Northern Prairie Wildlife Research Center
Effects of Grazing and Burning on Densities and
Habitats of Breeding Ducks in North Dakota
Arnold D. Kruse1 and Bonnie S. Bowen2
National Biological Service
Northern Prairie Science Center
Jamestown, ND 58401, USA
Abstract: Native grassland communities controlled by public agencies
become increasingly important to the maintenance of many wildlife species as
privately owned grasslands are destroyed or degraded for farming, mining, and
development. In turn, wildlife on publicly owned grasslands are affected by
the management techniques practiced by local managers. We studied the effects
of grazing and prescribed burning on upland-nesting ducks and the structure
and type of vegetation from 1980 to 1988 at the Lostwood National Wildlife Refuge
(NWR) in northwestern North Dakota. Mallard (Anas platyrhynchos), the
most abundant species at Lostwood NWR, had lower (P < 0.05) annual nest densities
on experimental and control herds in the later years than in the early years
of the study. Spring burning reduced (P = 0.016) nest densities of gadwall (A.
strepera). Spring grazing reduced nest densities of gadwall (P = 0.014),
and blue-winged teal (A. discors, P = 0.023). Nest density of gadwall
increased (P = 0.018) after spring grazing was terminated. On the summer burn/spring
graze herds, blue-winged teal had lower (P = 0.010) nest densities after treatments
(1987-88) than before treatments (1980-81). Nest success was high (mallard 34%,
gadwall 45%, blue-winged teal 31%) but was not influenced (P >/= 0.16) by
the burning and grazing treatments. During the study, the amount of grass/brush
increased, whereas the amount of brush and brush/grass decreased on control
and treatment herds. During the years with burning and grazing, short vegetation
increased and tall vegetation decreased. On the spring graze herds, 1 year after
grazing ended the vegetation was similar to that on the control herds. The spring
burn and summer burn/spring graze herds recovered more slowly. Brushy species
such as western snowberry (Symphoricarpos occidentalis) provided attractive
nesting habitat for many upland nesting waterfowl species, especially mallard,
gadwall, American wigeon (A. americana), and northern pintail (A.
acuta). Habitat needs of additional species of wildlife that depend on grasslands
may need to be considered when deciding how to manage habitat.
Key words: blue-winged teal, burning, ducks, gadwall, grazing, livestock,
mallards, nest density, nest success, North Dakota, prairie management, waterfowl,
wigeon.
This resource is based on the following source (Northern Prairie Publication
0956):
Kruse, Arnold D. and Bonnie S. Bowen. 1996. Effects of grazing and burning
on densities and habitats of breeding ducks in North Dakota. Journal of
Wildlife Management 60(2):238-246.
This resource should be cited as:
Kruse, Arnold D. and Bonnie S. Bowen. 1996. Effects of grazing and burning
on densities and habitats of breeding ducks in North Dakota. Journal of
Wildlife Management 60(2):238-246. Northern Prairie Wildlife Research
Center Online.
http://www.npwrc.usgs.gov/resource/birds/density/index.htm
(Version 31JUL97).
Table of Contents
Tables
- Table 1. -- Number of nests and initiation
dates for waterfowl at Lostwood National Wildlife Refuge, North Dakota,
1980-88.
- Table 2. -- Mean values of annual nest density
(nests/ha) of 7 species of waterfowl at Lostwood National Wildlife Refuge,
North Dakota, 1980-88.
- Table 3. -- Least-squares means of daily
nest survival rate (DNSR) and Mayfield (%) estimate of nest success of 3
species of waterfowl at Lostwood National Wildlife Refuge, North Dakota,
1980-88.
- Table 4. -- Proportions of duck nests found
in vegetation types and availability of vegetation types at Lostwood National
Wildlife Refuge, North Dakota in 1981 and 1987.a
- Table 5. -- Proportions of duck nests found
in vegetation types and availability of vegetation types at Lostwood National
Wildlife Refuge, North Dakota, 1980-88.
Appendices
- Appendix 1. -- Average burn times and grazing
periods, grazing rates (animal unit months/ha, AUM/ha), and treatment schedules
for each treatment at Lostwood National Wildlife Refuge, North Dakota, 1980-88.
- Appendix 2. -- Estimated differences and
95% confidence intervals (CI) for highest and lowest values of nest density
and daily nest survival rate (nest success) for cases in which there was
no effect of burning and grazing treatments, Lostwood National Wildlife
Refuge, North Dakota, 1980-88.
Figures
- Figure 1. -- Total nest density (no. of
nests during 1982-88 divided by the no. of upland ha) on treatment and control
fields of 7 species of waterfowl at Lostwood National Wildlife Refuge, North
Dakota.
- Figure 2. -- Annual nest density by treatment
of 3 species of waterfowl at Lostwood National Wildlife Refuge, 1980-88.
- Figure 3. -- Distribution of visual obstruction
reading classes (dm) in June for 3 burning and grazing treatments and control
at Lostwood National Wildlife Refuge, North Dakota, 1980-88.
- Figure 4. -- Comparison of nesting use
and availability of visual obstruction reading classes (dm) by 7 species
of waterfowl at Lostwood National Wildlife Refuge, North Dakota, 1980-88.
1Present address: U.S. Fish and Wildlife Service, Wetland Habitat
Office, 8711 37th St. SE, Jamestown, ND 58401, USA
2Present address: Department of Animal Ecology, Iowa State University,
Ames, IA 50011, USA.
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