Ecosystem service flow-based analysis of ecological compensation in the Yangtze River Delta Basin

Ecological compensation (EC) is crucial for balancing ecological protection and economic growth, particularly in river basins. However, existing studies often overlook regional disparities and ecosystem service (ES) supply-demand dynamics. This study integrated remote sensing and geospatial data into a ‘source-flow-sink’ framework, simulating ES flows using the D8 algorithm for water yield and wind-flow models for carbon sequestration. An ecological-economic synergistic compensation model (EESCM) assessed EC ratios in the Yangtze River Delta (YRD) from 2000–2020. Results showed carbon sequestration supply declined by 1.83%, while demand surged 191.95%, causing mismatches in 85% of high-demand areas. Water-yield gaps peaked, forming dual-core networks around Yangtze River–Taihu Lake (57%) and Chaohu Lake–Xin’an River (29%). Spatial polarization was evident: the Huanghuai Plain, bearing only 23.15% of ecological compensation intensity, received 74.75% of funds; the Dabie Mountains, generating 89.67% of carbon sinks, received just 18%, revealing a vast gap. Atmospheric transport redirected 60% of carbon sinks downstream, intensifying spillover-compensation conflicts. The proposed EC framework can offer scientific guidance for sustainable regional development.