[Ecological Function Zoning Based on the Coupling of Landscape Ecological Risk and Eco-Environmental Quality: A Case...

Persistent combined disturbances in the Loess Plateau's small watersheds chronically stress ecosystem stability and services， urgently requiring zoning-based governance frameworks for precision ecological management. This study coupled the landscape ecological risk （LER） and eco-environmental quality （EEQ） assessment systems to construct an ecological functional zoning framework for the Sanchuan River Basin from 1990 to 2023. The spatial distribution of LER was generated using landscape pattern indices， while the TIA-EEQ evaluation framework integrated seven indicators （soil conservation， water yield， landscape fragmentation， habitat quality， carbon sequestration， population distribution， and NDVI） through entropy weighting to calculate EEQ. A four-quadrant model was then employed to map LER and EEQ grid cells into a "risk-quality" two-dimensional space， systematically identifying ecological high-risk restoration zones （high LER-low EEQ） and low-risk high-quality conservation areas （low LER-high EEQ）. The results demonstrate that： ① From 1990 to 2023， LER exhibited significant spatial heterogeneity， showing a general "higher in the west， lower in the east" pattern， with high-risk areas decreasing by 8.25% and low-risk areas increasing by 23.32%. ② EEQ displayed notable spatiotemporal variations， improving from 1990 to 2010 but declining significantly by 2023， forming a concentric structure with high-value zones in the east， transitional belts in the central-western region， and low-value agricultural areas along rivers. ③ The quadrant analysis identified western river networks and cropland clusters as key ecological restoration hotspots， while eastern forested regions were prioritized for conservation due to their low-risk， high-quality characteristics. This work can provide spatially targeted decision support for developing differentiated ecological protection strategies in the watershed.