Wolves Benefit Free-Ranging Jackson Hole Elk Herds
Oct. 24. 2002
Note this article is by Meredith Taylor,
A Fremont County outfitter and staffperson for the Wyoming Outdoor
Council
Despite undocumented claims to the contrary, recent Wyoming Game &
Fish Department data has shown that wolves actually benefit local
wildlife herds. Researchers are now monitoring the effects of two
wolf packs, the Teton and Gros Ventre, on wintering elk in Jackson Hole.
Using information taken from the agency’s 1998 and 2000 Jackson/Pinedale
Region Annual Big Game Herd Unit Reports, the analysis compares such data
as the number of wintering elk on various native ranges and feedlots,
cow/calf ratios, disease incidence, and hunter success.
Higher numbers of elk are ranging among wolf-occupied habitat north of
Jackson from Spread Creek to Buffalo Valley with increased hunter success,
according to the report. This information also supports monitoring data
from Montana’s Department of Fish, Wildlife and Parks being analyzed on
the effects of wolves on wintering wildlife on public land north of
Yellowstone National Park (YNP).
More Calves, Less Disease
The portion of the Jackson Hole elk herd that is out on winter range has
increased somewhat during the past 11 years from a low of 2,474 to a high
of 4,843 with a mean of 3,593. “A total of 3,805 elk were observed on
native winter range [throughout the Jackson Herd Unit] in 2000,” according
to the 2000 WYGFD Report.
Of the entire Jackson elk herd counted in 1999-2000 about 35% of the elk
counted are wintering on native range. The number of elk north of Jackson
Hole has increased from a low of 137 in 1990 to a high of 1,139 in 2000
where there have been extensive habitat improvements in the Spread Creek
area. With habitat improvements such as prescribed burns in the Spread
Creek area, nearly nine times more elk wintered there in 2000 compared to
1990, prior to many vegetation management improvements.
Of particular note is the fact that there was at least one wolf pack in
this area, yet the elk population keeps increasing.
This significant increase is primarily due to habitat improvement
projects that enhances dispersal into areas of higher quality and
quantity forage. Dispersal is also increased by wolves when they spread
the elk out on their habitat.
The ratio of elk calves per 100 cows is considered by biologists to be a
good indicator of herd productivity. Calf/cow ratio data from the WYGFD
1998 and 2000 reports demonstrate that calf/cow ratios on feedlots on the
Gros Ventre and National Elk Refuge are lower (18-18.8%) than free-ranging
elk in the Gros Ventre (40-44%) and in the Buffalo Valley (50%) that do
not use feedlots. In fact, the data indicates that the further the elk are
away from the feedlots, the higher the calf/cow ratio. Conversely,
WYGFD data shows that disease is higher where calf/cow ratios are lower
among feedlot elk. It appears that brucellosis and other factors
associated with feedlots (such as decreased nutrition, stress from
increased density, etc.) may significantly reduce the elk reproductive
rates.
For example, during the past two winters, all of the elk harvested
during the late-hunt season in the Buffalo Valley tested negative for
brucellosis. This means that along with the higher calf/cow ratios, the
disease incidence is significantly reduced to negligible levels or zero
among these native winter range elk compared to their feedlot cohorts.
Higher elk harvest by hunters since wolves returned to Gros Ventre
According to the 2000 WYGFD Report: “In Hunt Areas 80-83 (the four elk
hunt areas between the NER and the 3 state feedlots in the GV) license
quotas have been decreased in recent years to address hunter concerns and
suspected predation from large predators. These hunt areas make up the
primary home ranges of two wolf packs. Since 1998 antlerless license
quotas (in these hunt areas) were reduced from 300 licenses to 150 during
the 2000 hunting season.” However, in spite of alleged “hunter
concerns” and undocumented, but “suspected predation from large predators”
the WGFD decreased antlerless licenses by 150. Yet, further in the same
paragraph, the report says, “The harvest survey indicates that a total of
973 elk were harvested (in the GVRD) in 2000 compared to 876 elk harvested
in 1999.” Since 1998, 150 fewer antlerless elk licenses were sold, but 97
more elk were killed by hunters over the last year compared to 1999. The
harvest statistics for 1998 for the GVRD are not available, but it appears
that even with wolves established in the area, the free-ranging elk herd
is flourishing and there were MORE elk killed by human hunters.
The effect of predator/prey balance appears beneficial to elk
According to the USFWS Wolf Coordinator, there are two wolf packs living
among the Jackson Hole elk herd. There are 12 wolves in the Teton pack and
7-9 wolves in the Gros Ventre pack. The monitoring of these collared
wolves has shown that although they have been seen in the Gros Ventre
feedgrounds during the past three years, even with the two packs of
wolves, the losses were actually less than normal, since 6 elk killed is
substantially less than the 25 year average of 14 dead elk on the
feedlots.
Comparing Montana to Wyoming, the MT Fish Wildlife and Parks, works
more closely with the National Park Service to monitor the interactions of
wolves and wildlife.There are now six wolf packs with 70-90 wolves in
residence among the Northern Range elk herd and according to the 2001
Gardiner Late Elk Hunt Annual Report “(e)lk permit numbers have been
relatively high since 1990 in response to increasing numbers of elk
wintering north of YNP.” Hunter success averages 63% for cows and 96% for
either sex licenses in the late hunt along the migration route north of
YNP to Dome Mountain, which may be the highest success ratio for hunters
on public lands anywhere in North America. Since 1995 the wolf presence
has increased to six packs among the Northern Range elk herd and 2001 elk
numbers counted were still within the herd objective.
Interestingly, the 2001 brucellosis rate for this herd was only
2.8%, the calf/cow ratio in 2001 was 29% (close to the historic average of
30%), the average 2001 calf weight improved by 9.4% and bull elk antler
length exceeded the previous six-year average of 45 inches at 47.2 inches
in 2001. These figures clearly point to an increase in herd health that
both conservation sportsmen and wildlife managers would be proud to see in
any big game herd.
This winter’s elk count on the Northern Range, although down slightly from
last year’s figures, is well within the 25 year average and within the
desired herd objective even given the presence of the complete array of
large predators including gray wolves, mountain lions, black and grizzly
bears. In addition, the 2001 data indicate a healthy elk herd despite the
effect of the drought conditions on the native range.
Conclusion
The free-ranging elk north of Jackson Hole sees the highest calf/cow
ratio and the lowest disease incidence among the highest density of wolf
sightings compared with the feedlot elk. Therefore, it may be concluded
that the free-ranging wild elk in the Buffalo Valley and Spread Creek
areas benefit from more dispersal on native range. It also appears that
with habitat improvements, more elk use native range (even with wolves
present) and avoid feedlots. The biologically sound conclusion is that
free-ranging wildlife are most healthy on native range managed at carrying
capacity with normal dispersal by a balanced large carnivore population.
(A special thanks to Lloyd Dorsey, WWF, for his assistance in this
article.)
