Date of Award
Master of Science
Reclamation of the boreal landscape, including both wetlands and uplands integrated into complex watersheds, has presented a challenge over the past decade with few attempts. Relevant today is wetland/peatland reclamation on reclaimed landscapes positioned on saline sand deposits left on ‘in-pits’ from open pit oil sands mining. The study site for the following questions was an experimental watershed, Sandhill Fen, located north of Fort McMurray, Alberta. Part of the reclamation challenge lies in choosing characteristic species that are tolerant of conditions present on the reclaimed landscape. Species need to both survive harsh environmental conditions and facilitate succession from mineral-based wetlands (marshes) to peat-based ones (fens).Beckmannia syzigachne is a species associated with rich fens in boreal Alberta but its potential to tolerate the given conditions of an open pit mine has yet to be explored. Thus the first question investigated was: How does Beckmannia syzigachne, respond to stress inherent in open pit mines, specifically sodium and soil wetness? Once plants are established, their success and health can be assessed by their physiological responses to the inherent conditions of an open pit mine and further compared to naturally occurring reference populations, called benchmarks, associated with boreal wetlands and peatlands.Carex aquatilis, Scirpus atrocinctus, and Triglochin maritima are three species naturally occurring or strong associated with rich fens and have established on an open pit reclamation site. The second question investigated was: how do Carex aquatilis, Scirpus atrocinctus, and Triglochin maritima physiologically respond to the soil moisture, sodium in the soil, and conductivity of the reclamation site and compare to benchmark populations? Given the large size and isolation from the natural landscape, revegetating the reclamation site may be difficult. Many species have begun to naturally colonize a reclamation site and the assemblage of species and how they might change affect the progression of fen reclamation is unknown. The third question investigated was: what does the early assemblage of species on a reclamation site consist of and do the species give indications of successional trajectory toward a peat-forming wetland? Lastly, active management of the reclamation site can have a great effect on the trajectory of the established species. Actively planting specific assemblages could assist in the trajectory of succession by encouraging the proliferation of desirable species and hindering the establishment of undesirable species. Planting assemblages of high diversity could be more beneficial than planting monocultures. Thus the last question investigated was: does the planting of diverse assemblages effect the establishment of desirable and undesirable species on a reclamation site? Overall, the investigation of these questions revealed some interesting results and concluded strong recommendations for ongoing and future fen reclamation of open pit mines. Beckmannia syzigachne shows decreased morphological and physiological performance with higher sodium concentrations, but tolerates the expected soil wetness and sodium concentrations of the reclamation site, Sandhill Fen. Carex aquatilis, Scirpus atrocinctus, and Triglochin maritima had very strong physiological relationships with percent soil moisture, but weak or no relationships with sodium in the soil or soil water electrical conductivity, and responded similarly to benchmark populations. Soil moisture may be the most important factor during the early development of an open pit reclamation site, as the different assemblages of species found at Sandhill Fen was strongly tied the percent soil moisture, the wetter the soil, the more desirable species were abundant. After one year, it does not appear planting diverse assemblages has nearly a strong effect on the species abundances as soil moisture does. Sandhill Fen serves as a model for future reclamation of fens on oil sands and these experiments have shown soil moisture is an important abiotic factor that requires attention and manipulation if fen reclamation is to be successful on open pit mines. Overall, at Sandhill Fen the establishment and proliferation of desirable species is a positive observation and the physiological responses similar to natural populations bodes well for the success of fen reclamation.
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