Greenhouse gas emissions and carbon sequestration potential in restored wetlands of the Canadian Prairie Pothole Region / Pascal Badiou, Rhonda McDougal, Dan Pennock and Bob Clark.

Includes bibliographical references (pages 254-256).

North American prairie pothole wetlands
are known to be important carbon stores. As a result
there is interest in using wetland restoration and
conservation programs to mitigate the effects of
increasing greenhouse gas concentration in the
atmosphere. However, the same conditions which
cause these systems to accumulate organic carbon
also produce the conditions under which methanogenesis
can occur. As a result prairie pothole
wetlands are potential hotspots for methane emissions.
We examined change in soil organic carbon
density as well as emissions of methane and nitrous
oxide in newly restored, long-term restored, and
reference wetlands across the Canadian prairies to
determine the net GHG mitigation potential associated
with wetland restoration. Our results indicate
that methane emissions from seasonal, semi-permanent,
and permanent prairie pothole wetlands are
quite high while nitrous oxide emissions from these
sites are fairly low. Increases in soil organic carbon
between newly restored and long-term restored
wetlands supports the conclusion that restored wetlands
sequester organic carbon. Assuming a sequestration
duration of 33 years and a return to historical
SOC densities we estimate a mean annual sequestration
rate for restored wetlands of 2.7 Mg C ha-1
year-1 or 9.9 Mg CO2 eq. ha-1 year-1. Even after
accounting for increased CH4 emissions associated
with restoration our research indicates that wetland
restoration would sequester approximately 3.25 Mg
CO2 eq. ha-1year-1. This research indicates that
widescale restoration of seasonal, semi-permanent,
and permanent wetlands in the Canadian prairies
could help mitigate GHG emissions in the near term
until a more viable long-term solution to increasing
atmospheric concentrations of GHGs can be found.