Peat CO2 production in a natural and cutover peatland: Implications for restoration

Although studies have shown that peatland drainage andharvesting alter local hydrology, microclimate, and peatcharacteristics, little is known about the effects of these changes onCO₂ production rates. This study examines the differentfactors affecting CO₂ production from natural and cutoverpeatlands. Laboratory peat incubations were performed under aerobic andanaerobic conditions to determine the influence of temperature, soilmoisture, and peat depth on CO₂ production rates from peatsamples taken from: (1) a natural peatland; (2) a 2-yearpost-cutover peatland and; (3) a 7-year post-cutover peatland.CO₂ production rates ranged from 0.21 to 4.87 µmolg^–1 d^–1 under anaerobic conditions,and from 0.37 to 15.69 µmol g^–1d^–1 in the aerobic trials. While no significantdifferences were found between the CO₂ production rates ofthe two cutover sites, the natural site consistently displayed higherproduction values. The natural site was also the only site to exhibitstrong depth dependent trends, thus indicating the importance of theupper peat layer with respect to substrate quality. Higher productionrates were found under aerobic than anaerobic conditions, with thegreatest response to oxygen observed at the natural site. Productionrates increased with both temperature and soil moisture, with maximumproduction rates found at 20 °C and 92% moisture content.Temperature responses were generally greater at the cutover sites, whilesoil moisture had greater effects on the natural site peat.Results of this work agree with previous studies that suggest that itis essential to begin restoration once a cutover peatland is abandoned.Re-wetting a cutover peatland (through restoration practices) isnecessary to prevent an increase in peat temperature and CO₂production since cutover peat has higher Q₁₀ values thannatural peat. A decrease in overall peatland oxidation should reduce thepersistent source of atmospheric CO₂ from cutover peatlandsand the irreversible changes in peat structure that impedeSphagnum re-establishment.