In the mountains of southeastern Australia the Snow Gums (Eucalyptus pauciflora and segregate species) generally dominate subalpine woodlands at the altitudinal limit to tree growth. Although dominating at high altitudes, their distribution in Victoria and Tasmania also includes a range of lowland sites, including some close to sea level. The distribution of Snow Gums is thought to have been dramatically affected by climatic fluctuations of the Quaternary glacial/interglacial cycles and is likely to be strongly influenced by impending human-induced climate change. Bioclimatic modelling suggests that they were more widespread in lowland areas at the last glacial maximum, and current lowland populations are interpreted as relicts of that time. Likewise, modelling suggests that of all forests in the Victorian highlands, snow gum woodlands are the most sensitive to global warming, as high altitude sites become more productive for other tree species.
Our research, funded by the Hermon Slade Foundation, aims to document genetic variation and diversity in Snow Gums using selectively neutral chloroplast and nuclear markers. Understanding geographic patterns will allow inference of: present and past connectivity between populations/geographic areas, the extent of geneflow between related co-occurring species (past and present), potential refugia during glacial times (higher diversity), and areas that have been more recently colonised (low diversity) in post-glacial conditions. Identifying areas of high and low genetic diversity will also inform prioritisation of conservation effort, or any active strategies, e.g., seed collection or translocation, to manage revegetation or to minimise the impacts of global warming on biodiversity. Genetic data will also be used to address outstanding issues surrounding the classification and taxonomy of Snow Gums.
Mike Bayly, The University of Melbourne
Gill Brown, The University of Melbourne
Erin Batty, The University of Melbourne
Frank Udovicic, National Herbarium of Victoria
We are also collaborating with Brad Potts, Dorothy Steane and Archana Gauli from the University of Tasmania