Evaluation of soil erosion vulnerability on the basis of exposure, sensitivity, and adaptive capacity: A case study in the Zhuxi watershed, Changting, Fujian Province, Southern China

Abstract Soil erosion by water is a critical issue in the red soil regions of Southern China. Particularly, Changting County experiences severe erosion due to unreasonable human activities, high rainfall intensities, steep slopes, erodible parent material, and poor vegetation cover. In this study, a quantitative soil loss analysis and qualitative social surveys (data from 1999 to 2015) are integrated to identify the erosion vulnerable areas in Zhuxi watershed of Southern China. Using Zhuxi watershed as an example in the investigation of soil erosion problems, analytic hierarchy and entropy value methods are adopted to evaluate soil erosion vulnerability and determine the proportions of factors in an index system. The vulnerability of soil erosion is evaluated from the human–nature system coupling perspective, considering socio-economic factors, which are synthetically analyzed and evaluated for soil erosion exposure, sensitivity, and adaptive capacity. Results show that (1) vulnerability is low in the east and west and highest in the middle of the Zhuxi watershed. The vulnerability of low, mild, and moderate soil erosions show a patchy distribution, wide range of intensity, and severe soil erosion fragility. (2) The degree of soil erosion vulnerability gradually decreased from 1999 to 2015. Low levels of vulnerability were distributed from fragmentation to concentrated distribution, while high vulnerabilities presented the opposite trend. However, the high levels of soil erosion showed a gradual decrease in vulnerability from 1999 to 2015. This study provides important theoretical and practical information for constructing a safe soil erosion control and management system and accelerating the sustainable development of social economy in the watershed.