘Baltic aphotic rock and boulders /mixed substrates dominated by sea squirts (Ascidiacea)’ (AB.A1F1/AB.M1F1).
AB.A1G/AB.M1G–Baltic aphotic rock and boulders/mixed substrate characterised by epibenthic cnidarians. These biotopes have four sub-habitats on HUB level 6 ‘Baltic aphotic rock and boulders dominated hydroids (Hydrozoa)’ (AB.A1G1) ‘Baltic aphotic rock and boulders dominated by sea anemones (Actiniarida)’ (AB.A1G2) ‘Baltic aphotic mixed substrate dominated hydroids (Hydrozoa)’ (AB.M1G1), and ‘Baltic aphotic mixed substrate dominated by sea anemones (Actiniarida)’ (AB.M1G2)
AB.A1H/AB.M1H–Baltic aphotic rock and boulders/mixed substrate characterised by epibenthic moss animals (Bryozoa) (all regions)
AB.A1I/AB.M1I–Baltic aphotic rock and boulders/mixed substrate characterised by epibenthic crustaceans (all regions)
AB.A1J/AB.M1J: Baltic aphotic rock and boulders/mixed substrate characterised by epibenthic sponges (Porifera) (all regions) but for mixed only Belt Sea and Gulf of Bothnia
AB.A1V/AB.M1V: Baltic aphotic rock and boulders/mixed substrates characterised by mixed epibenthic macrocommunity (all regions).

Justification Outstanding Example of Biogeographical Region:
Large areas of hard rock and boulders covered by bivalves, such as Mytilus edulis, bryozoans and other epifaunal turf communities are a typical habitat in the Baltic Sea.

Trends in Quantity:
Different trends in quantity have been identified for the different associated biotopes with all except one believed to have declined in extent by between 10-30% over the last 50 years. Future declines in extent are predicted for those biotopes dominated by bryozoans and by Mytilids.

Trends in Quality:
There have been some declines in quality of some of the associated biotopes (e.g. of the order of 10% for biotopes dominated by Mytilidae), but in most cases there is insufficient information on which to make a trend analysis.

Justification of Small Range/Regression:
Overall no, but some of the associated biotopes do have a small natural range following regression. This is the case for areas dominated by erect bryozoans and by epibenthic sponges.

Pressures and Threats:
Eutrophication is a major threat to this habitat with any associated increase in siltation rates reducing the availability of hard substrates, impeding the settlement of the larvae of colonising species. A higher particle concentration in the water may also impede the filter feeding efficiency of the some characteristic species such as adult Flustra foliacea. Oxygen depletion due to eutrophication could be an issue but is seen as a smaller threat. This habitat is also threatened by physical disturbances including bottom trawling and offshore construction work.

Conservation and Management:
All actions which aim to reduce physical disturbance of aphotic stony bottoms in the Baltic Sea are important for the conservation of epifaunal turf communities on rock and mixed substrates. In addition, appointing protected areas where the habitat is known to occur and restricting bottom trawling, offshore construction work and gravel extraction in these areas would constitute an effective conservation measure. Further mapping activities should be carried out to better delineate the area of occurrence.

Conservation Status:
Annex 1:
1160: MBAL U2
1170: MBAL U1
1650: MBAL U2
 
HELCOM (2013) assessments:
1160 VU C1 
1650 VU C1 
1170 VU C1 
HELCOM (2013) have assessed eight associated bi

Capacity to Recover its Typical Character and Functionality?:
The associated biotopes dominated by bryozoans have the potential to fairly quickly recolonise destroyed areas after the pressure/threat has been removed and the environmental conditions restored. Recovery rates are unknown for the other biotopes.

