Greenhouse Gas Exchange from Sites Used as a Source of Vegetation Donor Material for Peatland Restoration

English Abstract:

Horticultural extraction of peatlands converts them from carbon and greenhouse gas (GHG) sinks to sources. The moss layer transfer technique for peatland restoration may return the GHG sink function, but requires a source of vegetation donor material. This technique may also be incorporated into fen construction projects following oil sands extraction. Collecting this donor material creates an additional disturbance, often in a previously undisturbed peatland, and the recovery of these “donor sites” and the impact on their GHG emissions is unknown. We monitored growing season GHG fluxes and plant communities on donor sites in an ombrotrophic bog and minerotrophic fen in Alberta, Canada from which material was removed between 1-6 year prior to the study and compared results to neighbouring undisturbed peatland.

Plant recovery on both donor sites was rapid with 70% and 120% total plant cover after two growing seasons at the fen and bog, respectively. Of this, moss cover also returned, reaching 83% cover after 5 years at the bog. On the other hand, the majority of undisturbed peatlands in western Canada are treed and tree recruitment on the donor sites remained low likely due to higher water tables resulting from the removal of surface material. The strong vegetation recovery led to a growing season carbon sink at the 5-year bog donor site. However, methane emissions were higher from both donor sites than undisturbed areas due to the high water table and large cover of sedges that colonized the sites.