Study On Urban Ecological Construction Strategy In The Process Of Urban Renewal

Under the current "new normal",urban development is transformed from extensional scale expansion to urban renewal with intension mining.In the stage of rapid urbanization development,too much attention was paid to exogenous economic growth brought by urban expansion,while the coordinated development of ecological environment and urban growth was neglected.How to improve the quality of the ecological environment and promote the sustainable development of the city in the process of urban renewal is the core problem to be solved urgently.Taking the central city of Xuzhou as the study area,the strategy of ecological construction in the process of urban renewal is explored from the perspective of optimizing the ecological network.Firstly,the change characteristics of the quantity,structure and spatial pattern of the ecological land in the study area are studied,and the existing ecological environment problems in the city are further analyzed.Secondly,MSPA,landscape connectivity index,minimum cumulative resistance model,circuit theory,voronoi and other methods are used to construct,analyze and optimize the urban ecological network.In addition,the Xiadian District is taken as an example to verify the rationality and feasibility of the urban renewal land use plan based on ecological network optimization.Finally,according to the optimization results of ecological network,the strategy of ecological construction in the process of urban renewal and the policy suggestions for promoting the smooth implementation of ecological construction in urban renewal are put forward.The main conclusions of this paper are as follows:(1)From 2005 to 2015,the scale of construction land in the study area increased most significantly,and the scale of the arable land decreased the largest.Except for the reduction of water area scale,the scale of other ecological land has increased to a certain extent.The growth rate of green space in ecological land is the fastest,which is mainly converted from arable land.In general,the landscape patches in the study area showed a trend of increasing fragmentation.The ecological land generally shows the characteristics of the increase of fragmentation,the complexity of structure,the decrease of concentration and connectivity.(2)The shrinking and fragmentation of ecological land has aggravated the ecological and environmental problems such as urban heat island effect,air pollution and flood disaster.Ecological network is the material basis for maintaining the material cycle and energy flow of urban ecosystem,and improving the service function of urban ecosystem.Urban renewal is an important source of maintaining the vitality of the city.The organic combination of ecological network and urban renewal can improve the quality of the urban environment and promote the sustainable development of the city.(3)237 ecological sources and 435 ecological corridors were extracted from the study area.The distribution of some ecological sources were scattered and isolated,and the level of network connectivity needs to be improved.Through the optimization of ecological network,70 stepping stone spots were added,192 new ecological corridors were added,121 corridor pinch points were identified.The urban renewal scheme based on ecological network optimization is better than urban planning in the aspect of improving the landscape pattern of ecological land and enhancing the comprehensive value of land use.(4)The ecological construction strategy of urban renewal is put forward from the aspects of the ecological landscape pattern,the construction of ecological patch and ecological corridor,the allocation of vegetation types,and the arrangement of the construction time series.In order to ensure the smooth development of ecological construction in urban renewal,policy suggestions were put forward from the aspects of planning,participants,policies and regulations and funds.