Loading...
Testing restoration methods for Lake Ontario wetlands at a wetland scale
Journal Title
Journal of Great Lakes Research Vol. 48
Readers/Advisors
Journal Title
Term and Year
Publication Date
2022
Book Title
Publication Volume
Publication Issue
Publication Begin
Publication End
Number of pages
Research Projects
Organizational Units
Journal Issue
Abstract
Sedges and grasses have a competitive advantage over cattails at higher elevations in Great Lakes wetlands
where periodic low lake levels result in soils too dry to support cattails. Regulation of Lake
Ontario water levels eliminated low lake-level years, resulting in cattail invasion. At a wetland scale at
two Lake Ontario sites, we tested restoration methods by dredging channels through cattails, using spoil
materials to create mounds suitable for sedge/grass growth, seeding mounds, and controlling cattails
(T. glauca) using methods adapted from experimental studies. Soil moisture and subsidence of mound
soils were monitored. Vegetation was sampled pre-restoration and in shoreline sedge/grass meadow,
emergent, and mound zones for two years following implementation. Although spoil mounds decreased
in elevation at both sites, soil moisture increased more at the site with greater subsidence. Mean percent
cover and ramet counts of cattails were reduced in sedge/grass and emergent zones at both sites. Mounds
with greater soil moisture held more cattails post-construction. Across years at both sites, Carex lacustris
and Calamagrostis canadensis increased in the sedge/grass meadow zone with reduction in Typha;
Calamagrostis increased on the mounds. Key factors affecting results were cattail litter and, on the
mounds, a second year of seeding with in situ cold, moist stratification, as well as soil moisture related
to subsidence. Recommendations for future restorations include conducting more detailed soil surveys
to assess potential subsidence, dredging wider and deeper channels to provide spoil for higher mounds,
actively controlling invasive species, and conducting additional years of post-restoration data collection.
2022 International Association for Great Lakes Research. Published by Elsevier B.V. All rights reserved