Algal Assemblages in Multiple Habitats of Restored and Extant Wetlands

Abstract

The functional and structural attributes of algal assemblages were studied in 25 restored and 20 extant depressional wetlands in southern central Michigan. Environmental conditions and algal assemblages were compared between restored and extant wetlands and among habitats within wetlands. Restored marshes generally had lower shading by macrophytes, nutrient concentrations, and sediment organic matter. Relative biovolume of non-diatom algae was significantly different among plankton, macrophyte and sediment habitats in restored wetlands, but did not differ between macrophytes and sediments in extant wetlands. Species composition of diatom assemblages was not significantly different between plants and sediments in both restored and extant wetlands. The observed differences in non-diatom algae could not be attributed to any measured environmental variable; however, diatom assemblage differences between habitats increased with light irradiance. Differences in sediment diatom assemblages were observed between restored and extant wetlands and were related to differences in nutrients, pH, and canopy cover. Differences were also observed between epiphytic diatom assemblages in restored and extant wetlands and they were related to light and dissolved oxygen. In summary, differences in light and nutrient availability were the main environmental factors differentiating algal communities in wetlands.