Study On The Evolution And Optimization Of Landscape Ecological Pattern Of Villages And Towns In Ecologically Fragile Areas Of Western Sichuan

Along with the promotion of a series of national policies such as global tourism,Rural Revitalization Strategy and ecological civilization construction,as an important social space type,villages and towns are affected by natural conditions and human factors,and their landscape ecological pattern has been in a dynamic process.Especially in the ecologically fragile areas,in the current era of vigorous social and economic development,the role and status of towns are constantly changing,and their functions are constantly expanding.As the base of tourism development and rural revitalization,the landscape ecological pattern has a closer relationship with ecological protection.In order to coordinate the sustainable development relationship between socio-economic and landscape ecological pattern of villages and towns in ecologically fragile areas,this paper makes an in-depth study based on the dynamic evolution of landscape pattern and the optimization of landscape ecological security pattern of villages and towns.It deepens the relevant research links in the process of "process evolution driving force analysis scenario simulation pattern optimization development strategy",which has certain theoretical and practical significance.On this basis,Qingping town of Mianzhu City,an ecologically fragile town in Western Sichuan,is taken as the research object.Based on the theories and technologies of landscape ecology,land use/cover change and geographic information system,the spatial and temporal evolution characteristics and driving mechanism of landscape ecological pattern in Qingping town from 2008 to 2020 were explored.Based on Ca Markov model,three landscape pattern simulations in 2026 were carried out under natural development scenario,tourism development scenario and ecological protection scenario,and the change characteristics of the three scenarios were analyzed qualitatively and quantitatively.Based on the MCR model,the ecological source and resistance surface of Qingping town were selected to construct six phases of landscape ecological security pattern in 2008,2014,2020 and 2026 under three simulation scenarios.Finally,the paper puts forward relevant optimization strategies and suggestions for all levels of security zoning of landscape ecological security pattern.The main conclusions are as follows:(1)Based on the land use data of Qingping town in 2008,2014 and 2020,using ArcGIS,SPSS,FRAGSTATS and other spatial analysis and quantitative analysis software,this paper studied the spatial and temporal evolution characteristics and laws of landscape ecological pattern in the region,and discussed the scope and importance of natural environment and human and social driving forces on landscape pattern evolution.The results show that:the main landscape type of Qingping town is woodland,which accounts for more than 85%during the study period,and the area of woodland and grassland basically remains unchanged,followed by unused land,which accounts for more than 10%,while the area of construction land accounts for less,but it continues to grow,the total volume of cultivated land has decreased,the area of garden land has decreased,and the water area has increased significantly in 2014.In 2008-2014 and 2014-2020,the comprehensive dynamic degree is 0.33%and 0.10%respectively.The Shannon information entropy of 2008,2014 and 2020 are 0.5173,0.5324 and 0.5325 respectively,and the landscape land structure of the study area tends to be balanced.(2)The optimal granularity of landscape pattern analysis was determined to be 15m.The evolution characteristics of landscape pattern in Qingping town from 2008 to 2020 were explored at the type level and landscape level,and the distribution of landscape land types with different distance gradients in the horizontal direction were analyzed.The results show that:at the type level,the patches of cultivated land,construction land and water area are greatly affected by human activities,the agglomeration degree fluctuates greatly,and the agglomeration of water area patches is increasing.On the landscape level,Qingping town’s landscape aggregation degree is good and stable,the physical connectivity of landscape patches is slightly reduced,and the landscape fragmentation degree is slightly increased.(3)Based on the CA-Markov model,three simulation scenarios of landscape pattern in 2026,including natural development,tourism development and ecological protection,were designed.The area quantity and landscape pattern characteristics of each landscape type under different simulation scenarios were analyzed.The results show that:all the land use types under the three scenarios have different degrees of change,and the spatial changes of landscape patches under the three scenarios are similar.The results show that the landscape fragmentation of the three simulation scenarios has an increasing trend,and the fragmentation trend is more obvious in scenario 3;the landscape aggregation degree is better,and the landscape aggregation degree is the best in scenario 2;the landscape diversity is rich,but the woodland has strong control over the overall landscape pattern.(4)Based on the theory of landscape ecological security pattern(SP),the minimum cumulative resistance model(MCR)was applied to optimize and construct the landscape ecological security pattern of Qingping town.The results show that the total area of each district in each period of Qingping town is:high security zone>medium security zone>low security zone.The proportion of high security area is always more than 90%,the proportion of middle ecological security area is about 6%,and the proportion of low ecological security area is about 3%-4%.Finally,the optimization strategies and suggestions are put forward for the high security zone to focus on ecological protection,the middle security zone to combine control and prevention,and the low security zone to combine ecological restoration and ecological governance.To sum up,in view of the existing landscape pattern problems in the main town of Qingping Town,this paper puts forward optimization strategies for landscape patches and landscape corridors respectively,hoping to improve the landscape ecological security level of the main town of Qingping town.