Spatial Patterns of Mercury Accumulation in Wolverine (Gulo gulo) Across the Western Canadian Arctic: Landscape, Climate and Dietary Factors

Abstract

Mercury contamination in Arctic aquatic biota has been monitored for decades. Little information exists on mercury concentrations and drivers in terrestrial Arctic carnivores. I assessed spatial patterns of mercury concentrations in wolverine (Gulo gulo) and the relationship with environmental and dietary factors across the western Canadian Arctic.Environmental variables were measured at two scales: collection location and around a 150 km buffer. This buffer size was selected from correlation analysis between hydrogen stable isotopes in precipitation and hair from 80 individuals. Mean mercury concentrations in wolverines varied geographically in decreasing order Northwest Territories > Nunavut > Yukon. Regression models illustrated that nitrogen stable isotope ratios (diet), soil organic carbon, % cover of wet area, % of perennial snow-ice, and distance to the Arctic coast explained best this variation. Diet was the main driver of mercury concentrations in wolverines with contributions from landscape characteristics near Arctic coastal areas. iii Acknowledgements I acknowledge the support of the Natural Sciences and Engineering Research Council of Canada (NSERC) and Environment and Climate Change Canada (ECCC). I'm grateful for their funding provided for this project. The wolverine dataset used in this thesis was made possible through collaboration between the National Wildlife Research Centre -ECCC, territorial wildlife biologists and local trappers. My thanks and appreciation to Christine McClelland, Christine Rodford and Nicolas Pelletier for the laboratory analyses of wolverine tissue. Thank you to the local trappers who participated in the carcass collection programs in the Yukon, the Northwest Territories and Nunavut. I especially express thanks to the wildlife biologists who conducted the wolverine biomonitoring programs in the Yukon (Tom Jung and Piia Kukka), the Northwest Territories (Steve Baryluk and Marsha Branigan) and Nunavut (Malik Awan). Thank you to Garth Mowat (British Columbia Government) for the hair samples from wolverine in British Columbia. Thanks to William Harrower (University of British Columbia) for the nitrogen and carbon isotopic samples. I greatly appreciate the feedback provided by all the collaborators during meetings and electronic communications. I look forward to continuing to share the research findings with them and the local communities. I'm thankful to Ashu Dastoor and Andrei Ryjkov, from ECCC, for their contribution to meetings and for providing the atmospheric mercury deposition models used for this research. My deepest appreciation to my supervisors Dr. John Chételat and Dr. Murray Richardson for the opportunity to conduct the research with them and for their patience iv and support throughout Covid-19. Thank you to Murray Richardson for his guidance, honest feedback, and support with the data analysis. I'd like to thank John Chételat, for the funding and the remarkable coordination of this project. Also, I want to express my gratitude for all the time, attention, opportu...