不同大型底栖动物快速生物评价指数对河流水质指示比较

大型底栖动物是河流健康评价中最常用的生物类群,鉴于在大区域/流域进行大量生物样品采集与生物评价时需要消耗大量的野外调查时间、实验室内鉴定时间等时间成本的问题,基于浑太河流域98个采样点的大型底栖动物数据(如物种、丰度、敏感值等)和环境因子〔ρ(COD_Mn)、ρ(NH₃-N)、ρ(TN)、EC(电导率)等〕,选择比较常用的5种大型底栖动物快速生物评价指数〔SIGNAL指数(stream invertebrate grade number-average level)、EPT-Fa指数(Ephemeroptera, Plecoptera, Trichoptera)、BMWP指数(biological monitoring working party)、ASPT指数(average score per taxon)和BP指数(Berger-Parker index)〕和1项生物完整性指数(benthic index of biotic integrity,B-IBI)进行比较. 通过Spearman秩相关性分析、主成分分析、线性拟合回归分析等方法比较6种生物评价指数的相关性,构建水环境污染梯度,识别出主要的水环境影响因子,并探讨5种大型底栖动物快速生物评价指数对主要水环境影响因子指示程度的差异性. 结果表明:①5种快速生物评价指数以及B-IBI指数之间均呈两两显著相关(|R|为0.35~0.94, P<0.01),说明它们在评估河流健康状况时具有较高的一致性. ②主成分分析结果显示,轴1的解释率为59.14%,可以有效表征主要的压力梯度,并且5种快速生物评价指数与轴1的线性拟合度均较高(R2为0.23~0.31, P<0.01). ③各快速生物评价指数与不同水质指标的线性拟合结果差异性较高,其中BMWP、EPT-Fa、SIGNAL和ASPT指数对ρ(COD_Mn)的线性拟合度均较高,BMWP指数对ρ(COD_Mn) (R2=0.47, P＜0.01)、ρ(NH₃-N) (R2=0.31, P＜0.01)、ρ(TN) (R2=0.27, P＜0.01)的线性拟合度较高,BP指数对ρ(BOD₅) (R2=0.22, P＜0.01)、EC (R2=0.24, P＜0.01)的线性拟合度较高. ④BMWP指数与B-IBI指数的相关性最为显著,并且二者对水质健康评价的结果最为接近；在浑太河流域河流水质状况评估中,BMWP指数应当作为首选快速生物评价指数. 

Comparisons of Different Rapid Bioassessment Indices Based on Benthic Macroinvertebrates to Stream Water Quality

Abstract:Benthic macroinvertebrates are one of the most efficient and widely used indicator groups in river health assessment. At the large regional or watershed scale with huge number of sampling sites, field sampling, sorting and classification of benthic macroinvertebrates usually consumes a huge amount of research effort. In this study, based on 98 field monitoring samples of benthic macroinvertebrates and water quality parameters in Hun River and Taizi River Basin, five commonly used rapid bioassessment indices (stream invertebrate grade number-average level (SIGNAL), family level taxa richness of Ephemeroptera, Plecoptera and Trichoptera (EPT-Fa), biological monitoring working party (BMWP), average score per taxon (ASPT) and Berger-Parker index (BP)) were chosen to compare indices of biological integrity of benthic macroinvertebrates. The Spearman correlation analysis, principal component analysis and linear regression analyses were used to determine inter correlation, sensitivities and variations of the five rapid bioassessment indices. The results showed that the inter correlations of five indices were significant (|R|=0.35-0.94, P<0.01), which illustrated trend consistency of indices in first reflecting water comtamination. Secondly, the first axis could represent pollution gradient with accumulated 59.14% explanation. And all the five rapid bioassessment indices showed significantly linear regression interpretation rate (R2=0.23-0.31, P<0.01) with the first axis. Thirdly, the correlations were significant among the five indices, which showed similar consistency of the indices in river health assessment. Relative higher interpretation rates of linear regression between the permanganate index and BMWP, EPT-Fa, SIGNAL and ASPT confirmed its sensitiveties to organic matter pollution. Among those indices, BMWP showed better interpretation rate with ρ(COD_Mn) (R2=0.47, P<0.01), ρ(NH₃-N) (R2=0.31, P<0.01) and ρ(TN) (R2=0.27, P<0.01). And BP index showed better interpretation rate with ρ(BOD₅)(R2=0.22, P<0.01) and EC (R2=0.24, P<0.01). Finally, after the comparison of widely used indices of biological integrity of macroinvertebrates, BMWP showed the highest coefficient and similar river health grades in the Hun-Tai River.