Guidelines & Brochures — Global

The IUCN Red List Categories and Criteria: Comparison between versions 2.3 (1994) and 3.1 (2001)

All new assessments and reassessments for publication on The IUCN Red List must use the IUCN Red List Categories and Criteria. Version 3.1 (1st edition: IUCN 2001; 2nd edition: IUCN 2012). However, there are still some taxa on The IUCN Red List that have not been reassessed since the 1990s; these taxa still use the IUCN Red List Categories and Criteria. Version 2.3 (IUCN 1994).

This document summarizes the differences between the two versions of the IUCN Red List Categories and Criteria. [Available in English only.]