Optimization strategies of ecological security patterns through importance of ecosystem services and ecological sensitivity-A case study in the Yellow River Basin

With the aggravation of environmental conflicts, exploring the green development path is an inevitable choice to alleviate land tension, guarantee the harmony of human-land relations, and promote coordinated regional development. The Yellow River Basin (YRB) is an important national ecological barrier area, but the impact of its environmental problems can no longer be ignored. Ecological security patterns (ESPs) provide remarkable means for the identification, configuration, and optimization of ecological spaces, which can help people identify the most central zone that needs to be protected. In this paper, we proposed environmental optimization strategies applicable to YRB as a case area. Firstly, the basic framework of ESPs was constructed based on the "three-step" method, where ecological sources were delineated by importance/sensitivity, resistance surfaces were created by entropy weight method, and the distribution ranges of ecological corridors, nodes, and barriers were confirmed by circuit theory. Meanwhile, stepping stones were introduced to optimize the ESPs, which were obtained through hotspot analysis and buffer analysis. The results displayed that (1) ecological sources covered an area of 166,699.32 km2, occupying 21% of the basin area. They were widely distributed in the upper and middle junctions, southeast and east of the basin, and of the land types that make up them, cropland, woodland, and grassland account for 97.6%. (2) The spatial distribution of resistance values varied considerably with low values predominantly found along water systems and high values predominantly found in densely populated urban areas. (3) Through the Linkage Mapper tool, 344 ecological corridors were acquired, with dense and short corridors in the southeast and sparse and long corridors in the northwest; 146 ecological nodes were acquired, which were the priority areas for ecological protection; and 154 barriers were acquired, the improvement or removal of which can enhance the connectivity between sources. In addition, the application of stepping stones further enhanced the connectivity between landscapes. The ESPs assessment framework constructed in this paper can provide strong support for relevant departments to carry out ecological monitoring and formulate environmental protection strategies.