Changes in soil conservation service supply-demand coordinations and their influencing factors: Evidence from the Loess Plateau of China.

Soil conservation service (SCS) is crucial for the regulation of fragile ecosystems. As the Loess Plateau is a typically erosion-threatened region, determining the spatial matching pattern and drivers of SCS supply (soil conservation) and demand (soil erosion) is essential for sustainable development and effective resource management. This study innovatively proposed the coupling coordination framework between SCS supply and demand to assess the current state and clarify the subsequent regulation direction. First, the RUSLE model was employed to evaluate the SCS supply and demand from 1990 to 2020 and acquire the ecological supply-demand ratio (ESDR). Then, the SCS supply-demand coordination relationship was spatially quantified by utilizing the coupling coordination degree (CCD) model, and a function fitting was performed between ESDR and CCD. Using the geo-detector model, the Getis-Ord Gi^⁎ method, and the local Moran's I index, the influences of natural, engineering, and socio-economic factors on the SCS supply-demand coordination were explored from global and local perspectives. The results showed that: (1) the annual average supply of SCS increased by 64.93 % in 1990-2020; the average demand decreased by 52.43 %; the average ESDR increased by 28.06 %; supply surplus was the predominant feature, more conspicuously in the central and eastern regions; (2) the highest supply-demand CCD was captured in the central and eastern regions, showing "Moderate balance" and "High balance" respectively, and its area increased by 27 % in 30 years; the lowest CCD regions were mainly in the northwest and their area shrank; (3) enhancing the supply of SCS and reducing demand facilitated the coordination of the supply-demand relationship, and the threshold for the supply-demand coordination state decreased over time; (4) climate, topography and soil properties dominated the spatially non-stationary change of the SCS supply-demand pattern, followed by engineering measures such as afforestation and terraces, and finally socio-economic factors. This study offers support for cross-regional soil erosion management and natural ecosystem restoration on the Loess Plateau.