Reclaiming to Brackish Wetlands in the Alberta Oil Sands: Comparison of Responses to Sodium Concentrations by Carex atherodes and Carex aquatilis

• Published in: Plants
• Main Authors: Lilyan C. Glaeser, Melissa House, Dale H. Vitt
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2021
• Subjects: Alberta; boreal; Carex aquatilis; Carex atherodes; oil sands reclamation; Sandhill Wetland; Botany; QK1-989; Canada
• Online Access: https://doi.org/10.3390/plants10081511; https://doaj.org/article/0a1aa6bae91a401a83f71cfbbdb6ddbb

The variation in sodium concentrations in waters of natural fens and marshes on the western Canadian landscape provides a background for choosing the appropriate plants for wetland reclamation. Broad tolerances to salinity are especially important for reclamation trials on saline-rich ‘in-pits’ that were left from open-pit oil sands mining. One such species, Carex aquatilis , has been identified as a key species in early reclamation attempts; however, at the Sandhill Wetland on the Syncrude Canada oil sands lease, this species has aggressively colonized, dominating parts of the wetland and limiting species diversity. A second species, also widespread on natural lake shores and marshes, is Carex atherodes , with field observations suggesting a broad tolerance to salinity. Here, we examine the responses of this species to a series of sodium concentrations and compare these to those of C. aquatilis. In particular, we addressed three questions: (1) How do structural attributes of C. atherodes respond to a series of Na + concentration treatments? (2) Are different structural responses related to the functional attributes of photosynthesis, stomatal conductance, and/or transpiration rate? (3) How do these responses compare to those of C. aquatilis? We implemented a phytotron experiment to test the responses of these two species to either five or six concentrations of sodium, ranging from 20 to 3000 mg Na + L −1 . In general, structural responses of C. atherodes did not differ between 50 and 789 mg Na + L −1 , while performances of all attributes were reduced at 1407 mg L −1 . Physiological attributes had high variation, but also had reduced performances at similar treatment levels. In comparison, a clear threshold was present for structural attributes in Carex aquatilis between 1650 and 2148 mg Na + L −1 , while physiological attributes were reduced between 1035 to 1650 mg Na + L −1 . These responses from C. aquatilis were similar to those previously reported. Na + concentrations in porewater at the Sandhill Wetland ...