Innovative management of European frogbit and invasive cattail

Session: Great Lakes Coastal Wetlands: Innovative Research to Improve Restoration (3)

Andrew Monks, Loyola University Chicago, [email protected]
Shane Lishawa, Loyola University Chicago- Institute for Environmental Sustainabilit, [email protected]

Abstract

Plant-to-plant facilitation is critical in structuring communities, especially in ecosystems with high levels of natural disturbance, including Great Lakes coastal wetlands. We tested this hypothesis with the aquatic invasive species European frogbit (Hydrocharis morsus-ranae; EFB), a small floating plant, and invasive cattail (Typha spp.), a dominant emergent taxon, using a plant community dataset with environmental data from >500 Great Lakes coastal wetlands and another dataset collected as part of a large-scale Typha removal experiment. We compared logistic models of Great Lakes-wide data to determine which plant and environmental variables exerted the greatest influence on EFB distribution. We also conducted a field experiment to evaluate the effects of Typha removal on an EFB population. We found that Typha was a significant predictor variable for EFB abundance in all AIC-selected models, while finding a significant reduction of EFB in plots where Typha was removed in our field experiment. Our results support the hypothesis that invasive Typha facilitates EFB in Great Lakes coastal wetlands, likely by ameliorating wave action and wind energy, allowing EFB to persist in high energy environments. With the current widespread distribution of Typha and their capacity to facilitate EFB's expansion, the potential future distribution of EFB is vast, posing significant risk to native species diversity in Great Lakes coastal wetlands.