ABSTRACT Water supply and conservation are essential ecosystem services in river basins and serve as key indicators of regional ecological health. The middle and lower reaches of the Yangtze River (MLYR) constitute a world‐class urban agglomeration and an ecological security barrier, playing a critical role in promoting high‐quality economic development and sustaining regional ecosystem stability. However, understanding of the multi‐scale spatial characteristics of water supply and conservation functions, the drivers of their long‐term variations and the delineation of functional zones in this region remains limited. In this study, the InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) model was employed to quantify water supply and conservation in the MLYR from 1985 to 2024, followed by attribution analyses. The main findings are as follows: (1) Between 1985 and 2024, both water supply and conservation initially recovered but subsequently declined. The average annual water supply was approximately 685.18 × 10 9 m 3 , while the average annual water conservation was about 51.38 × 10 9 m 3 . High‐value areas for water supply are mainly distributed in the central and southern regions, whereas high‐value areas for water conservation are largely concentrated in the southeastern region. Dongting Lake and Poyang Lake serve as the principal basins supporting both water supply and conservation functions. (2) Areas with relatively high water supply functionality accounted for the largest spatial proportion (41.98%), primarily located in the southern regions of the Poyang Lake Basin, the Huai River Basin and the Tai Lake Basin. (3) Annual precipitation, mean annual temperature and land use types were the main drivers of spatial variation in water supply, whereas water conservation was more strongly influenced by annual precipitation, land use types and elevation. These findings underscore the need for region‐specific strategies that integrate climate and land use considerations to enhance ecosystem service resilience in rapidly urbanising river basins.
Liu et al. (Wed,) studied this question.