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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).

Summer at Mpala: water use and agriculture

This summer Drew Gower traveled to Kenya for a three-week mission wrapping up one project and launching another. From 2012 to 2014, researchers from the Caylor Lab and the Ostrom Workshop at Indiana University collected water use and agricultural production data in 25 community water projects (CWP) across the Laikipia region as part of a Coupled Natural and Human Systems Grant from NSF. The researchers then used this data to create individualized reports describing current practices in each project and comparisons with those of their neighbors. During the first week of his trip, Drew met with the management committees of ten CWP clustered around the Ngare Nything and Timau rivers to deliver the last of these reports and to discuss their content with interested members. 

After successfully closing out the project described above, members of the Ecohydrology Lab look forward to continuing its work in Laikipia through a new project funded by a Water Sustainability and Climate grant from the NSF. This project will use environmental data collected through a field-based sensor network, along with the results of farmer surveys, to better understand how smallholders respond to climate shocks and to predict when crop failures may be imminent. Drew spent the last two weeks of his trip working with the lab staff to assemble, program and deploy these sensors at sites around the Nanyuki and Likii Rivers. Since Drew’s departure, the lab staff has deployed additional sensors at sites near the Ngusishi River as well.

Report delivery with the management committee of the Mugo Kongo CWP
Report delivery with the management committee of the Mugo Kongo CWP
Drew and Boniface after finishing installation of a PulsePod sensor
Drew and Boniface after finishing installation of a PulsePod sensor

Teaching the TBI Field School students

TBI Origins Field School students and the members of the EcoHydrology Lab take a group photo under the tower
TBI Origins Field School students and the members of the EcoHydrology Lab take a group photo under the tower

Students from the Turkana Basin Institute Field School recently spent some time at Mpala, learning about the field ecology of African savanna. John Gitonga, helped by other members of the EcoHydrology Lab at Mpala, gave the students a short course on dryland hydrology. The group also went to visit our flux tower and got a full tour of the different instruments.

Learn more and see some pictures in this post.


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.