Response of small mammals and birds to partial cutting and clearcutting in northwest British Columbia

Abstract

A challenge facing forest managers is providing habitats for wildlife associated with mature or old-growth forests. One approach is to use partial cutting which maintains forest cover while still allowing timber harvest. We compared small mammal (voles, mice and shrews) and bird abundance after two intensities of partial cutting (30% and 60% volume removal) to clearcuts and uncut natural stands in coast-interior transitional forests of British Columbia. The 30% removal resulted in no significant difference in the bird community compared to the uncut stands, while southern red-backed voles (Clethrionomys gapperi) increased in abundance. Bird and small mammal communities in the 60% removal treatment were closer to the uncut forest than to clearcuts, but also included species typical of clearcuts. At least one bird species, Yellow-rumped Warbler (Dendroica coronata), was most abundant in the 60% removal treatment. Several species such as the meadow vole (Microtus pennsylvanicus) and Dark-eyed Junco (Junco hyemalis) were most abundant in clearcuts, and Lincoln's Sparrow (Melospiza lincolnii) and Chipping Sparrow (Spizella passerina) were almost exclusively found in clearcuts. Scattered aspen and birch trees left in two of the clearcuts were used as cavity nest trees by Red-breasted Sapsuckers (Sphyrapicus ruber), Hairy Woodpeckers (Picoides villosus), and Tree Swallows (Tachycineta bicolor). We concluded that both of the partial cutting treatments provided habitat for small mammals and birds typical of mature forest, although the heavy removal began to show a shift towards species typical of clearcuts. Because no single treatment was optimal for all species, we recommend that partial cutting be part of a landscape strategy to provide a range of habitat conditions similar to those occurring under natural disturbance regimes. Key words: Partial cutting, clearcutting, silvicultural systems, wildlife habitat, biodiversity, ecosystem management, birds, small mammals