Responses of carbon dioxide flux and plant biomass to water table drawdown in a treed peatland in northern Alberta: a climate change perspective

Biogeosciences

M. Strack²  M. Perkins²  B. Xu¹  T. M. Munir² 

[1]now at: NAIT Boreal Research Institute, Peace River, AB, Canada

[2]Department of Geography, University of Calgary, Calgary, AB, Canada

Others  :  983505
DOI  :  doi:10.5194/bg-11-807-2014

【 摘 要 】

Northern peatland ecosystems represent large carbon (C) stocks that aresusceptible to changes such as accelerated mineralization due to water tablelowering expected under a climate change scenario. During the growing seasons(1 May to 31 October) of 2011 and 2012 we monitored CO2 fluxes and plantbiomass along a microtopographic gradient (hummocks-hollows) in anundisturbed dry continental boreal treed bog (control) and a nearby site thatwas drained (drained) in 2001. Ten years of drainage in the bog significantlyincreased coverage of shrubs at hummocks and lichens at hollows. Consideringmeasured hummock coverage and including tree incremental growth, we estimatethat the control site was a sink of −92 in 2011 and −70 g C m−2 in2012, while the drained site was a source of 27 and 23 g C m−2 over thesame years. We infer that, drainage-induced changes in vegetation growth ledto increased biomass to counteract a portion of soil carbon losses. Theseresults suggest that spatial variability (microtopography) and changes invegetation community in boreal peatlands will affect how these ecosystemsrespond to lowered water table potentially induced by climate change.

【 授权许可】

   
© Author(s) 2014. This work is distributedunder the Creative Commons Attribution 3.0 License.