Response of the benthic macroinvertebrate community in a northern Michigan stream to reduced summer streamflows

• Published in: River research and applications Vol. 22; no. 7; pp. 819 - 836
• Main Authors: Wills, Todd C., Baker, Edward A., Nuhfer, Andrew J., Zorn, Troy G.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.09.2006; Wiley
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; benthic macroinvertebrates; Biological and medical sciences; Ephemeroptera; flow reduction; Fresh water ecosystems; Freshwater; Fundamental and applied biological sciences. Psychology; groundwater streams; Insecta; Invertebrates; PHABSIM; Plecoptera; Synecology; Trichoptera; United States; North America; America; Michigan; USA, Michigan, Hunt Creek; Low-water levels; Benthic organism; Flow rate; Ephemeroptera; groundwater streams; Insecta; Trichoptera; Plecoptera; Summer; benthic macroinvertebrates; Freshwater environment; Aquatic environment; Reduction; River discharge; Arthropoda; flow reduction; Benthos; Stream; Season; Invertebrata; PHABSIM; Community; Ground water; Benthic zone
• ISSN: 1535-1459; 1535-1467
• DOI: 10.1002/rra.938

We evaluated the response of benthic macroinvertebrates in a Michigan trout stream to flow reduction by diverting water from a 602 m reach of Hunt Creek from June through August of 1994, 1997 and 1998. We also assessed the utility of the Physical Habitat Simulation system (PHABSIM) in predicting the response of benthic insects to water withdrawals by testing the assumption of a positive linear relationship between modelled habitat (weighted usable area, WUA) and the density of 13 benthic insect families. Our findings showed that the density of filter feeding and grazing insect taxa, as well as insects classified as obligate erosional zone taxa, declined significantly in the dewatered (treatment) zone (TZ) when 90% of flow was diverted. Density of Ephemeroptera, Plecoptera and Trichoptera (EPT) taxa in the TZ was significantly lower when 90% of water was diverted as compared to density at baseflow or when flow was reduced by 50%. The density of all insects in an upstream reference zone riffle (RZ), where flow was not altered, did not change among experimental periods. Although overall reductions in the density of benthic insects at 90% flow reduction coincided with lower PHABSIM predictions of WUA, we found poor linear correlation between WUA at different flows and the density of the 13 benthic insect families for which WUA was modelled. The low proportion of variation explained by WUA for all families modelled suggests that WUA alone is not an accurate predictor of benthic insect density. Resource managers should consider the potential consequences of water withdrawals to all components of stream communities, including benthic macroinvertebrates. However, caution should be applied when using the PHABSIM technique in groundwater‐fed streams such as Hunt Creek, because most relationships between WUA and benthic insect density were insignificant. Copyright © 2006 John Wiley & Sons, Ltd.