Summary:
This benthic habitat occurs in the aphotic zone in areas of predominantly hard substrate. Fourteen different associated biotopes have been described variously dominated by epibenthic bivalves, chordates, cnidarians, bryozoans, crustaceans and sponges. It is present in all the Baltic Sea sub-basins although some of the associated biotopes have a more restricted distribution. Areas dominated by epibenthic sponges for example are only present in the Belt Sea and Gulf of Bothnia, while biotopes dominated by hydroids and sea anemones do not occur in the Gulf of Bothnia and Gulf of Riga. 
Eutrophication is considered to be a major threat to this habitat as a result of oxygen depletion, increased turbidity and sedimentation. This habitat is also threatened by physical disturbance by bottom trawling, offshore construction work and sand and gravel extraction. Actions which aim to reduce physical disturbance of aphotic stony bottoms in the Baltic Sea are important for the conservation of epifaunal turf communities on rock and mixed substrates. In addition, appointing protected areas where the habitat is known to occur and restricting activities which disturb the seabed would constitute effective conservation measures. Further mapping activities should be carried out to better delineate the area of occurrence.

References:
Barthel D., Wolfrath B. 1989. Tissue sloughing in the sponge Halichondria panacea: a fouling organism prevent being fouled. Oecologia 78(3): 357-360.
Bitschofsky F., Forster S., Scholz J., 2011. Introduction in: ‘Regional and temporal changes in epizoobiontic bryozoan-communities of Flustra foliacea (Linnaeus, 1758) and implications for North Sea ecology’. Estuarine, Coastal and Shelf Science 91(3): 423–433.
HELCOM, 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Avellan, L. (Ed). Helsinki, Finland.      
HELCOM, 2013. Biotope Information sheet. Available at: http://helcom.fi/Red%20List%20of%20biotopes%20habitats%20and%20biotope%20complexe/HELCOM%20Red%20List%20AA.A1H2,%20AB.A1H2,%20AA.M1H2,%20AB.M1H2.pdf. (Accessed: 16/07/2015).
HELCOM, 1998. Red List of marine and coastal biotopes and biotopes complexes of the Baltic Sea, Belt Sea and Kattegat. Baltic Sea Environmental Proceedings No. 75. Helsinki Commission, Helsinki. 115pp. Available at: http://helcom.fi/Lists/Publications/BSEP75.pdf. (Accessed: 16/07/2015).
Hiscock, K., Wilson, E., 2007. Metridium senile. Plumose anemone. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme. Plymouth: Marine Biological Association of the United Kingdom. Available at: http://www.marlin.ac.uk/speciesfullreview.php?speciesID=3806. (Accessed: 16/07/2015).
Moen, E., Svenson, E., 2009. Djurliv I havet – Nordeuropeisk marin fauna. Stockholm, Sweden.
Olenin, S. & Daunys, D., 2004. Coastal typology based on benthic biotope and community data: The Lithuanian case study. Baltic Sea Coastline Reports 4: 65-83. 
OCEANA, 2011. Conservation proposals for ecologically important areas in the Baltic Sea. Available at: http://oceana.org/sites/default/files/reports/OCEANA_Baltic_report_2011_ENG.pdf. (Accessed: 16/07/2015).
OSPAR, 2008. OSPAR List of Threatened and/or Declining Species and Habitats. Available at: http://www.ospar.org/content/content.asp?menu=00180302000014_000000_000000. (Accessed: 16/07/2015).
Picton, B.E., Morrow, C.C., 2010. Encyclopedia of Marine Life of Britain and Ireland. Available at: http://www.habitas.org.uk/marinelife/index.html. (Accessed: 16/07/2015).
Ryland J.S., Hayward P.J. 1977. British anascan bryozoans. Synopses of the British Fauna (New Series). Academic Press, London, UK.
Stresemann E., Hannemann H.-J., Klausnitzer B. Senglaub K., 1992. Exkursionsfauna von Deutschland. Band 1, Hannermann, H. and Klausnitzer, B., (Eds). Berlin, Germany.
Tyler-Walters H., Ballerstedt S. 2007. Flustra foliacea. Hornwrack. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme. Available at: http://www.marlin.ac.uk/generalbiology.php?speciesID=3342. (Accessed: 16/07/2015).

Criterion A Text:
Many of the associated biotopes have declined in extent. In some cases this has been estimated to be by up to 30% over the last 50 years. Expert opinion is that there has been an overall decline of between 25-30% over the last 50 years. This habitat has therefore been assessed as Near Threatened under criterion A for both the EU 28 and EU 28+.

