Testing the Sensitivity and Limitations of Frequently Used Aquatic Biota Indices in Temperate Mountain Streams and Plain Streams of China

Sen Ding,Yang Dai,Nan Zhang,Guangxia Shang,Yuan Zhang,Xin Gao

doi:10.3390/w13233318

Abstract

Different biological groups show biased responses to similar or different environmental stressors on different scales. The selection of bioindicators based on pressure characteristics is the basis for accurately assessing ecological quality. In this study, we investigated the responses of common bioindicators, namely, macroinvertebrates and fish, to multiple stressors in temperate mountain and plain streams of northeast China. We used 56 indices, including the single biological evaluation index and biological evaluation index system, to analyze and compare characteristic response to different scales under varying environmental stressors. The principal component analysis (PCA) showed that PCA axis 1 in the catchment scale explained 83.6% and 96.1% of the variance in mountain and plain rivers, respectively, which characterized the comprehensive pressure gradient integrated by land-use development and water pollution. PCA axis 1 explained 40.7% and 53.9% of variance in mountain and plain rivers on the reach scale and 63.1% and 61.8% of variance on the site scale. The correlation analysis showed responses of different indices to abiotic variables which did not overlap. Macroinvertebrate and fish indices successfully explained the change in water chemistry on a small scale, whereas fish indices additionally explained the change in land use on a large scale. Macroinvertebrate and fish indices were recommended because of their rich responses to environmental stressors, particularly in plain rivers. For mountain stream biomonitoring programs, especially in the Taizi River of northeastern China, we suggest that macroinvertebrates and fish should be used separately or jointly according to the actual capacity and cost, Moreover, compared with the possible differences in the evaluation results of different single biological evaluation indexes, the biological evaluation index system shows more stable monitoring results, and the single sensitivity index is more significant in biological evaluation, and more sensitive to some special environmental factors.

Highlights

Clean and healthy rivers and streams greatly enhance quality of life
We examined the relationships of indices with environmental pressure by investigating the response of various bio-indices for each taxonomic group to different scales of environmental stressors, including water chemistry and sediment type at the site scale, fluvial physical parameters in the reach scale, and land use patterns at the catchment scale, to build comprehensive pressure aimed to explore better bio-predictors of disturbance in the temperate mountain and plain streams in China
The correlation results between bioindicators and principal component analysis (PCA) axis 1 on three scales showed that the biological groups and indices responded slightly differently to the comprehensive pressure gradient describing the stressors (Table 2)

Summary

Introduction

Global river ecosystems have undergone tremendous changes due to human activities [1]. The question of measuring or quantifying the changes in river ecological status, or evaluating risk based on change has always been a challenge faced by the ecologists [2]. Changes in biological assemblages can modulate effects of multiple stressors and environmental variables over time; aquatic bioindicators have attracted extensive attention around the world [4,5]. There are hundreds of indices and methods for assessing river ecological equality using biological community data [6], from single index to multimetric index (MMI) to predictive models, which provide effective evaluation tools for river managers across a wide range of ecosystems

Methods

Results

Conclusion