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Mapping and Assessment of Ecosystems and their Services. Trends

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Invasive species

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Invasive alien species (IAS) are non-native species whose introduction and/or spread outside their natural, past or present, ranges pose a threat to biodiversity.

Invasive alien species occur in all major groups, including animals, plants, fungi and micro-organisms, and are considered, at least on islands, to be the second most important reason for biodiversity loss worldwide (after direct habitat loss or destruction).

About 10 000 alien species have been registered in Europe. Some of these species were introduced on purpose and remain economically important. However, a proportion of the alien species established cause significant damage to native biodiversity and can be classified as invasive alien species according to the Convention on Biological Diversity.

Invasive species can cause great damage to native species by competing with them for food, eating them, spreading diseases, causing genetic changes through inter-breeding with them and disrupting various aspects of the food web and the physical environment.

Cumulative number of alien species established in terrestrial environment in 11 countries

There is an upward trend in the establishment of new species, with impacts on biodiversity expected to increase because of the growing number of species involved, and an increasing vulnerability of ecosystems to invasions, which results from other pressures such as habitat loss, degradation, fragmentation, over-exploitation and climate change.

Globalization, particularly increased trade and tourism, have resulted in an upsurge in the number and type of alien species arriving in Europe. Marine and coastal areas are being drastically affected as a result of increased shipping and the building of canals between isolated seas. In order to gain better understanding of invasive alien species and their impact on European biodiversity a list of the worst invasive alien species threatening biodiversity in Europe has been established. The list currently contains 163 species or species groups.

 Map 1 Number of the listed 'worst' terrestrial and freshwater invasive alien species threatening biodiversity in Europe

 Number of the listed 'worst' terrestrial and freshwater invasive alien species threatening biodiversity in Europe

Note: The numbers on the map indicate how many species from the list are present in each country (e.g. out of 163 'worst' invasive alien species, 34 are present in Portugal).

Further reading

 

Indicators:

Cumulative number of alien species established in terrestrial environment in 11 countries Cumulative number of alien species established in freshwater environment in 11 countries Alien species in European marine/estuarine waters (October 2008) Number of the listed 'worst' terrestrial and freshwater invasive alien species threatening biodiversity in Europe


Selected links:

EC Invasive Alien Species

Delivering Alien Invasive Species Inventories for Europe - DAISIE

European Network on Invasive Alien Species - NOBANIS

East and South European Network for Invasive Alien Species  - ESENIAS

European Alien Species Information Network - EASIN

CIESM Atlas of Exotic Species in the Mediterranean

Global Invasive Species Information Network- GISIN

Global Invasive Species Database - GISD

CABI Invasive Species Compendium

Bern Convention Group of Experts on Invasive Alien Species (IAS)