Climate change scenarios forecast increased drought exposure for terrestrial vertebrates in the contiguous United States

Abstract

Anthropogenic climate change is altering patterns of extreme weather events across the planet, with far-ranging consequences for biodiversity. Increases in the frequency, duration, and severity of droughts are anticipated to substantially impact natural ecosystems. Here, we predicted the extent to which 1221 terrestrial vertebrates in the contiguous United States will be increasingly exposed to annual (12-month) and prolonged (36-month) drought, under three global climate models and two representative concentration pathways. On average, a 377% increase in annual drought exposure and a 579% increase in prolonged drought exposure are anticipated for the study area by 2050–2080, compared to 1950–2005. Species in the southwestern USA could see the largest increases in drought exposure, while this area also has the highest vertebrate diversity and an abundance of drought-threatened species. Our results aid in identifying vertebrates and ecoregions anticipated to see large increases in drought exposure, which can inform conservation strategies aimed at mitigating vertebrate extinction risks. Anthropogenic climate change is expected to significantly increase drought exposure for 1221 terrestrial vertebrates in the United States, with an average increase of 377% for annual drought and 579% for prolonged drought by 2050–2080, according to analysis of different climate scenarios to assess drought exposure across species and ecoregions.