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

## TL;DR

This study examines how climate change and human activities affect the habitat of an endangered high-altitude snake in Tibet, showing that while moderate warming may help, human land use and extreme warming threaten its survival.

## Contribution

A novel multi-scenario framework was developed to disentangle the independent and synergistic impacts of climate and land cover change on a high-altitude ectotherm.

## Key findings

- Moderate climate warming could expand the high-suitability habitat of Thermophis baileyi by 24.03–38.55%.
- Extreme warming (SSP5-8.5) would reduce habitat and cause a northward shift in the species' distribution.
- Human land use reduces habitat and diminishes climate-driven habitat gains by 4.99–11.31%.

## Abstract

As a high-altitude distributed reptile endemic to the Tibetan Plateau, the Tibetan hot-spring snake (Thermophis baileyi) is sensitive to accelerating climate change and expanding human land use, making it an ideal species for studying the effects of global changes on high-altitude ectotherms. In this study, based on field survey data and species occurrence records, we used species distribution model (SDM) under multiple future scenarios to assess the individual and combined impacts of climate and land cover change on its habitat. We identified four key environmental factors shaping its distribution and tracked changes in high-suitability habitat (HSH). The results demonstrated that anthropogenic landscape change would cause a reduction in the HSH area. Conversely, appropriate climate warming (SSP1-2.6, SSP2-4.5, SSP3-7.0) would expand the HSH area; however, this expansion effect would be diminished when superimposed with anthropogenic landscape changes. In addition, extreme warming (exceeding SSP5-8.5) would surpass the ecological niche limits of T. baileyi, subsequently reducing its HSH and triggering a northward shift in its distribution centroid. The quantification of climate–landscape change impacts on T. baileyi offers critical insights for high-altitude ectotherm distributions under global changes and evidence-based conservation planning.

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.