Construction And Coupling Of Ecological Security Pattern And Ecological Restoration System Of Urban Agglomerations Under The Background Of Territorial And Spatial Planning

Population growth and rapid urbanization have brought tremendous pressure to the environment.As the construction of ecological civilization is incorporated into the Overall Plan for Development in Five Areas,the optimization of the territorial and spatial pattern and the ecological restoration should be promoted to the strategic height.It has become a huge challenge for territorial and spatial planning and ecological civilization construction,that how to rationally plan the pattern from the perspective of ecological security and how to realize the transformation from end-treatment to early-planning,from a single-element partial restoration project to a multi-element ecological restoration system of mountains,rivers,forests,fields,lakes and grasses.This study took the Beijing-Tianjin-Hebei urban agglomeration as an example to explore the construction and coupling of ecological security patterns and ecological restoration systems.Based on the basic database and the spatial analysis method of Arc GIS,the importance of water conservation,soil and water conservation,biodiversity maintenance,wind and sand fixation was quantitatively evaluated.The ecological source area was identified on the basis of the evaluation.By using the Minimum Cumulative Resistance method,the ecological security pattern was built based on the paradigm of"identification of ecological sources-construction of ecological resistance surfaces-extraction of ecological corridors and ecological nodes".Then,the ecological security pattern was evaluated by using evaluation indicators of ecological network integrity and landscape pattern indexes.Finally,coupling the evaluation results with the ecological restoration system,considering the three scales of macro,meso,and micro,constructing a territorial and spatial ecological restoration system for urban agglomerations.The main research conclusions are as follows:(1)The importance of ecosystem services in Beijing-Tianjin-Hebei is high in the north and low in the south.The extremely important area covers an area of 59450.75km~2,showing the spatial distribution characteristics of"one area,one screen and two ribbons".Qinhuangdao,Tangshan,Chengde,and Zhangjiakou have high proportions of important areas of ecosystem services,and they are the focus of ecological conservation and restoration in the Beijing-Tianjin-Hebei urban agglomeration.(2)The ecological security pattern of Beijing-Tianjin-Hebei consists of 15 ecological sources,67ecological corridors and 43 ecological nodes.The northern region is rich in various ecological elements,and the network is crisscrossed,while the central and southern regions are the main living and production areas.With fewer ecological sources,the network is similar to a simple parallelogram.(3)The evaluation results of the ecological security pattern of Beijing-Tianjin-Hebei show that the ecological security pattern constructed based on the background evaluation of ecological functions has a certain degree of stability,but it still needs to be further optimized in terms of the radiation range of the ecological function of the source area and the connectivity of the corridor;The ecological sources of Beijing-Tianjin-Hebei can be divided into three types:key maintenance areas,targeted restoration areas,and key restoration areas according to patch concentration and landscape heterogeneity.(4)The ecological security pattern and the ecological restoration system can be coupled from the macro,meso,and micro scales:on the macro scale,based on the evaluation of the ecological network,the spatial pattern can be optimized by adding sources and corridors;on the meso scale,based on the landscape evaluation of the ecological source,the corresponding landscape restoration plan can be designed for the divided maintenance or restoration areas;on the micro scale,a top-down relationship can be formed with the pattern restoration on the macro scale and landscape restoration on the meso scale.Combined with the actual situation in Beijing-Tianjin-Hebei,specific ecological restoration projects can be implemented in forests and grasslands,mountainous areas,lakes and wetlands,river quality,groundwater overexploitation,and mines.