Photo: Alan Kwok

2020 Applied Forest Ecology Scholarship Winner

Julia Smith is a current Honours to Masters transition student at La Trobe University. She has worked in the Insect-Plant Interactions lab under Dr Martin Steinbauer since 2017, and is very passionate about forest and community ecology. Julia hopes to make her science community focussed and is currently collaborating on a citizen science project focussed on forest conservation.

Project summary: The functional roles of psyllid abundance and feeding damage in a bird mediated forest dieback

Insects are an intermediate link in trophic cascades connecting fluctuations of vertebrate predators to eucalypt dieback. Increases in insect-driven forest dieback are a growing global phenomenon because dominant insectivores such as birds and lizards are sensitive to habitat fragmentation and loss. Bell miner associated dieback (BMAD) is a uniquely Australian trophic cascade triggered by a reduction in insectivorous apex predators (birds) resulting in psyllid outbreaks and eucalypt dieback. BMAD is a key threatening process and affects tens of thousands of hectares of forest of world heritage significance.

Since different genera of psyllids vary in the type and severity of damage they can cause to their host trees, psyllid community composition is important to understand bottom-up mechanisms behind BMAD severity. Psyllids are often host specific meaning that different eucalypt species host different suites of psyllid species. Most literature concerning psyllid abundances in BMAD forests have focused on single species of eucalypt which limits our understanding of dieback at the forest level.

Our study proposes a multi-host tree analysis of eucalypt species and leaf types in forests affected by BMAD. We will document psyllid communities in BMAD affected and unaffected forests to understand whether some species of eucalypt and leaf type are more susceptible to damage due to the types of psyllids they host. Additionally, by working closely with the Department of Planning, Industry and Environment (DPIE), we will use this knowledge to better inform the management of these forests. This research will also expand our knowledge of the ecology and impact of native psyllids which represent some of Australia’s most diverse and potentially injurious forest insect herbivores.

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