Simulation and Optimization of the Ecological Networks in the Middle Yangtze River Basin

Exploring the simulation and optimization pathways of ecological networks under multiple scenarios is conducive to ensuring ecological security and achieving high-quality development of urban agglomerations. In this study, the PLUS model was utilized to perform spatial simulations of land use change in the urban agglomeration in the middle reaches of the Yangtze River under four alternative scenarios: natural development (ND), ecological protection (EP), cropland protection (CP), and economic development (ED). By integrating the InVEST and MSPA models with circuit theory, ecological networks and ecological security patterns were constructed within a dual-temporal framework of “past and future”. On this basis, ecological management zoning and corresponding optimization pathways were explored across different scenarios. The results indicated that: (1) During the period 2000–2020, land use in the urban agglomeration in the middle reaches of the Yangtze River was dominated by cropland and forestland. (2) Multi-scenario land use types showed divergent evolutionary trends. The ND scenario maintained the historical pattern; the EP scenario increased ecological land by 1.2%; the CP scenario expanded cropland by 11.74%; and the ED scenario raised construction land by 33.78%. (3) During the two decades, the habitat quality and landscape configuration of the study area remained largely stable. The connectivity of ecological corridors across scenarios ranked as EP > ND > ED > CP. Consequently, ecological networks under multiple scenarios and an ecological security pattern characterized by “three barriers, four corridors, three belts, and multiple nodes” were established. (4) The urban agglomeration was classified into three major categories of ecological priority conservation zones, namely ecological source conservation zones, ecological source coordination zones, and ecological source restoration zones, along with five levels of ecological management zones. Based on this classification, zoning optimization strategies were explored under multiple scenarios. This study provides valuable guidance for ensuring ecological security and implementing differentiated, multi-level ecological management strategies in the urban agglomeration in the middle reaches of the Yangtze River.