Ministry of Forests

Cariboo Region Research Section


The Effects of Juvenile Spacing on Wildlife Habitat use During Winter in the Interior Douglas-Fir Zone of Britsh Columbia

Data were collected for a second winter (1 and 2 years post-spacing) to reassess the changes in habitat use by common wildlife in response to juvenile spacing in a mature, uneven-aged interior Douglas-fir forest. The study examined the following species: snowshoe hare, red squirrel, mule deer, moose, and coyote/fox.

Snowshoe hares infrequently used recently spaced blocks probably because of dramatic reduction in cover and food. Since unspaced forest is high use snowshoe hare habitat, the size and spatial distribution of spacing blocks within a larger management unit requires careful consideration if snowshoe hare populations are an important management concern in the area. Red squirrel use was generally lower in spaced areas than in control b~cks. Thick patches of immature trees within a mature stand may provide superior thermal and security cover for squirrels. Habitat use by other species did not change measurably in response to spacing.

Unspaced strips left in spaced blocks were used by snowshoe hares and red squirrels. Hare habitat use appears to increase as unspaced strip width and proportion ot unspaced area left in the block increase. However, a replicated study is necessary to confirm this result. In any case, even the widest (33 m) strips do not maintain the same amount of use by either hares or squirrels as the control blocks do. Mule deer and moose may use the unspaced stnps indirectly forthermal and security cover. The size and shape of unspaced areas in spaced blocks and the placement of spaced blocks near unspaced areas need to be examined further.

Over a 1-year period, the mean slash depth in all blocks decreased by 43% while the area covered by measurable slash decreased by 22%. The trees were parallel felled, then bucked into 4-m lengths. Also, the felled trees were slashed to a depth of less than 0.5 m in five of six blocks. Deep, extensive slash in a block, especially in conjunction with snow, can impede animal movement. Rapid slash reduction makes habitat within the block available in a shorter time span.

Man-made trails may be necessary to provide access through deep, continuous slash. The first winterthat data were collected, mule deer, moose, coyote, and fox made extensive use of trails in 1 -year-old and recently spaced blocks. In the second winter (1989), however, shallower slash and a thick layer of snow made it impossible to assess trail use in all but one block.

Further research is necessary to determine the short- and long-term effects of spacing on wildlife in different seasons and under a variety of conditions.

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