Impact of alternative metrics on estimates of extent of occurrence for extinction risk assessment

摘要: In International Union for Conservation of Nature (IUCN) Red List assessments, extent occurrence (EOO) is a key measure extinction risk. However, the way assessors estimate EOO from maps species’ distributions inconsistent among assessments different species and major taxonomic groups. Assessors often area mapped distribution, but these exclude areas that are not habitat in idiosyncratic ways created at same spatial resolutions. We assessed impact on risk categories applying methods (minimum convex polygon, alpha hull) estimating 21,763 mammals, birds, amphibians. Overall, percentage threatened requiring down listing to lower category threat (taking into account other criteria under which they qualified) spanned 11–13% all combined (14–15% 7–8% 12–15% amphibians). These listings resulted larger estimates depended calculation method. Using birds as an example, we found 14% near could require based minimum polygon (MCP) approach, approach now recommended by IUCN. Other metrics (such had marginally smaller impacts. Our results suggest uniformly MCP may lead one-time hundreds ultimately ensure consistency across realign with theoretical basis metric was founded.