Friday, August 12, 2011: 8:00 AM-11:30 AM
17B, Austin Convention Center
Organizer:
Susan Schwinning
Co-organizers:
Georgianne W. Moore
,
James L. Heilman
,
Pieter Poot
,
Michael C. Duniway
and
Karin T. Rebel
Moderator:
Susan Schwinning
Continental scale soil depth maps suggest that a large proportion of the global land area has limited soil depth of 1 m or less. These regions are often underlain by weathered bedrock or cemented horizons that impede water infiltration and root development. Though most hydrologic models assume that these firm horizons do not contribute to ecohydrologic processes, isolated case studies in locations around the world suggest a significant role for fractured bedrock and petrocalcic horizons in plant water availability. Furthermore, vegetation adaptations to soil depth limitations and resulting impacts on hydrological processes have never been systematically explored. This presents new challenges and opportunities for modeling – predicting how these ecosystems will respond to a changing climate will require a mechanistic understanding of water movement, retention and, most critically, how and when plants utilize water from firm, root restrictive horizons. Many of these ecosystems are vulnerable to climate extremes, erosion and pollution, while often contributing disproportionally to regional biodiversity and water yield.
The central objective of this symposium is to work towards framing an integrated ecohydrological research agenda for the study of ecosystems with shallow soils for the purpose of improving the management of these plant communities as well as their representation in hydrological models. The spotlight will be on the following themes: 1) assessment of water storage contributions of weathered bedrock/cemented horizons; 2) plant adaptations to soil depth limitations and the use of fractured bedrock or cemented horizons for water uptake; 3) the representation of mixed soil/rock storage substrates and associated plant traits in ecohydrological models.
The symposium will begin with a brief introduction summarizing the global extent of shallow soils and the research questions they pose. On the topic of water storage in bedrock and cemented horizons, presentations will span multiple regions across three continents differing markedly in geological and climate characteristics. On the topic of plant adaptations, speakers will focus on identifying the morphological, physiological and ecological requisites for the extraction of rock water by plant roots and their fungal symbionts. Lastly, speakers will present their thoughts on developing hydrological models that best capture the moisture dynamics of regions characterized by shallow soils and firm subsoil substrates. The session will close with a call for audience feedback and a panel discussion to synthesize the information presented and distill common themes suitable for the framing of a unified ecohydrology of shallow soils.
10:10 AM
See more of: Organized Oral Session