Identifying ecosystem service drivers to inform land use scenario simulation: An InVEST-PLSR-PLUS framework for the Danjiangkou Reservoir Basin, China

The Danjiangkou Reservoir Basin is the core water source of the Middle Route of China's South-to-North Water Diversion Project, yet research in this basin has largely focused on static ecosystem service (ES) assessments, leaving the drivers of ES dynamics and their future trajectories poorly understood. This study develops an integrated InVEST–PLSR–PLUS framework that quantifies the spatiotemporal patterns of water yield, soil conservation, and carbon storage, identifies their dominant drivers objectively via Partial Least Squares Regression (PLSR), and projects land-use dynamics to 2030 using the PLUS model parameterized with PLSR-derived drivers rather than empirical selection. The main findings are as follows. (1) From 2010 to 2020, water yield increased markedly (from 79.22 to 895.38 to 166.69–1000.24 mm year −1 ), soil conservation declined (maximum from 941.60 to 641.91 t ha −1 year −1 ), and carbon storage remained stable (maximum around 20.4 t ha −1 year −1 ); high soil conservation and carbon storage values were concentrated in ecological and economic forests, whereas elevated water yield occurred mainly in farmland, orchards, and built-up land. (2) Vegetation and land-use variables dominated ES dynamics: EVI (VIP = 1.609), NDVI (VIP = 1.583), ecological forest area (VIP = 1.553), economic forest area (VIP = 1.476), and farmland area (VIP = 1.445) exerted strong positive effects; among landscape-pattern metrics, the landscape shape index (LSI; VIP = 1.313) was positively associated with all three services, whereas patch-subdivision metrics (PD, ED, IJI) showed negative associations; climatic and socioeconomic variables contributed only marginally (VIP < 0.8, except GDP at 0.864). (3) Under the natural evolution scenario, ecological forest and orchard areas are projected to decrease by 40.89 km 2 and 20.54 km 2 by 2030, while economic forest (+29.63 km 2 ), water area (+24.10 km 2 ), farmland (+1.68 km 2 ), and built-up land (+5.98 km 2 ) expand. These findings demonstrate that vegetation cover and landscape connectivity fundamentally regulate ES provision, and indicate that ecological forest protection, control landscape fragmentation, and regulate built-up land and orchard expansion to safeguard the ecological security of this strategic water-source region.