Extreme heat waves, droughts, and bushfires are becoming increasingly common in Australia. While such events impact plant performance individually, it is their interactions that pose a greater threat to long-term plant survival. Quantifying the thresholds of drought, heat, and fire tolerance of species is fundamental to forecast future responses and guide conservation practices. Unfortunately, limited information is available, and conservation decision-making is still primarily based on qualitative metrics (tolerant/not-tolerant), which lack a physiological basis and neglect multi-stress responses. For the first time, this project will develop a practical framework for quantifying the individual and combined tolerances of plants to multiple stressors, using endangered Australian plants as a model system. By combining fieldwork, laboratory experimentation, and modelling approaches, this project will create generalizable predictions of plant multi-stress responses. Project outcomes will fill a critical knowledge gap in the context of climate change, which is exposing vegetation to novel stress combinations.

Most of the traits used to describe plants' responses to drought are time-consuming/expensive to measure, so they are usually sampled in a single life stage - either mature trees growing in the field or in juvenile trees (seedling/saplings) growing in glasshouses. Those single-stage traits are then used interchangeably to model trees’ responses to drought and other stresses. However, saplings are not simply a miniature of mature trees. Instead, juveniles, adults, and even resprouting trees of the same species can greatly differ in their tolerance to drought, with juveniles/resprouting being usually, but not always more susceptible to water stress. Therefore, extrapolating results from one life stage to another is problematic and can either overestimate resilience in restoration projects if models are based on mature traits; or under-estimate resilience, if based on saplings/seedlings. This project is using Acacia and Eucalyptus - two of the most abundant genera of Australian trees - as a model system to investigate developmental variation in tree tolerance to drought. Project outcomes will represent a transformative advance in our capacity to forecast tree responses to droughts, providing a framework for predicting the effects of climate change that target specific plant developmental stages. This new knowledge will benefit conservation and restoration planning and decision-making around securing the medium- and long-term preservation of tree species as the world becomes drier.

During my master’s degree at the Botanical Garden of Rio de Janeiro (RJ, Brazil), I conducted field and greenhouse experiments to investigate how positive interactions among shrubs and seedlings could enhance the drought resilience of Restingas, a Brazilian coastal vegetation. Although all studied species showed higher seedling survival rates beneath shrubs, a few species grew better on bare and drier soils. Those intriguing results made me wonder why some plants succumb while others resist droughts. Read More

To further evaluate the differential resilience of plants to drought, I left the coastal plains and climbed up to the top of the highest mountains in Brazil. In the Campos de Altitude, the grassland vegetation that covers those mountains summits, I developed my Ph.D. dissertation, which explored the differential vulnerability of plant communities to drought. During my Ph.D., I conducted a meta-analysis of rainfall manipulative experiments performed on grasslands to evaluate their overall stability (resilience, recovery, and resistance) in response to droughts. I also investigated three different functional strategies that plants from the Campos de Altitude exhibit in response to drought, which included drought-tolerance, foliar water storage, and foliar water absorption (i.e. the ability to absorb atmospheric sources of water through the leaves). Read more

In my postdoctoral position at the University of California at Berkeley I led a multicultural team of 28 graduate and undergraduate students to investigate the rules linking leaf venation architecture and function. Working on this NSF-funded and cutting-edge project allowed me to continue evaluating mechanisms of plant resistance and resilience to drought, but also expand into other important functional processes at the leaf-level scale (e.g. herbivory, mechanical damage). Read more