Supply-demand matching relationship of ecosystem services in the Beijing-Tianjin Sandstorm Source Control Project Area

The Beijing-Tianjin Sandstorm Source Control Project is a significant ecological initiative in China, aiming to enhance the ecological environment quality in Beijing, Tianjin, and surrounding areas, thereby improving human well-being and social benefits. Ecosystem services are the benefits provided by ecosystems that support human activities and are essential for human well-being. The supply-demand relationship of ecosystem services reflects regional economic and social development levels and serves as a key indicator for assessing the balance between ecological environments and human needs. Studying the supply-demand relationship of ecosystem services in the project area aids in integrating ecological and human demands, evaluating project effectiveness, and informing ecological policies for improved restoration and compensation. This study examines the supply and demand of five ecosystem services—food provisioning, water retention, carbon sequestration, soil retention, and windbreak and sand fixation—from 2000 to 2020. Using modeling methods and a "people-based demand" approach, the spatiotemporal distribution of supply and demand is analyzed. The four-quadrant model and coupling coordination degree depict the matching relationship, while comprehensive management zoning offers governance recommendations. The results reveal significant spatial heterogeneity in ecosystem services. Except for windbreak and sand fixation demand concentrated in the eastern sandy regions, the distribution of other services shows a "high in the southeast, low in the northwest" pattern. Over time, food provisioning supply and demand rose by 61.93% and 16.84%, respectively; water retention supply increased by 48.01%, while demand decreased by 7.61%; carbon sequestration supply grew minimally (0.13%) against a 377.44% surge in demand; soil retention supply and demand rose by 38.38% and 73.2%, respectively; and windbreak and sand fixation supply grew by 1.21%, with demand decreasing by 3.36%. In terms of matching, the supply-demand relationship is dominated by "low-low" matches and "high-low" mismatches. Most regions are ecologically fragile and sparsely populated, with significant mismatches, especially for windbreak and sand fixation services. The coupling coordination degree is generally moderate to low, with few highly coordinated areas. Basic coordination and moderate imbalance dominate, while some regions face severe imbalance. Based on supply-demand relationships and coupling coordination, the study delineates four primary management zones. The "Enhancement and prevention" zone emphasizes ecological resource protection and efficiency improvement; the "Protection and development" zone balances resource safeguarding with industrial growth; the "Urban optimization" zone integrates urban development with ecological governance; and the "Comprehensive improvement" zone promotes industrial innovation to reshape ecology-economy dynamics. This study provides critical insights into ecological project management, resource optimization, and sustainable development of ecosystem services in the project area.