The effect of forest composition and canopy cover on small mammal species composition.

Abstract

The succession of a forest from mature big-tooth aspen stands to mixed coniferous-deciduous woodland may have many effects on species composition in the area. To accelerate the maturation of a forest over time, the Forest Accelerated Succession Experiment (FASET) research group at the University of Michigan Biological Station (UMBS) girdled over 6700 big-tooth aspen and birch trees within an approximately 39 hectare area. We trapped small mammals between the FASET plot and an unmanipulated control plot on UMBS property to measure differences in species composition, animal weight, reproductive activity, age group proportions, and gender proportions between plots. We found only one statistically significant result; we trapped significantly more P. leucopus in the FASET plot than in the control plot (p<0.05). Increased P. leucopus population may increase seed predation thus decreasing future forest recruitment and decreasing forest density over time. Increased P. leucopus may also provide the predator population the opportunity to expand. Overall we concluded that as a forest changes, it can influence changes in the mammal populations already inhabiting it, and this process has the capability to alter the predator-prey dynamics and structure of the forest in the future.