Lightning round presentations
12:30 PM - 1:00 PM Wed
Co-authors: Nicholas Danz, Reed Schwarting, and Kelly Beaster, UW-Superior
Title: Coastal wetland plant community responses to record-high Lake Superior water levels: An Allouez Bay case study
Abstract: Wetland plant communities at Allouez Bay, a coastal wetland marsh, were characterized six times over years 2011 - 2020, a period of progressively increasing Lake Superior water levels that reached record highs in 2017 and 2019. Here, we present findings to better understand plant community responses to rising water. Vegetation was sampled in 1 m2 quadrats along three replicate transects placed perpendicular to the shoreline that passed through three vegetation zones (submersed, emergent, and wet meadow). Along each transect, five evenly-spaced sampling points per vegetation zone were defined in each year of monitoring (15 sampling points per transect). During our six sampling campaigns, we encountered eighty-four vascular plant species, seven of which were non-native. Except for reductions in total plant cover in the wet meadow zone in later years, emergent and wet meadow plant communities were only moderately affected by rising water. Percent cover of non-native species did not increase in a clear pattern. Aquatic vegetation in the submersed zone was most affected by rising water. Submerged zone richness declined from sixteen plant species in 2011 to zero in 2020. Temporal composition changes were predominately driven by species turnover in the submersed vegetation zone, whereby floating aquatic species were replaced by non-floating species from 2011 to 2017, and an absence of aquatic vegetation along research transects in 2020. Tracking regeneration of aquatic vegetation is a focus of future research as unknown effects from prolonged exposure to record-high water levels may affect natural regenerative processes at Allouez Bay and potentially at other lacustrine Great Lakes wetlands throughout the basin.
Bio: Dr. Jeremy Hartsock is an associate researcher with the Lake Superior Research Institute at UW-Superior. His research is focused on monitoring coastal wetland vegetation associated with Lake Superior and Lake Michigan for the USEPA Coastal Wetland Monitoring Program.