Impacts of Copper on a Lotic Benthic Invertebrate Community: Response and Recovery

Abstract

We examined the impact of copper on invertebrate community composition in a small stream (Pelican Brook) originating from a zebra mussel infested lake in central Minnesota. One bay of the lake was treated weekly with chelated copper during the summers of 2004 and 2005, resulting in copper levels in Pelican Brook ranging from 0.1 to 0.8 mg/L for three months each summer. Benthic macroinvertebrates were collected from two sites in Pelican Brook in spring and fall over four years (2004)(2005)(2006)(2007), including one pretreatment collection (spring 2004). Samples were also collected from two reference streams (2005)(2006)(2007). Ephemeroptera, Trichoptera, and Plecoptera comprised over half of the community in pre-treatment and reference stream samples. During treatment seasons, mayflies were eliminated and the community shifted to only a few taxa (Hydropsychidae and Chironomidae, primarily Orthocladiinae). Reference stream communities showed seasonal fluctuations but not the massive shifts in taxa abundance seen in the impacted sites. Invertebrate communities began to recover in the first year post-treatment (2006), and by fall 2007 Ephemeroptera and Trichoptera again accounted for over half of the taxa collected. Ephemeroptera, particularly Heptageniidae, appear to be good signal taxa for copper impacts.

Invertebrate community responses to a particulate‐ and dissolved‐copper exposure in model freshwater ecosystems

“…For example, Tanypodinae were negatively affected by copper [14]; in the present study, however, no effect of copper was identified. Other studies that have considered the effects of copper on Tanypodinae in the field have also found species within the subfamily to be copper tolerant, which supports the lack of response in the present study [32,33]. There was also interspecies variation in copper susceptibility of Ostracoda within the present study, as 1 species of benthic Ostracoda was not affected by copper but another declined in abundance.…”

“…The effect of time on the total abundance of invertebrates in the water column was significant (F 8,120 ¼ 59, p < 0.001). However, there was no significant effect of treatment (F 4,15 ¼ 1, p ¼ 0.44) on total abundance, nor was there a significant interaction between time and treatment (F 32,120…”