Habitat Selection by Mountain Beavers Recolonizing Oregon Coast Range Clearcuts

In Oregon, mountain beavers (Aplodontia rufa) are managed as pests; they are normally removed from clearcuts prior to reforestation, but recolonization nevertheless poses problems to regenerating stands. Therefore, to determine those habitat features that render a site susceptible to recolonization, we investigated habitat selection by mountain beaver recolonizing clearcuts from which their populations had been removed. We used 8 clearcuts, 4 each of 2 different ages (1 yr old and 4-5 yr old), to identify habitat features selected by colonists in the Coast Range mountains of Polk and Lincoln counties, Oregon between June 1989 and August 1990. Clearcuts were recolonized throughout, irrespective of distances from edge (R2=0.01). Six habitat variables were selected by stepwise logistic regression to model recolonized versus non-colonized habitat. Mountain beavers selected areas with high amounts of small (25 cm) woody debris, forage plants, and uprooted stumps; they were likely to recolonize areas that had soft soils and areas in drainages. The logistic function that included these 6 variables had a correct classification rate of 85% based on a jackknife procedure. Forest managers should find these habitat features useful for predicting mountain beaver recolonization and damage. We suggest potentially productive approaches to habitat management and site preparation including reduction of habitat suitability and colonist numbers by minimizing dead wood accumulations, and provisioning of alternate food sources to minimize tree damage without reducing recolonization.