Creating fen initiation conditions: a new approach for peatland reclamation in the oil sands region of Alberta.
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. 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, -10, -20 and -30 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. 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 95.5 g m-2 in moss introduction mesocosms and was greatest under low shrubs and herbaceous plants and at the 0 and -30 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 -30 cm. 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. 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.