Associations of forest-floor vertebrates with coarse woody debris in managed forests of western Oregon

Forests managed primarily for wood resources may be lacking in adequate amounts of coarse woody debris (CWD) for forest-floor vertebrates. We assessed associations between captures of forest-floor vertebrates and volume of CWD in 18 closed-canopy stands of Douglas-fir (Pseudotsuga menziesii). The volume of CWD ranged from 14 to 859 m(3)/ha. Pitfall traps and timed, area-constrained ground searches were used to capture small mammals and amphibians. The abundance of ensatina (Ensatina eschscholtzii) and clouded salamanders (Aneides ferreus) increased with volume of CWD. In addition, the probability of encountering either ensatina or Trowbridge's shrew (Sorex trowbridgii) increased with cover of CWD on the forest-floor. The average distance from the nearest CWD for amphibians captured during timed, area-constrained ground searches was 0.5 m, versus 1 m between random points and the nearest CWD. Our study suggests that current management guidelines for CWD retention may not provide adequate habitat for forest-floor vertebrates that depend on this component of the habitat.