Research On The Construction Of Landscape Security Pattern In Wanzhou District Based On Ecological Sensitivity

The Three Gorges Reservoir area is an important ecological function area in my country and an important ecological protection barrier for the Yangtze River Basin.Due to its special geographical location,the ecological environment of the reservoir area has long been highly concerned by academic circles and regional governments.Wanzhou is located in the heart of the Three Gorges Reservoir area,with a fragile ecological environment.With the acceleration of regional urbanization,the expansion of construction land and the increasing intensity of land use,the conflict between people and land in the region has become increasingly acute,and a series of ecological risks such as soil pollution and soil erosion have become prominent,which not only contributes to greater regional ecological security.Hidden dangers have also largely affected the quality of life of the people in the district and the sustainable development of the society and economy.This study uses Wanzhou District as a sample,based on the theory of landscape ecology,using model analysis and Fragstats,Arc GIS,SPSS analysis tools to conduct research on land use changes,landscape pattern changes and their ecological sensitivity;On this basis,the regional landscape ecological security pattern is constructed through the least cumulative resistance model,and corresponding strategies and suggestions are put forward for the ecological security pattern.The conclusions obtained are as follows:（1）Analysis of characteristics of land use changeAmong the land types,forest land and arable land have the largest area and are the main land use types.During the study period,the difference between the dynamics of single land use is obvious,and the land for transportation is the most prominent;The overall dynamic degree of comprehensive land use is less than 1%,and the area change is relatively stable;From the perspective of the degree of land use,the overall land use index shows a rising trend,and the rate of increase gradually accelerates with the passage of time;From the perspective of land-use conversion types,during the study period,various land-use landscape types in the region experienced internal conversions to varying degrees and directions.Among them,cultivated land and rural residential areas were the main types of conversion,and urban industrial and mining land was the main type of conversion.（2）Analysis of characteristics of landscape pattern changesFrom the perspective of changes in the landscape level pattern,with the development of society and economy,the ability of unified planning and construction of the landscape pattern has been enhanced.The landscape types are becoming more and more abundant,and the patches of various landscape types are gradually evenly distributed in area,and the overall landscape pattern is developing towards a trend of diversification and uniformity.However,the degree of connection between different landscape types is reduced,and some large-area patches are fragmented.From the perspective of the change of landscape pattern,the landscape pattern in the region is relatively stable.Among them,the fragmentation degree of urban villages and industrial and mining land is the highest,and the fragmentation degree of garden land is the least;forest land and cultivated land are the main types of landscape,and its patches have obvious advantages degree.During the study period,human activities have the strongest interference to cultivated land,and are affected by both natural and man-made interference.The external boundary and internal morphology of landscape patches are complex and irregular.（3）Ecological sensitivity analysisFrom the overall analysis of ecological sensitivity,the ecological sensitivity indexes in 2009,2013,and 2018 were 0.620,0.618,and 0.614,respectively.All values above 0.59are considered to be highly sensitive,but generally speaking,the value gradually decreases,and there is a trend toward moderate sensitivity.From the perspective of different land types,the ecological sensitivity of waters,wetlands,woodlands,and grasslands in 2009-2018 was higher,all greater than 0.1.It can be seen that the ecological environment of these three land use types is relatively fragile and needs to be strengthened.（4）Ecological Sensitivity Spatial AnalysisFrom the perspective of the global spatial autocorrelation Moran’s I value,the Moran’s I values of the three phases are:0.265036,0.300722,0.330402,which are positive numbers and an upward trend,and have passed the test of p<0.01,indicating that the ecological sensitivity of land use is relatively strong The positive spatial correlation of,there is an agglomeration effect.In terms of local correlation patterns,the overall pattern is cold in the central part and hot in the west.The"cold spots"are mainly distributed in the center of Wanzhou District,such as Chenjiaba Street,Wuqiao Street,Shahe Street,Zhoujiaba Street,Shuanghekou Street,and Longdu Street,which have a good economic foundation and high frequency of human activities.Urban areas;"hot spots"are concentrated in Sunjia Town,a typical agricultural town in Wanzhou District.（5）Response of ecological sensitivity to landscape dynamics and land use changesAt the landscape level,fragmentation and separation index have the greatest impact on regional ecological sensitivity;At the patch type level,the average patch area index has the greatest impact on ecological sensitivity,followed by the fragmentation index and the number of patches.The response elasticity of ecological sensitivity with land use changes has different response effects in different research periods.2009-2013 ecological sensitivity showed a positive effect on land use change;2013-2018 ecological sensitivity showed a negative effect on land use change;2009-2018 also showed negative effects on the whole,and the impact of dynamic changes in land use on ecological sensitivity became smaller;It shows that land use change is no longer the main driving factor for the increase of ecological sensitivity in this area,and its influencing factors tend to be diversified and complicated.（6）Landscape ecological security pattern constructionThe current ecological security pattern of Wanzhou District in 2018 is constructed through the minimum cumulative resistance model（MCR）.The ecological source area is558.37km²,which is concentrated in the middle,southeast and northwest,forming a north-south trend.There are 25 ecological corridors with a total length of 398.01km,which are mainly distributed along forest land and river systems,and pass through most nature reserves and wetlands;107 ecological radiation channels were identified,which were used as supplementary channels for the flow between the source elements.Twenty-two ecological strategic points have been identified,which serve as the“footprints for species migration between adjacent ecological sources,which are mainly distributed in the central and southern parts of the study area.In the final low,medium and high ecological security pattern,the area of low-level ecological security pattern is 1232.27 km²,accounting for 35.65%of the total area of the region;the area of medium-level ecological security pattern is 770.53 km²,accounting for 22.29%of the total area of the region;The area of high-level ecological security pattern is 680.87 km²,accounting for19.70%of the total area of the region;the area of other regions is 772.87 km^2,accounting for 22.36%of the total area of the region.Finally,on the basis of the above,corresponding countermeasures and suggestions are put forward from the aspects of ecological source protection,ecological corridor area maintenance,and ecological strategic node protection and construction.