Objective  With the accelerated urbanization of the watershed, the development of natural resources and the expansion of urban land have led to the gradual deterioration of watershed ecological environment and the weakening of ecosystem service functions. It is important to construct an ecological network to improve and repair the structure and function of the watershed ecosystem and further realize the sustainable ecological development of the watershed.

  Method  Taking Beijing section of Yongding River Basin as an example, this paper quantitatively assesses three ecosystem services, namely water content, soil conservation and habitat quality, and identifies ecological source sites using Getis-Ord GI* hotspot analysis; extracts ecological corridors and ecological nodes using the minimum cumulative resistance model; and finally constructs an ecological network. And the ecological network perfection degree was evaluated by the network closure (α index), line point rate (β index) and network connectivity (γ index) to further explore the ecological network optimization strategy under the green ecological development goal.

  Result  16 ecological sources, 23 ecological corridors and 19 ecological nodes were identified in the Yongding River Basin. The ecological sources and nodes were distributed in the northern and central parts of the study area, mainly consisting of woodland and cropland; the total length of ecological corridors was 52.03 km, distributed in a network along farmland, woodland and rivers. Based on the analysis and evaluation of the ecological network, ecological buffer zones of ecological sources and ecological corridors were set, and blind areas of ecological nodes were identified to optimize the spatial structure of the ecological network.

  Conclusion  Through the construction and optimization of the ecological network of Beijing section of the Yongding River Basin, this paper clarifies the key areas for ecological protection and restoration in the basin to provide spatial guidelines for the future ecological construction and restoration planning of the basin.