Improvements to the Red List Index.

Stuart H.M Butchart,Jonathan E.M Baillie,Suhel Quader,Will R Turner,H Resit Akçakaya,Craig Hilton-Taylor,Ben Collen,Rajan Amin,Simon N Stuart,Janice Chanson,David Lusseau

doi:10.1371/journal.pone.0000140

Stuart H.M Butchart, Jonathan E.M Baillie + Show 9 more

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https://doi.org/10.1371/journal.pone.0000140

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Journal: PloS one	Publication Date: Jan 3, 2007
Citations: 289	License type: CC BY 4.0

Affiliation: Zoological Society of London, Conservation International

Abstract

The Red List Index uses information from the IUCN Red List to track trends in the projected overall extinction risk of sets of species. It has been widely recognised as an important component of the suite of indicators needed to measure progress towards the international target of significantly reducing the rate of biodiversity loss by 2010. However, further application of the RLI (to non-avian taxa in particular) has revealed some shortcomings in the original formula and approach: It performs inappropriately when a value of zero is reached; RLI values are affected by the frequency of assessments; and newly evaluated species may introduce bias. Here we propose a revision to the formula, and recommend how it should be applied in order to overcome these shortcomings. Two additional advantages of the revisions are that assessment errors are not propagated through time, and the overall level extinction risk can be determined as well as trends in this over time.

Highlights

In response to the accelerating rate of biodiversity loss, and the farreaching impacts of this, the governments of 190 countries have pledged to significantly reduce the rate of biodiversity loss by 2010 [1]
Red List Index (RLI) based on the relevant sets of species are currently being considered for adoption by the Ramsar Convention on Wetlands, the Convention on Migratory Species (CMS), the Agreement on the Conservation of Albatrosses and Petrels under the CMS, and for European threatened species through the Streamlining European Biodiversity Indicators-2010 initiative, which is coordinated by the European Environment Agency, the European Centre for Nature Conservation and UNEP-WCMC
RLI values cannot become fixed to zero (Figure 1E; see below for discussion of the particular meaning of zero under the new formulation) or become negative (Figure 1F); they are not affected by the frequency of assessments (Figure 1G), and species evaluated for the first time that differ in average extinction risk or in the rate of change of extinction risk do not introduce spurious trends (Figure 1H)