An Investigation of Potential Weed Management Practices and Multivariate Assessment Parameters for Alberta's Oil Sands Reclamation Efforts

  • Author / Creator
    deBortoli, Leah A.
  • Reclamation efforts that promote the re-establishment of native tree and plant communities subsequent of large-scale oil sands mining land disturbances are crucial in restoring natural ecosystems. It is important that reclamation procedures capable of facilitating the establishment of native species be identified and put into practice. The objective of the first study was to determine plant community development and aspen seedling establishment in response to different combinations of coversoil types and experimental plant establishment treatments on an oil sands overburden waste area. Eighteen field plots, established in 2014, were re-monitored annually to compare plant community development and trembling aspen seedling density on 3 coversoil types (forest floor-mineral mix [FFMM], transitional, peat-mineral mix [PMM]) with 4 plant establishment treatments (seeding native species, weeding undesirable weeds, seeding & weeding, control). Coversoil type was found to be a dominant plant community driver, with FFMM and transitional soils showing higher species richness, diversity, and total vegetation cover than PMM, while PMM supported greater aspen seedling densities. Minimal weed establishment on PMM coversoils resulted in weeding treatments having a lesser effect on plant community development; however, trembling aspen seedling densities were found to have increased. Weeding on FFMM and Transitional did not result in the significant increase of native forb presence. Instead, the decrease in introduced weed species prompted an increase in graminoid cover, particularly Calamagrostis canadensis on FFMM. In addition to the refinement of reclamation procedures, we must work towards developing an effective evaluation framework in order to track ecosystem recovery progress. To date, no official standards, nor suitable criteria and indicators have been established to thoroughly assess and certify reclamation sites. As such, the objective of the second study was to explore the use of multivariate datasets as parameters within a rudimentary ecosystem function assessment framework. Natural reference soil samples and reclamation coversoil samples corresponding to the aforementioned field plots were collected in 2016 following vegetation surveys and in-field bioavailable nutrient profiling. Following a two week laboratory incubation period, soil samples were used to determine microbial function via community level physiological profiling (CLPP). Through the use of non-metric multidimensional scaling ordination analyses, similarities and dissimilarities were determine for bioavailable nutrient profiles, microbial function, and plant community composition parameters between coversoils and natural soils. Ordination analyses were also completed to determine similarities between weeding and control plots on coversoils. As with the first study, coversoils/soils were the dominant drivers of dissimilarities, while weeding treatments did not significantly change bioavailable nutrient profiles or microbial function. Overall, the use of multivariate analyses was able to provide additional insight into the aboveground and belowground recovery on reclamation sites, suggesting that this method of assessment, with further research, holds potential.

  • Subjects / Keywords
  • Graduation date
    Spring 2018
  • 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.