The Role of Stress in Natural Populations

点击翻译按钮获取中文摘要

The objective of my research program is to understand the role that stress plays in nature, both in terms of individual effects and of population consequences. The stress axis is one of the key physiological systems that mediates the relationship of an organism with its environment, acting both on a daily basis to affect physiology and behavior and in response to acute and chronic environmental stressors (either biotic or abiotic). The axis and related components are central to long-term evolutionary adaptations to particular ecological challenges. Thus, the axis is a key part of the neuroendocrine pathway that integrates these challenges while at the same time playing a critical role in life history decisions to reproduce, to grow, and to allocate energy into storage. My lab uses the tools of endocrinology, animal physiology and metabolism, epigenetics, population ecology, and behavioral manipulations to study the stress axis. Our primary research models are wild mammals throughout Canada. Our goals over the next five years focus on three main areas: a) Maternal programming through stress-induced epigenetic changes resulting in long-term population effects. The cause of population cycles in snowshoe hares and small mammals remains unknown, yet these mammals are keystone species in the boreal forest and temperate/arctic ecosystems, respectively. We will examine the role of chronic stress caused by predator fear in hares and by social density effects in small mammals. Our hypothesis is that these factors cause maternal stress in reproducing females that then programs their offspring, affects their fitness, and ultimately, affects population demography. b) Climate Change and Chronic stress. We will examine how changes in winter conditions impact the snowshoe hare, both with respect to their food resources and predators. c) Adrenal steroids and life history processes: These steroids have evolved not only to deal with environmental stressors, but also with unique ecological problems such as nonbreeding season territoriality and preparation for hibernation. We will examine the role of adrenal androgens and their precursors as the underlying mechanism motivating spacing behavior to protect food resources in winter. Overall, the proposed research will make major contributions to understanding the role of stress in nature that will be both fundamental and aid in the conservation of wild mammals and birds. A team of students and postdoctoral trainees are essential to this endeavour.