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Research article - Peer-reviewed, 2020

Divergence of Arctic shrub growth associated with sea ice decline

Buchwal, Agata; Sullivan, Patrick F.; Macias-Fauria, Marc; Post, Eric; Myers-Smith, Isla H.; Stroeve, Julienne C.; Blok, Daan; Tape, Ken D.; Forbes, Bruce C.; Ropars, Pascale; Levesque, Esther; Elberling, Bo; Angers-Blondin, Sandra; Boyle, Joseph S.; Boudreau, Stephane; Boulanger-Lapointe, Noemie; Gamm, Cassandra; Hallinger, Martin; Rachlewicz, Grzegorz; Young, Amanda;
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Arctic sea ice extent (SIE) is declining at an accelerating rate with a wide range of ecological consequences. However, determining sea ice effects on tundra vegetation remains a challenge. In this study, we examined the universality or lack thereof in tundra shrub growth responses to changes in SIE and summer climate across the Pan-Arctic, taking advantage of 23 tundra shrub-ring chronologies from 19 widely distributed sites (56 degrees N to 83 degrees N). We show a clear divergence in shrub growth responses to SIE that began in the mid-1990s, with 39% of the chronologies showing declines and 57% showing increases in radial growth (decreasers and increasers, respectively). Structural equation models revealed that declining SIE was associated with rising air temperature and precipitation for increasers and with increasingly dry conditions for decreasers. Decreasers tended to be from areas of the Arctic with lower summer precipitation and their growth decline was related to decreases in the standardized precipitation evapotranspiration index. Our findings suggest that moisture limitation, associated with declining SIE, might inhibit the positive effects of warming on shrub growth over a considerable part of the terrestrial Arctic, thereby complicating predictions of vegetation change and future tundra productivity.


tundra shrubs; sea ice; Arctic; shrub rings; divergence

Published in

Proceedings of the National Academy of Sciences of the United States of America
2020, volume: 117, number: 52, pages: 33334-33344

Authors' information

Buchwal, Agata
University of Alaska Anchorage
Sullivan, Patrick F.
University of Alaska Anchorage
Macias-Fauria, Marc
University of Oxford
Post, Eric
University of California Davis
Myers-Smith, Isla H.
University of Edinburgh
Stroeve, Julienne C.
University of Colorado Boulder
Blok, Daan
Dutch Research Council (NWO)
Tape, Ken D.
University of Alaska Fairbanks
Forbes, Bruce C.
University of Lapland
Ropars, Pascale
University of Quebec
Ropars, Pascale
McGill University
Levesque, Esther
University of Quebec
Elberling, Bo
University of Copenhagen
Angers-Blondin, Sandra
University of Edinburgh
Boyle, Joseph S.
University of Edinburgh
Boudreau, Stephane
Laval University
Boulanger-Lapointe, Noemie
University of British Columbia
Gamm, Cassandra
University of Alaska Anchorage
Hallinger, Martin
Swedish University of Agricultural Sciences, Department of Ecology
Rachlewicz, Grzegorz
Xi'an Jiaotong-Liverpool University
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UKÄ Subject classification

Climate Research

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