¹Center for Water and the Environment, Natural Resources Research InstituteUniversity of Minnesota Duluth, 5013 Miller Trunk Highway, Duluth, Minnesota 55811-1442, USA
²Department of Biological Sciences, University of Windsor, Windsor, Ontario N9B 3P4
³Department of Biology, 205 Compton Science Center, Frostburg State University 101 Braddock Road, Frostburg, Maryland 21532-2303, USA
⁴Department of Natural and Applied Sciences, Cofrin Center for Biodiversity, University of Wisconsin-Green Bay, Green Bay, Wisconsin 54311-7001, USA
⁵Center for Biocomplexity Studies, South Dakota State University Box 2207B, Brookings, South Dakota 57007-0869, USA
⁶Ely Field Station, Center for Water and the Environment, Natural Resources Research Institute

*Present address:University of Minnesota Duluth, 1900 East Camp Street, Ely, Minnesota 55731, USA

*Corresponding author: gniemi@d.umn.edu

Abstract

   Our overall goal was to develop indicators that both estimate ecological condition and suggest plausible causes of ecosystem degradation across the U.S. Great Lakes coastal region. Here we summarize data gathered along the U.S. Lake Huron coastline for breeding bird, diatom, fish, invertebrate, and wetland plant communities. We sampled these biological communities on 88 sites in Lake Huron coastal wetlands, uplands, estuaries/bays, and high-energy shorelines. The sites were selected as part of a larger, stratified random design for the entire U.S. Great Lakes coastal region, using gradients of anthropogenic stress that incorporated over 200 stressor variables (e.g. agriculture, land cover, human populations, and point source pollution). The U.S. Lake Huron coastal region exemplified wide variation in human-related stress relative to the entire U.S. Great Lakes coast. In general, levels of stress decreased from south to north partly reflecting the change in climate and physiography, but also due to the greater human influences in the southern region as compared with the north. The primary stressors in the southern region are due to agriculture and human development, while the northern region has substantially less agriculture and less human population. The biological communities sampled were strongly related to the environmental stress gradients, especially agriculture and urbanization. The following indicators were developed based on responses to stress; 1) an index of biological condition for breeding bird communities corresponding to land use, 2) a diatom-inferred total phosphorus indicator corresponding to water quality, 3) exotic fish (carp [Cyprinus carpio] and goldfish [Carassius auratus]) corresponding to agriculture, and 4) a multi-taxa index for wetland plants corresponding to a cumulative stress index. These biological communities can all serve as useful indicators of the ecological condition of the Lake Huron coast. The ecological indicators provide a baseline on selected biological conditions for the U.S. Lake Huron coastal region and a means to detect change over time.