基于不同方法的水生态健康评估——以北京市典型水体为例

在北京选择密云水库、昆明湖、福海和北运河水系河流等9个典型水体,利用基于不同水生生物的多样性指数法和综合指数法开展水生态健康评价。结果表明,基于浮游植物和底栖动物的Shannon-Wiener多样性指数所指示的水生态状况分别对应轻污染~中污染和中污染~重污染等级,而结合生境、水质和水生生物指标的两项综合指数反映出的水生态状况分别为健康~亚健康和良好~轻度污染。多数评价方法的评价结果都显示出,近5年各水体的生态环境质量有所改善。其中,综合指数法提供的信息更为全面,对环境变化的响应更加灵敏,具有独特的综合优势和推广应用价值。“十二五”以来,北京市水生态健康水平明显提升,其中以北运河水系最为明显,这与一系列污染防治政策和综合治理工程的实施密切相关。

Aquatic Ecosystem Health Assessment Based on Different Methods: A Case Study of Typical Surface Water in Beijing

Nine typical aquatic systems in Beijing,such as Miyun Reservoir,Kunming Lake,Fuhai Lake and rivers in North Canal River basin were selected,and the water ecological health evaluation was carried out using the diversity index of different aquatic organisms and comprehensive index methods.The results showed that the Shannon-Wiener diversity index of phytoplankton and benthic animals corresponded to light to moderate pollution,moderate to heavy pollution levels,respectively.While the two comprehensive indices combining habitat,water quality and aquatic organisms mainly reflected health to sub-health and good to mild pollution water ecological conditions.Results of most evaluation methods indicated the improvement of aquatic ecology in the past five years,in which the comprehensive indices deserve extended application because they provide evaluation results with most integrated information and apparent change trend.The level of aquatic ecosystem health rose significantly from the "12th Five-Year Plan" period,with rivers in North Canal River basin being the most obvious.This is closely related to the implementation of a series of pollution prevention policies and comprehensive management projects in Beijing.