An Analysis of Methane and Carbon Dioxide Exchange in a Post-Extraction, Unrestored Peatland in Eastern Québec

Peatlands are significant long-term sinks of carbon. The extraction of peat (e.g. for agricultural purposes) leads to a shift in the natural carbon dynamics. Additionally, the change in environmental conditions after extraction could allow invasive species to establish and spread across the peatland. Many studies have shown the benefits and advantages of various restoration management practices, but the carbon exchange from unrestored peatlands has yet to be examined. We measured methane and carbon dioxide fluxes from a post-extraction, unrestored peatland in Eastern Québec at both the plant community scale (using static chamber measurements) and at the ecosystem scale (using tower flux measurements). Results at both scales indicate that the site is, as expected, an overall source of carbon to the atmosphere. Phragmites and Typha, both invasive species, have established themselves in the ditches, and are sources of methane; partially explaining why the peatland's net carbon flux to the atmosphere has changed. A vegetation survey provided insight into the relative contributions of each plant community to the total methane and carbon dioxide fluxes at the peatland site. The eddy covariance tower measures higher methane fluxes from the direction of the ditches and from where the invasive species are located. The net uptake of carbon dioxide from the peatland does not compensate for the total amount of methane released. Therefore, should the invasive species continue to spread, the peatland will become an even greater net carbon flux to the atmosphere. Ultimately, this study will help managers assess the importance of post-extraction peatland restoration.