The role of stress in natural populations

点击翻译按钮获取中文摘要

One of the fundamental realities of existence is the need to cope with stress. It impacts us all daily, can compromise health, increase the rates of mortality, and can accelerate the rate of aging. Animals in nature may be similarly affected, though they are exquisitely adapted to deal with many stressors. The stress axis is a pivotal part of the neuroendocrine system that integrates environmental change and through which life history decisions to reproduce, to grow, or to put energy into storage are implemented. One of the most vigorous areas of research today is the field of neuroscience and particularly how stress impacts the brain and body. Virtually all this research rests on a foundation of the laboratory rat and mouse models, yet in nature there are many solutions to the problem of existence. The objective of my research program is to bring to bear laboratory findings on the role of stress to help to understand the adaptations that animals in real world have in coping with stressful situations, what happens when these are insufficient (i.e. when chronic natural stressors negatively impact physiology, reproduction, brain organization, and demography through maternal effects), and how rapidly changes in the stress response can evolve. Thus though my findings may also have relevance to the human condition, my primary motivation is to understand the role of the stress axis in equipping animals for life in the natural world and how stressors modify their response. This is particularly relevant in the north, given the rapid changes occurring there because of global warming. My research takes place throughout Canada, including the Yukon, and builds on my extensive experience with wild mammals. It targets five key areas 1) the role of the chronic stress on maternal programming and epigenetic changes in the stress axis; 2) the impact of stress on population demography; 3) the impact of stress axis on reproductive success; 4) the role of the adrenals in life history processes associated with winter survival (spacing behavior and hibernation); and 5) the evolution of the stress axis.