Limited effect of increased atmospheric CO2concentration on ombrotrophic bog vegetation

Abstract
Summary: Boreal and subarctic peatlands contain 20–30% of the world’s soil organic carbon, and if growing, they constitute sinks for atmospheric CO2. We hypothesized that even in the nutrient‐poor bog environment, elevated CO2would stimulateSphagnumgrowth more than vascular plant growth, thereby improvingSphagnum’scompetitive strength and enhancing carbon (C) sequestration. Free‐air carbon dioxide enrichment (FACE) experiments took place on predominantly ombrotrophic peatbog‐lawns in Finland (FI), Sweden (SW), The Netherlands (NL), and Switzerland (CH). After 3 yr of treatment, increased CO2concentration (560 ppm on volume basis) had no significant effect onSphagnumor vascular plant biomass at either site. This research suggests that, just as with other nutrient‐poor ecosystems, increased atmospheric CO2concentrations will have a limited effect on bog ecosystems.