The role of Eriophorum vaginatum in CH4 flux from an ombrotrophic peatland

Vegetation composition was found to be an important factor controlling CH₄ emission from an ombrotrophic peatland in the UK, with significantly greater (P < 0.01) CH₄ released from areas containing both Eriophorum vaginatumL. and Sphagnum, than from similar areas without E. vaginatum. Positive correlations were observed between the amount of E. vaginatum and CH₄ emission, with the best predictor of flux being the amount of below-ground biomass of this species (r ² = 0.93). A cutting experiment revealed that there was no significant difference (P > 0.05) in CH₄ flux between plots with E. vaginatum stems cut above the water table and plots with intact vegetation, yet there was a 56% mean reduction in CH₄ efflux where stems were cut below the water table (P < 0.05). The effect of E. vaginatum on CH₄ release was mimicked by the presence of inert glass tubes. These findings suggest that the main short-term role of E. vaginatum in the ecosystem is simply as a conduit for CH₄ release. The longer-term importance of E. vaginatum in controlling CH₄ fluxes through C substrate input was suggested by the positive correlation between the night-time CO₂ and CH₄ fluxes (r ² = 0.70), which only occurred when the vegetation was not senescent. This revised version was published online in June 2006 with corrections to the Cover Date.