Date of Award

Winter 2015

Project Type


Program or Major

Natural Resources and Environmental Studies

Degree Name

Master of Science

First Advisor

Rebecca Rowe

Second Advisor

Richard Smith

Third Advisor

Erik Hobbie


Arctic tundra is being affected by a rapidly warming climate, which is accompanied by shifts in plant community composition and structure. Shrub expansion, a predominant consequence of this warming, is linked with changes in nutrient cycling and has direct implications to global change biology. Habitats are being altered across the landscape, with subsequent changes to arctic faunal communities. While herbivory has been noted as important in contributing to plant community composition in the arctic, with the potential to both exacerbate and mitigate shifts toward shrub-dominated tundra landscapes, little research has been conducted on herbivore dynamics. Microtine rodents (i.e., voles and lemmings) are the dominant vertebrate herbivores in the Alaskan Arctic. Through mark-recapture surveys and analysis of individual and population-level space use, I studied the population ecology of the microtine community to better establish the role of these small mammals in this rapidly changing region. Co-dominant species, the singing vole and the tundra vole, exhibit limited ecological overlap, preferring different habitat types and food sources. Results from surveys confirmed previously documented spatial segregation of the two co-dominant species by habitat along a moisture gradient. Interpretation of results suggest that extrinsic factors, possibly relating to stochastic winter climatic events impact these co-dominant species differently. Over the duration of the study, the singing vole was locally more abundant despite preferring regionally less available habitat, which suggests that its habitat may buffer singing vole populations from the affects of stochastic events. Analysis of space use by the singing vole indicated that both intraspecific interaction and microhabitat affinities played a role in local scale space use, which, through selective herbivory and concentrated deposition of nutrients, has implications on its role in structuring tundra plant communities. Further research on these species over a longer duration will classify the impact of extrinsic factors on population dynamics and the impact of resource use on local and landscape level changes to the tundra ecosystem.