Identification of ecological restoration areas based on the ecological safety security assessment of wetland-hydrological ecological corridors: A case study of the Han River Basin in China

In recent years, wetland resources have been threatened by human activities such as mining, agriculture and construction land expansion, and problems such as shrinkage of wetland area and deterioration of water quality have emerged, impeding the exchange of materials between wetlands and reducing the ecological function of wetlands. Water systems are important channels for material exchange between wetland sources, and evaluating the ecological safety of wetland–water system ecological corridors can aid in efficiently delineating ecological restoration areas and identifying ecological problems. In this paper, the ecological safety of wetland–hydrological ecological corridors in the Han River Basin was evaluated, and ecological restoration areas were delineated by adopting the method of "identification of source areas - construction of resistance surfaces - extraction of wetland–hydrological ecological corridors" with the watershed as the research unit. The study identified wetland–hydrological ecological corridors with a total length of 7,589.77 km and delineated 31 sections of wetland–hydrological ecological corridors with a total length of 1,076 km; these corridors were located in the Hanzhong Canyon area, tributaries of the Danjiang River and Tangbai River, and tributaries of the main streams below Danjiangkou. Among them, 8 sections of the primary corridor account for 27 %, 14 sections of the secondary corridor account for 33 %, and 9 sections of the tertiary corridor account for 39 %. This study breaks administrative boundaries, emphasizes the correlation between wetlands and water bodies, highlights the integrity of ecosystems, and establishes a multidimensional systematic restoration methodology of "points, lines and surfaces", which provides guidelines for the long-term planning of ecological corridors of wetlands and water systems in large-scale regions.