摘要
基于生态安全格局与韧性城市发展间的耦合诉求,提出“源—流—汇”三维生态韧性评价方法,并使用2005—2017年天津市TM/ETM+影像和ASTER GDEM数据,通过韧性源识别、生态足迹核算及最小累积阻力模拟分别对三种韧性指数进行分析。结果表明:“源—流—汇”生态韧性评价法能有效测度城市的韧性强度,三种韧性指标的组合共同决定城市生态安全格局的稳定性;天津市中心城区各组团韧性强度空间分布不均,三项指数对城市整体生态韧性水平的影响各异,其中韧性源指数是生态安全阈值划定的条件,应保持在1.5<Ts>2的范围内;韧性流指数是城市形态弹性调节的标准;韧性汇指数是城市空间安全扩展的瓶颈,Td>0.35下的增量建设会突破生态环境容量;并借此提出天津市生态韧性提升策略。
China is making ecological security the core issue of urban disease control.In the work of ecological restoration,it is faced with the double test of diversification of disaster causing factors and vulnerability of disaster bearing body.As an important ecological gateway facing the Bo-Hai Sea in the Beijing-Tianjin-Hebei region,Tianjin is facing a severe ecological security risk situation.However,the existing research results are still in the initial stage of putting forward risk management measures based on the concept of ecological resilience.Most of the resilience evaluation is aimed at the design of refuge and evacuation places and disaster prevention engineering,so it is impossible to establish a direct connection between the resilience system and ecological security pattern,and the related results are also difficult to be applied in the level of urban planning and management.Based on ecological security pattern and toughness coupling between urban development and demands,to Tianjin City as the object of empirical study,using 2005-2017,Tianjin TM/ETM+images and ASTER GDEM data,in accordance with the basic theories of landscape ecology and analysis tools was proposed based on“Source-Flow-Sink”3D evaluation methods of urban ecological resilience by toughness source identification,the ecological footprint accounting and minimum cumulative resistance simulation analysis of three kinds of toughness index respectively.Among them,resilience“Source”refers to the patches in the urban ecological security pattern that can provide ecological resilience services,such as vegetation buffer,habitat maintenance and water and soil conservation.The“Resilience Sink”refers to the resistance surface affecting the ecological resilience recovery,such as the scale of the built-up area,population density,etc.The resilient“Flow”refers to the safe space carrier connecting the“Source”and“Sink”,such as ecological corridor and urban form.In this way,the suggestions on improving the ecological resilience of the central urban area of Tianjin are put forward to ensure that the city has the resilience and resilience to respond to pressure or risk conditions in the face of uncertain disturbances.The“Source-Flow-Sink”index analysis method is a quantitative analysis and evaluation method of resilience strength based on the research on the coordination and symbiosis among the three basic ecological resilience factors,namely urban built environment,ecological resource background and residents’ecological footprint demand.Three kinds of resilience indexes not only restrict each other but also decide the stability of urban ecological security pattern.Through toughness“Source-Flow-Sink”three dimensional index evaluation found that Tianjin City center space distribution,each group toughness strength index of the three different influence on urban ecological resilience level,when the face of production safety accidents,environmental pollution and natural disasters such as risk still showed weaker elastic resilience,central city ecological resilience should be dynamic and continuous process,emphasis on toughness“Source-Flow-Sink”elements in time and space structure adjustment.The results show that:1)The“Source-Flow-Sink”resilience indexes restrict each other and affect the restoration of urban ecological resilience.A single index can only describe the strength of urban ecological resilience factors,so only the combination of three indexes can determine the stability of urban ecological security pattern.2)That the source of toughness index is the condition of ecological safety threshold is defined,and the toughness of the Tianjin City center source safety threshold should be kept in the range of 1.5<Ts>2,the lower the toughness index of source suggests that city construction the more serious the damage to the natural ecological environment,once broke the minimum safety threshold,the steady state will be difficult to restore the ecological environment system.Therefore,the change of resilience source index should be carefully treated as the primary condition to ensure urban ecological security.3)The resilience sink index is the bottleneck of the safe expansion of urban space and can represent the ecological footprint or ecological consumption intensity of residents under different urban densities.Tianjin City center toughness index should be maintained in the average level of 0.22 to ensure the sustainability of the urban construction,once the Td>0.35 breakthrough will lead to incremental construction ecological environment capacity and greatly reduce the intensity of ecological resilience,the resilience of constant resistance surface is too big to send proper erosion ecological source and cause of the ecological environment problems,and tough remit bearing surface is too small will cause the ecological footprint and trigger social security demand is too high,so both decided to urban spatial expansion of the scale and direction of safety.4)Ductile flow index is the standard for elastic regulation of urban morphology.Urban morphology with good toughness should be the spatial coupling between ductile source and ductile sink.The adjustment of urban morphological elasticity should not only control the disorderly expansion of ductile sinks,but also increase the number of blue-green landscapes.Greenways and water systems should be used to enrich the composition of urban ductile sources and improve the elastic adaptation to the expansion of ductile sinks.
作者
王思成
运迎霞
贾琦
WANG Sicheng;YUN Yingxia;JIA Qi
出处
《西部人居环境学刊》
2020年第1期82-90,共9页
Journal of Human Settlements in West China
基金
国家社会科学基金重大项目(13&ZD162)
关键词
源—流—汇
生态治理
韧性指数
中心城区
天津
Source-Flow-Sink
Ecological Management
Toughness Index
Central Urban Area
Tianjin
