Ecology and biology of invasive hybrid watermilfoil in northern tier waterbodies

Project manager: Daniel Larkin

Funded by: U.S. Army Corps of Engineers

Description: Eurasian watermilfoil is the most widely managed aquatic invasive plant in the United States. Recently in Minnesota, it has started hybridizing with native Northern watermilfoil, resulting in a new hybrid watermilfoil. This is of concern due to reports of increased invasiveness, greater success, and evidence of herbicide resistance of the hybrid. However, some of this is anecdotal.

Therefore, rigorous investigation of the ecology and invasiveness of this species is needed to inform evaluation of impacts and prioritization of management efforts. This study will help identify which invasive hybrid milfoil populations pose the greatest threat to public resources and that may warrant more aggressive responses. The project will address:

  1. How growth of hybrid watermilfoil compares with that of parental milfoil species, and whether performance varies among hybrid populations
  2. What the magnitude and outcome of competitive interactions are when the hybrid co-occurs with Eurasian and native watermilfoil
  3. How the phenology of hybrid compares with Eurasian and native, and whether it varies within hybrid populations

Project state date: 2016

Estimated project end date: 2019

Updates and progress: