Trends in Biodiversity: Vertebrates

Nearly one-fifth of all vertebrates are currently estimated to be threatened with extinction, with a range between 16% and 33%. There are two well-established means of understanding how status changes over time: monitoring changes in the abundance of populations and tracking change in extinction risk. Evidence indicates a decline of 58% in vertebrate population abundance over the last 42 years, for the former, while at least 52 species per year deteriorated by one IUCN Red List category between 1980 and 2008. As alarming as these observed trends are, they undoubtedly would have been worse in the absence of conservation actions. Ongoing work aims to improve existing metrics of change, and also their utility for projecting change into the future under various scenarios