Plant, fish, and invertebrate communities were sampled in each wetland. The resulting data were assessed in various forms against gradients of human disturbance to identify potential metrics that could be used in IBI development.

Our results suggested that the metrics proposed as potential components of an IBI for barrier beach wetlands of Lake Superior held promise. The metrics for Lake Michigan drowned-river-mouth wetlands were much less promising; those for Lake Huron open shoreline wetlands did not prove useful. Despite the potential displayed by the Lake Superior results, we concluded that an IBI for use in Great Lakes wetlands would not be valid unless separate scoring ranges were derived for each of several sequences of water-level histories. Variability in lake levels from year to year can produce variability in data and affect the reproducibility of data collected, primarily due to extreme changes in plant communities and the faunal habitat they provide. Substantially different results could be obtained in the same wetland in different years as a result of the response to lake-level change with no change in the level of human disturbance. We also evaluated our conclusions with respect to hydrologic variability and other major natural disturbances affecting prairie pothole wetlands, peatlands, riparian wetlands, wetlands along the ocean coast, and the Florida Everglades. We concluded that after segregation of wetland types by geographic, geomorphic, and hydrologic features, a functional IBI may be possible for wetlands with relatively stable hydrology. However, an IBI for wetlands with unpredictable yet recurring influences of climate-induced, long-term high water periods, droughts, or drought-related fires or weather-related catastrophic floods or high winds (hurricanes) would also require differing scales of measurement for years that differ in the length of time since the last major natural disturbance. Biological indicators may indeed be of value in determining the quality or status of wetlands, but we recommend a more detailed ecological analysis of the data rather than use of IBI scores.

Wilcox, D. A., J. E. Meeker, P. L. Hudson, B. J. Armitage, M. G. Black, and D. G. Uzarski. 1999. Development of evaluation criteria to assess and protect the biological integrity of Great Lakes wetlands. Project Completion Report to U.S. EPA, Duluth, MN on IAG DW14936071-01-0.

Armitage, B. J., P. L. Hudson, and D. A. Wilcox. 2000. Caddisflies (Insecta: Trichoptera) of fringing wetlands of the Laurentian Great Lakes. Verhandliungen-Internationale Vereinigung fur Theoretische und Angewandte Limnologie (in press).

Wilcox, D. A., J. E. Meeker, P. L. Hudson, B. J. Armitage, M. G. Black, and D. G. Uzarski. An evaluation of the applicability of Index of Biotic Integrity metrics to wetlands. Submitted to Wetlands.

Meeker, J. E., D. A. Wilcox, J. E. Elias, and S. G. Spickerman. 1995. Factors influencing the diversity in Lake Superior coastal wetlands. Society of Wetland Scientists, Boston, MA, USA.

Wilcox, D. A., J. E. Meeker, M. G. Black, B. J. Armitage, P. L. Hudson, and J. R. Keough. 1995. Developing biological indicators of degradation for barrier beach protected wetlands of western Lake Superior. Society of Wetlands Scientists, Boston, MA, USA.

Meeker, J. E. and D. A. Wilcox. 1996. Hotspot and periphyton sampling as two low-cost methods using plants as bioindicators of degradation in Lake Superior coastal wetlands. Society of Wetland Scientists, Kansas City, MO, USA.

Wilcox, D. A. and J. E. Meeker. 1996. Invasion of sedge/grass meadows in drowned-river-mouth wetlands of Lake Michigan by Typha, Phalaris, and Lythrum. Society of Wetland Scientists, Kansas City, MO, USA.

Financial support for this study was provided through Interagency Agreement DW14936071-01-0 between the U. S. Environmental Protection Agency–Mid-Continent Ecology Division and the U.S. Geological Survey–Great Lakes Science Center; additional funds were provided by the State Partnership program of the U.S. Geological Survey.