Resistance and change in a High Arctic ecosystem, NW Greenland : differential sensitivity of ecosystem metrics to 15 years of experimental warming and wetting
Jespersen, R. Gus; Leffler, A. Joshua; Väisänen, Maria; Welker, Jeffrey M. (2021-12-06)
Jespersen, R. G., Leffler, A. J., Väisänen, M., & Welker, J. M. (2022). Resistance and change in a High Arctic ecosystem, NW Greenland: Differential sensitivity of ecosystem metrics to 15 years of experimental warming and wetting. Global Change Biology, 28, 1853–1869. https://doi.org/10.1111/gcb.16027
© 2021 John Wiley & Sons Ltd. This article is protected by copyright. All rights reserved. This is the peer reviewed version of the following article: Jespersen, R. G., Leffler, A. J., Väisänen, M., & Welker, J. M. (2022). Resistance and change in a High Arctic ecosystem, NW Greenland: Differential sensitivity of ecosystem metrics to 15 years of experimental warming and wetting. Global Change Biology, 28, 1853–1869, which has been published in final form at https://doi.org/10.1111/gcb.16027. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."
https://rightsstatements.org/vocab/InC/1.0/
https://urn.fi/URN:NBN:fi-fe2021121761688
Tiivistelmä
Abstract
Dramatic increases in air temperature and precipitation are occurring in the High Arctic (>70 °N), yet few studies have characterized the long-term responses of High Arctic ecosystems to the interactive effects of experimental warming and increased rain. Beginning in 2003, we applied a factorial summer warming and wetting experiment to a polar semidesert in northwest Greenland. In summer 2018, we assessed several metrics of ecosystem structure and function, including plant cover, greenness, ecosystem CO₂ exchange, aboveground (leaf, stem) and belowground (litter, root, soil) carbon (C) and nitrogen (N) concentrations (%) and pools, as well as leaf and soil stable isotopes (δ¹³C and δ¹⁵N). Wetting induced the most pronounced changes in ecosystem structure, accelerating the expansion of S. arctica cover by 370% and increasing aboveground C, N, and biomass pools by 94–101% and root C, N, and biomass pools by 60–122%, increases which coincided with enhanced net ecosystem CO₂ uptake. Further, wetting combined with warming enhanced plot-level greenness, whereas in isolation neither wetting nor warming had an effect. At the plant level the effects of warming and wetting differed among species and included warming-linked decreases in leaf N and δ¹⁵N in Salix arctica, whereas leaf N and δ¹⁵N in Dryas integrifolia did not respond to the climate treatments. Finally, neither plant- nor plot-level C and N allocation patterns nor soil C, N, δ¹³C, or δ¹⁵N concentrations changed in response to our manipulations, indicating that these ecosystem metrics may resist climate change, even in the longer term. In sum, our results highlight the importance of summer precipitation in regulating ecosystem structure and function in arid parts of the High Arctic, but they do not completely refute previous findings of resistance in some High Arctic ecosystem properties to climate change.
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