The PhD will be carried out within the ENS Lyon component of the EVS laboratory (150 permanent researchers and administrators, 180 doctoral students), a mixed CNRS / University of Lyon multi-site research unit spread over the Lyon Saint-Etienne geographical area
Forests along rivers are under threat due to climate-driven changes in water availability to trees. When water in the rooting zone is limited, trees undergo physiological changes that affect their overall growth and health through water stress. This problem is particularly acute within forests in river floodplains in regions with warm, dry summers. Such forests provide a range of ecosystem services, but they are limited in area, species diversity, and are challenging to manage under a changing climate. There is currently limited understanding linking regional climate to water availability to water use by riparian trees across forests stands, which limits predictive capability of forest response to drought stress over decadal timescales.
This project aims to build new understanding of the ecohydrological links between water availability and stress by employing an interdisciplinary set of research methods along the Rhône River, France. The project will compare the ecohydrological responses to climate in water availability at forest sites along a strong climatic gradient based on 3 existing field installations with ongoing data collection (upper, middle and lower Rhône).
Using hydroclimate data, alongside isotopes in waters and plants, the PhD student will address three research questions: - i) How has groundwater versus surface water availability varied recently as a function of climate?;
- ii) How is water availability and water stress recorded in tree rings?;
- iii) Can riparian forest responses to water availability be predicted from hydrometeorological data, isotopes, and remote sensing?