How does critical zone structure mediate the response of seasonally dry ecosystems to climatic variability?

Investigator Names and Contact Info:

• David Dralle (Ecohydrology). Department of Earth and Planetary Science, University of California, USA & California State University Sacramento, USA
• Todd Ehlers (Geology/Geophysics). Dept. of Geosciences, University of Tuebingen, Germany

Chilean Collaborators Involved:

• Luca Mao (Geomorphology). Pontificia Universidad Catolica de Chile & University of Lincoln, UK

Project summary:

While purely climatic and physiological controls on ecosystem productivity have been thoroughly researched in seasonally dry ecosystems, few studies have explicitly examined the role of the subsurface (especially beyond shallow soil layers into saprolite and weathered bedrock). Yet the subsurface stores the water that may be expected to play a central role in ecosystem activity, especially during the dry season. This project explores how plant available water storage capacity (AWC) of the critical zone mediates the relationship between rainfall climatology and annual productivity in seasonally dry climates. We investigate this topic using catchment-scale mass balance and flow recession methods. Theories from stochastic ecohydrology are applied to predict AWC using vegetation remote sensing data. Shallow geophysics and direct observations of subsurface water storage dynamics constrain inferences made using new theory. The project is funded by the CZO SAVI International Scholars Program and is a collaboration the Eel River Critical Zone Observatory and the EarthShape Project.