Lightning round presentations
12:30 PM - 1:00 PM Wed
Co-author: Jeremy Hartsock, UW-Superior
Title: European frogbit (Hydrocharis morus-ranae L.) discovered in a coastal wetland with declining floristic quality
Abstract: While conducting botanical surveys for the Great Lakes Coastal Wetlands Monitoring Program (CWMP) in July 2021, we discovered the first Wisconsin record of European frog-bit in a Lake Michigan coastal wetland in Oconto County. European frog-bit is a free-floating, stoloniferous aquatic native to parts of Europe, Asia, and Africa. It can rapidly reduce available sunlight to submersed plants by its rapid growth in the summer (Catling et al., 2003). It has invaded two Canadian provinces (Ontario and Quebec) and eight states (New York, Michigan, Ohio, Maine, Vermont, Washington, Pennsylvania, and now Wisconsin). The site where we discovered it had been surveyed four times in the last decade, a period that corresponded with a dramatic rise in lake levels. Non-metric multidimensional scaling (NMDS) has shown strong separation in the floristic composition between the low water year (2011) and the high-water years (2016, 2017, and 2021). Floristic quality indices (FQI) showed an overall decline in FQI from 2011 to 2021, with mean C values declining from 4.2 in 2011 to 3.3 in 2021. While the cause of the decline in floristic quality cannot be known for certain, we suspect it is related to high water levels. Previous research on European frog-bit in North America suggests that the ecological conditions in the Green Bay region are strongly favorable for invasion, and we should undertake considerable effort to control and eradicate this new non-native aquatic invader.
Bio: Ryne Rutherford is an interdisciplinary community ecologist and co-owner of Biophilia, LLC, an ecological consulting firm. He has extensive experience conducting surveys for a broad range of taxa (reptiles, birds, amphibians, vascular plants, and lichens). He is currently pursuing a PhD at Michigan Technological University investigating rock outcrop communities in the context of climate refugia.