Population fluctuations and tree damage by red-backed voles (Myodes gapperi) after clearcutting of coniferous forest

Abstract

ABSTRACTAlthough Eurasian species of Myodes voles are indeed pest species in forestry, it is not clear if the southern red-backed vole (Myodes gapperi), a closed-canopy species in western North America, also feeds on tree seedlings. Thus, we tested the hypotheses (H) that (H1) abundance of M. gapperi would dominate the vole population immediately post-clearcutting and then disappear, and (H2) while at high densities, incidence of mortality from feeding damage to newly planted tree seedlings by M. gapperi would be comparable to that reported for long-tailed voles (Microtus longicaudus). We live-trapped both species of voles, and measured feeding damage to planted trees, on seven replicate sites for the first 2 years after clearcutting near Golden, British Columbia, Canada. Population changes of M. gapperi and M. longicaudus were essentially the converse of one another in the first 2 years post-harvest. Red-backed voles were the dominant species in the first year and long-tailed voles were prominent in the second year. M. gapperi did not persist on these cutover sites and was at, or near, extirpation after 2 years post-harvest, and hence H1 seemed to be supported. The range of tree mortality by red-backed voles was near the overall mean percentage tree mortality (33.9 ± 4.8%) by M. longicaudus, and hence H2 seemed to be supported. If new plantations have to survive relatively high numbers of two vole species and their feeding damage up to 4–5 years after harvest, then it may be worthwhile to delay planting until vole numbers have declined.