Migratory waterfowl habitat selection in relation to aquatic vegetation

PURPOSE: This technical note describes studies of environmental conditions and habitat quality of replicated pond ecosystems dominated by populations of exotic plants or mixed communities of native aquatic plants. Study ponds were similar in depth, size, and shape, as well as in (initial) water and sediment composition. One component of these studies included evaluation of migratory waterfowl utilization of pond habitats based upon vegetation community composition. Aquatic vegetation is a critical food source for many migratory waterfowl, and numerous studies have shown that water bodies with abundant aquatic plants receive the greatest use (White and Malaher 1964, Hobaugh and Teer 1981, Johnson and Montalbano 1989). In cases where aquatic vegetation is restricted or absent, waterfowl use is generally low (Heitmeyer and Vohs 1984). Additionally, declines in migratory waterfowl have been correlated with loss of submersed aquatic vegetation in numerous water bodies (Jorde et al. 1995, Orth and Moore 1981, Haramis 1991). The benefits of aquatic vegetation for waterfowl may be dependent upon the species of vegetation present, with studies showing that migratory waterfowl appear to prefer native aquatic plants as opposed to exotic species (Smith 2001, Benedict and Hepp 1996). Although reasons for this preference are not clear, native plants are held to be more nutritious than exotic species and ar