Keywords: ecology; natural populations; neuroendocrinology; aging; stress; Hypothalamo-Pituitary-Adrenal (HPA) Axis; demography; population regulation; maternal effects; fetal programming; epigenetics; climate change; ecosystem processes
Detailed Description: My research program has been based on three platforms, with the first providing the foundation and many of the ideas and hypotheses for the second; the third is an integration of the two. First, much of my research career has been engaged in testing general hypotheses in population and community ecology using primarily northern and temperate mammals throughout Canada, Norway, UK, and Australia. The central question here on population regulation: what are the processes that prevent unlimited growth or decline to extinction Second, the dominant, though not exclusive, focus of my research program now is into one of the key underlying mechanisms - understanding the impact and functioning of the stress axis in natural populations. The stress axis functions within the context of the factors that regulate and limit populations, and thus knowledge of the latter provide the foundation to understand how the former operates and its significance. The stress axis is one of the key neuroendocrine control mechanisms that mediate the relationship of the organism to its environment, both in terms of short-term responses to environmental changes (e.g. changes in population density, food, predators, weather, etc.) and of long-term evolutionary responses to particular ecological pressures. Thus, the axis is a vital regulator of adaptation in birds and mammals. The understanding of the functioning of the stress axis of wild species within the context of population and community processes is critical to their conservation and in ameliorating the rapid shifts in their habitat and distribution that is occurring because of global climate change. Third, I am examining how maternal effects casue epigenetic changes in offspring in wild populations of mammals that then affects population processes. Because of my knowledge of the life history of northern wild mammals, I used the comparative approach on natural animal models to test hypotheses in the natural world.
Current Research Projects - Ongoing research includes:
- Impact of Chronic Stressors on Population Processes: Individuals in all species must continually balance the conflicting demands of finding food and avoiding their predators. The direct effects of predation are obvious, but the indirect, sublethal effects of predators acting through the stress of fear may be equally severe from a population standpoint (reduced health, inhibition of reproduction, reduced growth). We have demonstrated the critical importance of high predation risk in causing negative demographic and physiological impacts acting through stress in Yukon snowshoe hares, Arctic ground squirrels, and song sparrows. A central thrust of my current research now is to examine the epigenetic effects of predator-induced stress as a key contributor to the demography of 10-year snowshoe hare cycle in the YUKON. .
- The role of dehydroepiandrosterone (DHEA) on the life history of mammals, particularly with respect to its role in being the basis for spacing behavior such as territoriality during the nonbreeding season.
- The evolution of the stress axis in mammals and the role of life history
- The impact of environmental stressors on maternal programming through epigenetic changes and ultimately on population changes.
Reseach Field Sites
- Arctic Institute Base, Kluane Lake Research Base, Yukon
- Southern Ontario
- Kananaskis, Alberta
Hippocampal Cells, Neurons
Procedures: Immunohistochemistry, Microarrays, RIA, RT-PCR, Enzyme Immunoassay System
Analytical Balances, Benchtop Centrifuge, Confocal Microscope, Cryostat, Departmental Beta and Gamma Counters, , Deconvolution Fluorescence Microscope, Dissecting Microscope, Electrophysiology Rig, Fluorescence Microscope, HPLC, Infusion Apparatus, Low- and High Speed Centrifuge, Low and ultralow Freezers, Micropipette Puller, Motorized Micromanipulators, Plate Reader, Real-Time/ Thermocycler, Stirrer/Hot Plate, Vibratome, Water Baths
Sophia Lavergne (PhD)
Brendan Delehanty (PostDoc)
Phoebe Edards (MSc)
Outside the Department of Physiology:
Ashley Monks Psychology, UTM
Patrick McGowan CSB, Biological Sciences/UofT Scarborough
Charles Krebs Zoology, UBC
Stan Boutin Biological Sciences, UBC
Andrew McAdam Biological Sciences, Guelph
Adrian Bradley School of Biomedical Sciences, Brisbane, Queensland
Harry Andreassen Hedmark University College, Evenstad, Norway
Dennis Murray Trent University
Committee member/officer of national/international scientific organizations
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