Carbon dioxide exchange across a range of soil moisture and vegetation communities in low-arctic tundra

Community-level knowledge of the effects of tundra vegetation and abiotic characteristics on carbon dioxide (CO2) exchange and more accurate remote sensing of vegetation characteristics can both contribute to reducing uncertainties in carbon budgets. CO2 exchange, temperature, soil moisture, vegetation characteristics and the Normalized Difference Vegetation Index (NDVI) were measured in birch, tussock, heath and sedge communities in 0.4x0.4m plots during the summer of 2008 in low-arctic shrub tundra in Northwest Territories. Within vegetation types soil moisture was generally positively related to net CO2 flux. Fluxes per unit of leaf area and per unit of nitrogen showed negative linear relationships to soil moisture. NDVI was a significant predictor of leaf area only in some vegetation communities. NDVI was a significant predictor of productivity and net CO2 exchange across all vegetation, but was related to respiration only in wet sedge tundra. The small-scale heterogeneity of vegetation distribution contributes to the variability in landscape estimates of CO2 exchange.;Keywords: carbon dioxide, vegetation, tundra, NDVI, soil moisture, climate change...