Yellowstone's Northern Range - Greater Yellowstone Science ...

THE NORTHERN RANGE
Figure 7.13.
NumelVus
scavengers quickly
consume the
carcasses of elk and
other ungulates on
the northern range.
NPSphoto.
Figure 7.14.
Yellowstone grizzly
bears are adaptable
omnivores, adjusting
to the varying
supplies of preferred
foods. Scat analysis
has shown that in
years of poor
whitehark pine lIut
crops, hears
compensated by
increasing their
consumption of
ungulates. The
northern Yellowstone
elk herd is an
important component
of the diet of the
threatened grizzly
bem:
Interagency Grizzly
Bear Study Team.
100
98
ecological and ungulate
management issue has entered
an imp0l1ant new phase
(Phillips and Smith 1996,
Schullery 1996). This addition
to the suite of predator/
scavengers (grizzly and bl,ack
bears, mountain lions, wolverines,
coyotes, faxes, plus
numerous bird species) is
significant (Figure 7.15).
Several writers have pointed
out the incompleteness of the
natural regulation experiment
as long as the full complement
of native mammalian predators
UNG =0.518 +0.065 YR- 0.0165 PIAL
r' was not in place (Peek 1980,
=0.99
R
Houston 1982, Mech 1991).
The arrival of the wolf is
Ungulates
perhaps the single most
important event in the evolution
of northern range manage­
, ,
, " ,, ,
ment since the 1967 Senate
,
,,
, hearings that led to the
,,
,
cessation of traditional elk,
Q"""""
, Whitcbark Pine Nuts
bison, and pronghorn control.
,,
, "'~--------Q.. ...---........."9
Prior to wolf reintroduction,
North American wolf
YEAR
experts, while expressing a
majority opinion about the
probable effects of Yellowstone
°7~7-------7LI8-------7~~-------8~~~----~8~1------~8L2------~83
Recent calculations by Singer et al. (1997) suggest
each grizzly bear within the calving range of the
northern elk herd kills and consumes, on the
average, about 15 elk calves per year. Of course,
this rate would vary from bear to bear since some
animals specialize more in the hunting of elk
calves than others, and the rate would also vary
from year to year (Singer et al. 1997). Based on
close observations of a small number of bears for
short time periods, French and French (1990)
calculated that some bears killed at least one calf
per day, on average, during the four to six weeks
each year that calves are vulnerable to bear
predation.
With the reintroduction of wolves to the
northern range in 1995, the entire northern range
wolves, also had minority views that expressed a
wide range of opinion in the probable effects (Vales
and Peek 1990, Boyce and Gaillard 1992, Singer
1991, Lyme et aI. 1993). All predicted some
decline in elk numbers and some predicted declines
or increases in other ungulates. Singer (U.S. Geo!.
Surv., unpub!' data) predicted a decline in coyotes
and an increase in faxes, and no effects on grizzly
and black bears, mountain lions, and wolverines.
They predicted an increase in pronghorns, moose,
bighorns, and beaver, and noted that mule deer
should be monitored closely. They also concluded
that the moderate wolf densities they expect in
future, and their effects on the large herbivore
populations would not likely result in any significant
effects on the northern range's vegetation. In