Spatiotemporal Transfer of Source-Sink Landscape Ecological Risk in a Karst Lake Watershed Based on Sub-Watersheds

Non-point source pollution is an important of ecological risk in karst lakes. The process source–sink landscapes the main pathway migration and plays role water quality. In this study, evolution past 30 years was studied a lake watershed with 495 sub-basins as basic evaluation unit, assessment model non-point improved by using rainfall fertilizer application. results show that (1) area cultivated land shrank significantly, forest construction showing upward trend general; (2) layout sink landscape continuously shrank, while gradually expanded, space high load values further increased shifted from flower-like distribution to concentrated contiguity, some exceeding 0.5; (3) 252 sub-watersheds migrated very low risk, changed medium 48 sub-watersheds; (4) terms overall transformation landscape, greater than landscapes, showed increasing trend.