Landscape Pattern Analysis And Ecological Network Space Optimization In Beijing

Rapid urbanization and construction of transportation networks have led to the fragmentation of habitat patches and the continuous reduction of connectivity between landscapes.The construction of ecological network can effectively improve the connectivity of severely fragmented landscapes and is of great significance to the protection of biodiversity.Taking Beijing as the research object,this paper uses the data of surface coverage of Beijing in 2007 and 2017 as the main data source,calculates the regional landscape indices by using Fragstats 4.2 software,and carries out quantitative analysis on the landscape pattern and its changes in Beijing in the past ten years.On this basis,according to the current situation of Beijing’s ecological pattern in 2017,considering the impacts of surface cover types,slopes,elevations and roads on species migration,the potential ecological corridors in Beijing are constructed based on the minimum cost distance,and the landscape structure is analyzed.The method of spatial connectivity evaluation are used to analyze and evaluate the ecological network structure,and the ecological sources,ecological corridors and ecological nodes of the regional ecological network are graded,the ecological fracture points are identified,and finally the regional ecological network structure space is Optimize to propose countermeasures and recommendations.The research results can provide a scientific basis for the construction and optimization of the ecological network in Beijing,and provide reference and reference for the construction of other urban ecological networks,and provide decision support for the government and relevant departments of planning.The main results are as follows:(1)From the dynamic changes of land cover in Beijing in 2007-2017,significant urbanization occurred in Beijing,and the area of construction land increased more,mainly in Daxing District,Tongzhou District,Shunyi District and Changping District;Mainly concentrated in Tongzhou District,Daxing District,Shunyi District,etc.;except for Dongcheng District and Xicheng District,the area of cultivated land within other administrative areas has decreased significantly,mainly concentrated in Tongzhou District,Daxing District,Shunyi District and other areas,reflecting the near Beijing The urbanization process in the past 10 years has encroached on cultivated land.From the trend of the landscape pattern change in Beijing in 2007-2017,the patch density of each landscape type increased,indicating that the degree of fragmentation of the regional landscape increased,making the landscape plaques in Beijing more fragmented.(2)This paper selects 214 ecological source patches in Beijing,including geological parks,scenic spots,forest parks,natural cultural reserves and natural cultural heritages.The five factors of water system,slope,elevation,surface cover and road are considered.The impact of species migration builds a resistance surface,and the cost value of Beijing comprehensive resistance surface is low in the middle and low in the middle,and the average cost of the landscape in Dongcheng District and Xicheng District is higher.On this basis,there are 657 potential ecological corridors generated by the minimum cost distance model and 827 ecological nodes.The main functional area data is superimposed to construct the Beijing ecological network system.(3)From the perspective of the ecological source shape index,the shape index of the ecological source in the central part of the study area is larger,while the shape index of the western part of the peripheral mountain area and the northeast area is lower;from the perspective of the ecological source degree,the ecological source of the large ecological source area is larger.It shows that it is more than the number of ecological corridors,and it also shows that the ecological connection of the ecological source is higher.From the perspective of the distribution of the ecological corridor comprehensive index,the ecological corridors with weak connectivity in the study area are mainly distributed.In the western and southeastern parts of Beijing,ecological corridors with medium connectivity are concentrated in the southern regions,and ecological corridors with strong connectivity are mainly located in the central and northeastern regions.The regional ecological elements are divided into three grades,among which the first-level ecological source,the first-level ecological corridor and the first-level ecological node have strong spatial connectivity,and the ecological function is dominant;the spatial connectivity of the secondary and tertiary ecological elements still needs to be Continue to strengthen the optimization,gradually play its role in assisting the spread of ecological flow;finally identified a total of 511 ecological breakpoints in the study area.(4)In the process of ecological source optimization,large plaques should be dominated,and small plaques should be supplemented.The two complement each other and set a buffer distance of 1500 m for the ecological source patches,so that they are more closely related to the surrounding ecological patches.The 1000 m buffer zone is set up for the ecological corridor to strengthen the ecological function of the first-level ecological corridor and promote the stable development of the secondary and tertiary ecological corridors.The ecological node blind zone identification method is used to complete the ecological source nodes and ecological nodes.Optimization;delineate the ecological framework for regional and urban sustainable development,and finally propose an ecological network structure of “one heart,one ring,two horizontal six axes”.