Using an improved method for calculating the extinction risk of species could lower the risk estimates for about one in ten threatened species.
The influential Red List from the International Union for Conservation of Nature (IUCN) groups thousands of threatened plants and animals into different categories of extinction risk. Lucas Joppa at Microsoft Research in Redmond, Washington, and his colleagues analysed different methods of calculating the 'extent of occurrence' (EOO) for 21,763 species of mammals, birds and amphibians on the Red List. The EOO is the total area over which a species might be found — the smaller the area, the greater the vulnerability of that species.
Past assessments often used EOO calculation methods that the IUCN now considers outdated. The researchers found that applying the IUCN-approved method would lower the risk category of many threatened animals for 14–15% of mammals, 7–8% of birds and 12–15% of amphibians.
Conserv. Biol. http://doi.org/6jq (2015)