FIRE EFFECTS AND USE
WILDLIFE SPECIES: Antilocapra americana | Pronghorn Antelope 



DIRECT FIRE EFFECTS ON ANIMALS : 
Ungulates are rarely killed in fires [72].  Pronghorn's capacity for
rapid flight probably enables them to escape most fires seasily.


HABITAT RELATED FIRE EFFECTS : 
Kindschy and others [41], McCarty [48], and Yoakum [77] have recommended
prescribed burning to improve pronghorn habitat.  As a primarily
forb-eating species with strong requirements for open cover, pronghorn
are favorably influenced by the increase in herbaceous species and
reduction of shrubs after fire [37].  Higher protein and mineral levels
and reduced levels of indigestible materials have been reported in
resprouts of grasses and shrubs [25,41].  Nutritional benefits of fire
on forage may last up to 4 postfire years with an increase in primary
productivity for a longer period, depending upon plant species [72].

Examples:  In 1954, a lightning-ignited wildfire burned 6,000 acres
(2,400 ha) of the Hart Mountain National Antelope Refuge in Lake County,
Oregon.  Prior to the fire, sagebrush (Artemisia spp.) cover was over 50
percent, with shrubs averaging 30 inches (76.2 cm) or more in height.
The fire converted the range from sagebrush steppe to a grassland-forb
community with small stands of shrubs.  Deming [26] reported that
pronghorn did not use tha area prior to the fire but began to use it
within the first postfire year.  Pronghorn used the burn for at least 11
years after fire.

Wildfires in another sagebrush steppe area reclaimed historic pronghorn
range adandoned by pronghorn for decades.  In the Long Valley of
California and Nevada, a series of wildfires in July 1973 burned 38,000
acres (15,200 ha).  Prior to the wildfires, big sagebrush comprised 60
percent cover and averaged 23 inches (58.4 cm) in height; grass cover
was 37 percent; and forb cover was 3 percent.  Pronghorn had not been
sighted in Long Valley for 60 years but moved into Long Valley from
adjacent ranges within a few years of the wildfires.  In 1980, postfire
plant composition was 60 percent grasses, 20 percent forbs, and 20
percent shrubs with a mean height of 17 inches (43.2 cm).  Pronghorn
still inhabited Long Valley at postfire year 7 (1980) [76].


FIRE USE : 
Because pronghorn require a mosaic of very open areas, areas with low,
sparse shrubs, and areas with taller, more dense shurbs for fawning,
field experts do not recommend large-scale prescribed burning for
pronghorn [38].  To maintain or create mosaics for pronghorn, Yoakum
[80] has recommended that prescribed fires burn less than 1,000 acres
(405 ha) and maintain shrub coverage of 5 to 10 percent.

Examples:  Following summer (July and August) prescribed burning in
Alberta, pronghorn used burned areas of needle-and-thread
grass-thickspike wheatgrass-western wheatgrass (Stipa comata-Elymus
lanceolatus-Pascopyrum smithii) prairie significantly more than unburned
prairie during fall, in winter after snowmelt, and in early spring.
Grasses on the burned areas began spring growth 3 weeks earlier than
grasses on unburned sites.  Burns containing plains prickypear (Opuntia
polyacantha) were especially heavily used:  Pronghorn grazed burns with
cacti significantly more than expected from August through February
(except in November), probably because the fires removed the spines from
the cacti, which are succulent and nutritious but usually inedible [24].
Shoop and others [64] found plains pricklypear digestibility to be as
good or better than high-quality alfalfa hay.  The fire-singed cacti
provided pronghorn with a high-quality food in fall and winter, when
nutritious forage is scarce in Alberta [24].

Prescribed grazing and burning has been successful in promoting
pronghorn populations in desert grassland.  In 1981 and 1982, 1,500
acres (600 ha) of tobosa (Hilaria mutica) prairie used as cattle range
was burned on the Prescott National Forest, Arizona.  Fire was used to
restore the prairie and enhance habitat for pronghorn:  The prairie was
invaded by woody species such as broom snakeweed (Gutierrezia spp.) and
honey mesquite (Prosopis glandulosa), and coyote predation on pronghorn
was heavy.  Managers hoped to reduce woody vegetation and reduce
predation on pronghorn.  The prescribed fires killed broom snakeweed and
reduced cover of sprouting shrubs.  From 1983 to 1989, an additional
60,000 acres (24,000 ha) were prescribed burned.  These fires were
initially successful, but tobosa thatch became thick within "a few"
postfire years.  At that point, pronghorn were allowed free range access
but cattle were put on a short-duration, high-intensity grazing system
to mimic presettlement grazing patterns of elk and pronghorn.  Used in
combination, prescribed grazing and burning reduced tobosa litter,
opened the canopy, and encouraged forb growth.  Following grazing and
fire treatments, the pronghorn population increased for 7 years, from
about 150 animals in 1982 to a peak of 366 animals in 1989.  Population
size declined to 320 in 1990 following a drought.  Fawn survival rates
in the burned area averaged nearly 50 percent compared to an overall
rate in Arizona of approximately 20 percent.  Using prescribed grazing
and burning treatments together, managers estimated that fire will be
needed about every 7 to 10 years [46].


REFERENCES : 
NO-ENTRY

Related categories for Wildlife Species: Antilocapra americana | Pronghorn Antelope