PhD Candidate: Chaminda Alahakoon

PhD Supervisors: Associate Professor Paul Rymer (WSU), Associate Professor Rachael Nolan (WSU), Associate Professor Mark Ooi (UNSW), Dr Cathy Offord (Australian Plant Bank, BGS)

Project Summary: Climate change presents a significant risk to biodiversity and ecosystem function, affecting plant species and ecological communities unevenly. The Cumberland IBRA subregion in Western Sydney, which supports over a hundred threatened species and communities, is especially susceptible to the rise in extreme climatic events. However, limited understanding of germination niches of Cumberland Plain species hinders our capacity to detect recruitment failures and anticipate shifts in community composition in the future. We assessed seed germination in 28 common species, representing different functional types, climate origins and vegetation communities to characterize the germination niche and predict climate change impacts. For temperature effects, seeds were germinated across six growth cabinets (10, 15, 20, 25, 30, 35 °C). For water deficit effects, seeds were germinated under varying water potentials achieved with differing polyethylene glycol concentrations (-0.00, -0.25, -0.50, -0.75, -1.00, -1.25 MPa) at 20 °C. The experimental component of this project was completed in March 2024. The data is currently being analyzed.