Assessing the impacts of multi-scenario climate and land use change on water-related ecosystem services: the case of the Yangtze River Economic Belt (2000–2030)

• Integrated BCC-CSM2-MR, PLUS, and InVEST models with dynamic trade-offs in the YREB • Future WY will rise 53.65% in CP585 scenario and WP optimized by 10.31% in EP585 • Future upstream WY surges while WP degrades, but downstream all improve • CC affects WY by more than 90%, LUCC affects WP much more than WY • EP scenario effectively reduces trade-offs, enhances synergy across the region Water-related ecosystem services (WESs) are essential for sustainable development, particularly in regions experiencing rapid land use and cover change (LUCC) and climate change (CC). This study evaluates the spatial and temporal impacts, independent contributions, and trade-offs of LUCC and CC on WESs in the Yangtze River Economic Belt (YREB) from 2000 to 2030. By integrating the BCC-CSM2-MR, InVEST, and PLUS models with dynamic trade-offs analysis, our findings indicate that water yield (WY) could increase by up to 53.65% under the SSP585 climate with cropland protection scenario (CP585), and the upstream surge is significant. Additionally, water purification (WP) is projected to improve across the region, as evidenced by a 10.31% reduction in phosphorus (P) export under SSP585 climate with ecological protection scenario (EP585), while upstream degrades in the urban expansion (UE) and CP scenarios. CC exerts a predominant positive influence (over 90%) on WY, while LUCC significantly affect WP especially in the downstream. Overall dynamic trade-offs reveal lowest upstream and highest downstream trade-offs between WESs. Meanwhile the spatial synergy between WESs is expected to be most extensive under the SSP245 climate and EP scenario (EP245). These findings underscore the importance of integrated land and water management strategies to optimize WESs and support sustainable regional development amid future environmental changes. However, this study is limited by its use of annual average precipitation, which ignores seasonal dynamics, and by focusing on the separate effects of LUCC and CC without considering their combined effects. Future research should address these gaps.