The Red List Index: measuring trends in the extinction risk of species

Ben Lascelles Wandering Albatross one of the species most affected by longline fishing. Zoom In

BirdLife, IUCN and the other partners of the IUCN Red List have developed the Red List Index (RLI) to measure trends in the extinction risk of species. The RLI is based on data from the IUCN Red List (the most authoritative and objective system available for classifying species in terms of their risk of extinction). The Red List Index (RLI) illustrates the overall rate at which species are slipping towards extinction.

• Red List Indices are robust and powerful tools for measuring biodiversity loss - they are already being used to track progress towards the 2010 target.
• RLIs illustrate the overall rate at which sets of species change in overall threat status (i.e. projected relative extinction risk), based on population and range size and trends as quantified by categories on the IUCN Red List.
• RLIs are based on the number of species moving between categories owing to genuine improvement or deterioration in status.
• The overall status of the world's birds has deteriorated steadily since 1988. RLIs for amphibians, mammals and corals also show declines, in some cases worryingly faster than those shown by birds.
• RLIs will soon be available for a suite of taxonomic groups, and methods are being developed to aggregate these indices into a single RLI for biodiversity. A sampled approach is being implemented for poorly known groups with many species, in order to increase the taxonomic breadth and representativeness.

Policy uptake:

The RLI has been adopted as a measure to report on the indicator 'proportion of species threatened with extinction' under the United Nation's Millennium Development Goal 7 'to ensure environmental sustainability'. For further information see:

• BirdLife News Story - BirdLife's pioneering approach adopted by Millennium Development Goals
• 2008 United Nations MDG report - PDF 3.25MB

The RLI is used by the Convention on Biological Diversity as a measure for the indicator 'change in status of threatened species' to track trends towards the 2010 target. For further information see:

• CBD webpage
• The Global Biodiversity Outlook 2 profiling the RLI - PDF 8.77MB

The RLI is being used by the Ramsar Convention on Wetlands. For further information see:

• Ramsar report on RLI for waterbirds - DOC 211KB

The RLI is being used to track trends in the status of migratory species. For further information see:

• Convention on Migratory Species (CMS), the Agreement on the Conservation of Albatrosses and Petrels under the CMS
• African-Eurasian Waterbird Agreement under the CMS - PDF 216KB
• 4^th AEWA Conservation Status Report - PDF 1.14MB

At a regional scale, the RLI has been adopted as an indicator under the Streamlining European Biodiversity Indicators (SEBI-2010) process. Download the technical report - PDF 8.1MB

The Red List Index for the world's birds

• There has been a steady and continuing deterioration in the threat status (projected extinction risk) of the world's birds between 1988 and 2008. Read State of The World's Birds case study.

RLI for the world's birds

• Birds have deteriorated faster in some regions than others. Read State of The World's Birds case study.

RLI for birds in different biogeographic realms

• Seabirds are more threatened and declining faster compared to other groups. Read State of The World's Birds case study.

Related Links

• Butchart (2008) Red List Indices to measure the sustainability of species use and impacts of invasive alien species. Bird Conserv. Internat. 18 (suppl.) 245-262.
• Butchart et al. (2007) Improvements to the Red List Index PLoS ONE 2(1): e140 (PDF, 219KB)
• Butchart et al. (2006) Biodiversity indicators based on trends in conservation status: strengths of the IUCN Red List Index. Conserv. Biol. 20: 579–581. (PDF, 156KB)
• Butchart et al. (2005) Using Red List Indices to measure progress towards the 2010 target and beyond. Phil. Trans. Roy. Soc. B. 360: 255-268. (PDF, 207 KB)
• Butchart et al (2004) Measuring Global Trends in the Status of Biodiversity: Red List Indices for Birds. PLoS Biol. 2 (12): e383 (PDF, 1.7 MB)
• Baillie et al. (2008) Toward monitoring global biodiversity. Conservation Letters 1: 18-26. (PDF, 159KB)
• 2010 Biodiversity Indicators Partnership factsheet on the RLI
• McGeoch et al. (2010) Global indicators of biological invasion. Diversity and Distributions 16: 95–108
• Download the Red List Index calculator – an excel template for entering RLI data and automatically calculating and presenting the RLI. Version: Excel 2003 and earlier
• Download the Red List Index calculator – an excel template for entering RLI data and automatically calculating and presenting the RLI. Version: Excel 2007
• Download the Red List Index Guidelines for National and Regional Application