Climate change and low species drought tolerance will negatively impact plant richness in the Neotropical seasonally dry forests

Abstract Neotropical seasonal dry forest (NSDF) is one of the most threatened ecosystems under global climate change (GCC) predictions, with likely species losses and uneven modification of diversity patterns all through its distribution. Nonetheless, few studies have evaluated the GCC impacts on the diversity patterns of NSDF plants. The lack of continental-scale approaches restricts our understanding of GCC consequences in the high beta-diverse NSDF. We showed some potential impacts of GCC on the distributions of over 1000 species of the NSDF, species richness patterns, and species composition of assemblages (beta diversity). We focus on five representative plant families that are abundant, dominant, and have a high endemism rate within the NSDF. These families were Cactaceae, Capparaceae, Fabaceae, Malvaceae, and Zygophyllacea. We reconstructed potential species distributions in the present and future scenarios (2040–2080) considering an intermediate Shared Socio-economic Pathway scenario and two dispersal ability assumptions on the taxa. We correlated climate-induced changes in the species distribution ranges with drought tolerance. We found that, even under a favorable dispersal scenario, species distribution and richness showed significant declines in the future across sites where temperatures are predicted to increase in the future. In Fabaceae, we observed a negative correlation between drought tolerance and changes in species distribution ranges in the future. Our results suggested biotic homogenization across the NSDF, but biotic heterogenization is the likely outcome at the continental scale under dispersal limitations. This information is critical for further planning of conservation actions as it can help to assess the current and future value of NSDF-protected areas and define new areas worth protecting.