Riparian Vegetation and Environmental Variables Differ Across Age and Management of Created Wetlands in an Agricultural Landscape

In response to the widespread loss and degradation of wetland habitats locally and globally, particularly in agricultural regions, restoration efforts often include the creation of completely new wetlands. Vegetational and abiotic trajectories and their relationships in the context of their histories and restoration strategies are important for informing and defining successful outcomes. We jointly explored vegetational composition and environmental variables across ten created wetlands grouped by site histories in Essex County and Pelee Island, Ontario, situated in the southernmost region of Canada. Surveys focused on the riparian zone of each wetland, a highly dynamic ecotone that can support high levels of vegetational biodiversity and biomass in healthier wetland environments. Quantitative species-level vegetation data were characterized using different species indices and in relation to environmental data (e.g., carbon fluorescence metrics). Through a series of comparative and multivariate statistics, we found that age and management, notably seeding, were significant in driving vegetational composition and carbon metrics in created wetlands. Recent sites with enhanced management were characterized by higher quality vegetation composition such as higher species richness, abundance of conservation valued species and presence of seeded species. In contrast, higher labile carbon levels and humic carbon signatures were correlated with greater total vegetation abundance in older/low management wetlands. Species composition and carbon fluorescence metrics were related across and within wetlands and were driven by wetland age and position within the land-water transition. This study provides a critical local and regional baseline and offers transferable insight for future wetland creation and monitoring.