Ecological risk and carrying capacity dynamics with future zoning simulation in an arid mountain region: a case study of the Tianshan Mountains

Ecosystems in arid regions are facing increasing anthropogenic and environmental pressures, raising global concern about their sustainable development. Landscape ecological risk (LER) and ecological carrying capacity (ECC) are essential assessment frameworks for optimizing resource allocation and ensuring ecological security. In this study, the spatial and temporal evolution characteristics of LER and ECC in the Tianshan Mountains, a typical arid zone in Central Asia, was systematically assessed between 2000 and 2020. The PLUS model was employed to project ecological zoning patterns for 2030 and 2040, while XGBoost-SHAP was used to quantify the influence of 16 driving factors. LER was dominated by low to moderate-low risk zones (89%), while moderate-high to high risk zones rose from 0.43% to 2.82%. ECC showed a central-high and peripheral-low pattern, with zones of moderately high and high carrying capacity covering 48% of the area and increasing by 2.56%. Grasslands remained the dominant land type (48%) and expanded by 12,054.94 km 2. Cropland (39.99%) and construction land (105.85%) also increased. In contrast, water and unused land declined significantly. Ecological conservation zones remained dominant, the cultivation zone expanded sharply (+452.77%), and the restoration zone contracted (−70.84%). Projections suggest continued dominance of the conservation zone, while the restoration zone may experience strong fluctuations. Land use, temperature, precipitation, GDP, and population density were identified as key drivers of LER and ECC, with different effects in the four zones. These findings can be used to augment conservation management strategies in semi-arid grasslands.