基于VSD框架的半干旱地区社会—生态系统脆弱性演化与模拟

利用VSD（Vulnerability scoping diagram）评估框架,改进了针对县域尺度的脆弱性评估方法和技术;以黄土高原半干旱地区的榆林市为例,对VSD框架和SERV（Spatially Explicit Resilience-Vulnerability）模型进行整合,将系统脆弱性分解为暴露、敏感性、适应能力3个维度。应用SERV模型筛选脆弱性指标,在充分理解区域地理背景和暴露风险源的基础上,构建了符合当地生态环境特征的指标体系,运用RS与GIS空间技术,定量测度了榆林市2000-2011年社会—生态系统脆弱性空间分异特征及演化趋势,探讨了脆弱性时空演化内在原因。结果显示：榆林市社会—生态系统脆弱性呈现“西北东南高,长城沿线低”的空间格局,2000-2011年间系统脆弱性程度明显降低,系统发展趋势好转,但系统脆弱性与暴露风险空间差异显著;其中,暴露风险因子是系统脆弱性演化的关键因素,区域脆弱性与暴露风险空间异质受社会敏感性和经济适应能力等因子影响。最后,采用OWA多准则算法,基于决策者不确定性偏好,模拟了不同决策风险设置下区域脆弱性未来情景,并基于决策者理性风险区间,预测了不同发展导向下区域系统脆弱性差异,为研究区可持续性评估和降低脆弱性的风险预警机制建设提供决策参考。

The vulnerability evolution and simulation of the social-ecological systems in the semi-arid area based on the VSD framework

Taking the semi-arid area of Yulin City as an example, this study improves the vulnerability assessment methods and techniques on the county scale using VSD (Vulnerability Scoping Diagram) assessment framework, integrates the VSD framework and SERV (Spatially Explicit Resilience-Vulnerability) model, and decomposes the system vulnerability into three dimensions including exposure, sensitivity and adaptive capacity. Firstly, with the full understanding of the background and exposure risk source of the research area, the vulnerability indexes were screened out by the SERV model and the index system was constructed to assess the characteristics of the local eco-environment. Secondly, with the aid of RS and GIS, this study measured the spatial differentiation and evolution of social-ecological systems in Yulin City during the period 2000-2011 and explored intrinsic reasons for spatial-temporal evolution of vulnerability. The results are as follows: (1) The spatial pattern of Yulin City's SESs vulnerability is "high in northwest and southeast and low along the Great Wall", although the degree of system vulnerability reduced significantly during the period 2000-2011 and the system development trend is better, there is a sharp distinction in the spatial distribution between the system vulnerability and exposure risk; (2) The evolution of system vulnerability is influenced by the risk factors of exposure, and the regional vulnerability and the spatial heterogeneity of exposure risk are affected by the social sensitivity, economic adaptive capacity and other factors. Finally, according to the uncertainty of decision makers, the future scenarios of regional vulnerability are simulated under different decision risks by taking advantage of the OWA multi-criteria algorithm, and the vulnerability of regional system under different development directions was predicted based on the decision makers' rational risk interval.