永定河是京津冀区域重要水源涵养区和生态屏障,为了解永定河水系的水生态健康状况,2016年对永定河水系大型底栖动物进行调查,共布设样点30个,采集到底栖动物38种,其中水生昆虫33种(摇蚊科16种),环节动物门3种,软体动物2种.从耐污值(Tolerance Value,TV)看,TV≤3的敏感类群所占百分比为13.2%,TV≥7的耐污类群所占百分比为44.7%.从类群出现频率看,出现频率最高的3个种分别为霍甫水丝蚓(Limnodrilus hoffmeisteri)、德永雕翅摇蚊(Glyptotendipes tokunagai)和云集多足摇蚊(Polypedilum nubifer),分别为46.7%、40.0%和36.7%,3个物种均为耐污值较高的种类.采用底栖动物完整性指数(Benthic Index of Biotic Integrity, B-IBI)方法评价永定河水系生态健康状况.通过分布范围分析、判别能力检验及相关性分析等,确定永定河水系生态状况评价 B-IBI 的核心指标体系,包括总分类单元数、摇蚊分类单元数和BI指数(Botic Index)3个指标.根据比值法,以参照点25%分位数确定永定河水系底栖动物完整性评价标准.根据参照点25%分位数确定永定河水系底栖动物完整性评价标准,即B-IBI>2.13为健康,1.60~2.13为亚健康,1.06~1.60为一般,0.53~1.06为较差,0~0.53为极差.B-IBI 评价结果显示,永定河水系6.7%河段处于健康状态,23.3%河段处于亚健康状态,36.7%河段处于一般状态,20.0%河段处于较差和13.3%处于极差状态.除官厅水库坝上和宁车沽闸下外,其余样点的底栖动物完整性均受到不同程度的损害,表明永定河水系水体的健康状况整体不容乐观.%Yongding River is an important water conservation area and ecological barrier of Beijing-Tianjin-Hebei Region. In order to evaluate the health condintions of Yongding River Watershed, benthic macro-invertebrate assemblages were sampled from 30 sites in April and May of 2016. A total of 38 benthic macro-invertebrates taxa were identified, in which aquatic insects 29 taxa (including Chironomidae 16), Annalida 3 and Mallusca 2 taxa. Of all the collected taxa, 13.2% were intolerant and 44.7% were tolerant;Limnodrilus hoffmeisteri,Glyptotendipes tokunagai and Polypedilum nubifer were the top three species.Aquatic ecosystem healthy assessment was researched using Benthic Index of Biotic Integrity (B-IBI). Analysis was done for the 19 candidate biological index about its value distribution, judgment ability and Pearson correlation. Meanwhile, the total number of taxa, number of Chironomidae taxa and Biotic Index (BI) were screened out to form a B-IBI index system for Yongding River Watershed. Ratio scoring method for B-IBI index was used to get a uniform score. Using 25 percentiles of reference sites as a criteria to evaluate the aquatic ecosystem health, the results showed that the health criteria was at that time when B-IBI>2.13, sub-health when 1.60~2.13, fair when 1.06~1.60, poor when 0.53~1.06, and very poor when B-IBI<0.53. Assessment results using B-IBI showed that in the whole Yongding River Watershed, 30.0% of sampling sites were in "health" and "sub-health" conditions, 36.7% of sampling sites were in "fair" conditions, and 33.3% of sampling sites were in "poor" or "very poor" conditions.
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