存量更新背景下城市生态基础设施优化与实施路径OA

At present,China's urbanization has entered a pivotal transitional period featured by stock-oriented quality improvement and intensive connotative development,which has fundamentally shifted the core focus of urban development to the optimal restructuring,multi-dimensional functional upgrading and comprehensive value reshaping of existing built-up areas.With the rigid constraints of land resources and the tightening of urban construction boundaries,large-scale incremental development is no longer feasible,making stock renewal the mainstream path of urban construction.However,the practical advancement of urban stock renewal is plagued by a series of prominent practical dilemmas in urban ecological space governance,such as serious fragmentation of ecological patches,blocked ecological connectivity,and the separation of ecological protection and urban construction.To effectively resolve these stubborn problems,this paper puts forward a targeted idea of optimizing urban ecological pattern,with the urban ecological infrastructure(EI)network as a solid tangible physical carrier and core supporting system.Urban ecological infrastructure deeply integrates ecosystem services with complete ecological structures,sustaining the structural and functional integrity of urban complex ecosystems by strengthening the supporting capacity and interaction efficiency of various ecological elements.It is highly similar to green infrastructure in core implication,and the two concepts have gradually converged in internal connotation and applicable spatial scales with the deepening of relevant researches and engineering practices.For the construction of urban EI systems,several relatively mature methodologies have been formed to build landscape-scale EI systems and shape complete corresponding spatial structures.Nevertheless,all these conventional approaches take EI systems as fundamental and pre-configured prerequisite elements for urban development and construction,which are completely unsuitable for stock-constrained cities with limited space for incremental expansion.Ecological pattern optimization for stock-constrained cities can never be achieved by blindly expanding new ecological spaces,but only by fully tapping the potential ecological value of existing inefficient and idle stock spaces.There are five major types of urban stock spaces eligible for EI construction and ecological restoration:declining industrial land,aging urban residential communities,waterfront open spaces,linear land along transportation corridors,and urban idle land and marginal plots.To realize the medium and long-term development strategy of urban EI under stock constraints,it is essential to anchor the spatial layout of urban ecosystem services to the ecological transformation of stock spaces,build multi-functional composite ecological corridors,form an optimized and integrated ecological network,and adopt an innovative reverse"point-line-area"construction approach.Starting with the targeted ecological transformation of scattered single stock spaces,this innovative approach drives steady ecological improvement from communities to urban functional districts and even the whole city,while supplementing and remedying the weak links and functional deficiencies of the original urban ecosystem,ultimately forming a multi-level,cross-scale and highly interconnected urban ecological spatial network.For the specific renovation and implementation of spatial nodes,ecological corridors and overall ecological networks,relevant practices are generally carried out in line with the actual pace of urban renewal and coordinated development,targeting the five typical types of urban stock spaces mentioned above.At the spatial node level,core efforts focus on diversified functional upgrading and targeted ecological renovation to balance ecological benefits and daily service demands;at the corridor level,priorities are given to smooth physical spatial connectivity,as well as the efficient development and utilization of ancillary spaces attached to gray infrastructure to improve land use efficiency;at the ecological network level,renewed stock spaces and original scattered ecological land are integrated to form district-level sub-networks,eliminating breakpoints of ecological corridors and linking fragmented ecological patches.Through networked weaving and systematic restoration of the original urban ecosystem,the overall network integration and systematic optimization of urban EI are thoroughly realized.This paper breaks through the limitations of existing studies that mostly focus on new urban district ecological planning,single green space construction or single engineering technologies,and strengthens the in-depth research on the coupling mechanism of stock constraints,ecological functions and spatial structures.It enriches and improves the theoretical framework of urban ecological space planning in the stock era,and puts forward operable EI optimization and implementation strategies under the stock background,providing direct practical references for various stock renewal projects.Additionally,it proposes feasible strategies for the coordinated development of intensive land use and ecological value improvement,offering a valuable practical demonstration for sustainable high-quality urban development under the rigid constraints of land resources.