长沙城市空间破碎化的格局特征及其影响因素

The pattern characteristics and influencing factors of urban space fragmentation in Changsha

空间破碎化是城市空间结构研究亟待深化的重要课题。从形态、联系以及功能3个维度构建城市空间破碎化测度指标,并运用地理探测器模型,探讨长沙城市空间破碎化的格局特征及其影响因素。主要结论:①城市空间破碎化可从形态分割、联系阻隔、功能失序三方面进行测度,形态分割可用平均地块面积指数表征,联系阻隔可用平均阻抗指数刻画,功能失序可用功能多样指数、邻接冲突指数来反映;②长沙城市空间破碎化呈现圈层式分异为主、扇形扩展分异为辅的格局特征,低破碎化区主要分布在城市核心区,高破碎化区沿着特定的扇面向外围扩展,且主要分布在大型封闭社区、工业园区、山地绿地及大型站场等区域;③长沙城市空间破碎化的空间分异是多因素综合作用的结果,其中海拔、坡度等自然因素是基础因素,土地价格、人口密度、设施投入是主导因素;④长沙城市空间破碎化治理可从突破市场供给约束、市场需求约束和设施丰度约束三方面着手,采取针对性调控对策,以最大程度地消减空间破碎化带来的负面效应。

Space fragmentation is an important issue to be deepened in the study of urban spatial structure.The measurement index of urban space fragmentation is constructed from three dimensions of form,connection and function,and its pattern characteristics and influencing factors in Changsha are discussed by using geographical detector model.The main conclusions are as follows:(1)fragmentation of urban space can be measured from three aspects:morphological segmentation,contact barrier and functional disorder.Morphological segmentation can be characterized by mean block area index(MBA),contact barrier can be featured by average impedance index(AI),and functional disorder can be reflected by functional diversity index(FD)and adjacency conflict index(AC).(2)The spatial fragmentation of Changsha presents a pattern of circle-shaped differentiation and fan-shaped expansion differentiation.The low-fragmentation area is mainly distributed in the urban core area,while the high-fragmentation area extends to the periphery along specific sectors,and is mainly distributed in large-gated communities,industrial parks,mountain green areas and large railway stations.(3)The spatial differentiation of urban space fragmentation is the result of the joint action of multiple factors,among which the natural conditions such as altitude and slope are the basic factors,while land price,population density and facility input are the dominant factors.(4)The governance of urban space fragmentation in Changsha should break through the constraints of market supply,market demand and facility abundance.In order to reduce the negative effect of space fragmentation,the corresponding countermeasures should be adopted.