| As the basic natural resources for human survival and development,land is an important bridge connecting the natural environment and human beings.With the continuous development of social economy,many unreasonable use activities of human land resources,resulting in the decline of ecological environment stability,and then threatening the survival and development of human beings.Land desertification is an important driving mechanism for ecological damage and land degradation.As an ideal tool for land desertification analysis and change,landscape pattern research on its evolution process and optimization plan is of great significance for sustainable development of ecological environment and harmonious coexistence of human and nature.In this paper,Wengniute Banner,Chifeng City,Inner Mongolia Autonomous Region,is selected as the research area.The remote sensing images of the same time phase in 2008,2013 and 2018 are selected.Based on the extraction of land use types,the temporal and spatial evolution characteristics of the landscape pattern in Wengniute Banner are analyzed.The scale effect of the landscape pattern is analyzed by changing the size of the landscape pattern,and the best selection is made by combining the size inversion method and the principal component analysis Based on MCR model,landscape pattern optimization analysis is carried out.The main research contents and conclusions were as follows:1.Based on the remote sensing images of the three phases of 2008,2013 and 2018 in the study area,the land use types of Wengniute Banner are divided into six categories,i.e.cultivated land,forest land,grassland,water area,construction land and unused land.The temporal characteristics and information entropy analysis of land use change,landscape dynamic degree change analysis,landscape pattern transfer matrix analysis and transfer network analysis,and focus shift are carried out Move analysis.It is found that during 2008-2018,the landscape pattern of the region changed greatly,and the cultivated land area changed from 291617.86 hm2 increased to 317424.50hm2,forest land area increased from 77306.86hm2 to 133216.53hm2,while grassland area decreased significantly from 634538.07hm2 to 539791.24hm2;from 2008 to 2013,the landscape dynamic degree of forest land was the largest,which was 0.14%;from 2013 to 2018,the landscape dynamic degree of water area was the largest,which was-0.07%;from 2008 to 2018,the information entropy increased first and then stabilized,which was 1.36 Nat in 2008 In 2013 and 2018,it reached 1.46Nat;in 2008-2013,the transfer of cultivated land to grassland accounted for 16.16% of the total transfer volume of the network,and the transfer of forest land to grassland accounted for 16.62% of the total transfer network;in 2013-2018,the transfer of cultivated land to grassland accounted for 27.31% of the total transfer network,and the transfer of forest land to grassland accounted for 11.47% of the total transfer network.In the past ten years,the center of gravity of grassland has been shifted to the northeast by 33.320 km,and the landscape fragmentation has increased.2.Six landscape indexes such as patch type level and landscape level were selected to analyze landscape pattern index,and the influence of different granularity on landscape pattern index was analyzed.The results showed that: in landscape level pattern index,patch density decreased from 0.40 to 0.32,Shannon diversity increased from 1.37 to 1.45,Shannon evenness increased from 0.76 to 0.81,indicating that no dominant landscape had been formed,and landscape fragmentation increased;in patch type level,patch area percentage did not change significantly with the change of grain size,and other landscape types changed with the change of grain size Change.Among them,in 2013 and 2018,the granularity effect of water area on patch density is stronger,from 0.005 to 0.035,from 0.010 to 0.034,respectively.The granularity effect of unused land on effective network size is stronger,from 24596 to 40697,and the granularity effect of construction land on aggregation and cohesion is stronger,from 0.92 to 0.32 and from 95 to 50.3.The connectivity index of landscape structure under different granularity is calculated.The optimal granularity is 3200 m by the method of particle size inversion and principal component analysis.51 ecological sources are selected according to the characteristics of the optimal granularity landscape.Combined with the regional characteristics,the ecological resistance surface is constructed,49 ecological corridors and 58 ecological nodes are extracted,and the density of corridors and nodes is analyzed to provide reference for the order of ecological construction.The results show that there are significant differences between the East and the West in the ecological situation of Wengniute Banner.The source areas and corridors in the western middle and low mountains and hills are concentrated,and there are three high node density areas that need to be focused on protection and construction.The eastern plain area has a wide range of sand,the source areas and corridors are scattered.The energy circulation mainly depends on the xilamuron River and Laoha River,and the ecological structure connectivity is poor.Based on the optimal granularity extraction of ecological source,the landscape connectivity and scale effect are considered comprehensively,which is more scientific and objective than the traditional methods,and provides an objective and effective basis for the optimization of regional landscape pattern. |
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