Effects of lake level regulation on coastal wetlands of eastern Lake Ontario: A simulation study (New York)

It has been widely assumed that the diversity of coastal wetland plants and communities of Lake Ontario has been negatively impacted by water level regulation. To assess the validity of this statement I created a spatial model that determines the effect of lake level regulation on wetland plant communities via plant response data. The model considers hydrology and plant response in relation to microtopography, in two coastal wetlands on the eastern shore of Lake Ontario: a medium fen and a freshwater marsh with fen elements. The model results showed an expansion of swamp and Typha communities, in the medium fen and marsh, respectively, similar to that seen in aerial photos from 1938 to 2001, seemingly validating the original hypothesis. However, running the model with three 40-year hypothetical lake level scenarios suggested that the current regulation plan would preserve a larger portion of open fen habitat than the more natural scenarios with lengthy drawdowns. Though the lake level regulation plan may have been beneficial for coastal fens and their associated rare plants, it could possibly be modified to better meet the needs of all biotic communities along the Lake Ontario shore.