Red List assessment of widespread and long-lived species

Abstract

Abstract The use of criterion A of the IUCN Red List to categorize species as threatened that have undergone recent decline can lead to the listing of relatively common and widespread species. Loss of habitat through deforestation is a common cause of decline throughout much of the world but is often not incorporated into assessments because of uncertainty about the magnitude of change. A recent assessment of eucalypt species in Australia subject to deforestation provides a method for assessment under criterion A and has implications for listing of long-lived, widespread species affected by deforestation. Scenarios for two widespread eucalypt species subject to extensive deforestation are used to demonstrate how the threat status of a species may be recategorized in a lower threat category as declines resulting from a threatening process are mitigated. I argue that criterion A indicates an appropriate assessment of extinction risk and I provide a simple function based on predicted diminishment of the population decline to identify when a species could be disqualified from a threat category under subcriterion A2 (past decline).