Interregional imbalance in the Yellow River Basin: Insights from flood-sediment transport, socioeconomic, and environmental subsystems

: The ecological environment, resource endowment, and the level of socioeconomic development vary extensively amongst regions in the Yellow River Basin (YRB). To ensure the basin's sustainable development, the supply and demand relationship of ecosystem services (ESs) within the basin was analysed from the perspective of three subsystems: flood-sediment transport, socioeconomics, and ecological environment. The supply, demand, and the ratio of supply to demand of typical ESs were initially computed for 385 counties and districts within the YRB. These ESs included soil retention (SR), flood mitigation (FM), water yield (WY), crop supply (CrS), carbon sequestration (CS), and natural accessibility (NA). Correlations among ecosystem service supply-demand ratios (ESDRs) were completed and the spatial characteristics of the weighted multiple ESs supply-demand index (WMESI) were then investigated. Finally, the importance of WMESI driving factors were explored using extreme gradient boosting. Calculated for three subsystems in 385 counties and districts, the coupling coordination degree (CCD) indicated that: (i) ESDRs exhibit spatiotemporal heterogeneity, with FM and WY having relatively lower ESDRs; (ii) the trade-off and synergy relationships among ESDRs vary in a dynamic manner. In particular, a disruptive change in the relationship between the ESDR of SR and other ESDRs occurred in 2010; (iii) in the basin's downstream region, WMESI exhibits low-low clustering, with both population and precipitation having a significant impact on WMESI. Moreover, precipitation factors shifted significantly towards population factors; (iv) Overall, the CCD of 385 counties and districts in the YRB is low, and the spatial imbalance of CCD was mainly attributable to socioeconomic factors. The present research findings provide new insights into the sustainable governance of the YRB.