A global reptile assessment highlights shared conservation needs of tetrapods

Comprehensive assessments of species' extinction risks have documented the extinction crisis(1) and underpinned strategies for reducing those risks(2). Global assessments reveal that, among tetrapods, 40.7% of amphibians, 25.4% of mammals and 13.6% of birds are threatened with extinction(3). Because global assessments have been lacking, reptiles have been omitted from conservation-prioritization analyses that encompass other tetrapods(4-7). Reptiles are unusually diverse in arid regions, suggesting that they may have different conservation needs(6). Here we provide a comprehensive extinction-risk assessment of reptiles and showthat at least 1,829 out of 10,196 species (21.1%) are threatened-confirming a previous extrapolation(8) and representing 15.6 billion years of phylogenetic diversity. Reptiles are threatened by the same major factorsthat threaten othertetrapods-agriculture, logging, urban development and invasive species-although the threat posed by climate change remains uncertain. Reptiles inhabiting forests, where these threats are strongest, are more threatened than those in arid habitats, contrary to our prediction. Birds, mammals and amphibians are unexpectedly good surrogates for the conservation of reptiles, although threatened reptiles with the smallest rangestend to be isolated from other threatened tetrapods. Although some reptiles-including most species of crocodiles and turtles-require urgent, targeted action to prevent extinctions, efforts to protect other tetrapods, such as habitat preservation and control of trade and invasive species, will probably also benefit many reptiles.

Automated summary

Global assessments have shown that 40.7% of amphibians, 25.4% of mammals, and 13.6% of birds are threatened with extinction, but reptiles have been excluded from these assessments. This study provides a comprehensive extinction-risk assessment for reptiles and finds that at least 21.1% of species are threatened, with similar major threats as other tetrapods. Reptiles in forests are more threatened than those in arid habitats. Threatened reptiles tend to be isolated from other threatened tetrapods.