Species richness, geographic distribution, pressures, and threats to bats in the Caatinga drylands of Brazil

Tropical dry forests (TDF) are threatened worldwide, affected by conversion to agriculture, fragmentation, fires, and climate change. Most of the remaining TDF are in South America, including Brazil's Caatinga. Understanding how the biota of TDFs responds to habitat loss and climate change is a scientific challenge, especially to diversified groups, such as bats, whose richness and ecological roles in TDF are usually underestimated. We updated and synthesized occurrence data and generated distribution models for Caatinga bats considering present and future scenarios. At least 96 species, 48 genera, and eight families were recorded, including two endemic species; five additional species may occur in the biome. The highest potential species richness occurs in the east, in the Caatinga/Atlantic Forest ecotone; the lowest in the west, in the Caatinga/Cerrado ecotone. Current and projected deforestation led to a reduction of 65% in areas with very high potential richness, and only 0.4% will remain within current protected areas. In a business as usual scenario (i.e., high and fast habitat loss + low in situ protection + high potential exposure to climate change) the bat fauna of the Caatinga will be negatively impacted. Improving the conservation of roosting and foraging sites, with the expansion and/or creation of protected areas is urgently needed.