Rodent response to harvesting woody biomass for bioenergy production

Harvest of low value trees and logging residues for bioenergy reduces downed wood post-harvest with potential indirect negative effects on ground-dwelling wildlife such as rodents. We assessed the influence of woody biomass harvests on rodent abundances using an operational-scale, randomized complete block experimental design study in North Carolina (4 blocks) and Georgia, USA (4 blocks). Each block contained 6 treatments randomly applied to a clearcut harvest, that varied by volume of woody biomass retained, and that represented existing woody biomass harvest recommendations. We livetrapped rodents in 2011–2013, calculated the minimum number known alive for each captured species, and used the value as an index of abundance. We compared abundance of the 3 most commonly captured species (deer mice [Peromyscus spp.], house mouse [Mus musculus], and hispid cotton rat [Sigmodon hispidus]) among treatments with generalized linear mixed effects models. We assessed relationships among species’ abundance and measurements of downed woody debris and vegetation in each treatment unit using linear regression. Although abundance varied among treatments in some cases, we did not detect consistent relationships between woody biomass retention treatments and abundance. Volume of downed woody debris in the treatment unit negatively influenced house mice but had varying influences on deer mice across years. Downed woody debris groundcover negatively affected deer mice in North Carolina in 2012. Litter groundcover negatively influenced deer mice and hispid cotton rats, whereas grass groundcover positively influenced the hispid cotton rat. The lack of consistent relationships between rodent abundance and volume of retained woody debris suggests that the rodent species captured in this study were not affected by current efficiencies of operational woody biomass harvests in southeastern United States loblolly pine (Pinus taeda) plantations. However, focal species were habitat generalists and less common species may have greater sensitivity to biomass harvests. © 2017 The Wildlife Society.