Criterion B Text:
This habitat is found in all the Baltic Sea sub-basins therefore EOO exceeds 50,000 km2 however with no quantitative data on habitat extent or area, accurate calculation of EOO and AOO is not possible at the present time. This habitat has therefore been assessed as Data Deficient under criterion B.

Synthesis:
There have been significant declines (up to 30%) in the extent of many of the associated biotopes and predicted future declines. Some decline in quality (up to an estimated 10%) has also been reported for some of the associated biotopes but the overall trend is uncertain. The lack of quantitative data means precise figures cannot be given at the present time.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed eight of the associated biotopes as Near Threatened (A1), and eight as Least Concern (A1). Two were not evaluated. Given the past and predicted future declines in extent of this habitat, current expert assessment is that it should be assessed as Near Threatened (A1) for both the EU 28 and EU 28+.

Sub-habitats in Need of Examination:
AB.A1F1 Baltic apotic rock and boulders dominated by sea squirts (Ascidiacea)
AB.A1G2 Baltic aphotic rock and boulders dominated by sea anemones (Actiniaria)
AB.A1H2 Baltic aphotc rock and boulders dominted by erect moss animals (Flustr


Habitat Type Name:
43 Sparse or no macrofaunal communities on Baltic circalittoral rock and mixed substrata (predominantly hard)

Habitat Description:
The Baltic Sea benthic habitat occurs in the aphotic zone with at least 90% coverage of rock, boulders or stones and mixed (predominantly hard) substrates according to the HELCOM HUB classification. It is typically found in depths of 20 meters or more Where sessile/semi-sessile epibenthic fauna is present they covers less than 10% of the seabed and in some cases no epibenthic vegetation or macrofauna is present. Though the habitat is more uncommon in the Northern Baltic (due to the siltation and prevalence of sand and soft bottoms) it does exist also in the Bothnian Bay where the aphotic zone starts in quite shallow water (5-10 m depth), increasing the amount of rock and hard bottom in the circalittoral zone.
Four associated biotopes have been identified:  Baltic aphotic rock and boulders characterized by sparse epibenthic macrocommunity (AB.A2T); Baltic aphotic mixed substrate characterized by sparse epibenthic fauna (AB.M2T); Baltic aphotic rock and boulders characterized by no macrocommunity ( AB.A4U); and  Baltic aphotic mixed substrate characterized by no macrocommunity (AB.M4U).
Indicators of quality:  
Unknown.
Characteristic species:
For sparse epibenthic communities Mytilus spp. Macoma balthica Bryozoa, Balanidae, Bryozoa, Porifera, Hydrozoa. Where there are no macrocommunities, by meiofauna and bacteria.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A4.4 Baltic exposed circalittoral rock, A4.5 Baltic moderately exposed circalittoral rock and A4.6 Baltic sheltered circalittoral rock
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1160 Large shallow inlets and bays
1170 Reefs
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD: 
Shallow sublittoral rock & biogenic reef
Shallow sublittoral mixed sediment
 
EUSeaMap: 
Shallow aphotic rock or biogenic reef
Shallow coarse or mixed sediments
 
IUCN:
9.2 Subtidal rock and rocky reefs
9.3. Subtidal Loose Rock/Pebble/Gravel
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AB.A2T: Baltic aphotic rock and boulders characterized by sparse epibenthic macrocommunity
AB.M2T: Baltic aphotic mixed substrata characterized by sparse epibenthic macrocommunity
AB.A4U: Baltic aphotic rock and boulders characterized by no macrocommunity
AB.M4U–Baltic aphotic mixed substrate characterized by no macrocommunity.

Trends in Quantity:
This habitat can be found throughout the Baltic Sea and there are no reports of decreasing quantity. It is believed to be stable. There are no historic trend data and no estimates of future trend in quantity.

Trends in Quality:
There is limited information on the quality of the habitat. Current expert opinion is that it can be considered stable.

Pressures and Threats:
No pressures and threats have been identified specifically for this habitat type.

Conservation and Management:
No conservation and management measures have been identified specifically for this habtiat.

