Age- and sex-specific responses of the gray-tailed vole, Microtus canicaudus, to connected and unconnected habitat patches

Abstract

We monitored demography, movement, and reproductive behavior of gray-tailed voles, Microtus canicaudus, in experimental habitat patches with and without corridors to test the hypotheses that more individuals would move among patches in corridor than in control unconnected habitats, and that individuals would distribute themselves more evenly among patches if corridors were present than if they were not. We predicted that more males than females would move among patches in both treatments and that juveniles in control habitats would exhibit delayed sexual maturation if their dispersal was delayed and opposite-sex relatives remained in proximity to each other. All experiments were conducted in eight 0.2-ha enclosures planted with alfalfa that was fragmented into four patches (each 156 m2) separated by 12.5 m of bare ground. In four of the enclosures, patches were connected by 1 m wide habitat corridors. Corridors facilitated movements, with males moving more than females. However, corridors did not result in an even distribution of animals in the four patches. Unconnected habitat patches resulted in female-biased juvenile dispersal, and females dispersed at a lower body mass than males in both connected and unconnected habitats. Males that did not disperse from their natal patch grew at a slower rate than those that did disperse. We conclude that movement was deterred in patchy environments, enhanced by corridors, and differentially affects males and females. Behavioral factors that affect an individual's dispersal or reproductive pattern should be considered in landscape design.