北京北部山区小水体生态评价指标筛选

Selection of indicators for ecological assessment on small water bodies of northern mountainous area of Beijing

为了保护分布广泛的北京郊区小水体,构建典型半干旱区的小水体生态评价体系,该研究选择北京北部山区无污染、受人为干扰相对较小的6个小水体为研究对象,在2007年7—8月调查了9个环境因子,并采集了17个样点的底栖动物数据。采用Pearson相关系数分析了16个代表底栖生物群落组成和多样性的生物指数以及9个环境因子间的相关性,从中筛选出5个相关性较低的生物指数(包括双翅目、蜉蝣目、集食者和优势分类单元所含个体数各占其捕获个体总数的百分比、Margalef物种丰富度)和3个环境因子(包括氨氮、水深、流速),构成北京北部山区小水体生态评价的基本框架。典型对应分析表明,所选择的3个环境因子可以解释所调查的6个小水体中59.4%的底栖生物群落的组成和多样性变化。

In order to protect the extensive small water bodies （SWB） in the suburb of Beijing, and construct the framework o.f ecological assessment of SWB in typical semi-arid areas, six comparable natural ones in northern mountainous area of Beijing were selected to make detailed investigation during the period from July to August, 2007. Sixteen biological indicators representing benthic macroinvertebrate communities and biodiversity, and nine related habitat environmental indicators of 17 samplings were collected. Pearson＇s correlation analysis was used to remove indicators that had high correlation among the sixteen biological indicators and nine environmental indicators. The results showed that five biological metrics, including percentage of Diptera, percentage of Ephemeria, percentage of collectors, percentage of the first dominant taxa and Margalef species richness, were chosen to compose the framework of ecological assessment of SWB in northern mountainous area of Beijing with three environmental indicators, including NH3-N, water velocity and water depth from water quality, geographical and ecological aspects. The canonical correspondence analysis （CCA） results demonstrate that the selected three environmental indicators can explain 59.4% of the changes happened in benthic macroinvertebrate communities and biodiversity of investigated SWB, which satisfies the basic requirements of this research.