Conservation Status:
Annex 1:
1110: MBAL U1
1130: MBAL U2
1160: MBAL U2
1170: MBAL U1
1650: MBAL U2
 
HELCOM (2013) assessments:
1110 VU C1 
1130 CR C1 
1160 VU C1 
1650 VU

Summary:
This habitat occurs in all Baltic sub-basins in the aphotic zone. It is characterized by sparse or no epibenthic macrocommunities. No specific pressures or threats have been identified nor any specific conservation or management measures.

References:
HELCOM, 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Baltic Sea Environmental Proceedings No. 138.

Criterion A Text:
Expert opinion is that habitat area and extent has been stable over the last 50 years. This habitat has therefore been assessed as Least Concern under Criteria A for both the EU 28 and EU 28+.

Criterion B Text:
This habitat is found in all the Baltic Sea sub-basins therefore EOO exceeds 50,000 km2 however with no quantitative data on habitat extent or area, accurate calculation of EOO and AOO is not possible at the present time. The habitat is therefore assessed as Data Deficient under Criteria B.

Synthesis:
The presence of this habitat type in the Baltic Sea is well known. It occurs in all the sub basins but quantitative data on the area covered is not available. Expert opinion is that habitat area and extent and habitat quality has been stable over the last 50 years.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed three associated biotopes AB.A2T, AB.A4U and AB.M2T as Least Concern (A1). AB.M4U was not evaluated. The extent and area of this habitat is believed to have been stable over the last 50 years and no change is expected in the near future. Current expert opinion is that this habitat be assessed as Least Concern for both the EU 28 and EU 28+.


Habitat Type Name:
46 Infaunal communities in Baltic upper circalittoral coarse sediment and shell gravel dominated by bivalves

Habitat Description:
This is a Baltic Sea benthic habitat in the upper circalittoral where at least 90% of the substrate is coarse sediment or shell gravel according to the HELCOM HUB classification. The substrate is usually poorly sorted with different proportions of gravel, coarse or medium sand, but may also contain finer sediment fractions. Macrovegetation and epibenthic macrofauna are generally absent and the biomass is typically dominated by infaunal bivalves. This habitat occurs in high energy exposure areas and two associated biotopes with different dominant species of macrofauna (at least 50% of the biomass) have been described.
‘Baltic aphotic coarse sediment dominated by multiple infaunal bivalve species: Macoma calcarea, Mya truncata, Astarte spp., Spisula spp.’ (AB.I3L10) is mainly restricted to small patches between hard substrates on ridges formed by lag sediment and till (e.g. Fehmarnbelt) in the photic and aphotic zone. It supports a high species diversity and high  biomass and only occurs in areas where the salinity exceeds 18 psu as all characteristic bivalve species are eumarine. For this reason it  has only been reported from the Kiel Bight to Isle of Fehmarn, and occasionally present from Mecklenburg Bight to the Darss Sill. 
‘Baltic aphotic coarse sediment dominated by multiple infaunal polychaete species including Ophelia spp.’ (AB.I3L11) is an associated biotope where biomass of bivalves still dominates but due to the large variety of interstitial space there is a specialised infauna, e.g., the polychaetes Ophelia limacina, O. rathkei and Travisia forbesii. This biotope is restricted to the Belt Sea (sandbanks) and parts of the ‘submerged belt’ of the Arkona Basin in the south-western Baltic Sea.  
Indicators of quality:  
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values havebeen determined and applied on a location-specific basis. Diversity, abundance and biomass of the dominant. species and associated fauna are potential indicators of quality of this habitat
Characteristic species:  
Depending on the biotope ‘Macoma calcarea, Mya truncata, Astarte spp., Spisula spp.’ Ophelia rathkei, Ophelia limacina, Travisia forbesii, Tanaissus spp. and Streptosyllis spp.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.11 Infralittoral coarse sediment in low or reduced salinity.
 
Annex 1: 
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM however this habitat may occur in the following Annex 1 habitats:
1110 Sandbanks slightly covered all the time
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES: 
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral coarse sediment
Shallow sublittoral mixed sediment
 
EUSeaMap:
Shallow coarse or mixed sediments
 
IUCN:
9.3 Subtidal Loose Rock/Pebble/Gravel
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AB.I3L Baltic aphotic coarse sediment characterised by infaunal bivalves This habitat has two biotopes on HUB level 6; ‘Baltic photic coarse sediment dominated by multiple infaunal bivalve species: Macoma calcarea, Mya truncata, Astarte spp., Spisula spp.’ (AB.I3L10) and ‘Baltic photic coarse sediment dominated by multiple infaunal polychaete species including Ophelia spp.’ (AB.I3L11).

