Amphibian biodiversity and conservation have become increasingly important issues in recent years mainly because of a worldwide decline in amphibian species. Many amphibians utilize wetlands for habitat and breeding purposes, but current environmental legislation limits wetland protection greatly, leaving many of these habitats unprotected. Hydrologically isolated, and ephemeral wetlands can provide important habitat for amphibians, and in Michigan—particularly along the lake shore—ephemeral and permanent wetlands within dune landscapes provide vital breeding habitat. However, many of these habitats are under threat of destruction and degradation due to anthropological stressors such as land development, recreation, and introduced species. These unique habitats and the corresponding amphibian metapopulations are understudied and threatened. We assessed amphibian species richness and terrestrial habitat type in 16 permanent and ephemeral wetlands along the coast of Lake Michigan in Grand Haven, MI. Wetland area, terrestrial habitat type, depth, hydroperiod, shade, and degree of isolation were measured from April to September of 2017 and correlated to community assemblage data.
Results/Conclusions
Nine species of amphibian were found in these wetlands; Green Frogs and Spring Peepers were most abundant and rare species included the Fowlers Toad. Non-metric multidimensional scaling (NMDS) revealed that wetlands in open dunes had significantly different species assemblages than larger wetlands in forested habitat. Least cost modeling (LCM) allowed us to determine the shortest path through navigable habitat between wetlands and provide an associated isolation score. Principle components analysis (PCA) of abiotic variables showed a positive correlation between hydroperiod, area, and depth. Non-parametric correlation testing showed a strong positive correlation between species richness and area / hydroperiod. However, some small temporary wetlands situated in the open dunes harbored rare species not found in other wetlands. These findings highlight the importance of protecting all of these habitats from land development, fragmentation and degradation in order to conserve multiple species, as well as overall landscape connectivity of the system.