Plant ecology

Heatwaves are increasing in frequency and intensity, and extreme heat poses a significant threat to tree growth and survival. This ARC DECRA project investigated how different Australian tree species responded to extreme heat by tracking dynamic changes in water use during both natural and experimental heatwaves, representing current and future stress levels. My lab group tested if there was a predictable response to compound heat and drought events among plant species to better forecast the potential effects of climate change on forests. We identified heat-tolerant tree species and their relevant physiological traits to improve the success of urban tree plantings and create cooler, greener cities throughout Australia.

This project investigated the suitability of various plant species under current and future climate scenarios, resulting in the creation of an online interactive tool that maps the distribution of suitable habitats for various plant species across Australia. Users can select from a range of filters to choose the right species of plant for various urban areas – from street plantings to housing developments and open spaces. As a Postdoctoral Researcher, I developed a protocol for assessing the heat and drought tolerance of species -- 113 plant species were grown in common glasshouse environments and subjected to an experimental heatwave and/or drought.

My lab group regularly uses controlled experiments to elucidate mechanisms of plant stress under changing environmental conditions. This is particularly useful for simulating future climate conditions, such as warming, drought, or extreme heatwaves, and for making species comparison under standardised conditions. Example studies include: potted plants in greenhouses or whole-tree chambers, planted trees in common gardens, or naturally-grown plants in open-top chambers in the forest understory. 

Nature-based solutions help to mitigate urban heat in cities, while contributing other associated benefits such as carbon sequestration, water storage and cycling, and promoting human health and well-being. My lab group studies urban street tree growth and ecophysiology. We have recently focused on water-sensitive urban design, such as how retrofitted passive-irrigation systems or bioretention basins can promote ecosystem services on hot summer days. For more information, visit our Urban Tree Ecophysiology Network -- we invite others to join our efforts. 

A major aim of our research is to better understand the responses of terrestrial ecosystems to compound heat and drought events. This requires monitoring whole-tree physiology by integrating leaf thermal tolerance with stem drought tolerance measurements. We examine how instantaneous responses may differ from longer-term responses due to acclimation to changing conditions by measuring how plant responses change over time, including before, during, and after stress events.

Eddy covariance measurements collect continuous carbon and water flux data and are important for monitoring the effects of ongoing climate change in natural ecosystems. As a Postdoctoral Researcher, I anlaysed two flux datasets of high-elevation tussock grasslands (1300-1500 m a.s.l.) in the Snowy Mountains, Australia. While cooler sites sustain winter snow cover, warmer sites do not. We also installed a PhenoCam to characterize seasonal changes in phenology at the warmer grassland site. See the OzFlux Network for further site details.