Forests across the globe are increasingly being threatened by various anthropogenic drivers, especially changes in climate. Climate variability is expected to increase in the future, leading to more frequent and more intense droughts. Yet, despite decades of research, understanding the drought vulnerability of forests has remained limited, primarily because of a lack of realism in vegetation models and, in particular, their lack of capacity to predict plant responses to unprecedented environmental conditions.
Thus, the Plant-FATE (Plant FunctionAl Trait Evolution) project has aimed to incorporate new and emerging paradigms in vegetation modelling centred on the principles of adaptation and evolution, to develop a new trait-based eco-evolutionary vegetation model and use it to predict global plant responses to drought and assess the vulnerability of forests to future changes in climate.
The two most important physiological processes determining the responses of individual plants to droughts are carbon uptake (photosynthesis) and water transport (hydraulics): accordingly, plants have evolved diverse photosynthetic and hydraulic strategies to respond to drought, addressing the fundamental tradeoff between their acquisition of CO2 and water and their survival from carbon starvation and hydraulic failure. With individual plant responses scaling up to the level of plant communities, these strategies influence emergent ecosystem properties in terms of community structure, ecosystem productivity, and biodiversity.
Through Plant-FATE Objectives 1 and 2, I have developed new optimality-based theory for the aforementioned fundamental physiological processes and embedded this theory into a trait-based eco-evolutionary vegetation model (Plant-FATE-EGVM) capable of representing competition for light, individual-level and community-level responses to drought, successional dynamics, and trait evolution. Through Plant-FATE Objective 3, I have calibrated the Plant-FATE-EGVM at both local and global scales, enabling predictions of the responses of current plant communities to future climate change.