VDM Isernhagen, B: The Effect of Beaver Pond Drainage on CO2 and

This study was undertaken in Mer Bleue Bog, Ontario, Canada to determine the response of a beaver pond to drainage (25 cm) as a sink or source of carbon. Plant distribution changed in response to a new water table gradient. Each vegetation community and the remaining beaver pond were sampled for fluxes of CO2 and CH4. A flow-through chamber system was used to measure CO2 flux from vegetated sites. Variations in CO2 flux amongst the sites along the gradient could not be related to differences in plant species composition, peat temperature, or water table. A closed chamber was used to measure CH4 on vegetated sites. The water table explained 83% of the seasonal average CH4 flux variability and the vegetation added another 11%. The seasonal measurements were integrated into an areal estimate of CO2 and CH4 flux for the beaver pond area prior to and after drainage. The beaver pond area sequestered 96 g m-2 before drainage, and the same area more than doubled the uptake to 231 g m-2 after being drained.