Population Ecology of Wolverines
Within Kobuk Valley National Park
Selawik National Wildlife Refuge
Last revision 12/17/98
Brad Shults, Wildlife Biologist, Western Arctic National Parklands
Gene Peltola, Wildlife Biologist, Selawik National Wildlife Refuge
Jerrold Belant, Wildlife Biologist, Denali National Park and Preserve
Kyran Kunkel, Wildlife Biologist, Alaska System Support Office
The Kobuk River Valley (specifically Kobuk Valley National Park, KOVA) and the
Selawik National Wildlife Refuge (SNWR) have historically experienced
relatively high use for wolverine (Gulo gulo) hunting and trapping . During the
last few years, concern has been expressed by agency personnel and local
hunters/trappers that wolverine abundance has declined appreciably in
northwestern Alaska. Sealing records indicate that the harvest has declined by
75% since the winter of 1977-1978. The ecological factors driving wolverine
population parameters are unknown and thus the cause of this particular decline
is unknown but may result from harvest pressure. We started collecting
wolverine carcasses in FY 96 in an effort to assess population demographics and
harvest impacts. We propose to significantly expand our current project to
better understand wolverine population ecology by initiating a telemetry study.
Our objectives are to:
Determine demographic parameters (i.e., survival, fecundity, age/sex structure)
for wolverines using radiotelemetry and carcass collections.
Determine home ranges and habitat selection of wolverines using conventional
and satellite radiotransmitters.
Derive a population estimate for the study area based on telemetry data,
carcass collection, and local knowledge.
Estimate the annual harvest of wolverines from the SNWR and KOVA using
radiotelemetry, carcass collection, harvest questionnaires, and informal
Quantify seasonal diet by sex/age classes
Use demographic data collected to develop a predictive model with which to
determine the effects of various harvest strategies on wolverine populations,
make long term management decisions with respect to trapping/hunting seasons
and set harvest limits that meet legal requirements and traditional harvest
Wolverines are highly prized for their use as a ruff and trim material for
parkas because the fur possesses unique qualities which allow less frost
accumulation than other furs. Due to a scavenging life style and large home
range, wolverines are very vulnerable to harvest in the open habitats of
northwestern Alaska. Under heavy trapping or hunting pressure, wolverine
populations can decline over a large area because of their naturally low
density and reproductive potential (Magoun 1985). Sealing records indicate that
the harvest has declined by 75% in northwestern Alaska since the winter of
1977-1978 ( Alaska Dept. of Fish and Game unpublished data). Wolverine harvest
has declined statewide by 38% over the last 20 years (Golden et al. 1993).
Because so little is known about what ecological factors drive wolverine
population dynamics, the cause for these declines are largely unknown but may
be related to harvest (Banci 1994). The current size and trend of this and
other wolverine populations in northwestern Alaska remain unknown. Sealing data
alone are inadequate for monitoring populations and protecting wolverines from
overharvest (McCullough 1996). Sealing data does not provide population
estimates, and the use of sealing reports are, at best, a minimum harvest
estimate, as many wolverine pelts are used locally and are not sealed.
Managers within national parks in Alaska are mandated to manage harvests of
wolverines to maintain "natural and healthy" populations of wolverines.
Harvests within preserves must be managed to maintain "healthy" populations of
wolverines. Whether these obligations are currently being met in the Western
Arctic National Parklands (Kobuk Valley, Noatak, Cape Krusentern, and Bering
Land Bridge national parks and preserves) or other national parks in Alaska is
unknown because we lack basic information on ecology and population
demographics of wolverines. Additionally, we currently do not have a reliable
and efficient way to monitor population trends. In order to be able to predict
population trends and harvest impacts, we need to determine population
parameters (survival, fecundity, density, dispersal rates) and factors that
drive these including the role of prey abundance, habitat factors, and harvest.
By learning the role and relative importance of these factors, we will be able
to meet agency mandates and ensure and achieve proper management.