Ms
Bryony Horton
PhD student
Topic: fire management and tree
decline:
mycorrhizal indicators of declining forest health
University of Tasmania
Decreasing health of mature trees leading to
premature death, known as "tree decline", is widespread throughout
Australia and is a serious problem effecting both conservation and
economic management of eucalypt forest.
One eucalypt species affected, Eucalyptus
delegatensis, occurs in high altitude forest in Tasmania.
Recent theories link eucalypt tree decline with changes in fire
management - from frequent burning by Aborigines in the past, to an
absence of fire under European management. In high altitude forests
where fire has been excluded, evidence suggests that eucalypt
dieback is associated with the invasion of rainforest understorey
plants, and that dieback is reversed after fire. Many other
environmental and biological variables, such as soil
characteristics, are also likely to change with an absence of
fire.
Mycorrhizal fungi are an important component of
Australian forests and live symbiotically with eucalypts on their
roots, helping the trees to absorb nutrients, protecting them from
pathogens and reducing toxicity. Previous research has indicated
that there are associated changes in the fungal community when a
forest is in decline. Fungal community structure changes over time
after fire, possibly also influencing other ecosystem processes
like nutrient cycling and plant dynamics.
My research project aims to link changes in the
mycorrhizal community of E. delegatensis forest to the
distribution of understorey plants (sclerophyll and rainforest)
that represent increasing time since fire. Other co-variables to
time since burnt include soil factors and canopy condition (which
will be used as an indicator of decline) and these will also help
explain any identified differences. The impact of fire on the
mycorrhizal community will also be investigated.
I will use molecular profiling techniques to
analyse samples of different mycorrhizal fungus species. Samples
will be collected from burnt and unburnt forests with either
sclerophyll or rainforest understorey.
This project will help to establish the role of
mycorrhizal fungi in the maintenance of healthy forests. It would
be a major achievement to identify indicators of forest health
within the mycorrhizal community that aid the long term sustainable
management of healthy forests.
I first studied mycorrhizal associations for my
Honours project at the University of New South Wales (UNSW) in
2002. Since then I have mostly worked in botany and vegetation
management and have occupied a variety of posts including further
mycorrhizal research at UNSW, plant taxonomy with Sydney Royal Botanic Gardens, ecological monitoring in
the UK for The Wildlife Trust, botanical consultancy in the
private sector and on various urban revegetation projects. I moved
to Hobart early 2006 but quickly relocated to Maatsuyker Island
where I spent an unbelievable four months before beginning my PhD
in July 2006.
My supervisors are Dr Neil Davidson (School of Plant Science,
University of Tasmania), Dr Morag Glen (Ensis), Associate Professor Caroline Mohammed
(School of Agricultural Science, University of Tasmania) and Dr
Tim Wardlaw (Forestry Tasmania).
My PhD studies contribute to CRC for Forestry
Biodiversity project 4.2 and project B7 of the Bushfire CRC.
To browse other PhD projects available with the CRC
for Forestry, click here.
My project is funded by the
Bushfire CRC, the
University of Tasmania and the
Holsworth
Wildlife Research Trust, with contributions and support from
Forestry Tasmania and the CRC for Forestry.
