Development of ecological indicators for the U.S. Great Lakes coastal region – A summary of applications in Lake Huron

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 biotic 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 biotic 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 communities can all serve as useful indicators of the ecological condition of the Lake Huron coast. The ecological indicators provide a baseline on selected conditions for the U.S. Lake Huron coastal region and a means to detect change over time.

Keywords:

• Birds
• diatoms
• fish
• macroinvertebrates
• plants
• wetlands

Acknowledgements

Diatom identification and enumeration results were supported by N. Andresen, G. Sgro, M. Ferguson, and A. Kireta; and diatom taxonomic support was provided by J. Kingston, E. Stoermer, and J. Johansen. D. Breneman, J. Schuldt, J. D. Holland, J.P. Gathman, R. Hell, A. Ly, J. Baillargeon, and J. Wiklund provided assistance with fish and macroinvertebrate data and sampling. R. Regal provided statistical advice. Although this research has been funded wholly or in part by the U.S. EPA through cooperative agreement EPA/R-82867501 to the Great Lakes Environmental Indicators project, and through grant EPA/R-82877701 to L. Johnson, it has not been subjected to the agency's required peer and policy review and therefore does not necessarily reflect the views of the agency and no official endorsement should be inferred. This is contribution number 490 from the Center for Water and the Environment, Natural Resources Research Institute, University of Minnesota Duluth.

Notes

∗Cumulative stress index comprised of the five individual stress gradients (i.e. excludes soils)