Small-mammal abundance at three elevations on a mountain in central Vermont, USA: a sixteen-year record

Abstract

As part of a study of forest resilience to gypsy moth ( Lymantria dispar) defoliation, small mammals were sampled with live (box) and pitfall traps for 16 years at three elevations on a mountain in west-central Vermont, USA. The more mesic, lower-slope location had the most diverse small-mammal community. White-footed mice ( Peromyscus leucopus) were the most commonly captured small mammal at all locations, but less so at the lowest elevation. Southern red-backed voles ( Clethrionomys gapperi), eastern chipmunks ( Tamias striatus), and northern short-tailed shrews ( Blarina brevicauda) were also regularly captured over the 16 years. Captures of all species showed considerable year-to-year variation. During the study, white-footed mouse density ranged from 3.7/ha (lower-slope June 1984) to 93.4/ha (mid-slope, July 1985). Over the 16 years, median density estimates across locations ranged from 12 to 19/ha in June and from 25 to 32/ha in July. Annual fluctuations in mouse abundance were synchronous across elevations, probably in response to regional-scale fluctuations in acorn production. In addition to those for white-footed mice, standardized capture rates are presented for the three other common species, and time to first capture is presented for 11 infrequently encountered species. The study demonstrates the importance of long-term surveys to properly characterize a small mammal community.