Status of Eastern Woodrats in Isolated Remnant Populations Following Genetic Augmentation and Habitat Disturbance

In Illinois, Neotoma floridana (Eastern Woodrat) experienced range reductions and population bottlenecking over the past century. During the period 2004-2005, the isolated remnant populations along the Mississippi bluffs in southwestern Illinois were genetically augmented with 47 Eastern Woodrats from Arkansas and Missouri, resulting in 40% admixture within the largest population. In 2009, a strong windstorm created canopy gaps and woody debris throughout this area, potentially improving habitat for Eastern Woodrats. We investigated the status of Eastern Woodrat populations in southwestern Illinois by livetrapping remnant populations and conducting sign surveys from 2011 to 2015. We captured 263 Eastern Woodrats; mean trapping success was 62.5% higher than trapping during the 1990s, and the number of individuals captured per trap-night was 3-6 times higher than trapping events during the previous 18 years (all P <0.001). We also located sign of Eastern Woodrat 8.9 km east of the remnant populations. We recommend further genetic monitoring to evaluate whether population increases are coupled with increased admixture and recommend forest-management actions that create habitat disturbance and resultant piles of woody debris that increase woodrat habitat quality.