[Ecological Function Zoning in the Upper and Middle Yellow River Basin Based on PLUS-InVEST Coupling]

Reasonable planning of ecological zoning can effectively promote habitat quality （HQ） restoration in a location-specific manner and avoid the waste of funds. By focusing on the dynamic changes and center-of-gravity migration laws of land use/cover in the Upper and Middle Yellow River Basin （UMYRB） over the past 20 years （2003-2023）， the InVEST model was employed to quantify regional habitat quality， and the spatial autocorrelation model was utilized to delineate agglomeration areas. Based on the coupling characteristics of land use/cover and HQ under different scenarios， ecological function zones were systematically defined to implement targeted habitat protection strategies. The results indicate that： ① Grassland， farmland， and forest land were the predominant land use/cover types in the UMYRB， accounting for average proportions of 59.96%， 22.44%， and 11.70%， respectively， from 2003 to 2023. The transfer of farmland， grassland， and bare land exhibited relative activity. Over the past 20 years， the areas of forest land and construction land increased continuously， while the area of bare land decreased by 7 372.26 km²， reflecting rapid regional economic development and the positive impacts of ecological policies. Due to the implementation of the "National Wetland Conservation Project Plan" and the "Ecological Protection of the Sanjiangyuan Nature Reserve" policy， the water bodies in Qinghai and Gansu provinces increased by 546.84 km². ② The PLUS model could effectively predict future land use/cover， achieving an overall accuracy of 89.07%. Among the driving factors， construction land and water bodies significantly responded to DEM， with contribution rates of 23.70% and 31.05%， respectively. ③ The UMYRB has maintained a relatively high HQ over the past 20 years， with higher and high grades accounting for nearly 70% of the total area， concentrated in regions dominated by forest land， grassland， and water bodies. Lower and low HQ grades accounted for 26.53% to 29.85% of the total area， closely associated with the distribution of farmland， construction land， and bare land. The average HQ exhibited a trend of first increasing and then decreasing. County-level HQ data revealed positive spatial autocorrelation and clustering patterns， with H-H clusters primarily located in the "Yellow River source area" and the border region between Shaanxi and Gansu provinces. ④ Based on these findings， four ecological function zones were developed， encompassing ecological conservation， farmland development， ecological governance， and economic development. The ecological conservation zone aims to sustain existing habitat quality levels. The farmland development zone should prioritize agricultural advancement and enhance grain production income. Farmland in hilly regions is encouraged to develop fruit tree industries. The economic development zone should focus on economic growth while implementing the "balancing occupation and compensation" land policy. In appropriate areas， consideration should be given to the slope of construction land. In ecological governance zones， innovative sand control measures， such as photovoltaic sand control， should be actively explored to improve vegetation coverage and enhance habitat quality. These research findings provide data support and spatial guidance for habitat improvement in the UMYRB and contribute to the formulation of more refined functional zoning strategies in future research.