Spatiotemporal Evolution and Scenario Simulation of Landscape Ecological Risk in Hilly–Gully Regions: A Case Study of Zichang City

The evolution of landscape ecological risk in ecologically fragile areas constitutes a critical foundation for optimizing territorial spatial planning and ensuring ecological security. This study takes Zichang City as the research object and integrates the dynamic analysis of land use, landscape ecological risk assessment, and spatial simulation into a single framework. By analyzing the laws of land use change in Zichang City from 1980 to 2020, the CLUE-S model was used to predict land use change and ecological risks under multiple scenarios in 2035. Statistical and spatial analysis methods were comprehensively applied to verify the robustness and spatial differentiation characteristics of the risk assessment. Key findings indicate the following: (1) From 1980 to 2020, forest land, water bodies, and construction land in Zichang City continued to increase, while cultivated land and grassland tended to decrease. Multi-scenario simulations showed that under the business-as-usual scenario, grassland and forest land expanded; under the economic development scenario, urban land increased significantly; under the ecological protection scenario, grassland grew substantially, while cultivated land contracted noticeably. (2) The overall LERI from 1980 to 2020 first declined and then slightly rebounded, reflecting an “initial improvement followed by fluctuation” in ecological security, with a spatial pattern of “high in the central area, low in the periphery.” By 2035, high-risk levels remain predominant across scenarios, although the proportion of high-risk areas is limited. Monte Carlo simulation confirmed the robustness of the assessment (mean CV = 0.038). (3) Spatially, from 2020 to 2035, the clustering characteristics of LERI varied among scenarios; however, high–high and low–low clustering patterns remained predominant, indicating that spatial aggregation of ecological risk is relatively stable across scenarios. This study demonstrates that integrating landscape ecological risk assessment with land use scenario modeling provides robust scientific support for optimizing spatial planning and ecological security in ecologically fragile regions. The proposed framework offers methodological guidance and practical reference for identifying key risk areas and designing differentiated land use and risk management strategies in similar hilly–gully landscapes.