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

点击翻译按钮获取中文摘要

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.