Ecological vulnerability assessment of typical grasslands on the Mongolian Plateau: Abrupt change detection and driving mechanism analysis

The typical grasslands of the Mongolian Plateau, a key component of the global temperate grassland ecosystem, play an essential role in maintaining regional ecological security and ecosystem stability. However, these grasslands exhibit high ecological sensitivity to climate change and human activities. Based on the sensitivity–resilience–pressure (SRP) model, this study constructs a comprehensive ecological vulnerability assessment indicator system that incorporates both ecosystem conditions and human activity factors. Ecological vulnerability in typical grasslands from 2001 to 2022 was systematically assessed using the spatial principal component analysis (SPCA) method. The results indicate a clear northeast–southwest gradient of increasing ecological vulnerability During 2001–2022, the ecological vulnerability grade index (EVGI) exhibited a slow decreasing trend (Slope = −0.001/a), indicating an overall reduction in ecological vulnerability and relatively stable ecosystem conditions. A significant abrupt change occurred in 2014, after which the area of ecological degradation expanded markedly (approximately 57.58%), primarily in the southern and northeastern parts of the study area. Natural factors were the primary drivers of the synthetic ecological vulnerability index (SEVI), with annual mean temperature, annual mean precipitation, potential evapotranspiration, normalized difference vegetation index, and net primary productivity showing higher explanatory power. Following the abrupt change in 2014, the influence of human activity indicators such as population density and livestock density increased. The SEVI in the northern and eastern regions were mainly controlled by natural factors, whereas the southern and western regions were more affected by human activities. Future predictions suggest that the SEVI in this region will decline over the next decade, indicating a gradual recovery of grassland, which may be attributed to the implementation of protection policies and rational grazing management, thereby mitigating human impacts. These findings provide valuable scientific support for ecological conservation, grazing management, and sustainable development of typical grasslands on the Mongolian Plateau.