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Effects of Grazing and Burning on Densities and
Habitats of Breeding Ducks in North Dakota

Study Site


We conducted our study at the Lostwood National Wildlife Refuge (NWR) in northwestern North Dakota from 1980 to 1988. The 10,829 ha study site was in northern Mountrail and southern Burke counties, about 26 km west of Kenmare, North Dakota. The early years of our study tended to be wetter than average, whereas the later years tended to be dry. Precipitation during the wettest years, 1982 (49.7 cm), 1984 (49.5 cm), and 1985 (46.7 cm), was 11-18% greater than the long-term average (41.9 cm; 1936-89). Precipitation during the driest years, 1983 (32.8 cm), 1987 (30.9 cm), and 1988 (33.5 cm), was 20-26% less than the long-term average. Precipitation of the remaining years was within ± 10% of the long-term average. Two successive years (1987 and 1988) with low precipitation resulted in drought conditions during 1988.

The study site was in the gently to moderately rolling Missouri Coteau physiographic region (Stewart and Kantrud 1973). Lostwood NWR was chosen as the study site because of its large size, extensive grassland, and large number of wetlands. The landscape was characterized by rolling mixed-grass prairie interspersed with more than 4,100 wetland basins that covered about 2,200 ha (K. A. Smith, pers. comm.). About 45% of the wetland area was temporarily and seasonally flooded wetlands (wetland basins classified by water regime according to Cowardin et al. 1979); the remaining 55% of the area was semipermanently flooded and intermittently exposed wetlands (K. A. Smith, pers. comm.). The upland portion of the refuge was primarily a cool-season, mixed-grass prairie, with a high frequency of brushy and exotic species. Plant species with >5% canopy coverage in 1980 were upland sedges (Carex spp.), western snowberry, Kentucky bluegrass, and needle-and-thread (Stipa comata). Species with 2-5% canopy coverage were prairie white aster (Aster falcatus), prairie wild rose (Rosa arkansana), white sage (Artemisia ludoviciana), green needlegrass (Stipa viridula), and fringed sagebrush (Artemisia frigida). Source for scientific and common names was Great Plains Flora Association (1986) for all species except for common names of prairie white aster and fringed sagebrush, which follow Scott and Wasser (1980).

In 1980 and 1981, data on vegetation and nesting birds were collected on 14 fields that were not subject to management activities. The fields ranged from 29 to 42 ha of upland. From these 14 fields, 12 were selected for further study, based on similarity of vegetation, number of ground-nesting birds, and suitability for prescribed burning. The data we report here came from the 12 selected fields.


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