Multi-Scale Spatial Relationship Between Runoff and Landscape Pattern in the Poyang Lake Basin of China

Runoff research serves as the foundation for watershed management, and the relationship between runoff and landscape pattern represents a crucial basis for decision-making in the context of watershed ecological protection and restoration. However, there is a paucity of research investigating the multi-scale spatial relationship between runoff and landscape patterns. This study employs the Poyang Lake Basin (PLB) as a case study for illustrative purposes. The construction of the soil and water assessment tool (SWAT) model is the initial step in the process of carrying out runoff simulation, which in turn allows for the analysis of the spatial-temporal characteristics of runoff. Subsequently, Pearson's correlation analysis, global linear regression and geographically weighted regression (GWR) models are employed to examine the impact of landscape composition on runoff. Finally, the spatial relationship between runoff and landscape pattern is investigated at the landscape and class scales. The results of the study demonstrate the following: (1) runoff in the PLB exhibited considerable spatial-temporal heterogeneity from 2011 to 2020. (2) Forest was the most prevalent landscape type within the PLB. Landscape composition's impact on runoff exhibited non-linear characteristics, with forest, cropland, barren, and grassland influencing runoff in decreasing order. (3) A spatial relationship between runoff and landscape pattern was observed. At the landscape scale, patch diversity significantly influenced runoff, and reducing patch diversity primarily increased runoff. At the class scale, forest and cropland patch areas had the greatest impact on runoff, potentially enhanced by improving patch edge density. (4) Nine sub-basins needing ecological restoration were identified, with restoration pathways developed based on spatial relationships between runoff and landscape patterns. This study elucidates the impact of landscape composition and pattern on runoff, thereby providing a basis for informed decision-making and technical support for the ecological restoration and management of the watershed.