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

THE NORTHERN RANGE
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appear suppressed by high densities of elk. Where
competition is suspected or proven between
ungulate species, it does not seem outside the realm
of normal sharing of a common range, and does not
seem to threaten the survival of any species. The
elk and bison are a crucial source of nutrition for
numerous predators and scavengers, including
federally listed rare species such as grizzly bears,
wolves, and bald eagles, all protected under the
Endangered Species Act.
7, Despite more than 60 years of dire
predictions of overgrazing and imminent disaster,
the northern range continues to produce large,
healthy ungulate herds year after year in harmony
with a productive range. The northern range elk
herd is regulated by a variety of natural and modern
human forces, including predation by a full suite of
native animals and variations in climate. Hunting
by humans north of the park may have also'
influenced both the population's dynamics (age and
sex ratio, population numbers), and certainly its
migratory and diurnal behavior. Since intensive
scientific study began on the n0l1hern herd in the
1960s, the herd has shown several strong densitydependent,
or naturally regulating responses.
8. Large ungulate herds and intensive
grazing on the northern range do not appear to be
negatively affecting native species biodiversity.
The evidence indicates the number of grass, forb
and shrub species on the northern range was the
same in grazed and ungrazed sampling plots.
Community plant diversity on the northern range,
however, may have experienced a slow decline in
the past century due to the decline in aspen and
willow stands, but this is somewhat unclear due to
the greater native species diversity outside of
exclosures versus inside excIosures. While some
species of native vel1ebrates (e.g., tall willowobligate
breeding birds) are selected against on the
northern range, there are appropriate similar
habitats available in other parts of the park and the
ecosystem, and there are other vertebrate species
that are favored in short willow and other riparian
habitats. Native invertebrate diversity appears to be
enhanced by the high levels of ungulates.
9. Yellowstone's northern range, one of the
few places remaining in the world with all of its
"component parts and processes," continues to
provide ecologists with one of the world's most
exciting and challenging "natural laboratories" for
studying the complexities of landscape ecology,
and clearly has much more to teach us about the
processes that shape wildlands and native grazing
systems.
10. The northern Yellowstone elk herd has
long had great social value, as demonstrated by
consistently high public interest in northern range
controversies. These elk have intrinsic value as
part of the Yellowstone experience, for visitors
from around the world. With the cessation of
artificial population control on the nOlthern herd,
this herd has also taken on great regional economic
value as tl,e basis of one. of North America's
premier recreational hunts and wildlife viewing
attractions. Communities near the park have
experienced significant economic gains because of
recreational interest in the northern herd, and the
negative economic impacts on those communities
must be considered in any deliberations over future
artificial manipulation of this elk herd.
11. In the past, the National Park Service and
others have refened to the natural regulation policy
on the northern range as an "experiment." In the
strict sense of the scientifiC method it is not
because it has no scientific controls and no
replication. It is instead, a management model in
the sense of Walters' (1986) and Macnab's (1983)
"adaptive management" of renewable resources,
where the management model is updated or revised
on a periodic basis as new information is obtained.
Such an update is warranted now in light of the
enormous amount of information becoming
available as a result of the recent research initiative.