Using Red List Indices to measure progress towards the 2010 target and beyond

Area of Science:

• Conservation Biology
• Ecology
• Biodiversity Science

Background:

• The International Union for Conservation of Nature (IUCN) Red List is the leading global system for assessing species extinction risk.
• Red List Indices (RLIs) quantify changes in the conservation status of species over time.
• RLIs are calculated using data on population size, range, and trends for fully assessed species.

Purpose of the Study:

• To illustrate the utility of Red List Indices (RLIs) in tracking biodiversity threat status.
• To present trends in extinction risk for key taxonomic groups, specifically birds and amphibians.
• To introduce the development of a sampled index for more comprehensive biodiversity trend analysis.

Main Methods:

• Calculating RLIs based on species reassessments and changes in IUCN Red List categories.
• Analyzing RLI data for birds globally from 1988-2004 across all biogeographic realms and ecosystems.
• Compiling a preliminary RLI for amphibians from 1980-2004.
• Developing a sampled index using a stratified sample of species across major taxonomic groups, realms, and ecosystems.

Main Results:

• The RLI for birds demonstrates a consistent deterioration in threat status globally between 1988 and 2004.
• A preliminary RLI for amphibians indicates similar rates of decline in conservation status over the period 1980-2004.
• RLIs provide a valuable, albeit coarse, resolution for understanding extinction-risk trends in fully assessed taxonomic groups.

Conclusions:

• Global biodiversity, represented by birds and amphibians, shows a significant increasing trend in extinction risk.
• RLIs are effective tools for monitoring conservation status and highlighting the need for targeted conservation actions.
• Ongoing development of sampled indices aims to provide more representative biodiversity extinction-risk trends across all life forms.