Impact of Multiple Ecological Stressors on a Sub-Arctic Ecosystem: No Interaction Between Extreme Winter Warming Events, Nitrogen Addition and Grazing
Climate change is one of many ongoing human-induced environmental changes, but few studies consider interactive effects between multiple anthropogenic disturbances. In coastal sub-arctic heathland, we quantified the impact of a factorial design simulating extreme winter warming (WW) events (7 days a...
Published in: | Frontiers in Plant Science |
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Language: | English |
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Frontiers Media S.A.
2018
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Online Access: | https://doi.org/10.3389/fpls.2018.01787 https://doaj.org/article/94cd6d8779e446cdb875767e078c22ef |
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ftdoajarticles:oai:doaj.org/article:94cd6d8779e446cdb875767e078c22ef 2023-05-15T14:58:08+02:00 Impact of Multiple Ecological Stressors on a Sub-Arctic Ecosystem: No Interaction Between Extreme Winter Warming Events, Nitrogen Addition and Grazing Stef Bokhorst Matty P. Berg Guro K. Edvinsen Jacintha Ellers Amber Heitman Laura Jaakola Hanne K. Mæhre Gareth K. Phoenix Hans Tømmervik Jarle W. Bjerke 2018-11-01T00:00:00Z https://doi.org/10.3389/fpls.2018.01787 https://doaj.org/article/94cd6d8779e446cdb875767e078c22ef EN eng Frontiers Media S.A. https://www.frontiersin.org/article/10.3389/fpls.2018.01787/full https://doaj.org/toc/1664-462X 1664-462X doi:10.3389/fpls.2018.01787 https://doaj.org/article/94cd6d8779e446cdb875767e078c22ef Frontiers in Plant Science, Vol 9 (2018) cryptogam CO2 fluxes fatty acids frost geometrid moth herbivory Plant culture SB1-1110 article 2018 ftdoajarticles https://doi.org/10.3389/fpls.2018.01787 2022-12-31T06:22:42Z Climate change is one of many ongoing human-induced environmental changes, but few studies consider interactive effects between multiple anthropogenic disturbances. In coastal sub-arctic heathland, we quantified the impact of a factorial design simulating extreme winter warming (WW) events (7 days at 6–7°C) combined with episodic summer nitrogen (+N) depositions (5 kg N ha-1) on plant winter physiology, plant community composition and ecosystem CO2 fluxes of an Empetrum nigrum dominated heathland during 3 consecutive years in northern Norway. We expected that the +N would exacerbate any stress effects caused by the WW treatment. During WW events, ecosystem respiration doubled, leaf respiration declined (-58%), efficiency of Photosystem II (Fv/Fm) increased (between 26 and 88%), while cell membrane fatty acids showed strong compositional changes as a result of the warming and freezing. In particular, longer fatty acid chains increased as a result of WW events, and eicosadienoic acid (C20:2) was lower when plants were exposed to the combination of WW and +N. A larval outbreak of geometrid moths (Epirrita autumnata and Operophtera brumata) following the first WW led to a near-complete leaf defoliation of the dominant dwarf shrubs E. nigrum (-87%) and Vaccinium myrtillus (-81%) across all experimental plots. Leaf emergence timing, plant biomass or composition, NDVI and growing season ecosystem CO2 fluxes were unresponsive to the WW and +N treatments. The limited plant community response reflected the relative mild winter freezing temperatures (-6.6°C to -11.8°C) recorded after the WW events, and that the grazing pressure probably overshadowed any potential treatment effects. The grazing pressure and WW both induce damage to the evergreen shrubs and their combination should therefore be even stronger. In addition, +N could have exacerbated the impact of both extreme events, but the ecosystem responses did not support this. Therefore, our results indicate that these sub-arctic Empetrum-dominated ecosystems are highly ... Article in Journal/Newspaper Arctic Climate change Empetrum nigrum Northern Norway Directory of Open Access Journals: DOAJ Articles Arctic Norway Frontiers in Plant Science 9 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
cryptogam CO2 fluxes fatty acids frost geometrid moth herbivory Plant culture SB1-1110 |
spellingShingle |
cryptogam CO2 fluxes fatty acids frost geometrid moth herbivory Plant culture SB1-1110 Stef Bokhorst Matty P. Berg Guro K. Edvinsen Jacintha Ellers Amber Heitman Laura Jaakola Hanne K. Mæhre Gareth K. Phoenix Hans Tømmervik Jarle W. Bjerke Impact of Multiple Ecological Stressors on a Sub-Arctic Ecosystem: No Interaction Between Extreme Winter Warming Events, Nitrogen Addition and Grazing |
