The effect of scale on the relative importance of climatic and biotic variables influencing methane fluxes from an Arctic wet sedge meadow

Methane fluxes (FCH4) from an Arctic wet sedge meadow at Daring Lake, NT, Canada were examined during the growing seasons of 2008-2017 over several temporal and spatial scales. The largest methane emissions (seasonal averages of of 118 - 277 mg CH4 m-2 d-1) were recorded at the plot scale mid-summer using manual chamber methods and were associated with wetter locations with more sedges. Plot-scale FCH4 were negligible where shrubby peat soils were raised above the water table. Ecosystem-scale FCH4 measured on a quasi-continuous basis employing an eddy covariance technique were roughly 50% of plot-scale FCH4. Moisture, temperature and vegetation-related variables explained up to 80% of temporal FCH4 variability (p<0.001). Both magnitudes of FCH4 and relationships with driving variables were not consistent between scales and measurement techniques, demonstrating both the importance of scale in deducing all processes influencing FCH4 variability and the difficulties in upscaling FCH4 at this heterogeneous wetland.