Climate Change vs. Human Activities: Conflicting Future Impacts on a High-Altitude Endangered Snake (Thermophis...

Endemic ectotherms in high-altitude regions face dual threats from climate change and human activities, yet quantifiable indicators to disentangle these stressors remain limited. We developed a novel multi-scenario framework to disentangle the independent and synergistic impacts of climate change and anthropogenic landscape change on the habitat suitability of the Tibetan hot-spring snake (Thermophis baileyi) across the Tibetan Plateau. Our analysis was based on field survey data and species occurrence records, utilizing the species distribution model and the CA-Markov model. We identified temperature seasonality (41.8% contribution) as the primary environmental factor influencing its distribution, followed by precipitation of the coldest quarter (15.1%) and land cover (13.8%). The results showed that moderate climate warming would benefit the survival of the species, with a 24.03-38.55% gain in high-suitability habitat (HSH) area under climate change-only scenarios. However, extreme warming (exceeding SSP5-8.5) would surpass the thermal tolerance threshold of T. baileyi, reducing its HSH and triggering a northward shift in its distribution centroid. Landscape change reduced the HSH (5.98% reduction under land cover change-only scenario), and attenuated climate-driven gains by 4.99-11.31% under combined climate-landscape change scenarios. In addition, only one-fifth of the current HSH was covered by national natural reserves. Synergistic anthropogenic pressures critically offset climate benefits, demonstrating the need for integrated conservation strategies to address the challenges posed by both extreme climate warming and land cover change threats to mitigate future habitat degradation. The quantification of climate-land cover change impacts on T. baileyi offers critical insights for high-altitude ectotherm distributions under global changes and evidence-based conservation planning.