Future of high mountain endemic species under climate change: predicting the potential scenarios for Stellaria pulvinata in the Altai Mountains.

Mountain ecosystems are vulnerable to climate change and unsustainable human activities worldwide, as evidenced by shifts in vegetation and losses of plant species diversity and habitats. These phenomena have a particularly important effect on narrow endemics that are sensitive to environmental and climatic changes. In the Altai Mountain Country (AMC), the endemic plant species Stellaria pulvinata Grubov (Caryophyllaceae) is found in small geographic areas at high elevations between 2,070 and 4,000 m. However, its current geographic range is shrinking owing to global warming, climate change, and habitat loss. Here, we aimed to assess the habitat suitability of S. pulvinata using MaxEnt to identify key environmental factors and predict shifts in its distribution under different climate scenarios (SSP2-4.5 and SSP5-8.5) for the 2050s and 2090s. We tested five algorithms using the "sdm" package in R, and found that the MaxEnt algorithm demonstrated the highest predictive performance (area under the curve (AUC) = 0.96, true skill statistic (TSS) = 0.89, correlation coefficient (COR) = 0.24, deviance = 0.23); therefore, MaxEnt was selected for subsequent analyses. Currently, the total potentially suitable habitat area for S. pulvinata spans approximately 169,659 km