Distribution characteristics and spatiotemporal evolution of soil and water conservation ecological space in the hilly and gully areas along the Yellow River: A case study of Liulin County, Shanxi Province

Enhancing soil and water conservation efforts is crucial in addressing soil erosion in the middle reaches of the Yellow River Basin. This undertaking is pivotal for both ecological preservation and the pursuit of high-quality development in the region. However, the soil and water conservation ecological spatial extent, the distribution pattern and their changes are still unclear, which limits the effective implementation of differentiated prevention and protection measures to a certain extent. In this study, Liulin County, which is situated along the middle reaches of the Yellow River and represents a typical county in a region characterized by hills and gullies, was selected as the study area, the soil and water conservation ecological space was demarcated and partitioned based on the identification and grading of water source conservation space, soil conservation space and erosion sensitivity. Then cold hot spot analysis and standard deviation ellipse were used to reveal the distribution characteristics of soil and water conservation ecological space in the study area and analyze its spatial and temporal evolution characteristics from 2000 to 2020.The results showed that: 1)The functional grade of the water conservation space in Liulin County shows a general trend of gradual decrease from north to south, with the area of high grade accounting for 35.2% of the total area of the study area; the intensity of soil retention is dominated by the low grade, which is centrally distributed in the western and central parts of the study area. 2) From 2000 to 2020, the percentage of highly sensitive erosion areas in Liulin County has been above 40% and the area has continued to increase, while the area of insensitive areas, mildly sensitive areas and moderately sensitive areas has continued to decrease.3) The distribution of soil and water conservation ecological space in Liulin County as a whole is south-north direction, there is no piecemeal continuous distribution, mainly concentrated in the inter-ditch area of the hilly and gully area, of which the key area and the core area are staggered in the steep slope area of the ditch, and the general area is mainly distributed in the area of sloping slopes of the river or along the ditch. 4) From 2000 to 2020, the size of the core area has been showing a decreasing trend, and the centers of gravity of the standard deviation ellipse for the general area, the focus area, and the core area have all shifted to the southwest, predominantly to the south.The results of the study on the identification of soil and water conservation ecological space and the trend of spatial and temporal evolution in Liulin County can provide a reference for the differentiated management of soil and water conservation in Liulin County, so as to effectively maintain soil and water resources, and promote the ecological protection and high-quality development of the Yellow River Basin.