Topographic Gradient Differentiation and Ecological Function Zoning Based on Ecosystem Services: A Case Study of Fuping County

Scientifically delineating ecological function zones is essential for national territory spatial planning and comprehensive management. In this study, we evaluated five ecosystem services, habitat quality, water yield, carbon sequestration, soil conservation, and food production, in Fuping County, China, and introduced the application of the topographic position index in exploring the topographic gradient effect of each service. We next applied the K-means clustering algorithm to identify the ecosystem services bundles and analyze the dominant type of ecosystem service in these bundles. A particle swarm optimization-support vector machine model was also constructed to identify the boundaries of ecological function zones and complete the ecological function zoning. The results are as follows: (1) In Fuping County, the high-value areas of habitat quality are distributed in the west, north, and southeast; those of soil conservation are in the northwest, northeast, and southwest; those of water yield are in the east and south; those of carbon sequestration are in the west, and those of food production is in the east. (2) The habitat quality first decreases and then increases with an increasing topographic gradient; food production and water yield decline with increasing topographic gradient; carbon sequestration and soil conservation increase with increasing topographic gradient. (3) Four types of ecosystem services bundles were identified. The dominant ecosystem functions of Type I, II, and III bundles are food production and water yield, carbon sequestration, and soil conservation, respectively. Type IV bundles generally have low levels of ecosystem services in the study area. (4) Four ecological function zones were delineated: food production zone, ecological conservation zone, potential restoration zone, and critical restoration zone. The research findings can provide a theoretical and practical basis for formulating and implementing ecological spatial management policies in the Taihang Mountains of China.