| China’s rapid urbanization process of more than 40 years resulted in a chaotic pattern of disordered development and degraded environment in urban fringe(UF),which induced a series of negative chain reactions in both urban and rural system.At present,the trend of networking and flattening of urban spatial structure is significant.With the new round of population restructuring and the suburbanization of innovative resources in China,the strategic position of UF continues to rise,becoming the forefront of urban development transformation and ecological civilization construction.However,UF is a part of the city’s complex adaptive system,with prominent characteristics of self-organization,nonlinearity,multi-stability,threshold effect and historical dependence.Under complex internal and external conditions,the traditional planning paradigm driven by mechanical rationalism fails to scientifically explain,predict and intervene the development of UF,and gradually falls into difficulties in practice.Based on the ecological rationality,this research is committed to exploring the sustainable developing path and the spatial optimizing methodology of UF system,so as to realize the dual transformation of knowledge and practice paradigm.The research contributes to promoting the spatial benefits of UF,and can provide decision-making reference for the practice of the territorial spatial planning(TSP)in the new era.This research is based on the logic of theoretical deduction and method construction,case demonstration and mechanism interpretation,conclusion integration and strategy making.Firstly,this research analyzed the dilemma formation mechanism of chaotic spatial pattern and ecosystem decline in UF.Taking the Panarchy model from complex science as reference,this research constructed a theoretical framework for the ecological adaptive evolution of the UF and an adaptive optimization approach for multi-scale spatial patterns.Then,Xiamen was taken as a case to carry out empirical analysis.Through the three-dimensional dynamic identification method,the UF of Xiamen from 1990 to 2018 was quantitatively identified,and its spatial evolution characteristics and driving mechanism were revealed.On this basis,the ecological network connecting urban and rural system was simulated and optimized on the macro scale.The spatial coordination of ecosystem service(ES)and urbanization was carried out on the meso scale.The multi-objective optimization of land use was carried out on the micro scale.Those were to clarify the mechanism and methodology of ecological adaptive optimization of UF system on multiple scales.Finally,integrating the multi-scale analysis conclusions of UF,this research put forward specific responding planning strategies of ecological adaptive evolution.The main results of this research are summarized as follows:(1)The UF of Xiamen kept expanding from the island to the inland,including four stages,i.e.,group forming,integrated expansion,leaping expansion,and internal differentiation.Additionally,it showed characteristic of simultaneous outward loop expansion and inward reduction.During the study period,the proportion of spatial units with multifunction continued to increase,and the construction land continued occupying cultivated land and other ecological spaces.The dynamic degree and changing rate of land use in the UF decreased and stabilized after peaking in 2010.(2)The optimized ecological network(OEN)of Xiamen in the UF consists of two parts,i.e.,the basic ecological network distributed in the hinterland and the connecting ecological network in the coastal area.The OEN includes 19 ecological sources,7 natural structural corridors,22 urban-rural connecting corridors and 8 urban structural corridors,which improves the spatial performance of urban-rural ecological structure.(3)The overall synergy level between habitat quality and runoff mitigation and thermal regulation in the UF of Xiamen was the highest,and the local synergy pattern was fragmented.The area of comprehensive ES above high value mainly distributed in the hilly forest land near the coast and the shallow mountain area in the UF.Integrating spatial characteristics of urbanization and ESs distribution,the ecological control zoning map of Xiamen was put forward,based on the spatial subdivision units.Furthermore,specific management strategies of four types of units in eight scenarios were proposed through the decision matrix.(4)The UF of Xiamen still has economic potential to be released on the premise of maintaining present ecological level.On the overall scale,the optimal areas of various types of land under global-scale constraints are 4643.46hm~2 of crop land,10182.39 hm~2 of forest land,6638.33 hm~2 of grass land,1469.58 hm~2of water body,39311.17 hm~2 of construction land and 0.07 hm~2 of unused land.On the unit scale,the optimal area ranges of different land use types in developing and ecological scenarios were matched with the spatial units of four adaptive evolution stages respectively.(5)Finally,coordinating the development logic of bottom-line thinking and growth doctrine,this research put forward responding strategies of ecological adaptive planning,i.e.,structure as the key link,function as the foundation,elements as the form,governance as the policy.The innovation of this research is reflected in the following three aspects:(1)The theory of ecological adaptive evolution of UF was proposed in this research,which clarifies the spatial system composition,evolution path and planning intervention mechanism of the UF;(2)A dynamic UF identification approach based on three attributes of“heterogeneity-transition-dynamics”was put forward,which solves the problems of UF identification of cities with complex structure and long-time monitoring of UF evolution;(3)An ecological adaptive optimization methodology of UF with“structure-function-elements”of multi-scale coupling was constructed,providing a quantitative decision-making tool for the practice of TSP. |
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