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).
As part of the PulseLab project, Adam Wolf, Lyndon Estes, Ben Siegfried and Matteo Kruijssen (PEI Grand Challenge intern working with Lyndon for the summer) went out in California in June to install sensors in agricultural fields with the goal of realtime monitoring of crop growth and microclimate in control, water limited, and N-limited corn fields. Since crop growth forecasts are largely driven by remote sensing, these observations help to improve space-borne satellite retrievals for modeling, but also provide important constraints to the local microclimate, including temperature and soil moisture, which are critical to improving the predictions of climate change impacts on crop productivity. Check out the pictures of their fieldtrip below!
End of July, Adam and Ben went out again, to New Mexico this time. You can see the pictures of the pods installation HERE.
The NASA grant was awarded to Lyndon under the New Investigator Program in Earth Science for his proposal entitled “Integrating crowdsourcing, in situ sensing, and spaceborne observation to understand the sustainability of smallholder agriculture in African wet savannas”. This project will use a combination of remote sensing, field observations by PULSE lab sensors, machine learning (led by Stephanie Debats), and crowdsourcing to detect trends in the area and productivity of Zambian maize farms since 2000. The aim is to assess 1) whether yield increases are correlated with cropland expansion or contraction, 2) whether yield increases precede cropland changes, and 3) whether yield gains correspond to increased climate sensitivity. This research will provide insight into the socioeconomic and ecological sustainability of agricultural expansion in a region of increasing climatic variability and rapid growth.
The Mpala Research Center just launched Mpala Live!, an interactive website featuring a round-the-clock view of the hippos, elephants, and other incredible species that frequent Hippo Pools. It allows vistors to experience Mpala with scientists as they study relationships among humans, animals, and ecosystems and to learn about the wildlife of Laikipia with a field guide featuring a wide range of species from aardvarks to zebras. In addition, the Mpala Live! classroom introduces teachers and students and parents and children to a unique curricula keyed to Mpala’s flora and fauna. Make sure to check it out!