AQUATIC COMMUNITY CHARACTERISTICS ASSOCIATED WITH EMERGENT MACROPHYTES OF COASTAL LAKE ERIE WETLANDS

Wetlands are important features of an ecosystem, especially in the Great Lakes region because they provide habitat for many species of all taxonomical levels; add economic value to the area by means of hunting, fishing, trapping, birdwatching, and other recreational activities; and they act as a natural filter by removing excess nutrients and toxins prior to reaching main water reserves. However, invasive macrophytes, such as European frogbit(Hydrocharis morsus-ranae), may negatively impact wetlands and increase the difficulty to properly manage wetland ecosystems services. Thus, the central focus of this study is to determine the abiotic and biotic wetland community characteristics that differentiate these aquatic macrophyte habitats. Monotypic patches of 4 different species of macrophytes, including open water (n = 27), were sampled at Ottawa National Wildlife Refuge in July and September of 2017. Data was collected on water chemistry, sediment nutrients, macrophyte biomass, periphyton growth, zooplankton, macroinvertebrates, fish, and water birds associated with each sample site. Dissolved oxygen measurements were taken at each site and showed extreme hypoxic conditions within sites of H. morsus-ranae, reaching levels as low as 0.07 mg/L midday when dissolved oxygen is typically highest. Low oxygen levels, as well as low light attenuation, caused by H. morsus-ranae could drive organisms such as fish and macroinvertebrates out of these habitats and prevent the growth of periphyton and submerged vegetation vital for a healthy wetland. This study reinforces the need for more research on how to best eradicate and prevent H. morsusranae from further invading aquatic ecosystems.