Author

Dave Keiter

Date of Award

4-2013

Document Type

Thesis

Department

Environmental and Forest Biology

Thesis Advisor

Jaqueline Frair

Abstract

Small mammals are commonly captured in baited traps for management-related estimates of population size and species diversity. Bait preferences by species may alter their trappability, affecting abundance or diversity estimates. Here our objective was to evaluate whether the trappability of different species varied according to bait type at 3 sites in interior Alaska. Between July and August of 2011, we deployed 200 Sherman live-traps spaced 10 meters apart at each site for 5 nights, and alternated 2 commonly used baits (a peanut butter/oat mixture or oats alone). We live-captured 52 animals of 6 species at the White Mountains site, 70 animals of 4 species at the Middle Tanana site, and 40 animals of 4 species at the Brooks Range site. We then tested for differences in initial capture and recapture rates using a McNemar’s test. No significant differences were observed between bait types for any variable or species. A machine-learning program, TreeNet, provided further evidence that bait type explained less variance and was less predictive of the initial capture or recapture of a species than elevation, ground cover, or shrub cover. Thus, estimates of relative abundance and species diversity should be robust across studies, although different baits than those tested may have greater effects for certain small mammal groups. Further investigation should be pursued into whether this lack of preference is a result of food limitations caused by a short growing season in higher latitudes.

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