An alternative field technique for estimating diversity of small-mammal populations

Abstract

Sampling of populations of small mammals has traditionally focused on use of live traps, which are often costly and labor intensive. We tested track tubes as an alternative technique for assessing populations of small mammals. Track tubes record footprints of small mammals and allow determination of their presence or absence without live capture. We compared results from livetrapping against data from track tubes on 5 sites over 1-week periods in June 1999 and June 2000. Correlations between indices of abundance from the 2 techniques were significant in 1999 (rs = 0.656, P < 0.001) and 2000 (rs = 0.715, P < 0.001). Using track tubes we distinguished footprints of 4 species. We were not able to distinguish Peromyscus from Clethrionomys gapperi; species of Sorex could not be distinguished. In comparison with livetrapping, track tubes are inexpensive, are much less labor intensive for researchers, and can be run simultaneously on several sites. The technique has good promise where investigators seek only to identify composition and relative abundance of small-mammal species.