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Invasive species

Cumulative number of aquatic introductions

Cumulative number of aquatic introductions rose fast in the second half of the 20th century

Source: FAO 1998 and Wellcome 1988

Invasive species are organisms (usually transported by humans) that successfully colonize native ecosystems. Such species have been a major threat to native species through the effects of predation, alteration of habitat or disruption of ecosystem processes. Notable terrestrial examples include the loss of many endemic land snail species of French Polynesia following the introduction of the predatory snail Euglandina rosea, and the decline in New Zealand's native birds due to the introduction of Australian brushtail possum. Aquatic examples include the introduction of the predatory Nile perch Lates niloticus to Lake Victoria around 30 years ago, which contributed to the apparent extinction of 250 endemic species of cichlid fishes (Harrison and Stiassny 1999). The number of aquatic introductions rose rapidly during the second half of the 20th century (see graph).

The CBD recognizes the importance of invasive species as a global problem and calls upon contracting parties to prevent the introduction of, control or eradicate those alien species that threaten ecosystems, habitats and species. In response to a recommendation from the CBD in 1996, the Global Invasive Species Programme (GISP) was developed, which is coordinated by the Scientific Committee on Problems of the Environment (SCOPE), in collaboration with IUCN, Centre for Agriculture and Biosciences International and UNEP. The programme will review current knowledge on invasive species and develop new tools and approaches to deal with the problem both locally and globally.