WG 50 Stomata and Climate Change

First meeting held 4-7 November 2008, at Macquarie U. Meeting lead by Dr Peter Franks. Second meeting 12-15 January 2010

PARTICIPANTS INCLUDE Peter Franks - James Cook U, Cairns - stomatal and plant environmental physiologist David Cantrill - Royal Botanic Gardens, Melbourne - palaeobotanist Dana Royer - Wesleyan U, USA - palaeobotanist and palaeoclimatologist David Beerling - Palaeobiology Research UK - Palaeobotanist, palaeoclimatologist, global modeller Joe Berry - Stanford U, USA - stomatal and plant environmental physiologist, climate and land surface modeller PARTICIPANTS AT SECOND MEETING Franks, Cantrill, Royer, Beerling, Berry, Jennifer McElwain (University College Dublin)

Nov 08 > Jan '10 >

GOAL

We ask the questions:
i) In responding to climate change, can stomata influence landscape hydrology at the continental scale, or do other hydro-meteorological factors dominate?
ii) Is there evidence of stomatal influence on landscape hydrology in the geological past?

Scientific basis
Stomatal influence on landscape evapotranspiration and hydrology has long been appreciated but poorly understood, primarily because of the complexities of the stomatal control system and its diverse characteristics across different vegetation types. The dominant climatic variables to which stomata respond instantaneously and in the long term (developmentally, evolutionarily) are environmental moisture and atmospheric CO2. Both of these variable have gone through massive, global scale changes in the geological past and these changes are thought to have been a major selective force in the diversification of land plants over the much of the Phanerozoic (last 450 Myr). Changes of similar magnitude are projected for the next century.

Two recent Nature papers (1, 2) propose that direct stomatal response to increasing atmospheric CO2 concentration over the last 50 years is the most plausible explanation for increased continental runoff over the same period. This marks a major development in understanding the linkage between stomata and hydrology. However, the claim is based on modelling only, and, for reasons noted above, the biological foundations are shallow. Through this working group we will evaluate the broader biological and palaeo-hydrological context of this phenomenon, and outline a research agenda to address the key questions listed above. Discussions will be evidence-based, drawing on member expertise in stomatal ecophysiology, palaeobotany, palaeohydrology and land surface modelling.

References
1. Gedney, N. et al. Detection of a direct carbon dioxide effect in continental river runoff records. Nature 439, 835-838 (2006).
2. Betts, R. A. Projected increase in continental runoff due to plant responses to increasing carbon dioxide. Nature 448, 1037-U5 (2007).

Last Updated February 2010