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The role of Eriophorum vaginatum in carbon dioxide (CO 2) and methane (CH4) dynamics of two restored peatlands in eastern Canada was examined. Sites were established in Riviere-du-Loup, Quebec from May to October of 1999 and 2000, and Shippagan, New Brunswick from May to October of 2001. / CH4 emissions from E. vaginatum collars were positively related to maximum photosynthesis in 1999 and 2001, when the water table was close to the surface. CH4 emissions were also positively related to end of season above ground plant biomass at both sites. CH4 emissions from E. vaginatum collars ranged from -0.015 to 14.7 mg CH4-C m-2 h-1 at Riviere-du-Loup and -0.15 to 5.4 mg CH4-C m -2 h-1 at Shippagan. It is likely that E. vaginatum provides substrate for methanogenesis through plant production and acts as a conduit transporting CH4 to the atmosphere. / Patterns of NEE from E. vaginatum depended on site-specific and year-specific conditions. E. vaginatum was a net sink for CO2 at high and low light levels at Shippagan, and a net source of CO2 at low light levels at Riviere-du-Loup.

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A static chamber technique was used to measure methane emissions in July and August, 1995 from peatland sites in the Fort Simpson area, Northwest Territories, at the southern fringe of the discontinuous permafrost zone. Sites were classified ecologically and geomorphologically, and water table and temperature regimes were monitored. / Methane emissions ranged from $-$3.3 to 1144.2 mg/m$ sp2 cdot$d, from raised frozen sites to pond sites, respectively, similar to emissions recorded from other boreal regions. Water table was the strongest predictor of CH$ sb4$ emission. Although peat temperature is significantly correlated to methane flux, it did not significantly improve the flux-water table relationship. Methane storage within the saturated portion of the peat profile ranged from 0.2 to 4.2 g/m$ sp2$ over depths ranging from 30 to 76 cm, and did not play a large role in surficial emissions. The zone immediately above and below the water table appears to regulate methane diffusion to the surface. Residence times (storage/flux) ranged from 12 to 30 days in poor fens, and from 6 to 5789 days in fens. / Ranges and mean fluxes of methane were determined according to landform and water table position. Based on the geomorphology of the area, overall flux determined for the Fort Simpson area, map NTS 95H, NW1/4, is estimated to be 19 mg/m$ sp2 cdot$d.

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