E&E PhD Exit Seminar: Exploring Australian Alpine Plant Trait Plasticity in Response to In Situ Climate Stress Across Varying Temporal Scales

ABSTRACT

Australia’s alpine regions are known for their rapidly changing weather, cold, snowy winters, clear running streams and wonderfully unique biodiversity. However, things won’t be this way forever, with future climates predicted to challenge plant communities through warmer soils, more frequent droughts and heatwaves, and potentially greater exposure to frost as snow cover declines. My thesis investigated whether alpine plants could adjust aspects of their form and physiological function to adequately tolerate changing conditions across various timescales.

First, I used portable heating chambers to expose eight alpine species to six days of simulated warming and followed their recovery. Despite observing high initial photosystem heat tolerance, tolerance continued to gradually increase further with relatively little heat exposure. Recovery of heat tolerance was fast, while we observed that graminoids had particularly high heat tolerance. Next, I investigated how five alpine species adjusted their photosynthetic thermal tolerance and non-structural carbohydrate reserves as seasonal cold acclimation occurred. Though the plants were grown under experimental warming and drought, background seasonal acclimation had a much stronger effect on plant responses than the simulated future climates did. As expected, acclimation was associated with improved cold tolerance and declining heat tolerance. Changes in starch storage differed among species, while soluble sugars appeared to respond more to moisture availability than warming and were not correlated with the changes in thermal tolerance. Finally, I examined how prolonged warming and drought affected plant survival, growth, water use and morphological traits, and whether plasticity in these traits helped plants maintain performance.

Together, my findings show that Australian alpine plants possess considerable resilience and the capacity for both short- and longer-term adjustment, but this flexibility is strongly species- and trait-specific. I will discuss why this makes future vegetation change difficult to predict—and why understanding when plasticity protects plants, and when it reaches its limits, is central to forecasting the future of Australia’s alpine ecosystems.

BIOGRAPHY

I’ve always had a certain fondness for the outdoors, but it wasn’t until I began my undergraduate studies in Queensland that I truly fell in love with plants and all that they do. It was then, during COVID, that I volunteered for a field trip with a PhD student, and they encouraged me to apply for a PhD scholarship within their old lab group, the Nicotra group. Indoctrinated into the plant world and with an ID book in hand, I jetted off to join ANU and run around the mountainside for what I thought was the adventure of a lifetime. I really am quite fascinated by plant plasticity and understanding how species persist throughout challenging conditions. So, please join me as I share my journey over the past few years and explore this theme within the context of climate change in the Australian Alps.