Creating fen initiation conditions: a new approach for peatland reclamation in the oil sands region of Alberta

Abstract

1.Reclaiming peatland ecosystems is challenging our understanding of how to rebuild functioning landscapes. Assisted succession may provide a practical approach to guide the reestablishment of peatlands in denuded landscapes. In Alberta, the majority of peatlands began as fens during the paludification process. This research focuses on creating fen initiation conditions to establish fen moss species on mineral sediment as an approach for peatland reclamation in the oil sands region. 2. In a field mesocosm experiment, we evaluated the establishment of five common fen mosses (Drepanocladus aduncus, Ptychostomum (Bryum) pseudotriquetrum, Campylium stellatum, Tomentypnum nitens and Aulacomnium palustre) introduced in equal proportions to clay loam. To determine the optimal hydrologic conditions for the establishment of each species, we tested four water levels (0, À10, À20 and À30 cm). We created vegetation types similar to those identified at the peat-mineral interface in peat profiles to determine the effect of herbaceous plant, low shrub and wood-strand mulch cover treatments on moss establishment. 3. Three seasons after introduction, total moss cover averaged 40% and was greatest under all cover treatments and at the 0 cm water level. Total moss biomass averaged 95Á5 g m À2 in moss introduction mesocosms and was greatest under low shrubs and herbaceous plants and at the 0 and À30 cm water levels. Fen moss species distribution was significantly influenced by water-table depth. Drepanocladus aduncus and Ptychostomum pseudotriquetrum were most common at 0 cm and Aulacomnium palustre and Tomentypnum nitens at À30 cm. 4. In this approach, we created vegetation types similar to those found on mineral sediments at the base of Alberta peat cores and successfully established distinct fen moss communities along a water-table gradient and under shade cover. Introducing a suite of fen moss species that inhabit a range of hydrologic niches under low shrubs or herbaceous plants improves moss establishment. 5. Synthesis and applications. Our research shows that it is possible to create fen initiation conditions on clay loam sediment by introducing foundation moss and vascular plant species at optimal water levels. Restoring the community structure and biomass accumulation that occurs in the initial stages of fen development appears to be a suitable target for peatland reclamation. These methods introduce a practical strategy to reclaim peatlands in the heavily impacted oil sands region of Alberta.

Tolerance of fen mosses to submergence, and the influence on moss community composition and ecosystem resilience

“…In boreal rich fens, T. nitens is one of the most abundant and has the widest habitat niche breadth among true peatland moss species (Gignac, ; Vitt, Wieder, Scott, & Faller, ). The ability of T. nitens to establish and dominate is likely influenced by its resistance and resilience to submergence along with its tolerance of desiccation (Borkenhagen & Cooper, ; Goetz & Price, ; Manukjanová et al., ). Our results stress the importance of T. nitens in maintaining ecosystem function and resilience to drying and flooding disturbances.…”

An overview of peatland restoration in North America: where are we after 25 years?

“…They found shade increased regeneration for most species, and a high water table was ideal. In northern Alberta, Borkenhagen and Cooper () found that they could establish a range of fen bryophytes on mineral soil that mimicked the initial conditions under which fens formed that is further facilitated with peat amendments as tested on well pads (Gauthier unpublished data). These studies suggest great promise in creating habitat suitable for true moss establishment in restored fens.…”

“…Two large‐scale fen reclamation projects have attempted to create watersheds and functioning peatland ecosystems on postoil sands extraction landscapes (Price et al ; Daly et al ). These projects have imported salvaged peat from donor wetlands and introduced plant propagules as soil seed banks, seed, vascular plants grown from seed in nurseries, and moss fragment transfer approaches (Borkenhagen & Cooper ). The potential effects of process water from oil sands, which can have high concentrations of toxins, strongly influence fen plant survival (Pouliot et al , ).…”

“…Other strategies include using natural saline communities as models for reclamation and their species as suitable candidates for introductions (Purdy et al ; Nwaishi et al ). Although many projects have relied on importing peat as the foundation for peatland restoration, others have demonstrated that it is possible to establish peatland plants and initiate peat formation on mineral soils (Vitt et al ; Borkenhagen & Cooper ).…”

Forest water use in the initial stages of reclamation in the Athabasca Oil Sands Region

“…A central component of the landscape reclamation strategy is the overall approach and feasibility of constructing heterogeneous boreal landscapes of lowland wetlands and upland forests on previously mined sites (Alberta Environment, 2010;Devito, Mendoza, & Qualizza, 2012). Although a focus of recent reclamation research efforts has been on the creation of wetlands (Borkenhagen & Cooper, 2016;Ketcheson et al, 2016;Mollard, Roy, & Foote, 2015;Nicholls, Carey, Humphreys, Clark, & Drewitt, 2016), earlier and ongoing reclamation activities have focussed on forests and aspects of forest establishment including soil water dynamics (Carrera-Hernández, Mendoza, Devito, Petrone, & Smerdon, 2012;Huang, Barbour, & Carey, 2015), vegetation cover (Pinno & Hawkes, 2015;Rowland, Prescott, Grayston, Quideau, & Bradfield, 2009), soil bacteria (Quideau, Swallow, Prescott, Grayston, & Oh, 2013), nutrient fixation (Kwak, Chang, Naeth, & Schaaf, 2015;Yan et al, 2012), and saline toxicity (Kelln, Barbour, & Qualizza, 2008;Lilles, Purdy, Macdonald, & Chang, 2012).…”