A Study On The Evaluation Of Landscape Ecological Safety Based On Grid GIS In Enshi City

With the rapid development of society,the impact of human activities on the ecological environment is deepening,leading to a greater degree of degradation of the regional ecosystem,or to a certain extent,the loss of ecological services,which directly threatens ecological security.As the most important link in the process of exploitation,utilization and protection of ecological resources,ecological security assessment has important theoretical and practical significance.Under the background of ecological protection and restoration,the evaluation and prediction of ecological security in Enshi City can provide theoretical reference for the formulation of landscape ecological construction and protection policies in this region.Based on remote sensing images and related monitoring data,coupled with 3S technology and related ecological models,this study interpreted the land use landscape type maps of Enshi City in 2000,2007 and 2014,and explored the land use change situation.On this basis,the landscape index of type and landscape level was calculated,and the landscape index was empty by using GIS grid technology.Interpolation was used to analyze the spatial and temporal changes of land use landscape pattern in Enshi City.Finally,based on the research of other scholars,an evaluation model of landscape ecological security in Enshi City was constructed,which included landscape ecological security pattern,landscape ecological quality and landscape ecological service.The spatial and temporal changes of landscape ecological security in Enshi City in three periods were analyzed and predicted.The main conclusions of this study are as follows:(1)The results of land use change research show that the dominant land use types in Enshi City are woodland and arable land during 2000-2014,and the total area of construction land and water area is in a low proportion.From the point of view of change,the area of construction land has changed dramatically and increased continuously.The area of cultivated land tends to decrease,and most of the reduction has been transformed into construction land.(2)The results of landscape index calculation and landscape pattern research show that the southwest and northeast regions of the central urban area are relatively flat,and are the main development direction of cities and towns.They are greatly influenced by human activities,and the landscape types are diverse,but the dominant landscape types are not obvious.The boundary of northwest,southwest and Southeast of Enshi City is located in the mountains,and the influence of human activities is relatively small,such as woodland.The dominant position of landscape types is obvious,and the types are relatively single.(3)The results of landscape ecological security assessment of Enshi City show that:(1)In spatial distribution,the high value area of landscape ecological security index mainly distributes in the mountains far away from the urban area,which is mainly woodland;the low value area mainly distributes in the surrounding area of the urban area,which is dominated by landscapes such as construction land,water area and cultivated land.(2)The change characteristics of landscape ecological security are as follows: from 2000 to 2007,the value of landscape ecological security index in the northern,southwestern and southeastern areas around the city decreased,while the value of landscape ecological security index in the northeast,northwest and southwestern areas of the city increased.From 2007 to 2014,the value of landscape ecological security index in southwest and other regions of the city declined,while the value of landscape ecological security index in North and south of the city increased.(3)The results of landscape ecological security prediction show that by 2020,the areas with higher landscape ecological security index in Enshi City are mainly in the north,South and southwest of Enshi City,while the areas with lower landscape ecological security index are mainly in the north and northwest of Enshi City.Compared with the background of ecological protection policy,the comprehensive level of landscape ecological security index in Enshi City in 2020 is higher when the policy remains unchanged.(4)Landscape ecological security protection countermeasures and suggestions in Enshi City: From the perspective of landscape pattern,landscape quality and landscape services,the current measures of closing hills and afforestation,returning farmland to forests,controlling rocky desertification,comprehensive management of natural forest protection in watershed and basic farmland protection are all practical and feasible.It is suggested that the current ecological protection policies and measures should be continued.Under the background of the current ecological civilization construction,we can even strengthen the protection,so as to better protect the ecological security of land use landscape in Enshi City.Finally,on the basis of comparing the research results of other scholars,this paper clarifies that the possible innovation of this study is to construct an evaluation model of landscape ecological security in Enshi City,which integrates "ecological pattern-ecological quality-ecological service",but there are also some problems such as the rationality and integrity of the indicators.Looking forward to the future,this study still needs to do further research in improving the accuracy of data sources,optimizing data processing methods,and improving the evaluation index system.