About our research

Drylands are undergoing changes in vegetation cover and plant community composition in response to shifts in climate conditions and land use dynamics. Such changes can alter the fire regime and the surface energy balance with important potential feedback on hydroclimatic conditions. To date, some of the impacts of shifts in dryland vegetation remain poorly understood. Our group is investigating drivers and feedbacks of woody plant encroachment, exotic grass invasions, and increased CAM plant dominance. We evaluate their impact on fire frequency, rainfall regime, or exposure to freezing stress, while investigating feedbacks on vegetation dynamics. More specifically, we evaluate the role of ecohydrological processes in biotic-abiotic interactions in dryland ecosystems. We focus on the impact of hydrologic conditions on plant water stress, vegetation growth, and pattern formation. We also look at the impact of vegetation on the physical environment (e.g., soil moisture, temperature regime, precipitation) and biogeochemical cycling with a focus on positive feedbacks whereby plants improve their habitat and favor their own survival in “harsh” dryland environments.  We evaluate the extent to which such feedback can lead to alternative stable states in vegetation dynamics.

We are currently investigating the feedback between fire and precipitation in African savannas, the impact of fire on savanna-forest transitions, and the drivers of other major shifts in dryland vegetation in the context of global environmental change and land use dynamics.

Water availability constrains humanity’s ability to meet the future food and energy needs of a growing and increasingly consuming human population. It also plays an important role in the production of energy, from both renewable sources and fossil fuels, and "climate change solutions". Competition for water between food and energy production is a fundamental aspect of the ‘food-energy-water nexus’. Such a competition is critically important to the study of food and water security, the analysis of agricultural resources needed to feed the global population, and the study of the way they can be used more efficiently to eradicate undernourishment and improve environmental sustainability. Our group is investigating multiple components of the food-energy-water nexus, the resilience of the global water and food systems, the globalization of water through global trade and international land (and water) investments, and the options humanity has to meet food and energy security with the limited renewable water resources of the planet. 

The rising demand for water by human societies raises critical questions about the feasibility of feeding the world with the planet’s finite freshwater resources. As human appropriation of water increases, some important ecohydrological processes are disrupted and ecosystem functions are lost. Increasing competition between human uses and environmental needs hampers the development of sustainable water security strategies. Much of humanity’s water use is linked to fulfilling the right to food, prompting questions about how these rights and the rights of Nature that protect environmental needs can be simultaneously met. Our research assesses the biophysical and social justice limitations to sustainable water use, considering hydrological constraints, human demands, environmental flows, inequalities, technological advances, and the impacts of globalization. We address this question at different scales, from the context of local water tenure arrangements to global virtual water trade.