Health assessment of Houxia River based on benthic index of biotic integrity

Abstract

[Objective] In order to understand the community structure of macrobenthos in Houxia River basin and evaluate the ecological health status of river water scientifically. [Methods] Through analyzing the community structure characteristics of macrobenthos in Houxia River Basin, building B-IBI health evaluation index system and correlation analysis of water environmental factors, 18 candidate parameters in 4 categories, including community richness, pollution capacity, functional feeding group and biodiversity index, were screened. After distribution range analysis, discrimination ability analysis and correlation analysis, Five core indexes, including total taxa, sensitive taxa and pollution tolerance taxa, were selected for evaluation. The ratio method was used to unify the dimensions, and the evaluation criteria were established with reference to 25% quantile of loci. [Results] The result showed as follows:(1) The benthos belonging to 3 phyla, 4 classes and 35 families were detected in Houxihe River basin, and arthropods were the dominant group in the basin. Shannon-wiener diversity index, Margalef species richness index and Pielou species evenness in wet season were higher than those in normal season. In terms of spatial distribution, three indices were relatively higher in the upper reaches of the river and the inlet of the reservoir.(2) The health status of river monitoring sites in Houxia River basin was generally better than that in wet season in terms of time distribution; In terms of spatial distribution, the health status of the middle and lower reaches of the river is generally poor, while the health status of the upper reaches is generally good. [Conclusion] The assessment criteria of river B-IBI health in Houxia River basin are as follows: B-IBI> 3.92 is healthy, 2.94 < B-IBI≤3.92 is sub-healthy, 1.96 < B-IBI≤2.94 is general, 0.98 < B-IBI≤1.96 is poor, and B-IBI ≤0.98 is extremely poor. The B-IBI index has a strong correlation with water environmental factors, in which the positive correlation with dissolved oxygen is extremely significant, and the negative correlation with chemical oxygen demand is extremely significant. In this study, the selection of reference points is reasonable, the construction of B-IBI evaluation index system is highly applicable to the river health status of Houxia River basin, and the research result can provide scientific basis and theoretical reference for the restoration and protection of water ecosystem in Houxia River basin and the evaluation method of mountain river health.

Keywords

Houxia River / large benthic animals / community structure / biological integrity index / health assessment / influencing factors