Integrative Assessment Tools for Monitoring Muskox Health and Vulnerability in a Changing Arctic

北极的气候变化正在影响土著人民的生计、健康和生活方式，以及他们赖以生存的动物和他们的传统文化。最近的气候变暖导致了南方动物及其病原体在北方范围的扩大，改变了宿主与寄生虫的相互作用，并出现了疾病。此外，北极地区越来越多的人类足迹(矿产和天然气勘探/开发、新的航道、更多的研究活动和旅游业)正在不可逆转地改变生态系统，加剧气候对野生动物的压力。 自2008年以来，我的团队一直在调查加拿大北极群岛麝牛的新出现的疾病和死亡事件。这些事件包括：(1)与大黄粉虫有关的多起严重、广泛的死亡事件，这是一种以前在麝牛身上没有报告的细菌，也没有在北极地区报告；(2)两种线虫在北极群岛上入侵并迅速扩大活动范围，以及(3)2013年在班克斯岛的麝牛身上出现新的严重脓胸或‘orf’样病变。与此同时，最近的调查和轶事证据表明，在这些地区中的一些地区，麝香的数量已经显著下降。总而言之，这些事件表明生态条件和压力源的变化最终导致疾病和死亡，并对人口水平产生影响。 这项研究的总体目标是开发和测试麝牛健康评估的综合措施，这些措施可以通过基于社区的监测来实施，用于了解和监测麝牛对环境变化的敏感性。 之前，我开发了几种工具来监测北极有蹄类动物的疾病。在接下来的五年里，我将在这一健康评估工具库中添加头发皮质类固醇。在生长过程中合并到毛发或羽毛中的皮质类固醇可以作为中长期应激的综合、追溯、生物标记和生存的预期标记。灰熊的毛发皮质醇在前一年夏天吃鲑鱼受到限制时会升高，秋季麻雀羽毛中皮质类固醇浓度的升高预示着越冬死亡。麝牛有两种皮毛，它们可能会提供不同的压力时间衡量标准。每年夏天生长并在第二年春天完全脱落的绒毛可能是一种压力的年度指标。警员的毛发全年生长，并持续多年，应该反映出几年来累积的压力。我将首先建立和验证测量绒毛和护发皮质类固醇的方法(Obj.1)，然后使用三个不同种群轨迹上的麝香种群(增加、减少和最近下降)，每年采样4年，测试这与不同的短期和长期个人健康指数(Obj.2)，包括身体大小和状况、繁殖力和传染病的多样性和丰富性。然后，使用这些相同的麝香种群，我将测试齐维特和护发皮质类固醇以及其他健康指数如何随着几个关键的天气、气候和栖息地因素(Obj.3)。这项工作将为三个麝香种群建立健康和传染病多样性的综合基线，测试哪些个体或健康指数组合最能反映种群的整体健康，并评估气候和栖息地驱动因素与健康之间的关系。最终，这将产生对疾病生态学的新见解，并将制定跟踪个人和群体健康并了解麝牛对自然和人为环境变化的适应能力的方法和综合措施。

Climate change in the Arctic is impacting the livelihoods, health, and lifestyles of aboriginal peoples, and the survival of animals on which they depend for food and their traditional cultures. Recent warming has led to northern range expansion of southern animals and their pathogens, altered host-parasite interactions, and emergence of disease. Further, an increasing human footprint in the Arctic (mineral and gas exploration/development, new shipping routes, increased research activities and tourism) is irreversibly altering ecosystems and exacerbating climate-mediated stress for wildlife. Since 2008, my group has been investigating emerging diseases and mortality events in muskoxen in the Canadian Arctic archipelago. These include (i) multiple severe, widespread mortality events associated with Erysipelothrix rhusiopathiae, a bacteria not previously reported in muskoxen, nor in the Arctic, (ii) invasion and rapid range expansion of two nematode lungworms on the Arctic archipelago, and, (iii) new in 2013, severe ecthyma, or ‘orf’ like lesions in muskoxen on Banks Island. Concurrently, recent surveys and anecdotal evidence indicate that muskox numbers have declined significantly in some of these regions. Together, these events suggest changes in ecological conditions and stressors culminating in disease and mortality with population level impacts. The overall goal of this research is to develop and test integrative measures for health assessment of muskoxen that can be implemented through community-based monitoring and used to understand and monitor the sensitivity of muskoxen to environmental changes. Previously, I developed several tools for disease surveillance in Arctic ungulates. Through the next five years I will add hair corticosteroids to this arsenal of health assessment tools. Corticosteroids incorporated into hair or feathers during growth can serve as integrated, retrospective, biomarkers of medium to long term stress and prospective markers of survival. Hair cortisol in grizzly bears is elevated when access to salmon the previous summer was limited and elevated corticosteroids concentrations in sparrow feathers in the fall predict over-wintering mortality. Muskoxen have two types of fur that may provide different temporal measures of stress. The qiviut (undercoat) growing each summer and fully shed the following spring is a probable annual indicator of stress. Guard hairs growing throughout the year and persisting over years should reflect cumulative stress over a period of several years. I will first establish and validate methods for measuring qiviut and guard hair corticosteroids (Obj.1), and then using three muskox populations on different population trajectories (increasing, decreasing, and recently declined), sampled annually for 4 years, test the relationship of this to different short and long term indices of individual health (Obj. 2), including body size and condition, fecundity, and infectious disease diversity and abundance. Then, using these same muskox populations, I will test how qiviut and guard hair corticosteroids, and other health indices, vary with several key weather, climate, and habitat factors (Obj. 3). This work will establish comprehensive baselines of health and diversity of infectious disease for three muskox populations, test which individual or combinations of health indices best reflect the overall health of a population, and evaluate the relationship between climate and habitat drivers and health. Ultimately this will generate new insights into disease ecology and will develop methodologies and integrative measures for tracking individual and population health and understanding the resilience of muskoxen to natural and anthropogenic environmental change.