Monitoring trends in biological invasion, its impact and policy responses

Biological invasions are a major threat to biological diversity and to human well-being, affecting all regions of the world, and all ecosystems. The global community has committed to prevent and mitigate the impacts of invasive alien species (IAS), and to monitor trends in invasions. Following a review of a range of candidates, the development of four indicators of invasions was prioritized in light of data availability and the practicality of reporting against the 2010 target. These comprise a measure of the state of the problem (the number of IAS per country), a measure of the pressures IAS place on biodiversity (the Red List Index of impacts of IAS), and two measures of responses to the problem (trends in the number of international agreements relevant to reducing threats to biodiversity from IAS, and trends in the adoption of national legislation relevant to the control of IAS).