Comparison of small-mammal community responses to broadcast burning and herbicide application in cutover forest habitats

Abstract

This study was designed to compare the responses of small-mammal communities to broadcast burning and herbicide-induced alteration of forest habitats. Study areas were located in south-coastal British Columbia, Canada, in the Coastal Western Hemlock (CWHdm) biogeoclimatic zone, and in west-central British Columbia in the Sub-boreal Spruce (SBSmk) and Engelmann Spruce–Subalpine Fir (ESSFmc) zones. Control–treatment comparisons for a herbicide application or a broadcast burning treatment were conducted at the coastal study area from 1982 to 1984. Replicate control–treatment comparisons between these two silvicultural practices were conducted at the interior study area within the period 1989 to 1992. Small-mammal populations were intensively livetrapped in all control and treatment blocks. Deer mouse (Peromyscusmaniculatus Wagner) populations showed short-term (1–2 months) declines after treatments at the coastal study area but appeared little affected by these habitat alterations at the interior area. Voles of the genus Microtus disappeared from burned blocks at the interior area but Microtusoregoni (Merriam) persisted on the burned block at the coastal area; however, the red-backed vole (Clethrionomysgapperi Vigors) did not. Chipmunks (Eutamiastownsendii Bachman and Eutamiasamoenus Allen) were little affected by either treatment. Neither treatment seemed to affect species diversity of these small-mammal communities. In terms of abundance of small-mammal populations, it is likely that broadcast burning is a more extreme means of habitat alteration than herbicide treatment.