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Polar Bear (Ursus maritimus) Habitat, Space Use,and Movements in a Seasonal Sea Ice Ecoregion

  • Author / Creator
    Sahanatien, Vicki A.M.
  • Polar bears (Ursus maritimus) are sea ice habitat specialists and climate change has affected sea ice throughout this species’ circumpolar range. The annual phenological cycle of sea ice growth and decay is a strong influence on polar bear distribution and ecology. Study of the habitat selection, movements and spatial ecology of polar bears in the seasonal sea ice ecoregion has been limited but this is where the most rapid loss of ice has occurred. In this thesis, to study movements and space use, I used satellite telemetry to collect year round (2007-2011) location data of female polar bears and ice-free season location data of male polar bears, and, satellite imagery to analyze sea ice habitat. I began with an overall assessment of the state of sea ice habitat in Foxe Basin. Using microwave satellite imagery (25 x 25 km² resolution) sea ice concentration maps were classified into four habitat quality categories and the trends (1979-2008) in fragmentation patch metrics analyzed. I found that the amount of preferred sea ice habitat declined in autumn and spring, sea ice season length decreased, and habitat fragmentation increased. The observed trends may affect polar bear movement patterns, energetics, and ultimately population trends. When on the sea ice, female polar bears were distributed in three spatial clusters that broadly coincided with the three marine water bodies, Foxe Basin, Hudson Strait and Hudson Bay. Differences in movement metrics (home range, movement rates, time on ice) were observed between clusters that may reflect sea ice habitat conditions and ocean productivity. Annual and seasonal home range fidelity were observed and the bears used two movement patterns: on-ice range residency and annual migration. High resolution (150 x 150 m) synthetic aperture radar (SAR) was tested as an information source to examine sea ice habitat structure, as described by floes and leads that were available to female polar bears during their daily movements. I found that the fine scale ice floe and lead patch density were the most important sea ice characteristics for bears when foraging on sea ice. Standard important broad scale variables, ice concentration, bathymetry and distance to land were not in the top resource selection models. I examined the terrestrial movement patterns and behaviour of female and male polar bears during the annual period of minimum ice cover. The bears remained near the coast but were segregated by sex and reproductive status. All bears moved extensively and swimming was a regular behaviour. I propose an explanatory mechanistic model for terrestrial movement patterns and behaviours during the ice free season based on external (abiotic and biotic) and internal (sex, reproductive status) factors. My research provides new analytical approaches for monitoring sea ice habitat and study of the functional relationships between bears, their prey and the sea ice ecosystem.

  • Subjects / Keywords
  • Graduation date
    2015-11
  • Type of Item
    Thesis
  • Degree
    Doctor of Philosophy
  • DOI
    https://doi.org/10.7939/R3J67975T
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
    English
  • Institution
    University of Alberta
  • Degree level
    Doctoral
  • Department
    • Department of Biological Sciences
  • Specialization
    • Ecology
  • Supervisor / co-supervisor and their department(s)
    • Andrew E. Derocher, Department of Biological Sciences, University of Alberta
  • Examining committee members and their departments
    • David Hik, Department of Biological Sciences, University of Alberta
    • Christian Haas, Department of Earth and Space Science and Engineering, York University
    • Colleen Cassady St. Claire, Department of Biological Sciences, University of Alberta
    • Ian Stirling, Department of Biological Sciences, University of Alberta
    • Philip McLoughlin, Department of Biologoy, University of Saskatchewan