Effects of Grazing and Burning on Densities and
Habitats of Breeding Ducks in North Dakota
Introduction
Native grassland communities controlled by public agencies in the northern Great
Plains are becoming increasingly important for the maintenance of wildlife species
as privately owned grasslands are destroyed or degraded by farming, mining, and
development. Grasslands that are idled or unmanaged become dominated by native
brush species such as western snowberry and silverberry (Elaeagnus commutata)
and exotic grass species such as smooth brome (Bromus inermis) and Kentucky
bluegrass (Poa pratensis) and are believed to be of lesser value to wildlife
(Kirsch et al. 1978). Grasslands occurring on national wildlife refuges are often
subjected to management practices (e.g., grazing, haying, and burning) intended
to maintain or improve the health and vigor of the native grassland flora for
the benefit of wildlife species, especially waterfowl. However, the effects of
these grassland management practices on vegetation communities and dependent wildlife
are not adequately understood (Holechek et al. 1982, Kadlec and Smith 1992). The
purpose of our study was to evaluate the effects of grazing and prescribed burning
on the nest density and nest success of breeding ducks and on the structure and
type of vegetation in which they nest. We focused on management practices that
have been recommended to improve the vigor of the native grassland flora and reduce
the abundance of woody species on public lands such as national wildlife refuges
in the northern Great Plains. We studied 4 multi-year management regimens that
consisted of burning, grazing and/or rest. We tested the hypothesis that there
was no effect of the treatments, years, or treatment-year interaction on waterfowl
nest density or nest success.
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