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Responses of tundra plant community carbon flux to experimental warming, dominant species removal and elevation

Sundqvist, Maja and Sanders, Nathan J. and Dorrepaal, Ellen and Linden, Elin and Metcalfe, Daniel B. and Newman, Gregory S. and Olofsson, Johan and Wardle, David A. and Classen, Aimee T. (2020). Responses of tundra plant community carbon flux to experimental warming, dominant species removal and elevation. Functional Ecology. 34 , 1497-1506
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Abstract

Rising temperatures can influence ecosystem processes both directly and indirectly, through effects on plant species and communities. An improved understanding of direct versus indirect effects of warming on ecosystem processes is needed for robust predictions of the impacts of climate change on terrestrial ecosystem carbon (C) dynamics.To explore potential direct and indirect effects of warming on C dynamics in arctic tundra heath, we established a warming (open top chambers) and dominant plant species (Empetrum hermaphroditum Hagerup) removal experiment at a high and low elevation site. We measured the individual and interactive effects of warming, dominant species removal and elevation on plant species cover, the normalized difference vegetation index (NDVI), leaf area index (LAI), temperature, soil moisture and instantaneous net ecosystem CO2 exchange.We hypothesized that ecosystems would be stronger CO2 sinks at the low elevation site, and that warming and species removal would weaken the CO2 sink because warming should increase ecosystem respiration (ER) and species removal should reduce gross primary productivity (GPP). Furthermore, we hypothesized that warming and species removal would have the greatest impact on processes at the high elevation where site temperature should be most limiting and dominant species may buffer the overall community to environmental stress more compared to the low elevation site where plants are more likely to compete with the dominant species.The instantaneous CO2 flux, which reflected a weak CO2 sink, was similar at both elevations. Neither experimental warming nor dominant species removal significantly changed GPP or instantaneous net ecosystem CO2 exchange even though species removal significantly reduced ER, NDVI and LAI.Our results show that even the loss of dominant plant species may not result in significant landscape-scale responses of net ecosystem CO2 exchange to warming. They also show that NDVI and LAI may be limited in their ability to predict changes in GPP in these tundra heaths systems. Our study highlights the need for more detailed vegetation analyses and ground-truthed measurements in order to accurately predict direct and indirect impacts of climatic change on ecosystem C dynamics.A free Plain Language Summary can be found within the Supporting Information of this article.

Authors/Creators:Sundqvist, Maja and Sanders, Nathan J. and Dorrepaal, Ellen and Linden, Elin and Metcalfe, Daniel B. and Newman, Gregory S. and Olofsson, Johan and Wardle, David A. and Classen, Aimee T.
Title:Responses of tundra plant community carbon flux to experimental warming, dominant species removal and elevation
Year of publishing :2020
Volume:34
Page range:1497-1506
Number of Pages:10
Publisher:John Wiley & Sons Ltd, British Ecological Society
ISSN:0269-8463
Language:English
Publication Type:Journal article
Article category:Scientific peer reviewed
Version:Published version
Copyright:Creative Commons: Attribution 4.0
Full Text Status:Public
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Ecology
Keywords:carbon, ecosystem respiration, global warming, gross primary productivity, leaf area index, normalized difference vegetation index, plant-plant interactions
URN:NBN:urn:nbn:se:slu:epsilon-p-105637
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-p-105637
Additional ID:
Type of IDID
DOI10.1111/1365-2435.13567
Web of Science (WoS)000529607900001
ID Code:17390
Faculty:S - Faculty of Forest Sciences
Department:(S) > Dept. of Forest Ecology and Management
Deposited By: SLUpub Connector
Deposited On:02 Sep 2020 11:21
Metadata Last Modified:02 Sep 2020 11:21

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