Changes in small mammal populations after clearcutting of northern Ontario black spruce forest

Changes in small mammal populations on upland black spruce (Picea mariana) clearcuts near Manitouwadge, Ontario, were monitored between 1973 and 1975 by live-trapping.Additional clearcuts and uncut stands were sampled by dead-trapping in September 1975.The September density of mice and voles was similar during the first, second, and third year after clearcutting (13.0/ha, 11.6/ha, and 10.0/ha, respectively).Red-backed voles (Clethrionomys gapperi), likely commonin uncut stands but increased on clearcuts until they predominated in the small mammal community by the end of the second harvest, and then declined markedly to rare status.Conversely, deer mice (Peromyscus maniculatus) likely were scarce in incut stands but increased on clearcuts until they predominated in the small mammal community by the end of the second summer after cutting.For less common species clearcut and uncut stands were compared.Meadow voles (Microtus pennsylvanicus) were more common on clearcuts than in uncut stands while the converse was true for rock voles (Microtus chrotorrhinus).Bog lemmings (Synaptomys cooperi) were taken only in uncut stands while heather voles (Phenacomys intermedius) and least chipmunks (Eutamias minimus) were captured only on clearcuts.Clearcutting of upland black spruce forest produced a dramatic change in the composition of the small mammal community but may have caused little change in density.