Journal Article

Abundance and Ecological Associations of Small Mammals

EPPS, CLINTON W., LINNELL, MARK A., FORSMAN, ERIC D., LESMEISTER, DAMON B., MANNING, TOM, WELDY, MATTHEW J.

2019

Overview

Effective conservation and management of small mammals require knowledge of the population dynamics of co-occurring species. We estimated the abundances, autocorrelations, and spatiotemporal associations of 4 small-mammal species from 2011–2016 using live-trapping mark-recapture methods on 9 sites across elevation and canopy openness gradients of a late-successional forest in the H. J. Andrews Experimental Forest, on the west slope of the Oregon Cascades. We also quantified species-specific spatial variation in adult sex ratios and body mass. We used Huggins closed capture models to estimate site- and year-specific abundances of 4 target species: Humboldt’s flying squirrels (Glaucomys oregonensis), Townsend’s chipmunks (Neotamias townsendii), western red-backed voles (Myodes californicus), and deer mice (Peromyscus maniculatus). We estimated the temporal autocorrelations among site- and species-specific abundance estimates and used generalized linear mixed effects models to investigate the effects of 7 spatiotemporal covariates on species-specific mean abundance estimates. Species-specific adult sex ratios, juvenile to adult ratios, and adult body masses were not widely variable among study sites. Abundance estimates varied by as much as 4-fold among years and 6-fold among sites. Humboldt’s flying squirrel abundance was temporally autocorrelated at intervals of 1 and 5 years, Townsend’s chipmunk abundance was temporally autocorrelated at intervals of 1–4 years, and western red-backed vole abundance was temporally autocorrelated at 1, 4, and 5 years. Mean fall abundance estimates were associated with elevation and climate and in some cases, canopy openness and berry-producing shrubs, but the direction of the association differed among species for some covariates. Our findings could provide additional management tools for small-mammal abundance objectives, and highlight the importance of careful covariate selection in studies using indices of small-mammal abundance.

• Publisher: Wiley,Blackwell Publishing Ltd
• Subject: Abundance / adults / Autocorrelation / Body mass / Body size / body weight / Canopies / canopy / Cascade Mountains / Cascades / climate / deer / deer mice (Peromyscus maniculatus) / Ecological effects / Elevation / Estimates / Forests / Glaucomys / Glaucomys oregonensis / habitat / Herbivores / Humboldt's flying squirrels (Glaucomys oregonensis) / Intervals / juveniles / Mammals / Management tools / mark-recapture studies / mark‐recapture / Myodes / Myodes californicus / Neotamias townsendii / Oregon / Peromyscus maniculatus / population cycle / population dynamics / Population Ecology / Sex / Shrubs / Small mammals / Species / Squirrels / Tamias / topographic slope / Townsend's chipmunks (Neotamias townsendii) / voles / western red‐backed voles (Myodes californicus) / Wildlife management