Plant endemic diversity in the Irano-Anatolian global biodiversity hotspot is dramatically threatened by future climate change

Climate change is affecting biodiversity across all taxonomic groups and ecosystems globally. Mountain ecosystems are particularly sensitive to climate warming, as temperature is generally a limiting factor for their vegetation. The Irano-Anatolian global biodiversity hotspot, which includes high elevations with a rich endemic biodiversity, offers good opportunities to study the effects of future climate change on its plant diversity. We used species distribution models to predict changes in species' habitat suitability by the end of the century (2071-2100) under two extreme shared socioeconomic pathways (SSPs), for 713 endemic plant species of the area. We found that a remarkably high number of species are predicted to experience a shift in their climatically suitable habitats from lower to higher elevations, resulting in a decrease in their potential range areas (79 % and 86 % of species, under the SSP 1-2.6 and SSP 5-5.8 scenarios, respectively). As a consequence, we also predicted a decrease in species richness in the low (< 1200 m) and middle (1200-2500 m) elevational belts, while an increase in species richness in high elevational belt (> 2500 m). This study demonstrates that climate change has the potential to cause a massive restructuring of plant community composition in this area, including the risk of extinction for many species. This poses a significant threat to the biodiversity of this region, which calls for urgent action to mitigate as far as possible the adverse effects of climate change in the region.