Ecosystem-scale flux of CO2 from a restored vacuum harvested peatland

At the ecosystem scale, the water and gas exchange processes are strongly coupled. Drainage and removal of a peatland's surface vegetation cover for peat harvesting alters its hydrology, and as a direct consequence the carbon budget. Previous studies have measured peatland-atmosphere carbon exchange using the chamber methodology. These studies have indicated that the spatial and temporal variability is large, suggesting the need for continuous ecosystem-scale measurements. This paper presents ecosystem scale measurements of the atmospheric exchange of water and carbon dioxide (CO2) from a restored vacuum-harvested peatland in eastern Quebec, Canada, using the eddy correlation measurement approach. Results indicate that the adopted restoration practices reduce the loss of water from the peat. Evapotranspiration from the restored site was 20 and 25% less than that from an adjacent abandoned comparison site in 2000 and 2001 respectively. However, CO2 emissions remain large during non-snow periods (478 and 468 g C m(-2) in 2000 and 2001, respectively). The blockage of drainage ditches and the existence of a mulch cover at the site keep the moisture and thermal conditions more or less constant. Consequently, the CO2 flux, which is predominantly soil respiration, is strongly controlled by peat temperature fluctuations.