Alien species are a principal cause of biodiversity loss
They have been partly or wholly responsible for the extinction of at least 68 bird species over the last 500 years.
Invasive alien species are species whose introduction and/or spread outside their natural distribution threatens biological diversity. Although not every non-native species causes problems, many do and the impact is severe.
Alien species are organisms introduced outside their natural habitat. Half of all biodiversity is the result of independent evolution of organisms in separate regions under different climatic conditions. Biodiversity is maintained thanks to natural barriers, such as oceans, mountains and deserts, preventing different ecosystems in different regions from mixing. When we import a species into a region where it does not belong, we break down these natural barriers and put biodiversity in danger.
Alien species are a principal cause of biodiversity loss. They have been partly or wholly responsible for the extinction of at least 68 bird species over the last 500 years. Alien species eat native species, compete with them for resources such as food, hybridize with them, disrupt and destroy their habitats or weaken and kill them by introducing pathogens, parasites and diseases into their environment. More than 12,000 alien species have gained a foothold in Europe, from Asian tiger mosquitoes to North American ragweed, and at least 1,500 are considered to be harmful by the European Commission. Alien species cause some 12.5 billion Euros worth of damage each year in the European Union alone.
Stichting BirdLife Europe gratefully acknowledges financial support from the European Commission. All content and opinions expressed on these pages are solely those of Stichting BirdLife Europe.