Nitrogen, plant and microbial community dynamics in sites recovering from wildfire and surface mining in the Athabasca Oil Sands Region

  • Author / Creator
    Martin, Jillian M
  • For reclamation to be considered successful, an ecosystem must be self-sustaining and have a recovery trajectory that falls within the range of variability of ecosystem function in natural ecosystems. This study compared the soil nitrogen availability, soil microbial community, and understory vegetation following natural (wildfire) disturbance and anthropogenic (reclamation) disturbance, in the Athabasca Oil Sands Region. Eleven natural (aged 2-131 years) and five reclaimed sites (aged 4-27 years) from upland aspen/ spruce stands were compared. Soil available nitrogen was assessed in-situ with ionic resin capsules and potentially mineralizable nitrogen was determined by anaerobic incubation. Microbial respiration was measured as an indicator of activity, and microbial community fingerprints and biomass were determined using phospholipid fatty acid analysis. The vegetation was characterized by canopy cover, plant functional group, and composition survey at the genus level. No significant difference for nitrate or ammonium availability was observed at the site level; however, there were trends with time and canopy cover. The potentially mineralizable nitrogen trend with time was much higher on the natural sites than the reclaimed sites. Non-metric multi-dimensional scaling ordinations of the soil microbial community and understory vegetation composition revealed that reclaimed and unburned sites had significantly different communities with a low degree of similarity. The burned sites (aged 2-39 years) were more variable and bridged the difference between the reclaimed and mature sites. The microbial community of the oldest reclaimed sites were most similar to naturally disturbed sites. This work shows that young naturally disturbed sites may be a more relevant comparison when evaluating reclamation trajectory than mature stands.

  • Subjects / Keywords
  • Graduation date
    Spring 2016
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • 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.