Year of Award


Document Type


Degree Type

Master of Science (MS)

Degree Name

Wildlife Biology

Department or School/College

W.A. Franke College of Forestry and Conservation, Division of Biological Sciences, Montana Cooperative Wildlife Research Unit

Committee Chair

Dr. Jedediah Brodie

Commitee Members

Dr. Scott Mills, Dr. Jason Ransom, Dr. Michael Schwartz


Fisher, Pekania pennanti, Reintroduction, Survival, Prey RSFs, Washington State


University of Montana

Subject Categories

Biodiversity | Biology | Population Biology | Zoology


Increasing human impacts on biodiversity highlight the global need for ecological restoration. For many wildlife species, reintroduction is necessary to re-establish populations in parts of their historic range where they have been extirpated. Reintroduction efforts are commonly used to help restore ecosystem integrity, but are often expensive, time consuming, and unsuccessful at generating self-sustaining populations. Thus, a more complete understanding of the factors affecting restoration success is important for ensuring successful outcomes and responsible stewardship. Fishers (Pekania pennanti) are one of the most commonly reintroduced carnivores in North America, but the success of such efforts is highly variable, potentially due to differences among sites in predator and prey assemblages. We examined factors associated with differences in survival rates between reintroduced fisher populations in the southern and northern Cascade Mountains, Washington, USA. Fisher survival rates, based on radio telemetry data, were significantly lower in the North Cascades than in the South Cascades. The relative abundance of important fisher prey species was significantly lower in the North than in the South. Our findings are consistent with the survival of reintroduced fishers being affected by differences in prey assemblages between release sites, though there are many other factors that also differ between the study areas, so we cannot necessarily infer that prey differences are the causative factor. We produced prey habitat maps across the North Cascades study area based on habitat use of three important fisher prey species: snowshoe hare (Lepus americanus), Douglas squirrel (Tamiasciurus douglasii), and mountain beaver (Aplodontia rufa). Future reintroduction efforts may benefit from preliminary assessment of prey assemblages, abundance, and habitat use prior to release site selection.



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