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Wildfires and climate change: their effects on moose (Alces alces) and white-tailed deer (Odocoileus virginianus) winter habitat in the boreal mixedwoods of Alberta, Canada

  • Author / Creator
    Routh, Melanie R
  • Understanding how species respond to wildfires and climate change is fundamental for land use management and biodiversity conservation. Wildfires provide generalist ungulates, such as moose (Alces alces) and white-tailed deer (Odocoileus virginianus), with high quantity and quality of winter browse. Climate change, however, is expected to reduce winter severity by creating milder winter conditions and increasing winter food availability for ungulates through changes in vegetation and fire regime.
    The goal of this thesis was to investigate the effects of wildfires and climate change on moose and white-tailed deer winter forage and habitat quality in the boreal mixedwoods of northeastern Alberta, Canada. First, I examined the changes in winter browse richness, evenness, abundance, and community composition, as well as their use (browse levels) by moose and white-tailed deer, in post-wildfire upland and lowland forests over a 150-year post-wildfire period. In the summer of 2019, I collected vegetation and ungulate browsing data from 164 upland and lowland forest sites in northeastern Alberta. I used analysis of covariance (ANCOVA) and ordinal logistic regression to examine changes in browse measures. Second, I assessed the long-term effects of climate-induced wildfires and vegetation change on the distribution and quality of moose and white-tailed deer winter habitat in the boreal mixedwoods. I developed a winter habitat quality model for moose and white-tailed deer based on predicted changes in vegetation (i.e., static and fire-mediated) and fire regime (i.e., constrained and unconstrained) under an RCP 8.5 climate scenario in the 2020s, 2050s and 2080s.
    Species richness and evenness peaked at both 10 – 25 years and 90 years post-wildfire in mixedwood forests, as a result of fluctuations in preferred and highly palatable browse species, while browse abundance remained constant. Black spruce and lowland forests had similar species richness, evenness, and abundance over the 150-year chronosequence. Browse abundance in lowland forests was higher than mixedwood forests, but consisted of low palatable browse. Therefore, wildfires in boreal mixedwoods provided higher foraging availability for ungulates in upland forests for far longer than reported in other boreal forests, whereas wildfires in lowland forests do not recruit preferred winter browse species consumed by ungulates. In the absence of vegetation change, moose and white-tailed deer winter habitat is projected to remain similar to baseline conditions; thus, climate-induced wildfires will continue to provide high amounts of winter forage resulting in higher moose populations and continuous expansion of white-tailed deer populations in northeastern Alberta. However, the expansion of deciduous forests in the boreal mixedwoods in the 2050s is projected to decrease moose and white-tailed deer winter habitat quality. Deciduous forests will further provide high quantity and quality forage, but the absence of coniferous cover will result in higher wolf predation risk for moose and white-tailed deer. Finally, the transition between deciduous and mixedwood forests to grasslands in the 2080s is projected to significantly reduce winter habitat quality as moose and white-tailed deer do not have the capacity to incorporate high amount of grasses, sedges and forbs in their winter diets.

  • Subjects / Keywords
  • Graduation date
    Fall 2021
  • Type of Item
    Thesis
  • Degree
    Master of Science
  • DOI
    https://doi.org/10.7939/r3-dt88-py37
  • 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.