Shifting snake ranges in a warming world

Climate change is driving major shifts in global snake biodiversity, yet large-scale assessments across taxonomic, phylogenetic, and genetic dimensions remain limited, hindering effective conservation. We compiled 3,486,894 records of 3044 species across seven biogeographic realms to evaluate current spatial patterns of diversity and to project future range dynamics and conservation priorities under different climate change scenarios. We constructed species distribution models for 1201 species to project range dynamics under four shared socioeconomic pathways across 10 global climate models and then applied generalized linear mixed models that integrated genetic and phylogenetic diversity to assess conservation priorities. Of 1201 species, 542 (45.1%) were projected to experience significant range contractions (a mean range loss of 11.62%). Of these, 175 species (14.6%) were projected to undergo both range loss and shifts of more than 400 km, and 103 of 775 species (13.3%) were projected to exhibit range contraction and low genetic diversity. Range shifts were widespread, especially in the Palearctic, with >60% of genera expected to move >100 km. Species in tropical forests and montane habitats were disproportionately at risk of range contraction and range shifts. Current protected areas (PAs) covered only 20-40% of the ranges of threatened snakes, and 81 of 341 genera (23.7%), such as Boa and Lachesis, were projected to lose habitat more rapidly inside PAs than outside. We identified four groups of conservation priority based on range vulnerability, genetic risk, and conservation gaps: taxa facing both range contraction and long-distance shifts; genetically vulnerable taxa with shrinking ranges; taxa inadequately covered by PAs; and taxa projected to lose habitat faster inside PAs than outside. These findings underscore the urgent need for spatially adaptive, genetically informed, and climate-resilient conservation strategies to protect the evolutionary potential of global snake diversity.