Global assessment of experimental climate warming on tundra vegetation: Heterogeneity over space and time

Citation

Elmendorf SC, Henry GHR, Hollister RD, Bjork RG, Bjorkman AD, Callaghan TV, Collier LS, Cooper EJ, Cornelissen JHC, Day TA, Fosaa AM, Gould WA, Gretarsdottir J, Harte J & Wookey P (2012) Global assessment of experimental climate warming on tundra vegetation: Heterogeneity over space and time. Ecology Letters, 15 (2), pp. 164-175. https://doi.org/10.1111/j.1461-0248.2011.01716.x

Abstract
Understanding the sensitivity of tundra vegetation to climate warming is critical to forecasting future biodiversity and vegetation feedbacks to climate. In situ warming experiments accelerate climate change on a small scale to forecast responses of local plant communities. Limitations of this approach include the apparent site-specificity of results and uncertainty about the power of short-term studies to anticipate longer term change. We address these issues with a synthesis of 61 experimental warming studies, of up to 20years duration, in tundra sites worldwide. The response of plant groups to warming often differed with ambient summer temperature, soil moisture and experimental duration. Shrubs increased with warming only where ambient temperature was high, whereas graminoids increased primarily in the coldest study sites. Linear increases in effect size over time were frequently observed. There was little indication of saturating or accelerating effects, as would be predicted if negative or positive vegetation feedbacks were common. These results indicate that tundra vegetation exhibits strong regional variation in response to warming, and that in vulnerable regions, cumulative effects of long-term warming on tundra vegetation - and associated ecosystem consequences - have the potential to be much greater than we have observed to date. © 2011 Blackwell Publishing Ltd/CNRS.

Keywords
Alpine; Arctic; climate warming; long-term experiment; meta-analysis; plants

Notes
Additional co-authors: Luise Hermanutz, David S. Hik, Annika Hofgaard, Frith Jarrad, Ingibjorg Svala Jonsdottir, Frida Keuper, Kari Klanderud, Julia A. Klein, Saewan Koh, Gaku Kudo, Simone I. Lang, Val Loewen, Jeremy L. May, Joel Mercado, Anders Michelsen, Ulf Molau, Isla H. Myers-Smith, Steven F. Oberbauer, Sara Pieper, Eric Post, Christian Rixen, Clare H. Robinson, Niels Martin Schmidt, Gaius R. Shaver, Anna Stenstrom, Anne Tolvanen, Orjan Totland, Tiffany Troxler, Carl-Henrik Wahren, Patrick J. Webber, Jeffery M. Welker

Journal
Ecology Letters: Volume 15, Issue 2