Coastal wetland vegetation community classification and distribution across environmental gradients throughout the Laurentian Great Lakes

Between 2011 and 2013, more than 300 coastal wetland sites were surveyed throughout the Laurentian Great Lakes as part of a coastal wetland monitoring project. Twenty-one wetland vegetation communities were identified through cluster analysis and indicator species analysis. Non-metric multidimensional scaling was used to ordinate sites based on species composition, and measured and calculated environmental parameters were used to evaluate environmental correlation with groups of sites (vegetation communities). Latitude, agricultural intensity, substrate, geomorphology, and water depth were found to account for the majority of the three-axis solution in the non-metric multidimensional scaling. Comparison with earlier studies indicates major increases in extent for several community types dominated by the common invasive species Phragmites australis, Typha angustifolia and T. × glauca. These invasive plants often formed similar species assemblages in both the meadow and emergent zones. Similarities in species composition between meadow and emergent communities indicate that species assemblages may be responding to fluctuations in water levels. This paper presents a unique classification of Great Lakes coastal wetlands with greater geographic range and increased detail in the meadow and emergent zones based on vegetation species composition. The classification is useful as a comparison to past and future ecological and restoration studies.