基于底栖动物完整性指数的南广河河流健康评价

根据2012 年南广河（四川境内段）17 个采样断面（3 个参照点,14 个受损点）6 次底栖动物采样数据,对18 个生物参数进行分布范围、判别能力和Pearson 相关性分析,最终确定南广河流域生物完整性指数（B-IBI）由EPT 分类单元数、甲壳动物和软体动物分类单元数、甲壳动物和软体动物的个体相对丰度、敏感类群分类单元数、耐污类群的个体相对丰度、捕食者个体相对丰度和襀翅目个体相对丰度等7 个指数组成.采用比值法统-各入选生物参数量纲,计算其IBI 指数值和B-IBI 指标赋分（BIBr）值.结果表明,在17 个采样断面中,BIBr 分值在90 分以上的有6 个,80～90 分之间的有3 个,70～80 分之间的有2 个,60～70 分之间的有4 个,60 分以下的有2 个.从分布趋势看,BIBr 分值较高的点（80 分以上）主要分布在支流（如塘坝乡、马家岩）和干流上游少数几个点（如石碑乡、沐滩村和凉水井）,而下游特别是接近河口部分的几个采样断面均较低,大窝镇和南广镇两个断面的分值更在60 分以下.

Health Assessment of Nanguanghe River and Its AdjacentWaters by a Benthic-Index of Biotic Integrity

Benthic macro-invertebrate samples were collected 6 times from 17 sample sections （3reference sites and 14 damaged sites） in the Nanguanghe River and its adjacent waters in SichuanProvince in 2012. And a benthic index of biotic-integrity （B-IBI） was developed for their healthassessment. The analyses of the range of index value distribution, Pearson correlation and judgmentability were performed on eighteen candidate metrics. Seven biological metrics were selected for theestablishment of B-IBI via number of EPT taxa, number of Crustacea and Mollusca taxa, densityproportion of Crustacea and Mollusca, number of intolerant taxa, density proportion of tolerant taxa ,predator and plectoptera. B-IBI and B-BIBr （B-IBI relative） were calculated when these selected indiceswere transformed into a uniform score by using the ratio scoring method. The results showed thatamong the 17 sample sections in Nanguanghe River and its adjacent waters, 6 sections had BIBr valueover 90, 3 between 80 - 90, between 70 - 80 was 2, 4 between 60 - 70 and 2 under 60. Moreover, the sampling sections with high BIBr value （over 80） were mainly situated in the influent（e.g., Tangba illage and Majiayan Village） and upper reaches of main stream （e.g., Shibei Village, Mutan Village nd Liangshuijin Village）; and the BIBr value of sampling sections of downstream, especially pproaching to the estuary, were relatively low, especially the two sample sections Dawo Town and anguang Town were below 60.