Unraveling ecosystem service supply-demand relationships and zoning optimization in the agro-pastoral ecotone of northern China

The agro-pastoral ecotone of northern China (APENC) is a critical ecological security barrier that has long faced imbalances, spatial mismatches, and functional degradation in ecosystem service (ES). Using multi-source remote sensing products and statistical data from 2000 to 2020, this study assessed five ESs in the APENC, including grain production, soil conservation, water yield, carbon storage, and windbreak and sand fixation. The spatiotemporal dynamics of ES supply and demand were quantified, dominant drivers were identified, and a zoning-based optimization framework was developed. From 2000 to 2020, the supply of all ESs increased significantly except for windbreak and sand fixation. In contrast, demand exhibited divergent trajectories, with declining demand for grain production and windbreak and sand fixation, increasing demand for carbon storage and soil conservation, and relatively stable demand for water yield. Although the overall supply-demand ratio improved, windbreak and sand fixation showed persistent deficits. Supply-demand coupling coordination was generally low and was mainly characterized by slightly and nearly uncoordinated states, while coordinated areas occurred only sporadically. The dominant matching pattern was low supply and low demand, whereas areas characterized by low supply and high demand expanded over time. The driving mechanisms shifted from predominantly environmental controls to a coupled regime integrating biophysical conditions and socioeconomic pressures, with vegetation conditions and population-economic intensity emerging as key interactive drivers. The proposed zoning scheme supports differentiated strategies for supply enhancement, demand regulation, and resilience strengthening, and provides guidance for ecological function improvement and spatial governance in the APENC. • Spatial mismatch between supply and demand intensified in ecologically sensitive zones. • Ecosystem service imbalance linked to dual pressures of environmental constraints and socioeconomic intensification. • Targeted zoning framework offers adaptive strategies for fragile and mismatched subregions.