Justification Outstanding Example of Biogeographical Region:
The habitat has a restricted range in the Baltic Sea and it mostly found in small patches surrounded by finer substrates.

Comment EU28+:
This habitat is only present in the EU28

Trends in Quantity:
This habitat only occurs in the southern and western Baltic Sea, and the distribution of the two associated biotopes differs; ‘Baltic aphotic coarse sediment dominated by multiple infaunal bivalve species: Macoma calcarea, Mya truncata, Astarte spp., Spisula spp.’ (AB.I3L10) is found in the westernmost areas such as The Kattegat, The Belt Sea and The Sound. ‘Baltic aphotic coarse sediment dominated by multiple infaunal polychaete species including Ophelia spp.’ (AB.I3L11) is found in the southern areas of The Belt Sea and in a small area in the southern Baltic Proper. This habitat is considered to have declined by approximately 25% during the past 50 years. No quantitative historic data are available and no estimates have been made of future trends although continuing decline is predicted.

Trends in Quality:
The quality of the habitat has in some areas shown moderate to severe reduction in quality of 10-15% over the past 50 years. A further reduction of  around 10% is envisaged over the next 50 years.

% of Distribution of the Habitat Type within the EU 28:
This habitat type does not occur in the Russian Baltic Sea area therefore 100% is hosted by EU 28.  The habitat may occur in other European Regional Seas.

Justification of Small Range/Regression:
This habitat has a small natural range and has decreased in quantity over the last 50 years.

Justification of Restricted Area:
Infralittoral shell gravel and coarse sediment areas are rare in the Baltic Sea.

Pressures and Threats:
Eutrophication,bottom trawling, water traffic, construction, sand extraction, dredging, dumping, contaminant pollution and coastal works have all been identified as past and current threats to this habitat. These are also likely to be threats in the future.
The biotope ‘Baltic aphotic coarse sediment dominated by multiple infaunal bivalve species: Macoma calcarea, Mya truncata, Astarte spp., Spisula spp.’ (AB.I3L10) is threatened by oxygen deficiency often caused by eutrophication in combination with poor water exchange. Eutrophication also causes an increased growth rate in planktonic or annual algae which in turn causes an increase in organic load which threatens the habitat. An additional threat is increased siltation which can be caused by various construction activities such as dredging and dumping. This biotope occurs relatively close to land, and therefore an increased siltation rate can also be traced back to changes in land use, such as run-off from intensively farmed areas. ‘Baltic aphotic coarse sediment dominated by multiple infaunal polychaete species including Ophelia spp.’ (AB.I3L11) is mainly threatened by bottom trawling, oil and gas exploration and exploitation, pollution, offshore installations.

Conservation and Management:
Bottom trawling and sediment extraction should be restricted in areas where this habitat occurs. All activities that can improve oxygen conditions through reduction of eutrophication will also support the conservation of the habitat. For the biotope ‘Baltic aphotic coarse sediment dominated by multiple infaunal polychaete species including Ophelia spp.’ (AB.I3L11) a Baltic-wide biotope inventory and a threat assessment is needed. For the time being this biotope should be considered as highly sensitive and worthy of protection.

Conservation Status:
Annex 1:
1110: MBAL U1
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1110 VU C1
1160 VU C1 
1650 VU C1 
HELCOM (2013) have assessed the biotopes AB.I3L10 and AB.I

Summary:
This is a Baltic Sea benthic habitat in the upper circalittoral. The substrate is usually poorly sorted with different proportions of gravel, coarse or medium sand, but may also contain finer sediment fractions. Macrovegetation and epibenthic macrofauna are generally absent and the biomass is typically dominated by infaunal bivalves. The habitat is only present in  the southern and western Baltic and the characteristic species vary along a salinity gradient and include the bivalves Macoma calcarea, Mya truncata, Astarte spp. Spisula spp., Mya arenaria and Cerastoderma spp. and polychaete species such as Ophelia spp. and Travisia forbesii. 
Eutrophication,bottom trawling, water traffic, construction, sand extraction, dredging, dumping, contaminant pollution and coastal works have all been identified as past and current threats to this habitat. These are also likely to be threats in the future. Further mapping of the extent of this habitat is needed and bottom trawling and sediment extraction should be restricted in areas where it occurs. Measures to reduce eutrophication (and therefore associated oxygen depletion and sedimentation) will also benefit this habitat.

