Rural Sustainable Development Potential Under Ecological Prerequisite Constraints: Structural Differentiation and Spatiotemporal Evolution in the Leishui River Basin, China

Villages within Key Ecological Function Zones (KEFZs) are governed by a common ecological-priority regime, yet their rural sustainable development potential (RSDP) continues to diverge. This suggests that ecological conditions are not sufficient determinants of rural development outcomes, but prerequisite boundaries within which social livability and economic sustainability are activated. Existing SDG localization studies often treat ecological, social, and economic dimensions as parallel and compensable components, making it difficult to identify the structural sources of village-level differentiation in ecologically constrained regions. Using 1108 administrative villages in the Leishui River Basin as analytical units, this study constructs a village-scale RSDP assessment framework based on panel data for 2010, 2015, 2020, and 2024. Ecological health is positioned as the prerequisite constraint layer, while social livability and economic sustainability are treated as development capacities. A three-dimensional coupling coordination degree model is used to measure the structural matching among ecological foundation, social support, and economic transformation capacity. Spatial autocorrelation, exploratory space–time data analysis, and K-means clustering are further applied to identify spatial dependence, evolutionary trajectories, and bottleneck types. The results show that the mean coordination level of RSDP increased from 0.5807 to 0.6522 during 2010–2024, but this improvement was driven by uneven subsystem trajectories. Economic sustainability improved most rapidly, and ecological health increased steadily, whereas social livability remained the main shortfall. Spatially, RSDP showed significant positive autocorrelation, but clustering intensity weakened and both high- and low-value clusters became more fragmented. The dominant constraint shifted from economic weakness to social-support deficits, indicating that population support, public services, and everyday living capacity became key bottlenecks once basic economic conditions improved. Four village types were identified: suburban integration-led, vulnerable fluctuation-constrained, stable balanced-development, and ecological-resource potential. By reframing ecological conditions as prerequisite constraints rather than parallel assessment dimensions, this study extends SDG-based rural sustainability assessment from composite level comparison to structural potential diagnosis and provides village-scale evidence for differentiated governance in KEFZs.