Aspen Stands as Small Mammal Hotspots Within Dry Forest Ecosystems of British Columbia

Forest stands of trembling aspen (Populus tremuloides) have been shown to support relatively abundant and diverse faunal communities, but this potential has not been extensively explored within the dry interior forests of British Columbia, Canada. These forests are primarily composed of conifers, particularly stands of Douglas-fir (Pseudotsuga menziesii), with only a small proportion consisting of trembling (or quaking) aspen. During 2005 and 2006, we live-trapped and compared small mammal assemblages within rare aspen stands to those in neighboring Douglas-fir and mixed-wood (aspen + Douglas-fir) stands. We captured a total of 4246 individuals of 10 small mammal species during 15,761 trap nights-with 54% of individuals captured in aspen stands. Commonly captured species included the deer mouse (Peromyscus maniculatus), southern red-backed vole (Myodes gapperi), long-tailed vole (Microtus longicaudus), montane vole (Microtus montanus), meadow vole (Microtus pennsylvanicus), yellow-pine chipmunk (Tamias amoenus), and common shrew (Sorer cinereus). Small mammal densities were most often higher within aspen stands than mixed-wood and Douglas-fir stands, as were species richness indices. Aspen stand communities also had consistently higher mean proportions of reproductive adult females and a higher proportion of juveniles. These results illustrate the importance of aspen stands as small mammal hotspots within dry forests. such as those found in British Columbia.