Marsh Management and Its Relationship to Vegetation, Waterfowl, and Muskrats

Management of Iowa marshes is primarily aimed at waterfowl production with secondary considerations for furbearing animals and non-game wildlife. Difficulty in maintaining the hemi-marsh, which is considered optimum for avian production, prompted this study to examine the interrelationships between duck breeding populations, muskrat (Ondatra zibethicus) population densities, and emergent vegetation. Blue-winged teal (Anas discors) populations responded more closely to changes in percent of the area that contained emergent vegetation than mallards (Anas platyrhynchos). Waterfowl populations were not totally dependent on vegetative conditions of the marsh. Muskrat populations were directly related to habitat quality but fall water levels were influential m regulating the number of muskrat houses and number of muskrats caught by trappers. The most beneficial management program for waterfowl production on glaciated marshes requires revegetation by man-induced droughts and maintenance of water levels until the open stage occurs, then the procedure should be repeated. Marshes are best managed individually by utilizing results from past management procedures