Basin Ecological Zoning Based on Supply–Demand Assessment and Matching of Green Infrastructure: A Case Study of the Jialing River Basin

Intensive anthropogenic disturbances have driven significant spatial disparities and progressive fragmentation of forest-based green infrastructure (GI) that delivers vital ecosystem services across river basins. To address these challenges, delineating ecological management zones and developing spatially targeted GI optimization measures are imperative for safeguarding regional ecological security and advancing nature-based solutions in coupled human–water–forest systems. Focused on the mainstream area of the Jialing River Basin, we establish an ecological optimization zoning system that reconciles forest ecosystem resilience with regional development equity. By using morphological spatial pattern analysis, landscape pattern analysis and the In-VEST model, the GI supply capacity was assessed from three dimensions: element composition, structural configuration, and ecosystem services. The demand intensity was evaluated based on environmental governance pressure, urban expansion demand and social development needs across counties. Supply–demand matching was analyzed using quadrant-based mismatch typology and coupling coordination degree model. The results reveal that the following: (1) supply-deficit counties are predominantly located in the middle and lower reaches of the basin, characterized by high urbanization and economic development; (2) supply-surplus and high-level balanced counties cluster in the ecologically conserved upper reaches; (3) low-level balanced counties are concentrated in agricultural zones; (4) the overall coordination degree of supply and demand show a preliminary state of coordination. Based on these findings, the basin was classified into five zones at the county level: GI restoration, management, rehabilitation, enhancement, and conservation. Tailored ecological management measures and policies were formulated for each zone to advance sustainable basin development.