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dc.contributor.authorColtrane, Jessica A.
dc.date.accessioned2018-08-07T18:44:01Z
dc.date.available2018-08-07T18:44:01Z
dc.date.issued2012
dc.identifier.urihttp://hdl.handle.net/11122/9120
dc.descriptionThesis (Ph.D.) University of Alaska Fairbanks, 2012
dc.description.abstractUnderstanding the ecology and physiology of wildlife is paramount to conservation and management of species. North American porcupines (Erethizon dorsatum) are mammalian herbivores that occupy a diverse array of habitats across a broad geographical range. However, few studies have explored the ecology and physiology of porcupines. I used captive and free ranging porcupines to 1) identify the physiological abilities that enable them to survive on low quality winter forage when thermoregulatory demands are high, 2) determine responses of porcupines to winter conditions, and 3) determine how winter conditions influence habitat selection and home range size at the northern limits of their range. My research revealed that the persistence of porcupines at the northern limits of their range is due to plasticity of food intake, as well as physiological tolerance of low-quality diets and low ambient temperatures. Captive porcupines gained mass when high quality diets were available. However, porcupines decreased their dry matter intake throughout winter, indicating a seasonal decrease in metabolic rate. Low requirements for energy and nitrogen minimized the loss of body mass when intakes were low, while plant toxins increased urinary losses of energy and nitrogen. Free-ranging porcupines conserved lean body mass in winter by catabolizing fat stores. Proportional fat loss was correlated positively with total fat mass at the start of winter. Fat losses were minimized by lowering rates of energy expenditure. Water turnovers were slow in wild porcupines and body temperatures were not reduced to save energy. In order to survive winter on a low quality diet of white spruce (Picea glauca ) needles and cambium and paper birch (Betula papyrifera ) cambium, porcupines maintained large home ranges comprised primarily of mixed conifer/hardwood forests. Occupying a mixed forest habitat allowed porcupine to switch their diet between two forage tree species, potentially alleviating saturated detoxification pathways. Overall, porcupines possess the physiological abilities of a specialist herbivore during winter; however, they rely on abundant high quality summer forages to replenish their stores of fat and protein for reproduction and survival in the subsequent winter.
dc.subjectPhysiology
dc.subjectEcology
dc.titleEcological And Physiological Adaptations Of The Porcupine To Winter Alaska
dc.typeThesis
dc.type.degreephd
dc.identifier.departmentWildlife Program
dc.contributor.chairBarboza, Perry
dc.contributor.chairSpalinger, Donald E.
dc.contributor.committeeFarley, Sean
dc.contributor.committeeBarnes, Brian M.
refterms.dateFOA2020-03-05T17:15:06Z


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