Small mammal communities in a pyrogenic habitat mosaic

Abstract

We studied the small mammal community across a mosaic of habitats created by a large wildfire in the mixed-wood boreal forest of Alberta, Canada, 5 years after the fire occurred. We focussed on four habitat types within this landscape mosaic, namely burnt stands, stands of unburnt forest within the burn, unburnt forest on the periphery of the fire, and areas harvested before the fire (and subsequently burnt). The abundance of the two most common species – red-backed voles (Clethrionomys gapperi) and deer mice (Peromyscus maniculatus) – often differed inside v. outside the burn’s perimeter; however, reproduction, survival and abundance showed little to no correlation with habitat. Year-to-year changes in the relative abundance of these two species appeared greater within the burn’s periphery; the heterogeneity of the burnt landscape also supported a higher diversity of small mammal species than seen at the periphery. Comparison of our results with those collected by a coincidental study of forest harvesting suggests that the responses of the communities and populations of the animals to the two disturbance types were relatively similar. The value of long-term and chronosequence studies notwithstanding, detailed study of the wildlife communities shaped by individual wildfires improves our overall understanding of the ecological effects of natural and anthropogenic disturbances.