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.
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.
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).
Kelly Caylor recently received the third place for the PulsePod at the Keller Center‘s 10th annual Innovation Forum. This event is the opportunity for University researchers to present potentially marketable discoveries. Kelly only had three minutes to convince the judges that the environmental sensing platform will indeed help empowering land managers to make better decisions about their resources. The PulsePod device is combination of hardware and software and provides in-field monitoring of crop health, microclimate, water and nutrients — information that is currently not easily available to farmers.
This year’s forum also included presentations on a new treatment for cancer, a possible solution to widespread water contamination and a type of laser that could diagnose diseases before any symptoms appear. The picture on the left shows this year’s winners (Kelly is in the middle of the second row). You can see the official announcement HERE.
This year was the tenth consecutive Innovation Forum and the Civil and Environmental Engineering Department has a long history of convincing innovators that their ideas are worth commercializing. See the summary of the latest CEE innovations success stories, including the PulsePod, HERE.
Kelly Caylor and a group of scientists from Princeton University recently published a paper in Science on the influence of termite mounds in dryland ecosystems. Spotty vegetation patterns in tropical savannas and grasslands can be a warning sign of imminent desertification. However, the group finds that termites can also produce spotty patterns. Their theoretical study, confirmed by field data from Kenya, shows that patterns produced by termite mounds are not harbingers of desertification. Indeed, the presence of termites buffers these ecosystems against climate change.
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.