Arctic Refuge: North Slope Moose
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During the early 1900's moose were rare on the Alaskan north slope (that portion of Alaska that
is north of the Brooks Range mountains). Moose gradually increased and
peaked in the late 1980's. In 1985 biologists of the Arctic Refuge began to monitor north slope
moose by conducting aerial counts during late fall when there is good snow cover, making moose easier to spot.
The graph above represents total moose counted in the area of the north slope between the Dalton Highway and the Canning River. Moose numbers in this area declined from high levels (about 600) in 1989 to a low of 97 counted in 1997. In the spring of 2001, a total of 146 moose were counted in this area. A similar reduction of moose was documented by the Alaska Department of Fish and Game in the region west of the Dalton Highway, including the Colville River area. In 1995
the State of Alaska Board of Game and the Federal Subsistence Board issued regulations closing
nearly all of the Alaskan north slope to moose hunting (a small harvest of moose was
authorized for subsistence in the vicinity of Nuiqsut).
Several possible explanations have been developed to try to account for the north slope
moose decline. During winter, moose are confined to relatively limited areas of riparian
willows along the northern margin of the Brooks Range where snow is usually not drifted by wind.
There is some evidence that concentrations of moose in these areas reached or possibly exceeded the
maximum level that the habitat could support. Thus moose may have declined as a result of habitat overuse.
Another consideration is that wolves and bears have become more abundant on the north slope as a
result of bear harvest restrictions established in the early 1970's and the elimination of aerial wolf hunting. In addition, during the 1980's, human harvest in some areas increased as the region became
more accessible due to completion of the Dalton Highway. It is likely that all of these factors
(habitat overuse, predation and human harvest) in combination functioned to reduce moose populations
on the Alaskan north slope.
Over the past half century, the increasing presence of moose on the Alaskan north slope added
diversity to the large mammal community and provided additional opportunity as a source of red meat
for hunters, especially in times when caribou are not available. Because moose are at the
northernmost edge of their distribution on the north slope, they may be more vulnerable to periodic
oscillations in abundance, requiring harvest closures during periods of low numbers.
Since north slope moose populations have remained at low levels, it is imperative to continue
monitoring their status.
September 12, 2008
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