ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

The primary reason for this discrepancy is that timber harvest consists of a
series of events, each of which can produce positive or negative responses by
animals and may have radically different effects in different seasons. Road con-
struction and logging activity, slash treatnient, road management, and postlogging
habitat development must be considered individually and in concert. It is espe-
cially necessary to recognize that big game animals do not rely solely on habitat
within treated sites. Any treatment evaluation requires simul taneous eval uation of
treated and untreated habitat in relation to species requirements, And, herein lies
a further problem in that habitat requirements are not well defined for most spe-
cies. In this paper, we summarize some of the more recent research in timber man-
agemen t/big game relationships and specify areas where additional research seems
most urgently needed. We confine the discussion almost entirely to the Rocky
Mountain elk (cervus elaphus nelsoni) and the grizzly bear (ursus arctos horri-
bilis). This is a narrow perspective, but the alternative would require discussion
of at least 11 species for which adequate Snformation is not readily available.
This limitation is not intended to suggest that the elk is a representative ungulate
and the grizzly a representative carnivore. We prefer to stress that other big game
species and their responses to timber management must be evaluated specifically
rather than by imp1 ication.
GENERAL CONSIDERATIONS
In a broad sense, Rocky 1"luntain elk and grizzly bears do provide justification
for a generalized logic of habitat management based on maintenance of diversity in
the forest environment. In addition to food, cover, and water -- needs common to
all big game --elk and grizzly bears utilize some fairly specialized habitat (breed-
ing areas for elk, denning areas for bears). A mosaic of vegetation types and edges
is considered indicative of productive big game range (Biswell and others 1952;
Leopold 1948; Stelfox and Taber 1969; Rackie 1978). A1 though elk can adapt to a
variety of habitat conditions, a heterogenous mosaic is most 1 i kely to contain all
the required components. In many areas of Pontana, Idaho, Oregon, and Washington,
specific proportions and juxtapositions of elk forage and cover areas have been
defined.
Less is known of the specific habitat required by grizzly bears, but current
research suggests that diversity of vegetation types is as important for bears as
for elk (Martinka 1976; Varney and others 1976). In the Yellowstone Park area, some
radio-monitored bears have annual home ranges in excess of 777 km2 (300 square miles)
(Knight and others 1978). Studies in this area (Mealey 1975; Graham 1978; Knight and
others 1978) corroborate findings el sewhere (Mundy and Fl ook 1973) that the grizzly
is an opportunistic omnivore. Food selection is often seasonally specific and con-
centrated within preferred habitat niches constituting a small proportion of the
annual range. The remaining, larger portions apparently serve as travel routes and
buffer zones. Presumably, the size of an individual range is dictated by the variety,
qua1 i ty, abundance, and juxtaposition of these habitats, rautes, and zones and their
combined capability to meet the bear's needs. Again, a diverse mosaic appears most
1 i kely to contain the required components.