基于VSD模型的区域生态系统脆弱性评价——以广西西江经济带为例

生态系统脆弱性受到自然与人文因素双重影响。以广西西江经济带为例，采用VSD模型，通过暴露度、敏感性和适应能力分解脆弱性，构建包含自然和人为因素25 个指标的评价体系，开展脆弱性评价与分区。结果表明，不脆弱区、一般区、脆弱区、很脆弱区和极脆弱区分别占11.31%、22.63%、27.60%、24.39%和14.07%，东西部地区脆弱性较高，中部地区脆弱性较低；自然因素导致的脆弱区主要分布于东西部山区，人为因素主导的脆弱区分布于中部盆地的城镇及其周边；经济带约53%的建设用地分布于很脆弱区和脆弱区，未来新增建设用地需要重点向不脆弱区和一般区转移。根据分区结果和诱因差异，提出了不同类型区开发与保护的相关建议。

Regional Ecological Vulnerability Assessment Based on VSD Model：A Case Study of Xijiang River Economic Belt in Guangxi

The interactive effects of natural and human factors on ecosystem have been focused on by quite a few researchers. Many theories and methods were proposed to carry out such research work, but few researches focused on the quantitative assessment on large-scale ecological vulnerability caused by natural and human factors and indicated the difference between nature- and human-induced vulnerability. Taking Xijiang River Economic Belt in Guangxi (XREB for short) as a case area, we carried out assessment on vulnerability based on VSD model developed by Polsky and his cooperators in 2007. Five kinds of ecological vulnerable zones were divided accordingly. XREB is a naturally vulnerable region, and recent rapid development intensified the vulnerability. Our indices were composed of three sub-objects, ten elements and 25 indicators, which included factors from both natural and human aspects. Assessment and zoning results based on VSD model indicated the spatial differentiation of zones with different vulnerability, and zones with the lowest, lower, middle, higher and highest vulnerability occupied 11.31%, 22.63%, 27.60%, 24.39%, and 14.07%, respectively. The eastern and western parts of XREB were more vulnerable than the middle part. Vulnerable zones caused by natural factors including high elevation and complicated topography distributed in the mountain areas, but that caused by human activities distributed in the surrounding areas of big cities mainly. From the over-lay relationship between five kinds of vulnerable zones and current construction lands, about 53% of the construction lands distributed at zones with higher and middle vulnerability, and less than 10% distributed in zone with the lowest vulnerability. However, the distributions of three types of construction lands were different. Most of the urban & town lands were located in zones with the highest, higher and middle vulnerability, accounting for 29.63%, 36.65% and 21.90%, respectively. Moreover, minute quantity of urban & town land was located in zone with the lowest vulnerability. The distribution of rural settlements was more dispersed than urban & town land, and zone with the lowest vulnerability was of least proportion, which was about 12%. The other construction land was of similar spatial distribution pattern with rural settlements, but zone with the highest vulnerability was of least proportion, which was about 9%. As human factor has already caused the increasing of ecological vulnerability, future economic growth and regional development should turn to zones with lower and the lowest vulnerability. Based on zoning results, inducing factors, and the spatial relationship with current construction lands, suggestions on regional development or ecological protection were proposed accordingly.