The Role of Stress in Natural Populations

我的研究计划的目标是了解压力在自然界中所起的作用，无论是在个体影响方面还是在群体后果方面。应激轴是调节生物体与环境之间关系的关键生理系统之一，它既在日常基础上影响生理和行为，也在响应急性和慢性环境应激(无论是生物还是非生物的)。轴和相关组件是长期进化适应特定生态挑战的核心。因此，轴是神经内分泌途径的关键部分，它整合了这些挑战，同时在生活史决定繁殖、生长和将能量分配到存储中发挥关键作用。我的实验室使用内分泌学、动物生理学和新陈代谢、表观遗传学、种群生态学和行为操纵学等工具来研究应激轴。我们的主要研究模型是加拿大各地的野生哺乳动物。我们在未来五年的目标主要集中在三个主要领域：*a)通过压力诱导的表观遗传变化进行孕产妇方案规划，从而产生长期的人口影响。雪鞋野兔和小型哺乳动物种群循环的原因尚不清楚，但这些哺乳动物分别是北方森林和温带/北极生态系统中的关键物种。我们将研究捕食者恐惧对野兔造成的慢性压力以及小型哺乳动物的社会密度效应所起的作用。我们的假设是，这些因素会导致生殖雌性产生母性压力，然后对后代进行编程，影响她们的健康，最终影响人口统计学。*b)气候变化和慢性压力。我们将研究冬季条件的变化如何影响雪鞋兔，包括它们的食物资源和捕食者。*c)肾上腺类固醇和生活史过程：这些类固醇的进化不仅是为了应对环境应激源，也是为了应对独特的生态问题，如非繁殖季节的领土和冬眠的准备。我们将研究肾上腺雄激素及其前体作为冬季保护食物资源的间隔行为的潜在机制的作用。*总体而言，拟议的研究将为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帮助。一支由学生和博士后实习生组成的团队对这一努力至关重要。************

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