Assessing moss transplant methods to enhance Sphagnum moss recovery in post-wildfire hydrophobic peat

Wildfire is the dominant disturbance in northern peatlands and can release large quantities of carbon to the atmosphere through combustion. Post-fire peat hydrophobicity can inhibit moss regeneration, thereby decreasing the potential for post-fire carbon sequestration. To investigate how to enhance post-fire recovery we assessed two moss restoration methods (plugs and fragments) in an Alberta poor fen two and three years following wildfire. We first characterized post-fire peat hydrophobicity and moss regeneration in four surface cover types: Severely Burned Feather moss hollows (SB-F), Severely Burned Sphagnum fuscum hummocks (SB-S), Lightly Burned S. fuscum hummocks (LB-S), and Lightly Burned Feather moss lawns (LB-F). Across burn severities, hydrophobicity was high in feather moss and relatively low in Sphagnum moss. Similarly, hydrophobicity increased with depth over the top several centimeters in feather moss, but not in Sphagnum moss surface cover. Peat hydrophobicity appears to limit post-fire regeneration. LB-S was the least hydrophobic of the four treatments and was the only cover type in which Sphagnum moss recovered to >10% surface area, though SB-F had marginal recovery of pioneer moss species. Consequently, we conducted experiments testing the success of moss plugs and fragments of varying moss species at LB-F and SB-F surface covers, which had high hydrophobicity and low post-fire moss recovery. Experimental results indicate that the species type used in transplants is less critical in their survival than the microenvironment into which they are transplanted (i.e., burn severity). Transplant success was slightly higher in plugs than fragments, and larger plug sizes (10–15 cm) were more successful than small plugs (<10 cm). Growth was greater in SB-F than LB-F surface cover, owing to differences in post-fire hydrophobicity, and thus moisture availability. We conclude that in appropriate areas post-fire, peatland management efforts could employ large mixed-moss or Sphagnum moss transplant units while accounting for pre-fire vegetation composition and burn severity to fast-track post-fire moss and ecosystem recovery.