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Welcome to the Princeton Ecohydrology Lab Website!

We've recently moved into a new site, so please let us know if you have any comments or - more likely - find any missing or dead links.

  • Dryland Ecohydrology

    Life in dryland savanna ecosystems is reliant on the spatial and temporal distribution of rainfall. In order to understand the impacts of changes in rainfall on woody vegetation patterns, our group has developed a set of modeling approaches that combine existing stochastic soil water balance models with a resource trade-off hypothesis pertaining to the organization of dryland vegetation communities. This framework has provided a mathematically tractable optimization problem which we have applied to southern African savannas, the Rio Salado basin in the US southwest, and a central Kenyan ecosystem.

  • Isotope Hydrology

    Understanding the coupled interactions between hydrology and ecology requires new measurements of environmental process at the landscape level. To this end we are beginning to use stable isotopes of hydrogen and oxygen as a tool for partitioning land surface water vapor fluxes into evaporation and transpiration components. We have recently constructed a new eddy flux tower in Likipia, Kenya which will be outfitted with a laser-based isotope analyzer from Los Gatos Research. This instrument allows continuous δ18O and δ2H measurements (1 Hz) in water vapor. It has great potential to answer both theoretical (e.g., kinetic fractionations in soil evaporation) and practical questions (e.g., the effect of vegetation structure on evaporation/transpiration partition).

First course on UAS for environmental monitoring

Last week Lyndon Estes and Kelly Caylor were in Italy to help teach a new course on UAS for Environmental Monitoring, which was organized by Kelly and Salvatore Manfreda, and run under the aegis of the University of Basilicata. Xurxo Gago from the Universitat de les Illes Balears provided instruction on multicopters and estimating crop water use from thermal imagery. The classes were held in the ancient city of Matera, while flight training and data collection practicals took place in farmland to the south near Metaponto. Read more

New article in Science

Adam Wolf from the Caylor Lab, along with researchers at Princeton University and other institutions, just published a new article in Science. In this paper, the authors studied a tree-ring database of 1338 forest sites from around the globe. They found that forests exhibit a drought “legacy effect” with 3 to 4 years’ reduced growth following drought. During this postdrought delay, forests will be less able to act as a sink for carbon. Incorporating forest legacy effects into Earth system models will provide more accurate predictions of the effects of drought on the global carbon cycle.

The paper was already featured in a series of news articles in the US and abroad, including The Washington Post, Newsweek, Reuters or Scientific American.

Collaboration with Textit for crop failure early warning system

Researchers from the Caylor Lab and the University of Indiana’s Ostrom Workshop worked with Textit, a company that builds SMS and voice applications, to design a crop failure early warning system for use among African smallholders. The system uses a series of short survey questions texted to farmers throughout the growing season to collect information on perceived climate dynamics, crop yields and agricultural decisions. The researchers are hoping to use this information, along with environmental data collected through a field-based sensor network, to better understand how smallholders respond to climate shocks and to predict when crop failures may be imminent.

Textit profiled the system and a pilot project conducted in Zambia in a recent blog post. Click below to see the article!

Where does water go when it doesn’t flow?

Former lab member Stephen Good, currently doing a post-doc at the University of Utah, and about to start a professorship at Oregon State University, just published an article in Science. For this paper, Stephen and his collaborators used water vapor isotope data from TES along with other datasets, like the GPCP and OAFlux, to provide a global estimate of evapo-transpiration partitioning. While the details can be found in the paper, the general result is that: 64 % of the water is transpired by vegetation • 6 % evaporates from soils • 3 % evaporates from lakes, streams and rivers • The other 27 % are being intercepted by vegetation.

The article is already getting some press around the www (see here, here or here), and will without doubt be a key study for future research on ecohydrology at the global scale. A good summary of the article is also provided in the “perspective” article by Renee Brooks, published in the same issue of Science.