ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

T:s a basic guideline for timber harvest on any big game range, managers should
avoid the creation of large areas of any single type or successional stage. The
wi 1 dl i fe habitat objective should be to maintain a continuing diversity of habitats
while simultaneously preserving the integrity of niches important to particular
species. In grizzly bear management, an equally important objective is to reduce
the probabi 1 i ty of encounters with man.
ROAD CONSTRUCTION AND TIMBER HARVEST
Road construction and timber cutting constitute a major disturbance of the
forest environment. El k, particularly on summer range, have responded by moving
form 0.8 tcl 6.4 km (0.5 to 4 miles) from the source of the disturbance (Beall 1974,;
Karcum 1975; Lyon 1975; Ward 1976; Lonner 1978). Specific movement patterns have
not been described, but research results suggest that the location of the distur-
bance is more irriportant than intensity in determining the distances moved, Elk
appear to move only as far as necessary to escape line-of-sight contact with men and
equipment (Karcum 1975; Lyon 1975; Ward 1976).
Under most circumstances, displacement is temporary, but the time elk require
to return has proved extremely variable. Some elk will remain quite close to a
logging area and return during the night and on weekends (Beall 1974; Narcum 1975;
Kard 1976). Others may leave for a short period and gradually return while logging
is in progress (&@all 1974). In a study of winter logging in British Columbia,
McLellan (1978) recorded increases in overnight use of active logging areas as
compared with elk use of the same areas before logging began. Some elk may even
become habituated to 1 ogging activity during day1 i ght hours (Beall 1974; McLell an
1978).
Most comnonly, at least some of the displaced elk return within a few days to
weeks after the disturbance has ended. Karcum (1975) has noted that animals forced
to move great distances to find security are less likely to return imxdiately , and
Lyon (1979b) has speculated that repeated disturbance in the same area over several
consecutive years can result in avoidance behavior for one or more years after
logging is completed. To date, all studies indicate that elk will eventually reoc-
cupy logged areas.
In summary, it appears that temporary displacement is a significant but not
fatal inconvenience for elk. If movement patterns are well known, it may be possi-
ble to protect key areas and time logging operations to avoid disturbances while elk
are in those areas (Roberts 1974). Providing an adjacent security area (Lyon 1975;
Marcum 1975), concentrating management activity in to the shortest possible period of
time (Black and others 1976), and confining the area of activity to a single drain-
age (Ward 1976; Black and others 1976) should mitigate most of the apparent dis-
placement problems.
Me are unaware of any study explaining how logging and road building affects
grizzly bears; however, we can speculate that in many instances the bear's charac-
teristic shyness will keep it from the logging area for the duration of the activ-
i ty, Displacement may be for much longer periods in specialized areas. For
instance, bears seek den sites far isolated from man's activities, presumably
because the bear's lethargic state imediately before and during hibernation renders
it particularly vulnerable to man (Craighead and Craighead 1972b). Students of the
European brown bear -- a conspecific of our grizzly -- suggest that logged areas may
be abandoned as denning sites for many years (Zunino and Herrero 19'12).