Multi-Model Assessment of Key Ecosystem Services in Horqin Sandy Land: Spatio-Temporal Dynamics, Drivers and Trade-Offs/Synergies

The spatio-temporal dynamics of ecosystem services (ESs) are essential for ecological restoration and sustainable management in arid regions. Although ESs have been extensively studied in sandy landscapes, research on the multi-model evaluation of various ESs remains limited. This study assessed the spatio-temporal quantification and driving factors of, and interrelationships among, Net Primary Productivity (NPP), Habitat Quality (HQ), Carbon Stock (C), Water Yield (WY), and Soil Retention (SR) in the Horqin Sandy Land. This assessment utilized the InVEST model, the CASA model, geographic detectors, and Spearman correlation analysis. The results indicate the following: (1) From 2000 to 2024, land use transformation in the Horqin Sandy Land was characterized by a substantial reduction in fixed sand dunes (−1047 km2) and a shift toward dryland and semi-fluid sand dunes, while semi-fixed sand dunes and forested areas expanded significantly. (2) NPP, HQ, and SR exhibited an overall increase with notable spatial improvement, whereas WY experienced a general decline. The changes in each service displayed marked differentiation in both time and space. (3) NDVI, land use and precipitation are the dominant factors of different services, and the explanatory power of the interaction among these factors is generally stronger, jointly driving the spatial pattern of ecosystem services. (4) The collaboration and trade-off relationships among services evolve dynamically over time. Among them, the transformation from trade-off to collaboration between C and WY is the most prominent, and the spatial distribution of various relationships shows significant regional heterogeneity. The research results provide a scientific basis for revealing the ecological restoration in arid areas.