The genetic and demographic impacts of contemporary disturbance regimes in mountain ash (Eucalyptus regnans) forests

Disturbances such as logging and fire are altering forest ecosystems globally, with changes to ecosystem functions and species composition and abundance occurring in many vegetation communities. Mountain ash (Eucalyptus regnans), one of the world’s tallest trees, dominates the mid-elevation wet forests of Australia’s southeast, and contributes substantially to the structure and function of these ecosystems. Mountain ash forests have not been immune to the changes wrought by anthropogenic pressures over the past two hundred years, with a substantial loss of old-growth forest due to widespread timber harvesting and increased frequency of high-intensity fires. This project aims to characterise how these contemporary disturbance regimes are influencing the population demographics and genetics of mountain ash, to further our understanding of the ways in which humans are modifying both ontogenetic processes (such as growth rate and maturation) as well as genetic parameters (such as population genetic differentiation and fine-scale genetic structure). In this seminar I will examine how mountain ash forests are responding to anthropogenic pressures, starting with their reproductive output in the early stages of development and progressing into an investigation of the species-wide genetic structure, hybridisation with messmate stringybark (Eucalyptus obliqua), and effects of logging on population genetic differentiation, before finishing with a discussion of the evidence for local selection and adaptive potential.

About the Speaker

Brenton Von Takach Dukai is an ecologist with a passion for conservation biology, molecular ecology, and evolutionary biology. He began his PhD at the Fenner School in 2015, under the supervision of Sam Banks and David Lindenmayer, having spent the previous two years working as a botanist and ecologist for a specialist environmental consultancy. Conducting dozens of environmental impact assessments led him to the realisation that there is still much that is unknown about Australia’s native ecosystems, and he decided to contribute to our growing understanding of ecosystem dynamics through an investigation of one of Australia’s most iconic eucalypts, mountain ash (Eucalyptus regnans).