作 者 ：周永娟,仇江啸,王姣,王效科*,吴庆标
期 刊 ：生态学报 2010年 30卷 24期 页码：6726~6733
Keywords:eco-environmental vulnerability, water-level fluctuation area, indicator, index, assessment,
摘 要 ：在对脆弱性的概念重新界定的基础上，从三峡库区消落带的生态环境实际出发，运用ArcGIS的空间叠加分析，分别进行了消落带崩塌滑坡脆弱性、水力侵蚀脆弱性、污染脆弱性和景观脆弱性的评价；在此基础上，进行了研究区各生态主题脆弱性的叠加分析；探讨了三峡库区消落带这一特殊地理区域上生态脆弱性的高低分布规律及其在不同主导因子作用下生态脆弱性的空间分异特征。结果表明：研究区的崩塌滑坡脆弱性、水力侵蚀脆弱性和景观脆弱性均以中轻度脆弱为主，分别占消落带总面积的82.06%，72.23%和74.59%；污染脆弱性为轻度以下脆弱为主，占消落带总数的74.59%；各生态主题脆弱性的叠加结果表明：70%的消落带至少面临一种生态问题，其余部分则同时面临两种以上的环境问题，四类环境问题皆是极脆弱的消落带有3%。总体而言，消落带是一个高度脆弱的生态系统，威胁着库区的生态环境安全。管理者应根据消落带的基本特点，合理规划、因地制宜的加以治理。
Abstract:In this study we evaluate several eco-environmental vulnerabilities caused by water level fluctuations of the Three Gorges Reservoir. The Three Gorges Dam (TGD) has been inserted in the middle of a biodiversity hot spot in south-central China. The fluctuation zones of the Three Gorges Dam are made up of very fragile ecosystems which will require careful management in order to preserve them as a unique and rich source of information. Behind the dam water level fluctuate between 145m and 175m, resulting in a belt of water which changes in depth and length throughout the year. In the winters of 2008 and 2009 the pool topped behind the Three Gorges Dam at 175 m above sea level. The result of the increased pool was upstream flooding extending to within reach of the city of Chongqing. These water levels flood former cities, homes, and farm fields of about 1.5 million people seasonally for up to 7 months of the year. So the studied area has many eco-environmental problems, such as landslide, water erosion, pollution, and landscape destruction and so on. And in this study we used landslide, water erosion, pollution, and landscape deterioration as indicators of vulnerability to flooding. Vulnerability varies widely across communities, sectors and regions. It has no universally accepted definition. This diversity of the “real world” is the starting place for a vulnerability assessment. And it is essential for users to define vulnerability in their own context. In this paper, we defined the concept of “vulnerability” as an inherent property of a system arising from its internal characteristics which make it more or less susceptible to external hazards. Each of our indicators of vulnerability used a set of unique measures. The individual measures of each indicator were ranked between 1 and 5. The geometric mean of these ranks was used to create a final index of vulnerability for each indicator. Using ArcGIS the vulnerability indices were assigned to a grid corresponding to the fluctuation belt. We conducted an overlay analysis of the grids to determine the location and number of eco-environmental problems along the fluctuation belt. The vulnerability indices for landslide, water erosion, pollution, and landscape destruction had high vulnerability ranks only 18 to 35% of the time. However, we found that these high ranking vulnerability problems did not overlap across the fluctuation belt. As a result 70% of our study area had at least one high ranking eco-environmental problem and 30% of the area had two or more. Therefore, every part of the Three Gorges Reservoir Area is experiencing at least one eco-environmental problem. Many countermeasures for the water-level-fluctuation area have already been proposed including: planning rationally, establishing slope protection, and adjusting rural industrial structures along the two sides of the area. The results from this study provide a scientific base for the government to make policies for distributing relief funds and help the regions to improve their capabilities of adaptability and mitigation. However, in order to take advantage of this opportunity, international funding and long-term collaborations will be needed.
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