Indicator 86. Red List Index

Rationale and definition:

The Red List Index (RLI), drawing on the IUCN Red List of Threatened Species, tracks the rate of extinction for marine and terrestrial species groups in the near future (i.e. 10-50 years) in the absence of any conservation action.1 A downward trend in the index implies that the risk of a species’ extinction is rising. The RLI is used to measure progress towards the Aichi Target 12 of the Convention on Biological Diversity (CBD)2 and the Millennium Development Goals.

The IUCN Red List is the most respected system to track the status of threatened species according to seven risk categories that range from “extinct” to “least concern.”3 The criteria for determining the risk status of each species are scientifically rigorous and easy to understand for the general public. The Red List Index is applicable to different major species groups, transparent, and can track trends over time.4 It has been developed for many major species groups, such as amphibians and birds, but important gaps remain, particularly among less well-studied major species groups, such as fungi. For species groups not yet covered by the RLI, a sampled approach can be used that is based on representative samples of species from taxonomic groups.5


By country and major species group, and for Internationally Traded Species. The RLI can also be disaggregated to regional and national levels, in particular via National Red Lists.6 We recommend that national and global RLIs be reported by key species group. In the case of smaller countries that cover contiguous marine or terrestrial biomes, it may be more appropriate to report regional RLI by key species group.

We propose that the RLI also be applied to internationally traded terrestrial and marine species including those identified in appendices I and II of the Convention on Internationally Traded and Endangered Species (CITES).7 The RLI for Internationally Traded Species will track the near-term extinction risk for species that are subject to international trade and whose survival is therefore heavily affected by non-host countries and cooperative international strategies.

Comments and limitations:

The Red List Index is a composite index comprising a large number of underlying variables. At first sight it might therefore fall foul of a general preference against composite indices. However, the underlying data for the Red List Index is collected and analyzed by one organization and therefore does not impose any additional burden on NSOs. In view of this fact and the very widespread use of this index its inclusion in an SDG indicator framework strikes us as sensible.

Primary data source:

International monitoring.

Preliminary assessment of current data availability by Friends of the Chair:


Potential lead agency or agencies:

IUCN and Partner organizations, in particular BirdLife International and UNEP-WCMC.

  1. Butchart, SH et al (2007). Improvements to the Red List Index, PLoS ONE 2(1): 140.

  2. See the Biodiversity Indicators Partnership for indicators to measure progress towards the Aichi targets.

  3. For more information, see the IUCN Red List.

  4. See the overview of the Red List.

  5. See Baillie, J.E.M., Toward monitoring global biodiversity, Conservation Letters 1 (2008) 18–26, and Zoological Society of London.

  6. See more information on national RLIs.

  7. See CITES website.