Study On The Evolution Of Blue-Green Landscape Pattern And Optimization Of Ecological Network In Huarong County

Blue-green space is the core carrier of urban biodiversity and a key area for the construction and restoration of urban ecological environment.In order to alleviate the situation that the blue-green space is squeezed and occupied and the ecological patches tend to be fragmented in the process of urbanization,this paper takes Huarong County as the research scope,and first analyzes the evolution of the blue-green space landscape pattern in the county from 2000 to 2020 to anchor the habitat.problems,and then solve them by constructing and optimizing the county-level blue-green ecological network.The research started from the idea of "Evolution of blue-green spatial landscape pattern in Huarong County-construction of blue-green ecological networkoptimization of blue-green ecological network".The main contents and results are as follows:(1)From 2000 to 2020,the landscape pattern of blue-green space in Huarong County has changed significantly.From the perspective of changes in the scale of blue-green space,the overall blue-green space in Huarong County has been fragmented and scattered in the past 20 years,and the area has continued to decrease.From the perspective of the dynamic transfer of landscape types,the overall scale of blue-green space in Huarong County has continued to decrease in the past 20 years,and the rate of reduction has accelerated significantly.From the perspective of landscape pattern index changes,since 2000,the landscape pattern of blue-green space in Huarong County has shown the evolution characteristics of fragmented distribution,enhanced heterogeneity,and gradual complexity,and urbanization is the main influencing factor.(2)Preliminary construction of blue-green ecological network in Huarong County and its spatial distribution characteristics.The coupled MSPA-InVEST model comprehensively extracted 15 blue-green ecological sources,and used the AHP to weight and superimpose six resistance factors including land use type,MSPA landscape type,habitat quality index,slope,elevation,and distance from the road to obtain the ecological resistance surface.Based on the MCR model,105 blue-green ecological corridors were initially constructed,with a length of 1,429.01km.From the perspective of spatial distribution,the existing blue-green ecological network structure is not perfect,and further key optimization of the ecological network space in the west and southeast of Huarong County is needed.(3)The optimization results of the blue-green ecological network system in Huarong County.According to the principle of habitat patch optimization,there are a total of 23 blue-green ecological sources after supplementing the sources,with an area of 296.62km2.Among them,there are 4 green sources with an area of 74.28km2;19 blue sources with an area of 222.34km2.According to the optimization principle of ecological corridors and ecological nodes,the three methods comprehensively increase the mutual verification of ecological corridors and nodes,and eliminate redundancy.There are a total of 285 corridors and 101 nodes.Among them,253 corridors and 23 nodes were extracted based on the minimum cumulative resistance model;40 corridors and 40 nodes were supplemented based on the Linkage mapper circuit theory;35 radiation channels and 38 nodes were supplemented based on the hydrological analysis principle.(4)Optimization evaluation and construction suggestions for blue-green ecological network in Huarong County.From the perspective of source centrality,the average centrality of each source after optimization is 67.81,an increase of 33.42 from before.From the perspective of the importance of ecological corridors and nodes,96 key corridors(including 21 radial corridors)and 189 general corridors were identified after optimization;81 key nodes and 20 general nodes were identified.From the perspective of the optimized network structure index,the α index is 0.9391,the β index is 2.8218,and the γ index is 0.9596,indicating that the overall structure tends to be perfect.Finally,based on the optimization results,a structural layout of "one city with three cores and two axes linkage,two belts and three points intertwined with blue and green" is proposed,and some construction suggestions are made for "three cores","two axes","two belts" and "three points".