Black-tailed deer Odocoileus hemionus columbianus
Richardson) were studied in the Nimpkish Valley on northern
Vancouver Island to determine the effects of clearcut logging
upon the ecology of the deer in winter. Because Provincial
government biologists suspected that logging was decreasing the
amount of winter range, and therefore the number of deer, on
Vancouver Island, most emphasis was placed upon the
interrelationships between logging, snow depth, habitat
selection by deer, and nutritional condition of deer.
The study was done during during the winters of 1971 - 72 and
1972 - 73 . The first winter was severe and had heavy snowfall, and
the second winter was mild and had light snowfall.
If deer sink deeper in snow than their chest height, they
have a hard time moving. In the Nimpkish Valley, fawns had chest
heights of about 17 inches, and adults about 22 to 23 inches.
During the first winter, snow in the logged habitats
averaged 4 ft deep, but snow in the mature timber habitats
averaged less than 2 ft deep. There was more snow at high
elevations than at low elevations. Snow was less deep than deer
chest height only in mature timber habitats at low elevations.
Snow was also shallowest in mature timber habitats having a high
crown closure. During the severe winter, only mature timber
habitats at low elevations with crown closures greater than 65%
were used heavily by deer.
The most important aspect of snow is not simple snow depth,
but how deeply deer sink in it. When a hard crust formed on deep
snow in the regenerated logging slashes, deer were able to move
freely on top of the crust, and made heavy use of these areas
for feeding.
Deer also used mature timber habitats heavily during the
mild winter. Deer made more use of timber habitats having a
shrub understory than these having a conifer understory,
probably because there was more food available in the timber
having a shrub understory. Many deer remained as high up the
mountains as snow conditions and food availability permitted.
Generally, deer made light use of the logged habitats
during both winters, but they used these habitats heavily in the
spring.
Deer were collected to measure their food habits and
physical condition. Deer were not able to eat as many plant
species in the severe winter as in the mild winter, and were in
worse physical condition in the severe winter than in the mild
winter.
In the Nimpkish Valley, deer made heavy use of nature
timber habitats during winter. In many other areas of western
North America, black-tailed deer use logged habitats for winter
range. However, the Nimpkish Valley is much more mountainous and
has more snowfall than many other areas in which deer ecology
has been studied. The habitat selection patterns of deer in the
Nimpkish Valley probably occur only in areas having similar
topography, vegetation, and climate.
Most other studies of black-tailed deer have concluded that
logging is beneficial to deer. However, continued clearcut
logging in the regions of Vancouver Island having high snowfall
will eliminate deer winter range and reduce deer populations. It
is recommended that legging companies leave strips of mature
timber, going from the subalpine to the valley bottom, and
including winter range habitats, in all those areas where deer
populations are desired. / Forestry, Faculty of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/41946 |
| Date | January 1975 |
| Creators | Jones, Gregory William |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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