What to Survey? A Systematic Review of the Choice of Biological Groups in Assessing Ecological Impacts of Metals in Running Waters.

Which biological groups (in the present study, periphyton, macroinvertebrates, and fishes) are surveyed is a fundamental question in environmental impact assessment programs in metal-contaminated rivers. We performed a systematic review of 202 studies that investigated the ecological impacts of metal contamination on aquatic populations and communities in streams and rivers to examine 1) which biological groups were surveyed, 2) whether their responses were correlated with each other, and 3) which biological group was most responsive to changes in metal contamination level. In these studies, published from 1991 to 2015, benthic macroinvertebrates were most frequently chosen throughout the period (59-76% in different 5-yr periods), followed by periphyton and fishes, and the number of studies that surveyed at least 2 or 3 biological groups was very limited (10%). Pearson's correlation coefficients calculated between the metrics of different biological groups were often low, emphasizing the importance of investigating multiple biological groups to better understand the responses of aquatic communities to metal contamination in running waters. Despite the limited data collected, our meta-analysis showed that, in most cases, biological metrics based on macroinvertebrates were more responsive to changes in metal contamination level than those based on periphyton or fishes. This finding suggests that benthic macroinvertebrates could be a reasonable choice to detect the ecological impacts of metal contamination on a local scale. Environ Toxicol Chem 2020;39:1964-1972. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.