Effects of milfoil weevils and weather on the control of Eurasian watermilfoil |
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| Authors: | Fred Van Dyke Seth Harju John Korstad Nathan Goelzer Colten L Wolfe Brian Keas |
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| Institution: | 1. Au Sable Institute, 6981 Rainbow Lake Road NE, Mancelona, MI, 49659 U.S.A.;2. Heron Ecological LLC, P.O. Box 235, Kingston, ID, 83839 U.S.A.;3. Department of Biology and Chemistry, Oral Roberts University, 7777 South Lewis Avenue, Tulsa, OK, 74171 U.S.A.;4. Department of Biology and Chemistry, 2965 N Riley Court, Buckeye, AZ, 85396 U.S.A.;5. Department of Biology and Chemistry, Oral Roberts University, 29 Blair Crescent, St. Catherines, Ontario, L2P3A9 CAN Canada;6. Au Sable Institute, 7526 Sunset Trail NE, Mancelona, MI, 49659 U.S.A. |
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| Abstract: | We examined the response of Eurasian watermilfoil (Myriophyllum spicatum) coverage on Manistee Lake, Michigan (U.S.A.) in the presence of milfoil weevils (Euhrychiopsis lecontei). Among 150 sites, milfoil presence declined from 2008 levels of 34 (23%) sites to 2 (1%) sites by 2015 coincident with cumulative stocking of 259,500 weevils from 2007 to 2014. Severe winter temperatures also were associated with milfoil declines. Each 1°C decline in average low temperature during the preceding winter was associated with 3.4 (95% CI 0.8–6.1) fewer sites with milfoil. Impacts of weevil herbivory on watermilfoil may be accentuated by severe winter temperatures. Lake managers should, when possible, integrate weather conditions with weevil stocking regimes to control Eurasian watermilfoil. |
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| Keywords: | additive effects aquatic macrophyte biological control invasive species lake restoration |
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