Browsing by Subject "peatland restoration"

Nitrous oxide (N2O) is an important greenhouse gas with a lifetime of 121 years and radiative efficiency of 219 times that of carbon dioxide (CO2). Nitrous oxide concentration has increased in the atmosphere from the 1800’s, in recent decades with increasing rate. Pristine mires have detected to have small N2O emissions, but drained peatlands are a major source of anthropogenic N2O emissions. Peatland restoration has been detected to be a tool for climate change mitigation. Peatlands act as a major carbon storage and carbon balance of pristine and drained peatlands has been widely studied. Nitrous oxide is one of the major peatland related greenhouse gases but has not been studied as intensively from restored peatlands in the boreal zone. Peatland restoration area has increased in Finland in recent decades due to biodiversity conservation and climate change mitigation. The total impact of peatland restoration on all greenhouse gas emissions has not been thoroughly studied. Nitrous oxide has received less attention than methane (CH4) and carbon dioxide. This thesis aims to gain more information on N2O emissions from restored peatlands and evaluate which factors affect the emissions. N2O flux data from 25 restored peatlands from Southern and Central Finland was analysed. The data was collected during May–August of 2022 from forestry-drained restored peatlands. Measurements were conducted on former strips and ditches of restored peatlands. Measurement sites had been divided into drained peatland forest types according to vegetation. The research indicates that N2O fluxes from rewetted, forestry-drained peatlands centre to small positive and negative values. Variation is wider than with pristine mires, but mean values for this measurement period were not significantly higher. Drained peatland forest type had a weak impact on N2O emissions, nutrient-rich sites had higher mean N2O emissions compared to less fertile sites of the study. Highest N2O emissions were measured from nutrient-rich site ditches. Less fertile sites of the study acted as a net sink of N2O on both strip and ditch. Environmental factors as water table (WT) level and soil temperature had an impact on N2O emissions, thus WT level as the only individual explanatory variable explained the variation in N2O emissions the most. N2O emission seemed to slightly decrease with years passing since restoration activities. This trend was the most visible with nutrient-rich sites. C/N ratio had a slight negative trend with site mean N2O emissions on both strip and ditch during the measurement season. Future research is needed to understand the dynamics of higher spatial and temporal N2O emissions.