Habitat use and abundance of deer mice: interactions with meadow voles and red-backed voles

Abstract

In this study we investigated the influence of competitive interactions on the use of habitats and relative abundance of deer mice (Peromyscus maniculatus). If interspecific competition is influencing the habitat use and relative abundance of deer mice, then removal or introduction of potential competitors will change habitat use and abundance of this species. During the first field season we removed meadow voles (Microtus pennsylvanicus) to look at the effect on the contiguous population of deer mouse. The removal of one species had no effect on the other species' distribution or demography. In the second field season, meadow voles declined to very low numbers and we used their natural fluctuation as a removal experiment. Deer mouse populations were not affected even when the natural decline of meadow voles was more effective in maintaining the sedge meadow free of voles than the previous removal manipulation was. During the 3rd year, meadow voles colonized two areas of forest where deer mice had been alone the previous two field seasons. Red-backed voles (Clethrionomys rutilus), in turn, increased from very low numbers in four grids. Neither meadow voles nor red-backed voles affected the spatial distribution or abundance of deer mice. The results of this study indicate that competitive interactions have no influence on the use of habitats and relative abundance of the common species of small mammals in the southwestern Yukon.