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dc.contributor.authorParmentier, Frans-Jan W.
dc.contributor.authorRasse, Daniel
dc.contributor.authorLund, Magnus
dc.contributor.authorBjerke, Jarle W.
dc.contributor.authorDrake, Bert G.
dc.contributor.authorWeldon, Simon Mark
dc.contributor.authorTømmervik, Hans
dc.contributor.authorHansen, Georg Heinrich
dc.description.abstractExtreme winter events that damage vegetation are considered an important climatic cause of arctic browning—a reversal of the greening trend of the region—and possibly reduce the carbon uptake of northern ecosystems. Confirmation of a reduction in CO2 uptake due to winter damage, however, remains elusive due to a lack of flux measurements from affected ecosystems. In this study, we report eddy covariance fluxes of CO2 from a peatland in northern Norway and show that vegetation CO2 uptake was delayed and reduced in the summer of 2014 following an extreme winter event earlier that year. Strong frost in the absence of a protective snow cover—its combined intensity unprecedented in the local climate record—caused severe dieback of the dwarf shrub species Calluna vulgaris and Empetrum nigrum. Similar vegetation damage was reported at the time along ~1000 km of coastal Norway, showing the widespread impact of this event. Our results indicate that gross primary production (GPP) exhibited a delayed response to temperature following snowmelt. From snowmelt up to the peak of summer, this reduced carbon uptake by 14 (0–24) g C m−2 (~12% of GPP in that period)—similar to the effect of interannual variations in summer weather. Concurrently, remotely-sensed NDVI dropped to the lowest level in more than a decade. However, bulk photosynthesis was eventually stimulated by the warm and sunny summer, raising total GPP. Species other than the vulnerable shrubs were probably resilient to the extreme winter event. The warm summer also increased ecosystem respiration, which limited net carbon uptake. This study shows that damage from a single extreme winter event can have an ecosystem-wide impact on CO2 uptake, and highlights the importance of including winter-induced shrub damage in terrestrial ecosystem models to accurately predict trends in vegetation productivity and carbon sequestration in the Arctic and sub-Arctic.nb_NO
dc.rightsNavngivelse 4.0 Internasjonal*
dc.titleVulnerability and resilience of the carbon exchange of a subarctic peatland to an extreme winter eventnb_NO
dc.typeJournal articlenb_NO
dc.typePeer reviewednb_NO
dc.rights.holder© 2018 The Author(s).nb_NO
dc.source.journalEnvironmental Research Lettersnb_NO
dc.relation.projectNILU - Norsk institutt for luftforskning: 115048nb_NO
dc.relation.projectFramsenteret: 362222nb_NO
dc.relation.projectAndre: EEA Norway Grants: 198571nb_NO

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Navngivelse 4.0 Internasjonal
Except where otherwise noted, this item's license is described as Navngivelse 4.0 Internasjonal