Spatial Partitioning Among Three Sympatric Ungulates in the Tibetan Plateau: Identifying Critical Variables.

Spatial dimensions play a significant role in niche differentiation, facilitating species coexistence. Understanding how sympatric ungulates optimize habitat utilization and how they co-exist in resource-limited environments is essential for effective wildlife conservation and reserve management. Tibetan antelope (chiru, Pantholops hodgsonii), Tibetan wild ass (kiang, Equus kiang), and wild yak (Bos grunniens) are sympatric ungulates co-evolving over generations across the Tibetan Plateau, but limited information is available on their spatial partitioning and the key variables affecting both single-species and multi-species distributions. In this study, using a combination of maximum entropy model, joint species distribution models, and random forest analysis, we examined the spatial partitioning of the three ungulates and identified the critical factors influencing their distributions with their spatial distribution data collected from the Arjin Shan National Nature Reserve in the Tibetan Plateau. Our key findings: (i) Notable differences were observed in the spatial distributions of the three ungulates, with only 16% overlap in their suitable habitats. Temperature had a stronger influence on the habitat selection by chiru and kiang, whereas precipitation played a more significant role in determining the distributions of kiang and wild yak. (ii) During summer, the interspecific relationships between chiru and wild yak, and between chiru and kiang exhibited positive correlations, while the relationship between wild yak and kiang was negatively correlated. In winter, all interspecific relationships were negatively correlated. (iii) Temperature seasonality and mean temperature of the driest quarter emerged as the most critical variables influencing multi-species habitat selection. Human interference had a significantly negative impact on all three ungulate species. Our findings underscore the importance of spatial heterogeneity in facilitating species coexistence under both climatic and anthropogenic pressures, offering valuable insights for multi-species conservation planning in resource-limited ecosystems.