Objective Exploring the spatio-temporal evolution of ecosystem health and its nonlinear response to hydrological elements on the Loess Plateau is crucial for optimizing regional ecological restoration and water resource management.

Method Focusing on farmland, forest, and grassland ecosystems on the Loess Plateau, this study assessed ecosystem health using the "Vigor-Organization-Resilience-Ecosystem Stress" (VORS) framework. We employed both traditional and spatial Markov models to reveal their dynamic evolution patterns and utilized the XGBoost-SHAP model to analyze the specific impacts of hydrological cycle elements on ecosystem health.

Result (1) Ecosystem health improved significantly overall. Forest ecosystems showed the most pronounced increase in high-health areas (proportion increased by 35.52%), expanding eastward from central regions. Grassland ecosystems exhibited the most significant reduction in low-health areas (proportion decreased by 25.60%), contracting westward. (2) Low-health areas exerted a negative spillover effect, reducing the probability of neighboring ecosystems transitioning to higher health levels. Conversely, high-health areas demonstrated a positive spillover effect, promoting health level upgrades in adjacent areas. (3) Farmland and grassland ecosystems were highly sensitive to changes in hydrological elements, primarily dominated by precipitation (contributing 38.80% and 45.80% to their health changes, respectively). Forest ecosystem health, however, relied more on the synergistic coupling of multiple hydrological elements, where the combined interaction effects were approximately 1.18 to 1.43 times the main effects of individual factors.

Conclusion This study reveals significant differences in the hydrological driving mechanisms for the health of distinct ecosystems on the Loess Plateau and elucidates the complex nonlinear relationship between ecosystems and hydrology within the context of vegetation restoration. It provides a theoretical basis for regional zoning management and sustainable development.