Species diversity across the dune swales of Lake Michigan at Sturgeon Bay

Abstract

The dune system of Lake Michigan at Sturgeon Bay leads back thousands of years into the surrounding forest and intermittently form small pools in the swales of the dunes. Maintained by rainwater and including a unique composition of species and chemistry, the pools of the dunes and the surrounding terrestrial life show a pattern of diversity unique to dune swales. Percent cover of species at four different swales of the dune system at Sturgeon Bay were effective in showing the differences in diversity, evenness, and species richness patterns across swales and within the dunes, separating the terrestrial and lentic elements to also discover differences between the two substrates. Diversity between aquatic and terrestrial areas was found to differ greatly, with terrestrial species following the pattern of increasing diversity as age increased. The aquatic species pattern did not follow this, and instead the diversity decreased from swales 1 to 3, and then increased in swale 4. Evenness across dune swales initially increased from the first to the second swale, and then dropped considerably from the second to the fourth swale. Richness followed the same pattern of evenness, and decreased from the second swale to the fourth. This data concluded that species diversity across swales cannot be lumped together with aquatic and terrestrial elements, and instead both elements must be considered separately, as they have different successional patterns. While terrestrial succession matches that of older research, the lentic patterns were very different.