Derrick Y.F. Lai, Nigel T. Roulet, Tim R. Moore, Elyn R. Humphreys, Mike Dalva
Proceedings of the 14th International Peat Congress
autochamber, co2-exchange, ecosystem-respiration, gross-ecosystem-production
Theme X. Peatland carbon budgets and greenhouse gas (GHG) fluxes
We measured CO2 fluxes at half-hourly intervals with automatic chambers in three vascular plant communities at the Mer Bleue bog in 2009 to compare the responses of gross ecosystem production (GEP) and ecosystem respiration (ER) to changing environmental and biotic conditions among communities. Based on the parameterized GEP models, we detected a significant decrease in effective quantum yield in the order of Eriophorum > Chamaedaphne > Maianthemum/Ledum community, indicating the most efficient photosynthetic activity in sedges at low light levels. The rate of linear increase in GEP with vascular green area index was considerably lower in the Maianthemum/Ledum community, probably related to the high specific leaf area of forb foliage. The ER model parameters (R10, E0) were significantly different among communities, with the highest temperature sensitivity of ER in the Eriophorum community. The observed significant difference in the overall parameterized GEP and ER models among all three communities implies that modelling of CO2 fluxes in this bog should take into account the functionally different plant communities separately.