Effects of grazing activities on ecosystem health in three-river-source national park

The Three-River-Source National Park (TNP) represents a vital ecological stronghold for China. Grazing, the primary anthropogenic disturbance activity in the region, is not only vital for sustaining local livelihoods but also a potential risk factor triggering ecosystem health degradation. However, comprehensive and dynamic analyses of grazing impacts on ecosystem health remain limited, hindering the development of strategies that simultaneously promote ecological conservation and community well-being. Based on multi-source data, this study quantified grazing intensity and ecosystem health dynamics in TNP from 2000 to 2020. We applied Geodetector and bivariate spatial autocorrelation analysis to examine the spatiotemporal responses of ecosystem health to grazing intensity. The results indicate that the park's ecosystem health improved overall in 2000-2020, displaying a distinct southeast-to-northwest declining gradient. Grazing intensity initially increased and then decreased, with noticeably intensified grazing hotspots emerging in the eastern region. Grazing activities generally exerted positive ecological effects, yet these benefits diminished marginally as grazing intensity increased. Bivariate Moran's I analysis revealed a spatially heterogeneous relationship characterized by "overall synergy coupled with local conflict" between grazing and ecosystem health. Furthermore, climatic factors, particularly precipitation, regulate the response of ecosystem health to grazing activities. This study offers a scientific basis for formulating spatially targeted grazing management policies that enhance ecological resilience while supporting sustainable livelihoods in the national park.