Post a comment on the text below


Invasive alien species (IAS) threaten native wildlife, alter communities, affect the food webs, and introduce new constraints to the recovery of the native biodiversity. Some also cause economic damage.

Examples of invasive plants are curly waterweed (Lagarosiphon major), floating pennywort (Hydrocotyle ranunculoides) and large flowered waterweed (Egeria densa). Such plants may cover large areas of water and wetlands making natural vegetation and ecosystems impossible. Invasive plants have disrupted navigation and damaged waterworks by blocking pipes and pumps. This also included pumping intakes for cooling water of nuclear power plants resulting in safety problems (Sarat, et al., 2015). For example to control damage of floating pennywort in the Netherlands the total annual control costs have been  around 1 million Euro (BirdLife International, n.d.).

Some invasive aquatic invertebrates have had major effects on the ecosystems that they invade, e.g. the red swamp crayfish and the distribution of the crayfish plague. The plague is estimated to have economic cost in Europe of over €53 million/year (EC 2019c). The zebra mussel Dreissena polymorpha forms dense encrustations, which provoke serious damage to infrastructure, clogging up the water-intake of industrial and drinking water plants. The killer shrimp Dicerogammarus villosus can feed on a variety of freshwater invertebrates, including other native shrimp species, fish eggs and young fish, and can significantly alter ecosystems (BirdLife International, n.d.). Alien species may also act as carrier of fungus organisms or spread diseases (Strayer, 2010).

Invasive freshwater fish e.g. from stocking disrupted the food web, when predating the native smaller fish and their food, and simplified the original communities (BirdLife International, n.d.). Escapes from aquaculture (e.g. salmon) changed genetic behaviour of natural populations.

You cannot post comments to this consultation because you are not authenticated. Please log in.