三峡库区流域生态健康评估——以东河流域为例

Watershed Ecosystem Health Assessment of Three Gorges Reservoir:Dong River Watershed as a Case Study

流域是其集水区内各种生态环境特征的综合表征体,它能够反映区域景观的环境条件及其变化。作为人类最重要的环境资源之一,流域生态系统健康动态已经成为区域可持续发展的聚焦点。本文以位于渝东北三峡库区腹心区域的开县东河为例,对东河流域生态系统健康进行评估。选择陆域生态、河岸带生态、水域生态健康状况作为一级评价指标,构建流域生态健康综合指数模型。研究表明,东河流域生态健康得分为7.10,评估等级为"良"。评估结果与实际情况基本吻合。东河流域生态健康的问题主要是梯级水电开发导致的河流生境片段化和生境质量衰退,中下游挖沙导致的局部河段底栖生境破坏,以及流域下游部分场镇生活污水排放的局部不利影响。通过东河流域健康评估,明确了流域健康水平及压力,针对生态健康存在的问题,提出了东河流域健康保护目标。对东河流域生态健康的评估,积累了流域生态健康本底数据,为三峡库区流域管理提供了科学依据。

Watershed is a special ecosystem type which can reflects ecological conditions of the regional integrally.As one of important environments and resources,the dynamics of watershed ecosystem health have been a focus of regionally sustainable development.Taking Dong River Watershed(DRW) of the Three Gorges Reservoir Area(TGRA) as an example,it's ecosystem health assessment was carried out.Choosing the terrestrial,riparian zone,and aquatic ecosystem health status as the first grade indices,a model of watershed ecosystem health index was established.Research shows that the score of the DRW ecological health is 7.10,and that the DRW health is good.The evaluation results are basically consistent with the actual situation.The DRW ecological health problems are as follows:river habitat fragmentation and habitat quality decline caused by cascade hydropower development,river benthic habitat destruction induced by sand excavation in the middle and lower reaches,and local adverse effects resulted from domestic wastewater discharge of some towns in the lower reaches.This assessment showed the actual level and pressure of DRW ecosystem health,and some strategies maintaining and managing the river ecosystem health are proposed.Based on the DRW assessment,the baseline data of TGRA watershed ecosystem health was accumulated,and scientific basis of the watershed management was provided.