Study On Land Use Change And Ecological Security Pattern In Densely Built-up Areas Of Chengdu

With the transformation of urban development mode in China from denotation to connotation,urban development mode is also gradually changing to the direction of green and sustainable development.The ecological security pattern is an urban ecological network based on "mountains,water,lakes,fields and grass",which is also the cornerstone of urban ecological development and ecological civilization construction.With the continuous development of cities,construction areas continue to expand and spread,and the huge changes in land use also have a series of negative effects on the pattern of ecological security,so more and more scholars at home and abroad pay attention to it.The construction of ecological security pattern can provide ideas for the transformation of unreasonable land use in urban development and alleviate the contradiction between man and land.With the introduction of the urban development strategy of "advancing eastward,expanding southward,controlling westward,reforming northward,and improving the quality of the city" in Chengdu,the rational layout of urban functions and the improvement of urban quality have become the goals of urban construction.The dense construction area in the downtown area of Chengdu is the core area of the "medium and excellent" urban development strategy,and the gathering of a large number of resources and funds makes the status of this area continuously improve.As the gathering place of Chengdu construction area,the optimization of regional ecological security pattern plays an important role in the ecological security pattern of the whole city.Therefore,starting from the land use change of densely built-up areas in Chengdu,the impacts of land use change on regional ecological security pattern in the study area from 2005 to 2018 were analyzed with the help of Arc GIS spatial analysis function.It is beneficial to consolidate the ecological background advantage of Chengdu,further strengthen the connectivity and stability of regional ecological security pattern,and thus guide the sustainable development of the city.This paper is mainly divided into the following parts:Paper first through the literature research and sorting,analysis summary of the existing urban dense evaluation,related research progress of the ecological security pattern,from the general characteristic of the urban construction area,selection of spatial density index and evaluation system of the dense population agglomeration index to construct city proper,the analysis of the built up area of Chengdu dense evolution characteristics,determine the scope of the study.The second is the analysis of spatiotemporal characteristics of land use in densely built-up areas of Chengdu.Based on land use type,land use structure,land use transfer and other indicators,the characteristics of land use change in different time series in the study area from 2005 to 2018 were analyzed.Based on the spatial pattern of the built-up area and the landscape pattern of land use,the spatial evolution characteristics of the built-up area were analyzed.The characteristics of the evolution trend,driving factors and driving mechanisms of land use change in densely built-up areas were summarized.Then it evaluates the ecological elements quantitatively and constructs the regional ecological security pattern.According to the research logic of "sources-resistance plane-corridors",the ecological security pattern of built-up areas under urban intensive development was constructed.The patches of ecological source areas were extracted from the perspectives of landscape connectivity and biodiversity,and the network system of regional ecological security pattern was formed by identifying potential corridors with the MCR model.The evolution law of regional ecological security pattern over the years and the influence of land use change on ecological security pattern were analyzed and summarized.Finally,based on the characteristics of land use change and ecological security pattern evolution,and based on the road of urban sustainable development and the idea of ecological development,this paper puts forward the optimization strategy of densely built-up areas in Chengdu from two aspects of construction and management.