Browsing University of Alaska Fairbanks by Subject "Mammals"
Now showing items 1-4 of 4
Habitat relationships and activity patterns of a reintroduced musk ox populationA reintroduced muskox herd in arctic Alaska was studied over a 2-year period to assess seasonal changes in activity patterns and feeding behavior. This large herd showed high calving rates and early breeding in females, characteristic of a rapidly expanding population. Age- and sex-specific differences in activity budgets reflect seasonal energy demands of the different cohorts. Comparison with high arctic muskoxen shows that characteristics of suckling behavior provide a more sensitive indicator of differences in range quality than does variation in summer activity patterns. In summer, muskoxen appear to select vegetation types on the basis of abundance and phenological stage of preferred forage species; snow characteristics strongly influence habitat selection in winter. The herd remained within a limited home range with overlapping seasonal ranges and a distinct calving area. The restricted movements and conservative activity budgets permit minimization of energy expenditure and forage requirements, allowing for a year-long existence in areas of low primary productivity.
Marine associated bird and mammal habitat use at the Five Finger Lighthouse IslandIn summer 2017 I studied the abundance and distribution of marine associated birds and mammals from four observational points on the southernmost of the Five Finger Islands (FFI). My objectives were (1) to identify the areas of highest habitat use by species of conservation concern, and (2) to use this information to make recommendations for an ecosystem-based management plan at the Five Finger Lighthouse Island (FFLI). I found higher relative abundance and higher biodiversity of both birds and marine mammals on the South and West facing sectors compared to the North and East facing sectors. I attribute this to the greater habitat complexity that comprises a near-shore reef, a mixed kelp forest, and a channel between the reef and the side of the island with the highest cliff, areas used extensively for foraging, nesting, traveling, socializing, and resting by many of the documented species. I therefore recommend avoiding development and minimizing anthropogenic disturbance on the southern and western portions of the island including the adjacent reef and channel between the reef and island. As both the FFI ecosystem and the Five Finger Lighthouse (FFL) management continue to evolve in response to changing environmental conditions and human needs, this study provides a useful baseline for future comparison. Continued study and monitoring is also recommended at this site to inform future adaptive management, document changes over time, and engage community stakeholders in science and conservation.
Modulation of ischemia- reperfusion injury in mammalian hibernators and non-hibernators: a comparative studyEvents characterized by ischemia/reperfusion (I/R), such as stroke and cardiac arrest, are among the most frequent causes of debilitating neurological injury and death worldwide. During ischemia, the brain experiences oxygen and nutrition deprivation due to lack of blood flow, and tissue damage ensues. Arctic ground squirrel (AGS; Urocitellus parryii), a hibernating species has the innate ability to survive profound decreases in blood flow (ischemia) during torpor and return of blood flow (reperfusion) during intermittent euthermic periods without any neurological deficit. However, the mechanisms by which AGS tolerate the extreme fluctuations in blood flow remain unclear. The main focus of this thesis is to investigate the modulation of I/R injury in mammalian hibernators and non-hibernators. The first study validates the microperfusion approach for studying in vitro I/R injury (oxygen glucose deprivation, OGD) modeled in acute hippocampal slices and investigates the complex interactions of glutamate-mediated excitotoxicity with acidosis-mediated acidotoxicity to understand the role of acid-sensing ion channels (ASIC1a) and pH in mediating cellular injury during OGD. Using an ischemic tolerant animal model, AGS, the second and third studies explore if hibernation season or state influences tolerance to I/R injury and tests hypotheses regarding mechanisms involving nitric oxide and superoxide radicals in mediating cellular damage during cerebral I/R. Together, this dissertation demonstrates that when OGD is combined with acidosis as occurs in vivo, acidotoxicity mediated via ASIC1a occurs but low pH abolishes NMDAR mediated excitotoxicity. This dissertation also presents evidence that AGS tolerate OGD injury independent of hibernation season and state. At the tissue level, when tissue temperature is normalized to 36°C despite ATP depletion, ionic derangement, tissue acidosis, and excitatory neurotransmitter efflux, AGS hippocampus resists OGD injury. Finally, the dissertation shows that AGS resist brain injury caused by ONOO- generated from NO or O2•− during OGD while rat brain tissue succumbs to this mechanism of injury.
Outreach and Technology Transfer on the Effectiveness of Wildlife Fences and Wildlife Crossing Structures in a Multifunctional LandscapeThis project undertook outreach and technology transfer tasks on the effectiveness of wildlife fences and wildlife crossing structures in a multifunctional landscape. The tasks accomplished included (1) publication of an article in an international peer-reviewed journal on the effectiveness of wildlife mitigation measures along U.S. Highway 93 North; (2) submitting an abstract to, presenting at, and attending the 2017 International Conference on Ecology and Transportation in Salt Lake City, Utah; and (3) updating the website and outreach material of the People’s Way Partnership (http://www.peopleswaywildlifecrossings.org/).