应用底栖动物完整性指数评价水源地水库溪流健康状态

及时了解水源地水库入库溪流的水生态健康状态对保障供水安全十分重要。依据2010-2011年对浙江省水源地汤浦水库的环境和底栖动物观测资料建立了底栖动物完整性指数(B-IBI)。根据Shannon-Wiener指数、百分比模式相似性指数(PMA)和多元统计分析结果对参照条件进行量化并确立参照点群。从60个候选参数中筛选出6个核心参数参与构建B-IBI指标体系,采用四分法进行量纲的统一,以参照点群25%分位值作为水生态系统健康与否的阈值,并对小于25%的分位值分布范围进行2等分,确立了水源地汤浦水库入库溪流健康评价标准:B-IBI>25.50,健康;B-IBI 12.75～25.50,亚健康;B-IBI<12.75,差。B-IBI分值与溶氧水平和pH显著正相关(P<0.05)。

The Use of Benthic Index of Biotic Integrity(B-IBI) to Assess the Stream Health in the Upper Watershed of Reservoir-Based Water Resources Area

In order to guarantee the water supply safety,it is necessary to assess the health of streams flowing into reservoirs timely.A benthic index of biotic integrity(B-IBI) was developed according to the survey data from 2010 to 2011,which was collected from the streams located in the upper watershed of reservoir-based water sources area(Tangpu Reservoir),Zhejiang Province.The reference sites were established by quantifying the reference conditions according to the results of the Shannon-Wiener index,percent model affinity(PMA) and multivariate statistical analysis.Seven core metrics were selected from sixty candidate metrics to join into the index system.Scores(6,4,2,0) were developed for normalizing the different numerical scales of metrics selected.The value of 25% percentile of B-IBI in reference sites was used as the health threshold.The distribution range below 25% percentile was also bisected.The bio-criteria of this index were then as follows: >25.50,healthy;12.75-25.50,sub-healthy;<12.75,poor.The B-IBI scores were positively correlated with DO and pH(P<0.05).