South Asian protected areas insufficiently reduce extinction risk in terrestrial vertebrates

Abstract

Biodiversity loss, accelerated by anthropogenic climate and land-use change, poses a major threat to humanity and is especially acute in global biodiversity hotspots. South Asia (SA), a region of exceptional biological, geographic, and cultural diversity undergoing rapid economic and population growth, is one such hotspot of change and extinction risk. Through protection, monitoring, and legislative designation, Protected Areas (PAs) can buffer against extinction risk by safeguarding habitats and threatened species, but their effectiveness is constrained by limited resources, fragmented management, and sometimes taxonomically biased designation. A thorough appraisal of species richness, distribution, and extinction risk inside and outside PAs is therefore essential to assess how well a region's PAs mitigate extinction risk. This study evaluates the efficacy of SA's PAs by identifying the region's most threatened terrestrial vertebrate classes, quantifying the relationship between extinction risk and ecogeographic factors, examining associations of PA occupancy and extinction risk, and mapping the distribution of extinction risk in SA. Results show that PAs in SA represent threatened mammals best and are 33% more likely to host threatened species overall. However, high extinction risk aligns with biodiversity hotspots where overlap with PAs may be limited. SA's PAs are small, fragmented, and unevenly distributed, underrepresenting many threatened species. Despite these limitations, they remain crucial for conserving key habitats and species. Improved design, spatial placement, and representativeness are needed to mitigate terrestrial vertebrate extinction risk effectively in this megadiverse region.