ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

During the years of high forage production in clearcuts, snow in the opening
may prevent utilization by elk. Elk begin to experience difficulty at snow depths
of 46-61 cm (1 8-24 inches) (Gaffney 1941 ; Telfer and k1 sall 1971 ; Beall 1974; Leege
and Hickey 1977). Piovement to areas with less snow, to lower altitudes or uncut
timber, appears to occur without regard for forage availability (Bcall 1974; Leege
and Hickey 1977). Beall (1974) reported that elk in the winter have a strong association
with cover types and less association with forage. Stelfox and others
(1976) found no winter use of 17-year-old clearcuts in Alberta and estimated that
summer use was less than 10 percent of capacity because cover was so poor. And in
Montana, Lyon and Jensen (1980) reported that cover at the edge of clearcuts as well
as cover height inside the opening was an important determinant of elk use.
The grizzly bear evolved from its forest-dwelling Pleistocene ancestors (Kurten
1968) into a species adapted to treeless habitat (Herrero 1972; Martinka 1976) a t a
time when prinlitive man posed no threat. In response to modern txan's capacity to
annihilate it, the grizzly today shows an apparent dependence on timber cover in
proximity to foraging areas (Graham 1978; Knight and others 1978) and den sites
(Craighead and Craighead 1972a). The amount of cover necessary for security remains
to be defined.
liuch of the unused portion of the bear's range is in broad expanses of conifer-
ous forest. Of apparently minor value for feeding, and presumably in excess of
minimurr~ cover needs, these forests appear to offer the potential for creating new
foraging sites through 1 ogging and subsequent successional devel opment . Rl though
the floristics of sera1 stages in the various habitat types are not we1 1 documented,
it is reasonable to assume that prudence in the timing and spacing of logging opera-
tions wi 11 maintain a heterogeneity of conditions beneficial to the bear. The
challenge is whether this can be done without adversely affecting the bear. We need
additional knowledge of habitat components, of a1 ternate food sources, of travel
corridors, of minimum buffer zones, and of how to maintain the integrity of these
collective habitat components. Meanwhile, we can only recommend a cautious and
conservative approach to 1 ogging in grizzly range.
The influence of postlogging habitat development on big game can be described
as the most important and complicated influence of harvesting and residue manage-
ment. Road construction, timber harvest, slash treatment, and road management are
short-term problems for which partial solutions are a1 ready available. Repeated or
prolonged timber sale activity will compound the negative effects on elk and grizzly
bears, but when the disturbance is over, the slash treated, and the roads closed,
the habitat will represent some combination of cover, forage, and diversity with an
ability to support both species. This capability may be higher or lower than that
before timber harvest, and it will change constantly as forest vegetation grows and
changes.
LITERATURE CITED
A1 len, Eugene 0.
1971. El k-logging relationships in the northern Rocky Flountains. Paper read.
Northwest Section, The Wi 1 dl i fe Society, Eozeman, Montana, 7 pp. , (rnimeo) ,
Anderson, C.
1958. The elk of Jackson Hole. tdyoming Game Fish Corn. Bull. 10. 184 pp.