REWETTING POCOSIN WETLANDS LOWERS GREENHOUSE GAS EMISSIONS

Abstract

Restored peatlands are known to be highly efficient carbon sinks and wetland restoration efforts take advantage of this efficiency to use as a climate change mitigation strategy. Evaluating the carbon sequestration capacity of peatland requires a greater understanding of how the seasonal fluxes of greenhouse gases (GHG) change, both in magnitude and direction, during and after peatland restoration. One aspect that has not received much attention is how carbon dioxide, methane and nitrous oxide emissions change during peatland restoration involving a hydrologic manipulation (i.e. raising water table depth). This study involved field data collection of GHG fluxes, soil temperature, soil moisture, and water table depths before and after hydrologic manipulation. I investigated the role of water table depth and soil temperature on changes in GHG fluxes pre- and post-hydrologic manipulation of a pocosin wetland (a shrub/scrub bog containing low nutrient, acidic soils). The study revealed that higher water table depths correlated to lower carbon dioxide (CO2), higher methane (CH4) and nitrous oxide (N2O) emissions. I found that the reduction in CO2 outpaced the increases in CH4 and N2O by a factor of 100. In addition, rewetting the pocosin wetlands also decreased the susceptibility to fire as evidenced by the decreased smoldering potential of soils undergoing hydrologic restoration. Taken together, the decreased CO2 emissions and reduced smoldering potential of rewetted soils indicates that hydrologic restoration of a pocosin wetland may be an effective mechanism to lower soil greenhouse gas emissions.