Transitions in Boreal Wetland Macroinvertebrate Community Composition Across a Natural Salinity Gradient
Date
2022-06
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Abstract
Nearly 65% of Alberta’s northern boreal landscape is comprised of wetlands (primarily peatlands), which are lost in the process of open pit mining for oil sands. Demonstration wetlands recently created in reclaimed postmining watersheds are productive and support diverse biota. However, their water tends to be sodic due to the presence of salts in the soils used in their construction and residual sodium from the bitumen extraction process. Saline wetland systems occur in northern Alberta in areas where deep aquifer upwellings contribute significantly to a wetland’s water budget. I sampled the water chemistry and aquatic invertebrates in a suite of 52 pools ranging in specific conductance from 3,757 to 20,170 S/cm in a patterned fen southeast of Fort McMurray, Alberta, to identify patterns of community composition along the salinity gradient. Sodium, chloride, magnesium, and calcium were the dominant ions present in the saline fen. Pools with relatively low salinity supported abundant densities of gastropods and odonates whereas the most saline pools were dominated by Diptera larvae, especially genera of mosquitos. Threshold Indicator Taxon Analysis (TITAN) identified a set of 11 sensitive and 9 tolerant taxa diagnostic of specific conductivity. Community composition changed markedly at a threshold of 6,335-9,385 S/cm, equivalent to chloride concentrations of 1,579- 2,535mg/L. These findings may provide a useful frame of reference for anticipating community composition in wetlands forming in sodic areas of the reclaimed postmining landscape of the AOS.
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Keywords
Aquatic invertebrates, Community composition, Threshold
Citation
Vercruysse, B. (2022). Transitions in boreal wetland macroinvertebrate community composition across a natural salinity gradient (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.