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  • Peter Haswell
    University of California, Davis
  • Andres M. Lopez-Perez
    California Department of Fish and Wildlife
  • Deana L. Clifford
    University of California, Davis
  • Janet E. Foley
    University of California, Davis
Greater understanding of intraguild dynamics in rodent communities and of how house mice, Mus musculus, interact with wild sympatric rodents is needed. House mice can be a particularly virulent invasive species, presenting a potential threat to native biodiversity. In the Mojave Desert, western harvest mice, Reithrodontomys megalotis and the endangered Amargosa vole, Microtus californicus scirpensis, inhabit a fragmented desert wetland ecosystem. The Amargosa vole relies heavily on bulrush, Schoenoplectus americanus, for food, as well as thermal and predator refuge. We used two species occupancy models and estimated activity pattern overlap to explore spatial and temporal interactions within this rodent guild. For each species pairing, we compared the relative performance of a series of candidate occupancy models, with the most supported model structures and components distinguished by AICc and AICc weight. We found that voles reduced the detectability of western harvest mice and house mice, but did not spatially exclude them. Our findings also suggested that voles were more detectable in bulrush stands as bulrush cover increased, whereas house mice and western harvest mice were negatively associated with bulrush cover. House mice and western harvest mice had high activity pattern overlap, (Δ4 0.89, 95% CI = 0.85-0.96), which was greater with each other than with voles (Δ4 0.69, 95% CI = 0.57-0.75 and Δ4 0.66, 95% CI = 0.49-0.70, respectively). House mice were also more detectable in the presence of western harvest mice, suggesting niche overlap or an attraction to them. Our observations suggest that, during the summer months, Amargosa voles could be a limiting factor on the behaviour and/or population densities of smaller rodent species in bulrush habitat. Drought exacerbated habitat changes may have contributed to house mouse expansion and vole decline in the region. While a deeper understanding of trophic dynamics is required, continued efforts to preserve the endangered Amargosa vole and it's habitat may also help mitigate any potential harm caused by free-living house mice in these desert wetlands.
Original languageEnglish
Article numbere00267
JournalFood Webs
Early online date9 Dec 2022
Publication statusPublished - 1 Mar 2023
Externally publishedYes
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