References:
HELCOM. 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Baltic Sea Environmental Proceedings 138. 
Krause, J. Ch. 2000. Der Einfluss von Sand- und Kiesabbau auf bestandsgefährdete Makrofauna-Populationen in der südlichen Ostsee. PhD thesis University of Rostock.
Moen, F. E., Svensen, E. 2004. Marine fish & invertebrates of Northern Europe. KOM, Kristiansund. 608pp.
Schiewer, U. 2008. Ecology of Baltic Coastal Waters. p. 12. Springer, Berlin, Germany.
Trutschelt, K., Samtleben, C. 1988. Shell growth of Astarte elliptica (Bivalvia) from Kiel Bay (Western Baltic Sea). Marine Ecology progress Series 42: 155–162.
Zettler, M. 2002. Ecological and morphological features of the bivalve Astarte borealis (Schumacher 1817) in the Baltic Sea near its geographical range. Journal of Shellfish Research 21: 33–40.

Criterion A Text:
This habitat only occurs in the southern and western Baltic and is therefore not present outside the EU 28 in the Baltic Sea. There is a lack of quantitative data on the area covered but it is considered to have reduced in extent by more than 25% in the last 50 years. This habitat has therefore been assessed as Near Threatened under Criterion A for both the EU 28 and EU 28+.

Criterion B Text:
This habitat only occurs in the southern and western Baltic. EOO and AOO figures are maximums as they are based on presence in 100 x 100 km grid squares converted to 10 x 10km grid squares. Eutrophication and activities which disturb the seabed are threatening process which are considered likely to cause continuing declines in the quanity of this habtiat within the next few years. This habitat has been assessed as Vulnerable under Criterion B for both the EU 28 and EU 28+ although because it is present in very few 'locations' (defined by threats) it could also be considered Endangered. 
This assessment should be reviewed when more detailed mapping of the extent of this habitat has been undertaken because the EOO and AOO calculations are based on data derived from a general mapping exercise.

Criterion C/D Text:
The quality of the habitat has in some areas shown moderate to severe reduction of 10-15% over the past 50 years and a further qualitative reduction of 10% is estimated over the next 50 years however experts considered there to be insufficient data on which to assess criteria C/D.

Synthesis:
This habitat has a limited distribution in the Baltic, being confined to areas of high salinity where coarse sediments or shell gravel is also present. There is insufficient information on which to base a quantitative assessment of current area, and changes in quality and extent, however, expert opinion is that it has declined in area by approximately 25% during the past 50 years and that a continuing decline is likely. The quality of the habitat has in some areas shown moderate to severe reduction of 10-15% over the past 50 years and a further qualitative reduction of 10% is estimated over the next 50 years.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed the two biotopes AB.I3L10 and AB.I3L11 as Near Threatened (A1). 
Current expert opinion is that this habitat should be assessed as Vulnerable under Criterion B for both the EU 28 and EU 28+ because of its restricted distribution and predicted continuing decline  although, because it is present in very few 'locations' (defined by the extent of the main threats), it could also be considered Endangered. This assessment should be reviewed when more detailed mapping of the extent of this habitat has been undertaken because the EOO and AOO calculations used to apply Criterion B are based on data derived from a general mapping exercise.

