Application of Benthic Index of Biotic Integrity to Assess the Ecosystem Health of Hongze Lake

摘要

The present study aims to assess the ecosystem health of Hongze Lake by constructing a benthic index of biotic integrity (B-IBI). In accordance with the data of benthic animals collected from 10 sampling points (4 reference points and 6 interference points) from October 2012 to October 2013, a total of 19 biological parameters were analyzed for distribution scope, Spearman correlation and identification ability. Eventually, the following parameters were selected to construct the B-IBI for Hongze Lake: the number of (crustacean + mollusk) classification units, Collector%, Predator% and the pollution-tolerant group%. The ratio method was used to unify the dimension in order to calculate the value of each biological parameter. The obtained values were added together to get the final B-IBI value. The health classification criteria were determined based on the 25% quantile of the B-IBI value. The values less than 25% quantile were divided into 4 levels evenly to form the assessment criteria of biotic integrity: B-IBI≥2.48 healthy, 2.01l≤B-IBI<2.48 sub-healthy, 1.24≤B-IBI<2.01 general, 0.42≤B-IBI< 1.24 poor, B-IBI<0.42 very poor. The assessment results show that the 10 sampling points of Hongze Lake consist of 4 healthy, 4 sub-healthy, 2 general and 2 poor points. Overall, Hongze Lake is in the state of light-moderate pollution. The B-IBI value is closely related to TN, water temperature and NO_(3-)-N, but not with other physiochemical factors.