IUCN Red List Categories and Criteria
The IUCN Red List Categories and Criteria are intended to be an easily and widely understood system for classifying species at high risk of global extinction. This second edition of the IUCN Red List Categories and Criteria: Version 3.1 retains the same assessment system presented in the first edition. To allow for occasional changes in documentation requirements for assessments, information that was previously outlined in Annex 3 has been moved to a separate reference document.
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