Ongoing declines for the world's amphibians in the face of emerging threats

Abstract

Systematic assessments of species extinction risk at regular intervals are necessary for informing conservation action^1,2. Ongoing developments in taxonomy, threatening processes and research further underscore the need for reassessment^3,4. Here we report the findings of the second Global Amphibian Assessment, evaluating 8,011 species for the International Union for Conservation of Nature Red List of Threatened Species. We find that amphibians are the most threatened vertebrate class (40.7% of species are globally threatened). The updated Red List Index shows that the status of amphibians is deteriorating globally, particularly for salamanders and in the Neotropics. Disease and habitat loss drove 91% of status deteriorations between 1980 and 2004. Ongoing and projected climate change effects are now of increasing concern, driving 39% of status deteriorations since 2004, followed by habitat loss (37%). Although signs of species recoveries incentivize immediate conservation action, scaled-up investment is urgently needed to reverse the current trends.

Fig. 1. The distribution of 2,873 globally threatened amphibian species.

The darker colours correspond to higher species richness. The colour scale is based on 10 quantile classes. Maximum richness equals 61 species. The cell area is 865 km². One species was excluded because no spatial data were available.

Fig. 2. The types of threats affecting amphibian species in threatened categories.

The threats to a species were coded using the threat-classification scheme and grouped for ease of comparison (see the ‘Classification schemes’ and ‘Threats to threatened species’ sections of the Methods). All threats shaded in green are causing habitat loss and degradation. The grey sections denote the number of species for which the threat timing is in the future rather than ongoing. Note that most species are experiencing multiple threats. Source data

Fig. 3. RLIs showing trends in overall extinction risk.

a, The RLIs of all comprehensively assessed taxonomic groups on the IUCN Red List. b, The amphibian RLI disaggregated by biogeographical realm. c, The amphibian RLI disaggregated by breeding strategy. d, The amphibian RLI disaggregated by order. Source data

Fig. 4. Geographical pattern of the primary drivers of deteriorating status among amphibians.

a,b, The primary drivers of deteriorating status among amphibians during 1980–2004 (482 species; a) and 2004–2022 (306 species; b). Cell colour was determined by the primary driver impacting the most species. Where two primary drivers equally contribute to a cell, an intermediate colour is shown. The stars indicate where the primary driver is undetermined or there are numerous primary drivers. The cell area is 7,775 km².

Fig. 5. Species moved into a higher Red List category coded by the primary driver causing the change.

a,b, The number of species moved into a higher Red List category, coded by the primary driver causing the change, during 1980–2004 (a) and 2004–2022 (b). Red List categories are ordered by highest to lowest threat level: Extinct (EX), Extinct in the Wild (EW), Critically Endangered (CR), Endangered (EN), Vulnerable (VU) and Near Threatened (NT). CR species that are likely to be extinct have the Possibly Extinct (PE) tag. Source data

Extended Data Fig. 1. Geographical pattern of 120 amphibians that improved in status between 1980–2022.

Outlined hexagons indicate at least one species improved due to conservation.