Dr. Anke Hildebrandt
Seminar in the Department of Geology & Geography
Title: Biotic and abiotic controls on soil water and canopy fluxes in a temperate grassland diversity experiment.
Thursday, Feb. 11th, 4-5pm
Herty Building, Statesboro, GA, United States (Room 2112)
The Jena Experiment, located in the Saale floodplain in Thuringia (Germany, temperate mid latitude climate) investigates how loss of grassland diversity reflects on ecosystem function. 82 artificial ecosystems of varying species diversity (1,2,4,8,16 and 60 species) and functional diversity (1,2,3,4) were sown in 2002 and maintained to the same diversity levels by weeding. Our group investigates whether and how grassland species diversity and functional groups reflect on canopy fluxes and soil water. We investigated soil texture, structural parameters, hydraulic properties and soil water in each ecosystem. We also derived water fluxes and root water uptake profiles for 12 selected ecosystems on extracted soil monoliths in an ECOTON facility (CNRS, Montpellier). Our results show a relation between species diversity, soil water and canopy fluxes in multiple ways that were strongly related to changes of the soil structure due to enhanced soil organic carbon content in diverse plots. This affected soil hydraulic conductivity, the average soil water content and supposedly improved water use efficiency by facilitating fast vertical flow and deep root water uptake. Also, functional groups affected some given processes independently. Interestingly, soil texture had little influence on any of the observed patterns. Our results underline that plant species diversity affects processes below ground, some of which are typically considered abiotic, and that those effects move deeper with time.
Dr. Hildebrandt is visiting Georgia Southern University as a collaborator on a recently funded National Science Foundation grant seeking to determine how hydro-meteorological processes in forests are altered with urbanization. Although much is known about how urbanization affects routing of water at and below the surface, little work has quantitatively characterized how urban alterations to forest canopy structure influences the amount of water available to the surface and subsurface. Working with Georgia Southern professors, Drs. Van Stan and Underwood, and other international scholars (Jan Friesen – Helmholtz Centre for Environmental Research, Jean-Francois Cote – Natural Resources Canada) on this project, Dr. Hildebrandt will assist in developing models to allow water resource managers to better predict precipitation inputs in forested urban watersheds.
During her February visit she will present current work on grasslands at Friedrich-Schiller University and Max Planck Institute for Biogeochemistry.