Increased Methane Emissions from Boreal Peatlands Following Linear Disturbances

Boreal peatlands serve as long-term carbon (C) sinks and a significant source of methane (CH₄) to the atmosphere. However, peatlands are threatened by both natural and anthropogenic disturbances, resulting in potential release of large amounts of C to the atmosphere. Linear disturbances, such as seismic lines for geologic exploration, constitute the largest area of disturbance in boreal Canada. The impact of seismic lines on peatland C cycling is not well understood, although physical changes in topography and lack of tree re-establishment are well-documented. This study used the closed chamber technique to measure growing season understory CH₄ fluxes on the footprint of the seismic line disturbance and in adjacent intact peatlands and assessed environmental controls on CH₄ dynamics across a treed fen and two treed bogs near Peace River, Alberta, Canada. Seismic lines were significantly warmer and wetter providing ideal conditions for increased CH₄ emissions at all sites. Methane emissions relative to natural areas were almost tripled in the bog sites (261–308 %) and close to double in the fen (176 %). These results will contribute to accurate greenhouse gas reporting for anthropogenic disturbances in boreal peatlands and provide a scientific foundation for practices and policies related to peatland restoration.