Disease and predator ecology of white-footed mice in the upper Wabash River Basin
Abstract
Although White-footed mice (Peromyscus leucopus) have been extensively studied, data are lacking regarding the role that raccoons (Procyon lotor) play in regulating their populations in highly-fragmented, agricultural regions like the Upper Wabash River Basin (UWB). I utilized a raccoon eradication experiment to evaluate whether white-footed mouse populations exhibited a demographic response to raccoon removal. Mice were live-trapped concurrent with and 1 year after raccoon removal in 30 patches, and in 30 different control patches. A significant (F = 5.06; d.f. = 2, 56; p = 0.0096) ANCOVA model indicated that mice in the removal group had higher densities than in the control group 1 year post removal. This also was confirmed by a significant (p = 0.023) non-parametric ANCOVA test. These data support the idea that raccoons can regulate white-footed mouse populations in this landscape, and future research should explore the causal mechanisms of this relationship. Another area lacking in data is the distribution of the Baylisascaris procyonis in areas like the UWB. The raccoon is the definitive host of this organism, while the white-footed mouse is an intermediate host. Page et al. (2001b) developed models for B. procyonis infection based on landscape-scale attributes in a fragmented landscape. To evaluate the utility of those models and the landscape metrics used therein in my landscape, I sampled mice in 22 habitat patches to recreate the variables used by that study. Linear regression showed little concordance between values observed in the UWB and those predicted by previous models (p > 0.10 for all correlations). However, landscape variables such as patch size and the proportion of forest within 150m of each patch did explain significant (p<0.01) amounts of variation in patterns of B. procyonis infection when modeled independently. Differing landscape configurations likely explain the conflicting findings of these two studies. Another reason may be that factors below the landscape scale exert more influence on B. procyonis infection in this UWB, and future work should focus on identifying those factors.
Degree
M.S.
Advisors
Jr., Purdue University.
Subject Area
Forestry
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