Ecological adaptation mechanisms of plateau ungulates to seasonal nomadic pastoralism on the eastern Qinghai-Tibetan plateau

• Introduce a novel “low-cost niche differentiation strategy” for sympatric ungulates under seasonal nomadic pastoralism. • Reveal that Tibetan Gazelles adjust spatially, whereas Kiang shift temporally to mitigate livestock competition. • Demonstrate that SNP accelerates habitat degradation and drives dietary niche broadening in both species. • Advance niche theory and provide actionable insights for grazing management in plateau ecosystems. Seasonal nomadic pastoralism (SNP), a traditional practice uniquely adapted to the harsh climatic conditions of the Qinghai-Tibetan Plateau, plays a critical role in alleviating grazing pressure on alpine grassland ecosystems. However, the responses and underlying adaptive mechanisms of dominant plateau ungulates to SNP remain poorly understood. This study investigated the disturbance sensitivity of the Kiang ( Equus kiang ) and the Tibetan Gazelle ( Procapra picticaudata ). It further explored their adaptive mechanisms across multiple ecological niche dimensions in the context of SNP in Shiqu County, eastern Qinghai-Tibetan Plateau. Based on our findings, the Tibetan Gazelle exhibits greater sensitivity to disturbance compared to the Kiang. The herd sizes of both species were significantly and positively correlated with their distance from pastoral tent sites. SNP contributes to substantial habitat degradation and landscape fragmentation for both species. SNP significantly alters the Kiang’s activity rhythms, while the Tibetan Gazelle’s activity patterns remain relatively stable. In grazed areas, the Kiang exhibited reduced daytime activity and increased evening and nocturnal activity. Both species reduced the proportion of optimal food in their diets, increased their reliance on suboptimal food sources, broadened their dietary niche breadths, and decreased their dietary overlap with Yaks ( Poephagus grunniens ). This study establishes a critical foundation for understanding the complex interplay between grazing practices and alpine ungulate ecology. It also provides support for the development of sustainable grazing strategies and biodiversity conservation efforts within the fragile alpine grassland ecosystems.