Extinctions since 1970

The recently-launched GEO-3 report roused interest in species extinction, so we provide a very brief introduction to some of the technical issues involved in tracking extinction and a recent compilation of extinct species in three better-known animal groups that have been authoritatively assessed (see below for sources). Further discussion will be provided in the forthcoming World Atlas of Biodiversity prepared by UNEP-WCMC.

The extinction of species is natural and expected, but all evidence suggests that recent and current extinction rates are considerably higher than would be expected without human influence.

It is impossible to record contemporary extinction events with precision. There is often disagreement on whether a population deserves recognition as a full species. The species involved may well be unknown, and even if they have been discovered and named, they may be too small to be noticed without special sampling procedures. The entire process of decline and eventual extinction may take place over many years or even centuries. Typically, many years elapse before sightings of a species become sparse enough to generate concern, and many more years may pass before negative evidence (ie. failure to find the species despite repeated searches) accumulates to the point where extinction is the most probable explanation. Unless circumstances are unusual, monitoring recent extinction events has a resolution limit measured in decades.

There is considerable agreement on the lists of extinct species from different organisations. They differ where different criteria for extinction are used. A relatively small number of extinctions are regarded as "fully resolved" when the strict criteria adopted by the Committee on Recently Extinct Organisms (CREO; http://creo.amnh.org) are applied, but a larger number results when using the categorisation system developed by IUCN (see http://www.redlist.org). Bird extinctions were summarised in 2000 by BirdLife International (Threatened birds of the world. Lynx Edicions: Barcelona.) using CREO criteria.

Fishes believed to have become extinct since 1970 (Source: CREO, 2001

Mammals believed to have become extinct since 1970 (Source: CREO, 2001)

Birds believed to have become extinct since 1970 (Source: Birdlife International 2000)

Species in bold are categorised as resolved.