Are Cattails Squeezing Out Diverse Meadows?

Ann Arbor, MI — Historically, periodic low water levels in the Great Lakes helped control cattails and allowed highly diverse wet meadows to expand in coastal wetlands. In recent years, however, invasive cattails have been overtaking the diverse meadows despite low water levels in the coastal wetlands of Green Bay, Lake Michigan.

Using aerial photographs, researchers at the University of Wisconsin-Madison tracked changes in wet meadow and marsh/cattail area in response to changes in water level from 1960 to 2000.

Before 1992, wet meadow and marsh/cattail areas increased during low water years as they expanded toward the lake. However, as water level fell between 1998 and 2000 cattail area expanded into the wet meadow instead, decreasing the size of the meadow. This is similar to what happens when water levels are not allowed to fluctuate naturally.

"Fluctuating water levels are very important to the diversity of coastal wetlands," says Christin Frieswyk, a scientist at the University of Wisconsin-Madison. "However, stresses like invasive species and land-use change may be able to overwhelm their beneficial impact."

Original Publication Information

Results of this study, "Vegetation Change in Great Lakes Coastal Wetlands: Deviation from the Historical Cycle," are reported by Christin B. Frieswyk and Joy B. Zedler in the latest issue (Volume 33, No. 2, pp. 366-380) of the Journal of Great Lakes Research, published by the International Association for Great Lakes Research, 2007.

Contacts

For more information about the study, contact Joy Zedler, Department of Botany, University of Wisconsin-Madison, Madison, WI 53706; jbzedler@wisc.edu, (608) 262-8629.

For information about the Journal of Great Lakes Research, contact Marlene Evans, Editor, National Water Research Institute, 11 Innovation Boulevard, Saskatoon, SK, S7N 3H5, Canada; editor@iaglr.org; (608) 692-1076.

Links

Since 1967, IAGLR has served as the focal point for compiling and disseminating multidisciplinary knowledge on North America's Laurentian Great Lakes and other large lakes of the world and their watersheds. In part, IAGLR communicates this knowledge through publication of the Journal of Great Lakes Research, available to members in print and electronic form. A searchable archive of the journal is available online and includes the abstracts of articles from the journal's inception in 1975 through the most recent issue. In addition, complete articles are available to members who have signed up for an electronic subscription.