Rewetting of Cutaway Peatlands: Are We Re-Creating Hot Spots of Methane Emissions?

Hot spots of CH4 emissions are a typical feature of pristine peatlands at the microsite and landscape scale. To determine whether rewetting and lake construction in a cutaway peatland would result in the re-creation of hot spots, we first measured CH4 fluxes over a 2-year period with static chambers and estimated annual emissions. Second, to assess whether rewetting and lake creation would produce hot spots at the landscape level, we hypothesized a number of alternative land use scenarios for the peatland following the cessation of peat extraction. Using the results from this study and other studies from literature, we calculated the global warming potential (GWP) of each scenario and the respective contribution of CH4. The results showed that hot spots of CH4 fluxes were observed as a consequence of microsite-specific differences in water table (WT) position and plant productivity. CH4 fluxes were closely related to peat temperature at 10 cm depth and WT position. Annual emissions ranged from 4.3 to 38.8 g CH4 m−2 yr−1 in 2002 and 3.2 to 28.8 g CH4 m−2 yr−1 in 2003. The scenario results suggest that lake creation is likely to result in the re-creation of a hot spot at the landscape level. However, the transition from cutaway to wetland ecosystem may lead to a reduction in the GWP of the peatland.