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- Title
The role of isohydric and anisohydric species in determining ecosystem-scale response to severe drought.
- Authors
Roman, D.; Novick, K.; Brzostek, E.; Dragoni, D.; Rahman, F.; Phillips, R.
- Abstract
Ongoing shifts in the species composition of Eastern US forests necessitate the development of frameworks to explore how species-specific water-use strategies influence ecosystem-scale carbon (C) cycling during drought. Here, we develop a diagnostic framework to classify plant drought-response strategies along a continuum of isohydric to anisohydric regulation of leaf water potential ( Ψ). The framework is applied to a 3-year record of weekly leaf-level gas exchange and Ψ measurements collected in the Morgan-Monroe State Forest (Indiana, USA), where continuous observations of the net ecosystem exchange of CO (NEE) have been ongoing since 1999. A severe drought that occurred in the middle of the study period reduced the absolute magnitude of NEE by 55 %, though species-specific responses to drought conditions varied. Oak species were characterized by anisohydric regulation of Ψ that promoted static gas exchange throughout the study period. In contrast, Ψ of the other canopy dominant species was more isohydric, which limited gas exchange during the drought. Ecosystem-scale estimates of NEE and gross ecosystem productivity derived by upscaling the leaf-level data agreed well with tower-based observations, and highlight how the fraction of isohydric and anisohydric species in forests can mediate net ecosystem C balance.
- Subjects
EDDY flux; ECOSYSTEMS; DROUGHTS; FORESTS &; forestry; ECOPHYSIOLOGY
- Publication
Oecologia, 2015, Vol 179, Issue 3, p641
- ISSN
0029-8549
- Publication type
Article
- DOI
10.1007/s00442-015-3380-9