Study On The Construction Of Ecological Security Pattern In Caoxian County Based On Circuit Theory

Rapid economic development and large increase in population size lead to ecological problems such as irrational development and utilization of land resources,intensification of landscape fragmentation,reduction of ecosystem service function,loss of biodiversity,etc.Therefore,ensuring that regional ecology is in a safe state and free from external threats is the key to solving ecological and environmental problems.By identifying the status quo of ecological environment and constructing ecological security pattern,key landscape elements can be identified to achieve the purpose of regulating and improving important ecological processes,which is of great significance for protecting regional ecological security,maintaining ecosystem stability and ecological sustainable development.As the main producing area of national agricultural products and the ecological security barrier of the lower reaches of the Yellow River,Caoxian County is particularly important for ecological security and needs to strengthen the construction of ecological and environmental protection.Taking Caoxian County as an example,this study analyzed the spatio-temporal evolution characteristics of land use and landscape pattern and the status quo of important ecological reserves from 2009 to 2019 to grasp the status quo of the ecological environment and current ecological problems in Caoxian County.On this basis,ecosystem service function evaluation indexes and single resistance factors that fit the characteristics of the ecological environment in Caoxian were selected to screen the ecological source area and construct the comprehensive resistance surface.The minimum cumulative resistance surface was constructed by using the minimum cumulative resistance model(MCR),and the ecological security zones were divided according to the resistance values.Based on the circuit theory,the ecological security pattern was constructed according to the research paradigm of“source area-corridor-pinch point-obstacle point”,and the ecological spatial structure layout was optimized,and the optimization strategy of ecological security pattern was proposed.The main research results are as follows:(1)According to the spatio-temporal evolution of land use in Cao County from 2009 to2019,the main land use type in Cao County is cultivated land.The cultivated land area in2019 is 125283.33hm~2,accounting for 63.66%of the total area of Cao County,and distributed in various towns and townships of Cao County.During the decade,the area of cultivated land decreased by 1.14%and was mainly converted into forest land and construction land.Other types of land area increased,garden and grassland increased by 20.03%and 16.50%,respectively.According to the spatio-temporal evolution results of landscape pattern,the degree of landscape fragmentation is intensified,the landscape shape becomes irregular,and the connectivity decreases,but the distribution of landscape types is more uniform,and the landscape diversity is improved.The important ecological protection areas are mainly the old Yellow River route,wetland park and reservoir,which are of single type and small area.(2)Based on the ecological background of Caoxian County,biodiversity,water conservation and carbon storage were selected to evaluate the importance of ecosystem service functions,and the regions with high importance were selected as the results of ecological source identification.A total of 32 ecological sources were selected,accounting for4.75%of the total area of Caoxian County.They were mainly distributed in the southern and eastern edges of Caoxian County,and the land use types were woodland and water.Six single-factor resistance were selected from natural factors and economic factors to generate a single resistance surface,and a comprehensive resistance surface was generated according to the corresponding weights.The minimum cumulative resistance surface was constructed based on the MCR model,and the ecological safety zones are divided into three levels of low,medium and high according to the magnitude of resistance values.The low level ecological security zone area was the largest,accounting for 48.81%of the total area of Caoxian County.It includes the ecological source area and the area with good ecological quality around the ecological source area,which is the key area of ecological protection.Based on the circuit theory,70 potential ecological corridors and 47 important ones are constructed.The ecological corridors mainly pass through cultivated land,water area and forest land.In terms of spatial distribution,the ecological corridors are sparse in the north and dense in the south,sparse in the east and dense in the west,with a net-like distribution.According to the identification map of current density,the area with high current density was taken as ecological pinch points.A total of 54 ecological pinch points were extracted,mainly distributed in the forest land and water area with low resistance value.According to the resistance identification map,the area with large resistance was taken as the ecological obstacle points.A total of 35 ecological obstacle points were extracted,mainly distributed in the construction land and cultivated land with high resistance value.(3)According to the constructed ecological security pattern,the ecological spatial layout optimization scheme of“One belt,two corridors,three cores and three districts”was proposed.According to the ecological problems identified and the ecological security pattern constructed,the corresponding ecological optimization strategy is proposed.In order to provide scientific theoretical basis for the ecological security and sustainable development of Caoxian County,the ecological security pattern of Caoxian County was constructed by using circuit theory,and ecological problems were identified and optimization strategies were proposed.