基于不同生物类群的河流健康评价研究

基于浑太河流域鱼类与大型底栖动物群落结构和功能层面上的指标,构建了多指标指数评价河流健康状况。首先,基于土地利用指数、水质和栖息地质量指数构建ILWHQ(Index of land use and water and habitat quality)指数定量筛选参照点位。然后,采用判别分析、逐步回归分析、相关分析筛选对不同压力响应敏感的核心参数。最后,采用比值法计算其多指标指数(MMI-HT)。结果表明:筛选了5个点位作为参照点,共确定8个(鲤科鱼类种类数、底栖鱼类比例、杂食性鱼类比例、耐受性鱼类个体比例、产沉性卵鱼类比例、产沉性卵鱼类个体比例、EPT、黏附者比例)核心参数构建多指标评价指数。底栖动物核心参数对底质中粗颗粒物、悬浮物和电导率变化响应更敏感,而鱼类核心参数对底质中细颗粒物、氮素、DO和Cl-浓度变化响应更敏感。二者对多重环境压力响应的敏感性不尽相同。太子河流域的35个点位中,9个为健康,6个为亚健康,7个为一般,7个为较差,6个为极差。浑河流域的19个点位中,没有点位属于健康状态,5个为亚健康,4个为一般,5个为较差,5个为极差。太子河流域较差和极差的点位共占37.14%,浑河流域较差和极差的点位共占52.63%。说明相比于太子河流域,浑河流域的健康状况较差。

Research on river health assessment based on different biological assessmblages

In this study,a multimetric index based on fish and macroinvertebrate at the levels of community structure and function for the Hun-Taizi River basin (MMI-HT) was developed to assess river health. First,an index of land use,water and habitat quality (ILWHQ) was calculated to evaluate the environmental quality in the studied sites. Then, core metrics were selected using a stepwise procedure (the analysis of the range of index value distribution, stepwise regression analysis, Pearson correlation) that evaluated metric stability,responsiveness to stressors. Finally,ration scoring method was used to score multimetric index in the Hun-Taizi River(MMI-HT). Eight metrics (Cyprinidae species, Proportion of benthic species, Proportion of omnivore species, Proportion of individuals as tolerant species, Proportion of demersal eggs species, Proportion of individuals as demersal eggs species, EPT, Proportion of clingers) were selected to construct MMI-HT. Generally, macroinvertebrate metrics were more sensitive to coarse substrate, electric conductivity and suspended solid,whereas,fish metrics were more sensitive to fine substrate,dissolved oxygen,chloride,nitrogen,Permanganate index,water temperature,land use and perturbations of hydrological processes. Two groups responded differently to multiple stressors. The results showed that nine sites were in excellent condition, six were in good condition, seven in normal condition, seven in poor condition, and six in very poor condition in the Taizi River basin. There was no site in excellent condition, five in good condition,four in normal condition,five in poor condition,and five in very poor condition in the Hun River basin. These findings indicate that ecosystem health is worse in the Hun River than that in the Taizi River.