The Role of Stress in Natural Populations

我的研究项目的目的是了解压力在自然界中所扮演的角色，无论是从个体影响还是群体影响的角度来看。应激轴是调节生物体与其环境关系的关键生理系统之一，在日常基础上影响生理和行为，并对急性和慢性环境应激源（生物或非生物）做出反应。轴和相关组件是长期进化适应特定生态挑战的核心。因此，该轴是神经内分泌通路的关键部分，它整合了这些挑战，同时在生活史决策中发挥关键作用，以繁殖，生长和分配能量储存。我的实验室使用内分泌学、动物生理学和代谢学、表观遗传学、种群生态学和行为操纵等工具来研究压力轴。我们的主要研究对象是加拿大各地的野生哺乳动物。我们在未来五年的目标集中在三个主要领域：***a)通过压力诱导的表观遗传变化导致的长期人口影响的产妇规划。雪鞋兔和小型哺乳动物种群周期的原因尚不清楚，但这些哺乳动物分别是北方森林和温带/北极生态系统的关键物种。我们将研究由野兔对捕食者的恐惧和小型哺乳动物的社会密度效应引起的慢性压力的作用。我们的假设是，这些因素在繁殖雌性时引起母亲的压力，然后对后代进行编程，影响它们的健康，最终影响人口统计学。***b)气候变化与慢性应激。我们将研究冬季条件的变化如何影响雪靴兔，包括它们的食物资源和捕食者。***c)肾上腺激素与生活史过程：肾上腺激素的进化不仅是为了应对环境压力，而且还解决了非繁殖期的领土和冬眠准备等独特的生态问题。我们将研究肾上腺雄激素及其前体作为激励间隔行为以保护冬季食物资源的潜在机制的作用。***总的来说，拟议的研究将对理解压力在自然界中的作用做出重大贡献，这将是保护野生哺乳动物和鸟类的基础和援助。一个由学生和博士后学员组成的团队对这项工作至关重要。************

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. ************