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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).

EcoHydrology Lab at the AGU Fall Meeting



The Caylor Lab will be taking over the AGU Fall Meeting next week. Check out the list of all of our presentations!


Current Members

Kelly CaylorAdam Wolf and Ben SiegfriedB11I-06 – Addressing critical environmental data gaps via low-cost, real-time, cellular-based environmental monitoring, Oral Presentation,  Monday, December 15, 2014, 09:15 AM – 09:30 AM, Moscone West, 2003

Keita DeCarlo, Marcus Spiegel and Kelly CaylorH31D-0646 – Biological Dimensions of Crack Morphology in Dryland Soils, Poster, Wednesday, December 17, 2014, 08:00 AM – 12:20 PM, Moscone West, Poster Hall

Cynthia Gerlein-Safdi, Craig Sinkler and Kelly CaylorH31G-0684 – Modeling Foliar Uptake in Colocasia Esculenta Using High Resolution Maps of Leaf Water Isotopes, Poster,  Wednesday, December 17, 2014, 08:00 AM – 12:20 PM, Moscone West, Poster Hall

Craig Sinkler, Cynthia Gerlein-Safdi and Kelly CaylorPP31D-1177 – Creating High-Resolution Maps of Leaf Water Isotopes Using IM-CRDS and IRMS Techniques, Poster,  Wednesday, December 17, 2014, 08:00 AM – 12:20 PM, Moscone West, Poster Hall

Stephanie Debats, Dee LuoLyndon Estes, Thomas Fuchs and Kelly CaylorB44C-05 – Mapping Agricultural Fields in Sub-Saharan Africa with a Computer Vision Approach, Oral Presentation,  Thursday, December 18, 2014, 05:00 PM – 05:15 PM, Moscone West, 2002

Kelly Caylor, Tom Evans, Lyndon Estes, Justin Sheffield, Beth Plale and Shahzeen Attari, GC53D-06 – Impacts of Agricultural Decision Making and Adaptive Management on Food Security in Africa, Invited Speaker,  Friday, December 19, 2014, 02:55 PM – 03:10 PM, Moscone West, 3005

Hilary Wayland and Kelly CaylorH51E-0661 – Continuous Observations of Leaf Transpiration Isotopic Composition in Two Dryland Species Highlight Sensitivity to Changes in Irradiance and Soil Water Content, Oral Presentation, Friday, December 19, 20140, 4:00 PM – 04:15 PM, Moscone West, 3022



GC11E - The Influence of Changes in Farming Practices, Vegetation, and Land Use on Climate Adaptation, Mitigation, and Ecosystem and Socioeconomic Services I PostersMonday, December 15, 2014, 08:00 AM – 12:20 PM, Moscone West, Poster Hall chaired by Merle Anders , Robert Parkhurst , Kelly Caylor and Lyndon Estes

GC14B – The Influence of Changes in Farming Practices, Vegetation, and Land Use on Climate Adaptation, Mitigation, and Ecosystem and Socioeconomic Services II,  Monday, December 15, 2014, 04:00 PM – 06:00 PM, Moscone West, 3003, chaired K. Kritee, Lyndon Estes, David Lutz and Joe Rudek


Alumni and Collaborators

Catherine Riihimaki, Kelly Caylor and David Wilcove, ED23D-3503 – Planetary boundaries and environmental citizenship: enhancing environmental science through the Princeton University Science and Engineering Education Initiative, Poster, Tuesday, December 16, 2014, 01:40 PM – 06:00 PM, Moscone South, Poster Hall

Salvatore Manfreda, Kelly Caylor and Stephen GoodH33L-02 – An ecohydrological framework to explain shifts in vegetation organization across climatological gradients, Oral Presentation, Wednesday, December 17, 2014, 02:05 PM – 02:20 PM, Moscone West, 3022

Lixin Wang, Stephen Good and Kelly CaylorH51D-0639 – Global Synthesis of Vegetation Control on Evapotranspiration Partition, Poster, Friday, December 19, 2014, 08:00 AM – 12:20 PM, Moscone West, Poster Hall


New paper in Biogeosciences

We recently published a paper in Biogeosciences, in which we generate different rainfall scenarios with fixed total annual rainfall but shifts in (i) frequency vs. intensity, (ii) rainy season length vs. frequency, (iii) intensity vs. rainy season length. These scenarios are fed into SEIB-DGVM to investigate changes in biome distributions and ecosystem productivity. We find a loss of ecosystem productivity with increased rainfall frequency and decreased intensity at very low rainfall regimes (<400 mm year−1) and low frequency (<0.3 event day−1); beyond these very dry regimes, most ecosystems benefit from increased frequency and decreased intensity, except in the wet tropics (>1800 mm year−1) where radiation limitation prevents further productivity gains.


New paper in GRL

We recently published a paper in Geophysical Research Letters that investigates the relationship between the ratio of transpiration over evapotranspiration (T/ET) and leaf area index (LAI). We developed a function relating T/ET to the growing stage relative to the timing of peak LAI. LAI and growing stage collectively explained 43% of the variations in the global T/ET data set, providing a new way to interpret and model global T/ET variability.


Summer at Mpala: plant physiological response to water stress

This summer, Hilary and her intern Kathy joined Drew and Keita in Laikipia, Kenya to collect data on plant physiological response to water stress. Hilary spent her summer recording photosynthesis and transpiration rates of Acacia mellifera along a water availability gradient at the Caylor Lab’s eddy covariance-isotope tower at Mpala Research Center. By looking at differences in carbon fixation rate, water loss and leaf hydraulic conductivity of the same species in various stages of water stress, it is possible to gauge the vulnerability of species to drought. Hilary hopes to pair this information with landscape-scale data from the flux tower to better understand and predict patterns in species distribution and abundance.

Summer in the lab: foliar uptake in Colocasia esculenta

This summer, Cynthia Gerlein and her intern Craig Sinkler spent the summer in the lab in Princeton to conduct an experiment looking at foliar uptake in Colocasia esculenta, a tropical specie. After a few weeks spent growing the plants, they subjected half of the plants to a drought treatment, while the other half received isotopically enriched water sprayed on the surface of the leaves every two days. The treatment experiment lasted 4 weeks during which they collected leaves from both treatments. They used the Picarro Induction Module and spatial interpolation techniques to obtain high resolution maps of the spatial distribution of the isotopes within the leaves. This experiment, coupled with water potential experiments and a rigorous validation of the induction module data against IRMS data, will be the basis for Cynthia’s effort to include foliar uptake into a leaf water balance model.