Effects of Amur honeysuckle invasion and removal on white‐footed mice

Abstract

ABSTRACTAmur honeysuckle (Lonicera maackii) is an exotic shrub that has invaded many forests throughout the United States. Although effects on native plants and birds have been documented, little is known about the influence of Amur honeysuckle on small mammals. We examined the short‐term effects of removing Amur honeysuckle and other exotic shrubs on the abundance of white‐footed mice (Peromyscus leucopus; a generalist rodent species found throughout North America), in 6 hardwood forests of Indiana. We cut and removed exotic shrubs from treatment (removal) areas in fall and winter of 2010–2011. We used mark‐release‐recapture (MRR) methods by trapping mice for 6 nights in the summer of 2010 and 4 nights in the fall of 2010 (before exotic shrub removals), and again during the summer and fall of 2011 (after removals). For both trapping seasons, mean abundance of mice increased from 2010 to 2011 in both removal and reference areas, but the magnitude of increase within removal areas was substantially greater (permutation P ≤ 0.05 for removal areas). For the feasible subset of mice, we calculated mean squared distance (MSD) as an index of space use and investigated how environmental variables influenced space use by individuals. For mice captured in the summer, percent cover of leaf litter was the most important predictor (relative variable importance = 0.94) of MSD, whereas canopy cover and mouse abundance were the most important predictors of MSD for mice captured in the fall (canopy cover relative variable importance = 0.71, mouse abundance relative variable importance = 0.74). Our results indicate that management efforts to control the spread of Amur honeysuckle and other exotic shrubs may lead to short‐term increases in the abundance of generalist rodents such as white‐footed mice. Furthermore, factors such as leaf litter cover, canopy cover, and abundance may influence space use by individual mice within invaded habitats. © 2014 The Wildlife Society.