Eurasian watermilfoil (Myriophyllum spicatum L.) hybridizes with the native northern watermilfoil (M. sibiricum Kom.), which raises new issues regarding management strategies to control infestations. To determine the distribution of hybrid (and coincidentally Eurasian and northern) watermilfoil in Minnesota, we sampled lakes across the state during 2017-2018 for watermilfoil. A total of 62 lakes were sampled, spanning a range of sizes and duration of invasion. Forty-three lakes contained Eurasian, 28 contained hybrid and 21 contained northern watermilfoil. Eurasian watermilfoil populations were widespread throughout the state. Hybrid populations were more commonly found in lakes in the seven county Twin Cities Metro and northern watermilfoil populations were more commonly found in lakes outside of the Metro area. We found no evidence that hybrid watermilfoil occurred in lakes environmentally different than those with Eurasian and northern watermilfoil, suggesting that hybrid watermilfoil is not associated with a unique niche. Hybrid watermilfoil presence was significantly associated with the Metro area, which may likely be due to spatial and temporal factors associated with hybrid formation and spread. Hybrid watermilfoil presence was also significantly associated with lakes that had more parking spaces and older infestations, but this relationship was not significant when the effect of region was considered. Hybrid watermilfoil populations were the result of both in situ hybridization and clonal spread and continued assessment is needed to determine if particularly invasive or herbicide-resistant genotypes develop.
Bibliographical noteFunding Information:
Funding: This research was funded by the Minnesota Environmental and Natural Resources Trust Fund as recommended by the Minnesota Aquatic Invasive Species Research Center (MAISRC) and the Legislative-Citizen Commission on Minnesota Resources (LCCMR). Additional funding and resources for this project were provided by the USDA National Institute of Food and Agriculture, Hatch grant MIN-41-081, Minnesota Aquatic Invasive Species Research Center, and the University of Minnesota, Diversity of Views and Experiences and the College of Food, Agriculture and Natural Sciences Diversity fellowships through the Water Resources Science Graduate Program.
- Biological invasions
- Invasive plants
- Myriophyllum sibiricum
- Myriophyllum spicatum
- Population genetics