Fellow: Kyle D. Zimmer, Department of Biological Sciences, NDSU
Advisor: Malcolm Butler, Professor of Biological Sciences, NDSU
Matching Support: Minnesota Department of Natural Resources, St. Paul, MN; Institute for Wetland and Waterfowl Research, Winnipeg, Manitoba; USGS Northern Prairie Wildlife Research Center, Jamestown, ND
Degree Progress: Ph.D., May 2001 

Dissertation Abstract:

Many studies have shown that fish can influence the structure and processes of aquatic ecosystems, but studies with replication at the ecosystem level are rare, as are studies involving wetlands. Some wetlands of the Prairie Pothole Region of North America support fish communities dominated by fathead minnows while others are fishless, providing an opportunity to assess the influence of these fish on wetland ecosystems. Additionally, extensive drainage of prairie wetlands has led to restoration of thousands of basins, but the success of these efforts is poorly known. 

I assessed the effects of fathead minnows and prior drainage on characteristics of prairie wetlands by studying 20 semipermanent wetlands in Minnesota from 1996-1999. I used a 2´2 factorial design to examine the effects of minnows (presence/absence) and drainage (restored/non-drained) on the abundances of aquatic invertebrates, aquatic macrophytes, and amphibians, as well as water-column levels of chlorophyll a, total phosphorus, total nitrogen, and turbidity. Results showed that presence/absence of fathead minnows is an important determinant of many biotic and abiotic characteristics of prairie wetlands. Wetlands with minnows had significantly fewer aquatic insects, large and small-bodied cladocerans, calanoid copepods, ostracods, and larval tiger salamanders, as well as a higher abundance of corixids and higher levels of turbidity and chlorophyll a. In contrast, higher concentrations of phosphorus in restored basins was the only consistent history effect, and no consistent fishxhistory interactions were detected. 

From a management perspective, these effects should be considered prior to landscape manipulations that alter the regional proportion of basins supporting fathead minnow populations.

A copy of the dissertation can be obtained from Prof. M.G. Butler. 

Relevant Publications of K.D. Zimmer and the Butler Research Group

Refereed Journal Articles

     Noraker, T.D., K.D. Zimmer, M.G. Butler, and M.A. Hanson, 1999, Distribution and dispersal of marked fathead minnows (Pimephales promelas) in prairie wetlands, Journal of Freshwater Ecology 14, 287- 292.

     Hanson, M.A., C.C. Roy, N.H. Euliss, K.D. Zimmer, M.R. Riggs, and M.G. Butler, 2000, A surface activity trap to capture water surface and aquatic invertebrates in wetlands, Wetlands 20, 205-211.

     Zimmer, K.D., M.A. Hanson, and M.G. Butler, 2000, Factors influencing invertebrate communities in prairie wetlands: a multivariate approach, Canadian Journal of Fisheries and Aquatic Sciences 57, 76=85.

     Zimmer, K.D., M.A. Hanson, M.G. Butler, and W.G. Duffy, 2001, Influences of fathead minnows and aquatic macrophytes on nutrient partitioning and ecosystem structure in two prairie wetlands, Archiv für Hydrobiologie, 15, 411-433.

    Zimmer, K.D., M.A. Hanson, M.G. Butler, and W.G. Duffy, Size distributions of aquatic invertebrates in two prairie wetlands, with and without fish, with implications for community production, Freshwater Biology, in press.

    Muscha, M.J., K.D. Zimmer, M.G. Butler, and M.A. Hanson, A comparison of horizontally and vertically deployed aquatic invertebrate activity traps, Wetlands, in press.

    Zimmer, K.D., M.A. Hanson, and M.G. Butler, Effects of fathead minnow colonization and removal on a prairie wetland ecosystem, Ecosystems, in press.

    Melaas, C.L., K.D. Zimmer, M.G. Butler, and M.A. Hanson, Effects of rotenone on aquatic invertebrate communities in prairie wetlands, Hydrobiologia, in press.

Reports and Book Chapters

    Hanson, M.A. and K.D. Zimmer, 2000, Effects of fathead minnows on prairie wetland ecosystems: summary of results from 1996-1999, In B. Joselyn (ed.), Summaries of research findings 2000, MN DNR Wildl. Pops. Res. Unit, St. Paul, MN. 

    Zimmer, K.D., M.G. Butler, M.A. Hanson, and W.G. Duffy, 1999, Influences of fathead minnows on phosphorus and nitrogen cycling in prairie wetlands, In B. Joselyn (ed.), Summaries of research findings 1999, MN DNR Wildl. Pops. Res. Unit, St. Paul, MN. 

   Hanson, M.A. and K.D. Zimmer, 1999, Effects of bait fish on ecological characteristics of restored and nondrained prairie wetlands: a pre-treatment summary, In B. Joselyn (ed.). Summaries of research findings 1999, MN DNR Wildl. Pops. Res. Unit, St. Paul, MN.

Dissertatation

   Zimmer, K.D., Effects of Fathead Minnows and Drainage on Wetland Ecosystems, Ph.D. Dissertation, North Dakota State University, Fargo, May 2001. 

Other

   Hanson, M.A. and K.D. Zimmer, 1999, Fish in waterfowl marshes: cause for concern? Minnesota Waterfowler 12, 7-9.