Jeffrey D. Muehlbauer Charles B. Yackulic D.A. Lytle S.A. Miller Kimberly L. Dibble Eric W. Kortenhoeven Anya N. Metcalfe Colden V. Baxter Theodore A. Kennedy 2016 <p><span>Dams impound the majority of rivers and provide important societal benefits, especially daily water releases that enable on-peak hydroelectricity generation. Such &ldquo;hydropeaking&rdquo; is common worldwide, but its downstream impacts remain unclear. We evaluated the response of aquatic insects, a cornerstone of river food webs, to hydropeaking using a life history&ndash;hydrodynamic model. Our model predicts that aquatic-insect abundance will depend on a basic life-history trait&mdash;adult egg-laying behavior&mdash;such that open-water layers will be unaffected by hydropeaking, whereas ecologically important and widespread river-edge layers, such as mayflies, will be extirpated. These predictions are supported by a more-than-2500-sample, citizen-science data set of aquatic insects from the Colorado River in the Grand Canyon and by a survey of insect diversity and hydropeaking intensity across dammed rivers of the Western United States. Our study reveals a hydropeaking-related life history bottleneck that precludes viable populations of many aquatic insects from inhabiting regulated rivers.</span></p> application/pdf 10.1093/biosci/biw059 en American Institute of Biological Sciences Flow management for hydropower extirpates aquatic insects, undermining river food webs article