Soil and water conservation effects driven by the implementation of ecological restoration projects: Evidence from the red soil hilly region of China in the last three decades

China’s soil and water conservation (SWC) has gradually developed into a national key ecological construction project, and its scale and coverage have been expanding. However, the distribution characteristics of soil and water conservation measures (SWCMs) under ecological restoration projects and the water storage and soil conservation benefits from a macro perspective are not yet clear. To solve this problem, first of all, the red soil hilly region (RSHR) of China has been chosen to analyze the 30-year process and spatial trends of SWCMs in ecological restoration projects. The spatial distribution of SWCMs is analyzed from the three-dimensional plane of level and elevation. In addition, four benefit characteristics of SWCMs have been obtained by comparing the amount of water and soil protected and the intensity of soil erosion. Finally, the paper explores methods that improve the efficiency of SWC in key areas. The research results show that the paradigm of SWC changes from comprehensive management to ecological rules and the goal of SWCMs has shifted from initial farmland maintenance to natural forest restoration, and the average soil erosion has not only decreased by 291 t/(km²•a) as a whole but has also reflected the transformation from agriculture to ecology in the national ecological restoration project strategy. The distribution model of SWCMs on the horizontal plane is a convex second-order function. In the vertical direction, the proportion of measures distributed in hilly areas was 38%, higher than that in plain and mountain areas. Moreover, SWCMs are concentrated in cultivated land and forest land, among which the proportion of terraces, SWC forests and grass planting measures is as high as 35% in areas with high erosion. For the RSHR in the four SWC benefits of group characteristics and the distribution ratio, respectively: SWC ability and soil erosion intensity are lower (group 1, 9%). There is a lower amount of soil and water storage and higher intensity of soil erosion (group 2, 19%). The amount of soil and water storage is large, and the intensity of soil erosion is low (group 3, 27%). Soil and water storage and soil erosion intensity are both high (group 4, 13%). In a word, it is necessary to improve the proportion of SWC forest construction in river basins and intensive agricultural cultivation areas in national key SWC areas to enhance ecosystem service functions. This paper analyzes the pattern changes and benefit characteristics of SWCMs from a macro perspective, which provides a new perspective for the large-scale study of SWC in the future. This result in preventing soil erosion aims to make China’s ecological civilization construction and ecological management more sustainable.