Herbivore grazing represents the dominant land use practice in grasslands, critically affects soil and water conservation (SWC) services. Yet its spatially heterogeneous impacts across vegetation, climate, and soil gradients remain poorly understood. Here, using model simulations and statistical analyses (i.e., ridge regression, geographical detector, and piecewise linear regression), we quantified herbivore intake (HI) impacts on SWC, unveiled spatial determinants of HI-SWC interactions, and identified abrupt changes in SWC values along grazing intensity gradients as well as shifting HI-SWC correlations with increasing aridity in China's Qilian Mountain grasslands. The methodological framework enables global assessments of social-ecological system resilience in montane grasslands. The results showed that the amount of SWC initially increased and then declined sharply beyond HI thresholds specific to three natural grassland types. Significant negative HI impacts affected 71.1 % of grasslands for water conservation and 49.8 % for soil retention, with grazing pressure emerging as the dominant environmental driver in 52.5 % and 30.3 % of grassland areas, respectively. Vegetation productivity primarily governed HI-SWC interactions, followed by aridity, rainfall seasonality, mean annual temperature, and soil properties. Critical aridity thresholds for abrupt SWC deterioration under grazing were identified at similar to 0.50, 0.53, and 0.59, respectively, for temperate steppes, alpine steppes and alpine meadows, reflecting escalating ecosystem resilience to atmospheric drying. Our findings suggest widespread exceedance of safe grazing thresholds, particularly in aridifying grasslands, where negative SWC responses amplify before reaching tipping points. This study provides scientific evidence for dynamic stocking regulation and adaptive grazing management in the Qilian Mountains and other dryland montane grasslands.