topic_facet |
cryptogam CO2 fluxes fatty acids frost geometrid moth herbivory Plant culture SB1-1110 |
description |
Climate change is one of many ongoing human-induced environmental changes, but few studies consider interactive effects between multiple anthropogenic disturbances. In coastal sub-arctic heathland, we quantified the impact of a factorial design simulating extreme winter warming (WW) events (7 days at 6–7°C) combined with episodic summer nitrogen (+N) depositions (5 kg N ha-1) on plant winter physiology, plant community composition and ecosystem CO2 fluxes of an Empetrum nigrum dominated heathland during 3 consecutive years in northern Norway. We expected that the +N would exacerbate any stress effects caused by the WW treatment. During WW events, ecosystem respiration doubled, leaf respiration declined (-58%), efficiency of Photosystem II (Fv/Fm) increased (between 26 and 88%), while cell membrane fatty acids showed strong compositional changes as a result of the warming and freezing. In particular, longer fatty acid chains increased as a result of WW events, and eicosadienoic acid (C20:2) was lower when plants were exposed to the combination of WW and +N. A larval outbreak of geometrid moths (Epirrita autumnata and Operophtera brumata) following the first WW led to a near-complete leaf defoliation of the dominant dwarf shrubs E. nigrum (-87%) and Vaccinium myrtillus (-81%) across all experimental plots. Leaf emergence timing, plant biomass or composition, NDVI and growing season ecosystem CO2 fluxes were unresponsive to the WW and +N treatments. The limited plant community response reflected the relative mild winter freezing temperatures (-6.6°C to -11.8°C) recorded after the WW events, and that the grazing pressure probably overshadowed any potential treatment effects. The grazing pressure and WW both induce damage to the evergreen shrubs and their combination should therefore be even stronger. In addition, +N could have exacerbated the impact of both extreme events, but the ecosystem responses did not support this. Therefore, our results indicate that these sub-arctic Empetrum-dominated ecosystems are highly ... |
format |
Article in Journal/Newspaper |
author |
Stef Bokhorst Matty P. Berg Guro K. Edvinsen Jacintha Ellers Amber Heitman Laura Jaakola Hanne K. Mæhre Gareth K. Phoenix Hans Tømmervik Jarle W. Bjerke |
author_facet |
Stef Bokhorst Matty P. Berg Guro K. Edvinsen Jacintha Ellers Amber Heitman Laura Jaakola Hanne K. Mæhre Gareth K. Phoenix Hans Tømmervik Jarle W. Bjerke |
author_sort |
Stef Bokhorst |
title |
Impact of Multiple Ecological Stressors on a Sub-Arctic Ecosystem: No Interaction Between Extreme Winter Warming Events, Nitrogen Addition and Grazing |
title_short |
Impact of Multiple Ecological Stressors on a Sub-Arctic Ecosystem: No Interaction Between Extreme Winter Warming Events, Nitrogen Addition and Grazing |
title_full |
Impact of Multiple Ecological Stressors on a Sub-Arctic Ecosystem: No Interaction Between Extreme Winter Warming Events, Nitrogen Addition and Grazing |
title_fullStr |
Impact of Multiple Ecological Stressors on a Sub-Arctic Ecosystem: No Interaction Between Extreme Winter Warming Events, Nitrogen Addition and Grazing |
title_full_unstemmed |
Impact of Multiple Ecological Stressors on a Sub-Arctic Ecosystem: No Interaction Between Extreme Winter Warming Events, Nitrogen Addition and Grazing |
title_sort |
impact of multiple ecological stressors on a sub-arctic ecosystem: no interaction between extreme winter warming events, nitrogen addition and grazing |
publisher |
Frontiers Media S.A. |
publishDate |
2018 |
url |
https://doi.org/10.3389/fpls.2018.01787 https://doaj.org/article/94cd6d8779e446cdb875767e078c22ef |
geographic |
Arctic Norway |
geographic_facet |
Arctic Norway |
genre |
Arctic Climate change Empetrum nigrum Northern Norway |
genre_facet |
Arctic Climate change Empetrum nigrum Northern Norway |
op_source |
Frontiers in Plant Science, Vol 9 (2018) |
op_relation |
https://www.frontiersin.org/article/10.3389/fpls.2018.01787/full https://doaj.org/toc/1664-462X 1664-462X doi:10.3389/fpls.2018.01787 https://doaj.org/article/94cd6d8779e446cdb875767e078c22ef |
op_doi |
https://doi.org/10.3389/fpls.2018.01787 |
container_title |
Frontiers in Plant Science |
container_volume |
9 |
_version_ |
1766330220229427200 |