Permafrost thaw affects boreal deciduous plant transpiration through increased soil water, deeper thaw, and warmer soils

Jessica M. Cable, Kiona Ogle, W. Robert Bolton, Lisa P. Bentley, Vladimir Romanovsky, Hiroki Iwata, Yoshinobu Harazono, Jeffrey Welker

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

The effect of thawing permafrost on boreal ecosystem water cycling represents a significant knowledge gap of how climate change will affect northern landscapes. Evapotranspiration, particularly transpiration, may be changing in response to changes in permafrost conditions, vegetation, and climate. This study focuses on the effect of permafrost thaw on boreal plant transpiration over two summers with contrasting weather conditions. We quantified the response of stomatal conductance (gs), from which transpiration was calculated, of deciduous and evergreen plants to soil environmental factors that permafrost thaw affects: soil water content (S), depth of seasonal thaw (D), and soil temperature (T). We found that gs was least sensitive to T compared with S and D at both sites and across both years. At the thawing site, gs was more sensitive to S in a dry year (2009) and to D in a wet year (2010). In the wet year, S of ~50cm represented a threshold wherein the sensitivity of gs to T and D switched between positive (S<50cm) and negative (S>50cm). However, the sensitivities to T and D were negative when S was consistently less than 50cm in the dry year. This is one of the first studies to explore the effect of permafrost thaw on boreal plant gs and transpiration, and our model predicted higher transpiration rates from deciduous plants located on thawing permafrost.

Original languageEnglish (US)
Pages (from-to)982-997
Number of pages16
JournalEcohydrology
Volume7
Issue number3
DOIs
StatePublished - Jun 2014

Keywords

  • Active layer
  • Bayesian
  • Boreal ecohydrology
  • Interior Alaska
  • Soil water storage
  • Stomatal conductance

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science
  • Ecology
  • Earth-Surface Processes

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    Cable, J. M., Ogle, K., Bolton, W. R., Bentley, L. P., Romanovsky, V., Iwata, H., Harazono, Y., & Welker, J. (2014). Permafrost thaw affects boreal deciduous plant transpiration through increased soil water, deeper thaw, and warmer soils. Ecohydrology, 7(3), 982-997. https://doi.org/10.1002/eco.1423