Supply–Demand Synergy Assessment of the Water–Energy–Food Nexus in the Hanjiang River Basin Under Future Land Scenarios

Abstract

Understanding the supply–demand matching and trade-offs of ecosystem services is crucial for formulating land use policies. However, there remains a lack of clear understanding on how to coordinate the supply–demand mismatch of ecosystem services under different future scenarios. In examining the Hanjiang River Basin (HJRB), this study utilizes the PLUS and InVEST models to evaluate present spatiotemporal changes in water yield (WY), carbon storage (CS) and food provision (FP) within the water–energy–food nexus context. It further explores the spatiotemporal patterns and correlation analysis of the WEF nexus across varying scenarios. The findings suggest the following: (1) Between 2000 and 2020, there was a notable rise in both forest and built-up land. Compared to the year 2020, in the cropland protection scenario (CPS), cropland increased by 2.19%. In the ecological protection scenario (EPS), forest area increased significantly by 4.06%. In the natural growth scenario (NGS), the largest increase was observed in construction land, which expanded by 26.31%. (2) Land use and cover change (LUCC) has a limited impact on the WEF nexus supply, accounting for about 1%. From 2000 to 2020, both WY and CS's ESDR exhibited a ‘decrease-followed-by-increase’ trend, while FP's ESDR gradually increased, with only the mismatched area between supply and demand for WY decreasing. (3) Unlike the grid scale, the WEF nexus correlation at the county/city scale has significantly increased, and intense LUCC will alter the synergy and trade-offs within the WEF nexus. Additionally, there exists a pronounced spatial misalignment between CS and WY. Therefore, this study can provide a comprehensive reference for land use planning aimed at achieving the coordinated development of humans and nature.