Hypothesized reasons for the decline of many woodrat populations in the eastern United States include parasitism by raccoon roundworm (Baylisascaris procyonis), hard mast shortages, owl predation, and reductions in suitable structure (e.g., rock crevices) for nest construction. We investigated whether abundance and apparent survival of eastern woodrats (Neotoma floridana) within a successfully reintroduced metapopulation in southern Illinois could be predicted by factors underlying these hypothesized reasons for woodrat declines. We analyzed capture histories of 205 eastern woodrats from 8 rock outcrop sites in summers of 2013 and 2014 to estimate local population size and apparent survival. We then used repeated-measures models to test how woodrat abundance or apparent survival is associated with availability of mast trees measured by basal area, owl abundance measured by callback surveys, risk of raccoon roundworm measured by visual surveys and fecal floatation of raccoon (Procyon lotor) latrines, and crevice availability measured by visual surveys around trap stations. Mean monthly estimated woodrat abundance at sites ranged from 0.78 to 21.58 in 2013 and 0.48 to 18.08 in 2014, while monthly apparent survival ranged from 0.00 to 0.76 during the summers and 0.05 to 0.90 during the trapping intersession. Crevice availability was positively associated with both abundance and apparent survival of woodrats. Contrary to the hypothesis that owls reduce woodrat populations, woodrat abundance was positively associated with owl abundance across sites. No raccoon roundworm was found at any site. We conclude that crevice availability was the best predictor of woodrat population success in our study area, while owl abundance may be a proxy for other habitat variables or a response to woodrat abundance. Our findings suggest that increasing availability of nesting structure along outcrops, through forestry practices or providing artificial nesting structures, could benefit woodrat survival and abundance.
|Original language||English (US)|
|Title of host publication||Midwest Fish and Wildlife Conference 2020|
|State||Published - 2020|