基于暴露-敏感-适应性模型的生态脆弱性时空变化评价及相关分析——以中国大运河苏州段为例

Evaluation and correlation analysis of spatio-temporal changes of ecological vulnerability based on VSD model: A case in Suzhou section, Grand Canal of China

为了及时掌握运河流域生态系统脆弱性的真实状况,以中国大运河苏州段区域为例,基于VSD模型建立生态脆弱评价指标体系,结合层次分析法-熵权法以及遥感-地理信息系统技术,以栅格为基础评价单元,运用空间叠置分析计算生态脆弱度,揭示其生态脆弱性时空分布格局及演变趋势。通过生态环境脆弱性综合评价及相关分析,其结果表明:(1)2008—2018十年间研究区生态脆弱度以潜在脆弱和轻微脆弱为主,合计占比从62.63%增长到68.79%,非常脆弱区与极度脆弱区占比较小,合计占比从22.45%下降到15.61%;(2)研究区生态恢复情况良好,根据时空演变趋势将研究区划分为生态修复区、生态持平区和生态退化区,生态修复率为37.09%,生态持平率为37.93%,生态退化率为24.89%;(3)对生态修复区与生态退化区进行划分,各包含四种等级区,其中生态修复区以Ⅰ级修复区为主,占比为13.31%;生态退化区以Ⅰ级和Ⅱ级退化区为主,合计占比为18.80%,Ⅳ级退化区占比仅有1.50%。

Ecosystems are closely related to the external environment, both human and natural factors will affect the ecosystem continuously. Ecological vulnerability research can grasp health of regional ecosystem, which is an important basis for regional ecological environmental restoration and planning and governance. It is necessary to conduct research on ecological vulnerability to effectively comprehend the health of the ecosystem. Many theories and methods were proposed to carry out such research work, but few researches will consider the three factors of humanity, nature, and society at the same time. For the purpose of understanding the real situation of canal ecological vulnerability in time, the evaluation index system of ecological vulnerability was established by Vulnerability-Scoping-Diagram(VSD) model based on Suzhou section of the Grand Canal of China. What′s more, founded on grid evaluation unit, the spatial overlay analysis was used to calculate the ecological vulnerability and then to reveal the spatio-temporal distribution pattern and evolution trend of ecological vulnerability combined with analytic hierarchy process(AHP)-entropy weight method and remote sensing(RS)-geographic information system(GIS) technology. Through comprehensive evaluation and correlation analysis of ecological vulnerability, the results showed that:(1) from 2008 to 2018, the ecological vulnerability of the study area was mainly potentially vulnerable and slightly vulnerable with the total proportion increasing from 62.63% to 68.79%, while the proportion of very vulnerable areas and extremely vulnerable areas was relatively small with the total proportion decreasing from 22.45% to 15.61%;(2) The ecological restoration of the study area was favorable. According to the temporal and spatial evolution trend, the study area was divided into ecological restoration area, ecological flat area and ecological degradation area. The ecological restoration rate was 37.09%, the ecological flat rate is 37.93%, and the ecological degradation rate was 24.89%;(3) The ecological restoration area and the ecological degradation area were divided, each including four grade areas, of which the ecological restoration area was mainly Grade I restoration area, accounting for 13.31%;The ecological degradation areas were mainly Grade I and Grade II degradation areas, accounting for 18.80% in total, while Grade IV degradation areas accounted for only 1.50%. As human and social factors have a greater impact on ecological vulnerability than natural factors, future economic growth and regional development should turn to potentially vulnerable areas and slightly vulnerable areas reasonably to reduce the influence of human activities. This study can provide scientific support and research suggestions for the development of ecological restoration and governance for place like Suzhou section, Grand Canal of China.