EGU2020-18697, updated on 16 Mar 2021
https://doi.org/10.5194/egusphere-egu2020-18697
EGU General Assembly 2020
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

The CO2 balance of a boreal fen is more sensitive to drought than surrounding forests

Mats Nilsson, Joshua Ratcliffe, Anne Klosterhalfen, Peng Zhao, Jinchu Chi, and Matthias Peichl
Mats Nilsson et al.
  • Swedish University of Agricultural Sciences, Department of Forest Ecology and Management, Umea, Sweden (Mats.B.Nilsson@slu.se)

The boreal zone is one of the most carbon-dense biomes in the world and is comprised of a highly interconnected mosaic of forest and wetlands which are warming at a rate several times the global average with extreme weather events, such as droughts, becoming increasingly common. At the ecosystem scale, both forests and peatlands are often vulnerable to drought-induced carbon loss, however, the relative resilience of these two ecosystems within the boreal landscape is not well understood. Here we study the effect of the 2018 drought on CO2 fluxes in two boreal forests and a boreal peatland within <20km radius, i.e. experiencing the same weather conditions. The peatland displayed the strongest response to the drought, with the site becoming a net annual source for CO2 for the first time in 17 years, with the CO2 sink slow to recover after the drought broke. In contrast, the response of the forests was mixed, a  spruce/pine forest on glacial till remained unaffected by the drought, whereas a nearby pine forest, situated on drier sandy soil, responded strongly to vapour pressure deficit and declining soil moisture content, decreasing with CO2 uptake weakening, but still allowing the forest to function as a CO2 sink. In contrast to the bog, the pine forest CO2 sink quickly recovered following the end of the drought. We conclude that boreal peatlands are likely to be the most vulnerable component of the boreal landscape to drought and that soil type is likely to play a role in regulating the response of boreal forests.

How to cite: Nilsson, M., Ratcliffe, J., Klosterhalfen, A., Zhao, P., Chi, J., and Peichl, M.: The CO2 balance of a boreal fen is more sensitive to drought than surrounding forests, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18697, https://doi.org/10.5194/egusphere-egu2020-18697, 2020.

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