Integrating ecosystem service dynamics into multidimensional diagnosis of watershed ecosystem health in the Yangtze River Basin

The widening urban footprint has increasingly encroached on ecological resources, posing a cumulative threat to sustainable ecosystem service flows and system health in the Yangtze River Basin, a critical socioecological engine in China. This study establishes a multidimensional health diagnostic system that endogenizes inter-service interactions through a synergy-tradeoff adjusted weighting scheme in the 'services' dimension, by coupling InVEST modeling and spatial autocorrelation within the vigor-organization-resilience-services (VORS) framework. The results indicate that while provisioning services followed an upward evolutionary trajectory from 2000 to 2020, with water supply exhibiting the most substantial increase (17.18%) along a distinct west-east gradient, the basin exhibited a pronounced spatial decoupling among regulating services. Inter-service interactions were significant and remained relatively stable in terms of synergy or trade-off over the two decades, with synergy-maintained areas dominating greening-advantaged zones, functioning as vital ecological buffers and a critical foundation for long-term health resilience. Overall ecosystem health improved markedly (5.21%), primarily driven by enhanced vigor and the synergy-adjusted comprehensive service index. However, this growth exhibited distinct spatial heterogeneity: while densely vegetated forests anchored the basin's high-health baseline, widespread improvements were primarily concentrated across croplands, sharply contrasting with localized health erosion in expanding urban footprints. These findings underscore the importance of transitioning from uniform conservation to spatially tailored strategies, optimizing urban-ecological boundaries and harnessing synergistic service flows to advance the basin's green, high-quality development.