Sub-habitats in Need of Examination:
AB.I3L10 Baltic aphotic coarse sediment dominated by multiple infaunal bivalve species: Macoma calcarea, Mya truncata, Astarte spp. Spisula spp.
AB.I3L11 Baltic aphotic coarse sediment dominated by multiple infaunal polychaete s


Habitat Type Name:
47 Infaunal communities in Baltic upper circalittoral coarse sediment and shell gravel not dominated by bivalves

Habitat Description:
This is a Baltic Sea benthic habitat in the upper circalittoral where at least 90% of the substrate is coarse sediment or shell gravel according to the HELCOM HUB classification. Four associated biotopes have been described characterised by mixed infaunal macrocommunities with substrates ranging from coarse and well sorted shells and shell fragments (AB.E3X) to fine shell fragments (AB.E3Y), and also areas where the substrate is predominantly coarse and the biotope characterised by infaunal polychaetes (AB.I3M) or infaunal crustaceans (AB.I3N). In the latter case a sub-habitat identified by a large representation of Bathyporeia pilosa, which constitutes at least 50% of the biomass of the infaunal crustacean has also been described.
The habitat occurs in high energy areas, typically below 20m and for the coase sediments more usually below 30m. The community composition of macroinfauna is presumed to be different in the sand like shell gravel sand compared to coarser shell gravel of mainly semi-intact shells. These substrates support many different animals including non-burrowing animals but where the interstitial space is smaller burrowing polychaetes and amphipods can build tunnels using the small grains. The biotopes on shell gravel have a restricted distribution in the Baltic, especially where the substrate is comprised of  fine sand-like shell fragments as this has only been reported from The Belt Sea.
Indicators of quality: 
Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time. There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values havebeen determined and applied on a location-specific basis. Diversity, abundance and biomass of the dominant. species and associated fauna are potential indicators of quality of this habitat
Characteristic species:
For the biotope AB.I3M: polychaetes mainly of the family Spionidae (Pygospio elegans, Streblospio shrubsoli), and for the biotope AB.I3N Bathyporeia pilosa.

Classification:
EUNIS:
The closest correspondence in EUNIS (2004) level 4 is A5.11 Infralittoral coarse sediment in low or reduced salinity.
 
Annex 1:
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by HELCOM, however this habitat may occur in the following Annex 1 habitats:
1110 Sandbanks slightly covered all the time
1160 Large shallow inlets and bays
1650 Boreal Baltic narrow inlets
 
MAES:
Marine - Marine inlets and transitional waters
Marine - Coastal
 
MSFD:
Shallow sublittoral coarse sediment
Shallow sublittoral mixed sediment
 
EUSeaMap:
Shallow coarse or mixed sediments
 
IUCN:
9.3 Subtidal Loose Rock/Pebble/Gravel
 
Other relationships:
Level 5 of the HELCOM HUB classification (2013): 
AB.E3X Baltic aphotic shell gravel characterized by mixed infaunal macrocommunity in coarse and well sorted shells and shell fragments
AB.E3Y Baltic aphotic shell gravel characterized by mixed infaunal macrocommunity in fine sand-like shell fragments
AB.I3M Baltic aphotic coarse sediment characterized by infaunal polychaetes
AB.I3N Baltic aphotic coarse sediment characterized by infaunal crustaceans and a level 6 ‘Baltic aphotic coarse sediment dominated by sand digger shrimp (Bathyporeia pilosa)’ (AB.I3N3).

Justification Outstanding Example of Biogeographical Region:
It is unkown whether this habitat presents an outstanding example of the typical characteristics of the Baltic region.

Trends in Quantity:
There has been a decline in quantity of the associated biotope which occurs on fine sand-like shell fragments. One other biotope is considered to be stable and the remaining two have not been evaluated. There is no data on which to base a historic trend assessment and estimates of future trends in quantity.

Trends in Quality:
The distribution of sand-like shell gravel bottoms in the Baltic Sea is largely unknown, with only a few small patches thought to be present in German waters. Known examples have declined due to degradation of the environmental quality caused by pollution and may degrade further in response to climate change. There is insufficient information on which to determine any trends in overal quality of this habitat or any trends over the last 50 years.

