ALTERNATIVE CONIFER RELEASE TREATMENTS AFFECT SMALL MAMMALS IN NORTHWESTERN ONTARIO

Density changes of small mammals responding to different conifer relea se treatments (motor-manual [brush saw] cutting; mechanical [Silvana S elective] cutting; helicopter-applied herbicides [Release(R) (a.i. tri clopyr), Vision(R) (a.i. glyphosate)]; controls [no treatment] were qu antified. A total of 4,851 small mammals were captured and released du ring the three-year study. The most commonly captured (81% of total) s pecies were: shrews (masked [Sorer cinereus Kerr], pygmy [S. hoyi Bair d], arctic S. arcticus Kerr]), southern red-backed voles (Clethrionomy s gapperi Vigors), and deer mice (Peromyscus maniculatus Wagner). Nort hern short-tailed shrews (Blarina brevicauda Say), eastern (Tamias str iatus L.) and least (T. minimus Bachman) chipmunks, meadow voles (Micr otus pennsylvanicus Ord), ermine (Mustela erminea L.), and meadow jump ing mice (Zapus hudsonius Zimm.) were common. Shrew (masked, pygmy, ar ctic, short-tailed) densities were statistically unaffected by these t reatments. Red-backed vole densities were highest on control plots dur ing the first post-treatment growing season, and highest on control an d Vision(R) plots during the second post-treatment growing season. Dur ing the first two growing seasons after treatment, deer mouse densitie s were highest on Silvana Selective plots; eastern chipmunk densities were highest on control Vision(R) and Silvana Selective plots; least c hipmunk densities were highest on Vision(R) and Release(R) plots; and meadow vole densities were highest on Release(R) plots. Small mammal r esponses to the alternative conifer release treatments examined were s pecies specific one and two-growing seasons post-treatment, but simila r to responses common to the standard (Vision(R) herbicide) conifer re lease treatment.