Role of Landscape and Land-Use Transformation on Nonpoint Source Pollution and Runoff Distribution in the Dongsheng Basin, China

Non-point source pollution (NSP) and runoff intensities distribution are primarily affected by landscape structure composition. Multiple causalities hinder our ability to determine significant variables that influence NSP. Therefore, we developed an approach integrates the Soil Water Assessment Tool (SWAT), random forest regression model, redundancy analysis, correlation coefficient assess role of on NSP in Dongsheng basin. We used R calculate metrics SWAT simulate loads from 1990 2019. analysis (RDA), forest, Pearson were analyze relationships among variables. The largest patch index (LPI) shows a negative with NSP, R2 −0.58 for TP TN −0.62 sediment load. findings indicate landscapes larger sizes, high number patches, aggregation patches largely distribution. Overall, results suggest patterns outweighs runoff. Moreover, infer connectivity contribute decline load vice versa cropland cover. Thus, sustainable watershed management, it is crucial encourage unfragmented landscapes, especially pollutant-intercepting landcovers such as forests.