Justification of Small Range/Regression:
The distribution of sand-like shell gravel bottoms in the Baltic Sea is largely unknown, with only a few small patches thought to be present in German waters. Known examples have declined due to degradation of the environmental quality caused by p

Justification of Restricted Area:
The distribution of sand-like shell gravel bottoms in the Baltic Sea is largely unknown, only a few small patches thought to be present in German waters. The distribution of the habitat has declined due to degradation of the environmental quality cause

Pressures and Threats:
Eutrophication and increase in atmospheric CO2 leading to ocean acidification, are seen as the major threats to this  habitat. Ocean acidification is assumed to increase the dissolving rate of the calcium carbonate in mollusc shells. It is however unclear how the process will affect the sand-like shell gravel. Due to higher acidity, shell gravel may be ground down to a sand-like substrate at increasing rates possibly making the sand like shell gravel more common. On the other hand, the increased acidity may also increase the dissolving rate of the grains thus decreasing the amount of sand-like shell gravel. Eutrophication affects the habitat adversely by increasing the organic load in the Baltic Sea. The increasing organic load can lead to local oxygen depletion.

Conservation and Management:
The extent and occurrence of the biotope needs to be mapped in more detail to determine its environmental requirements. Measures to reduce eutrophication will benefit this habitat type.

Conservation Status:
Annex 1:
1110: MBAL U1
1160: MBAL U2
1650: MBAL U2
 
HELCOM (2013) assessments:
1110 VU C1 
1160 VU C1 
1650 VU C1 
HELCOM (2013) have assessed associated biotopes

Summary:
This is a Baltic Sea benthic habitat in the upper circalittoral where the substrate is predominantly coarse sediment or shell gravel. Four associated biotopes have been described characterised by mixed infaunal macrocommunities with substrates ranging from coarse and well sorted shells and shell fragments to fine shell fragments, and also areas where the substrate is predominantly coarse and the biotope characterised by infaunal polychaetes (Pygospio elegans, Streblospio spp.) or amphipods (Bathyporeia pilosa). The habitat occurs in high energy areas, typically below 20m and for the coase sediments more usually below 30m. The biotopes on shell gravel have a restricted distribution in the Baltic, especially where the substrate is comprised of  fine sand-like shell fragments as this has only been reported from The Belt Sea.
Eutrophication and increase in atmospheric CO2 leading to ocean acidification, are seen as the major threats to this  habitat. Measures to reduce eutrophication will benefit this habitat. The effects of changes in pH associated with climate change have still to be determined but may be a threat particularly in areas where the substrate is shell gravel.

References:
HELCOM. 1998. Red List of marine and coastal biotopes and biotopes complexes of the Baltic Sea, Belt Sea and Kattegat. Baltic Sea Environmental Proceedings No. 75. Helsinki Commission, Helsinki. 115pp. Available at: http://www.helcom.fi/stc/files/Publications/Proceedings/bsep75.pdf
HELCOM. 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Baltic Sea Environmental Proceedings No. 138.

Criterion A Text:
There are no qualitative estimates of the decline in this habitat but expert opinion is that in areas where shell gravel is the main substrate there have been declines of more than 25% in the last 50 years but overall the decline is not considered to reach the threshold for Near Threatened Status under Criterion A. This habitat has therefore been assessed as Least Concern under criterion A for both the EU 28 and EU 28+.

Criterion B Text:
This habitat is present in all the Baltic sea basins therefore EOO exceeds 50,000km2 however with no quantitative data on habitat extent or area, accurate calculation of EOO or AOO is not possible at the present time. This habitat has therefore been assessed as Data Deficient under criterion B for both the EU 28 and EU 28+.

Synthesis:
This habitat is present in all the Baltic Sea sub-basins sub-basins.There has been a decline in quantity of the associated biotope which occurs on fine sand-like shell fragments but quantitative data are lacking. One other biotope is considered to be stable and the remaining two have not been evaluated. There is insufficient data on which to base a historic trend assessment and estimates of future trends in quantity or quality.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed AB.E3Y as Near Threatened (B1a(ii)) and AB.I3N3 as Least Concern (A1). Biotopes AB.E3X and AB.I3M were not evaluated. Current expert opinion is that as the associated biotope which has shown some decline is small in extent compared to the other components of the habitat the assessment is Least Concern (A1) for both the EU 28 and EU 28+.

Sub-habitats in Need of Examination:
AB.E3Y Baltic aphotic shell gravel characterized by mixed infaunal macrocommunity in fine sand-like shell fragments.


