Construction Of Ecological Security Pattern In Donglan County Based On Ecological Importance And Sensitivity

At present,the implementation of rural revitalization strategy is an important means to solve the economic development and environmental problems in Donglan County.Donglan County has developed karst landform and fragile ecological environment.The construction of ecological security pattern is of great significance to the ecological protection and economic development planning of Donglan County by providing reference for the territorial spatial planning of Donglan County and ensuring the coordinated development of economy and ecological environment.Firstly,this study analyzed the ecological environment status of Donglan County through the evaluation of ecological environmental sensitivity and ecological service function importance,so as to identify the ecological source and ecological function zones of Donglan County.Secondly,MCR model was used to construct the minimum cumulative resistance surface,and the ecological corridor in Donglan County was identified by Arc GIS platform.Then Arc GIS was used to identify ecological nodes in Donglan County.Finally,various elements were superimposed to build the ecological security pattern model of Donglan County.The main results were as follows:(1)The eco-environmental sensitivity levels of Donglan County were mainly moderate and mild,accounting for 45.09%and 34.83%,respectively.The highly sensitive areas were concentrated in Donglan Town,Changjiang Town and other towns in the east and southwest of Donglan County,accounting for only 20.08%.In Donglan County,the importance levels of ecological service function were mainly very important and important,accounting for 37.06%and 54.80%,respectively.Generally important areas were distributed in the county boundary,accounting for only 8.14%.(2)Based on the evaluation of ecological sensitivity and importance of ecological service function in Donglan County,the ecological source area of Donglan County was initially identified as 294.90km~2,accounting for 12.10%of the total land area of the county.In addition,there are also three functional zones,including ecological key zone,ecological buffer zone and ecological control zone,whose areas are 937.55km~2,804.55km~2and 400.01km~2respectively.(3)Based on the optimization analysis of ecological source and the ecological environment status of Donglan County,a total of 15 ecological source patches with an area larger than 1.5km~2were obtained,and the total area of ecological source was 50.96km~2,accounting for 2.11%of the total land area of Donglan County.The ecological source patches were mainly distributed in the central region of Donglan County,among which the ecological source patches in Donglan Town and Changjiang Town were the most distributed.They’re both 4 pieces.(4)By constructing the minimum cumulative resistance surface,105ecological corridors in Donglan County are identified by consensus.After hierarchical optimization by gravity model,it is finally obtained that there are13 first-level corridors,26 second-level corridors and 66 third-level corridors in Donglan County.The total length of all corridors is 1620.93km,mainly distributed in the central and eastern parts of Donglan County.However,Arc GIS software was further used to identify 15 ecological nodes in Donglan County,whose distribution was consistent with the ecological source.(5)Finally,the ecological security pattern of"One belt,three corridors,three districts and many points"in Donglan County was constructed,including:ecological source distribution belt,first,second and third corridor ecological network,three ecological function zones and multiple ecological node distribution.According to the analysis of the results of ecological security pattern construction,the ecological environment of Donglan County is still fragile and sensitive.The southwest area is affected by karst landform,the landscape patches are broken and the ecosystem is seriously damaged,which poses a certain threat to the overall ecological security pattern of Donglan County.The research results provide theoretical reference for future ecological environmental protection and economic development planning and ecological civilization construction in Donglan County,and have certain practical significance.