From the ashes: Project to test growth in fire-affected soils

University ecologist delves into the link between wildfires, alpine plants and their associated soil microbial communities to inform ecological restoration

For millions of years, wildfires have helped to maintain nature’s ecological balance, cleaning out leaf litter and helping to return nutrients into the soil.

However, this process is complex, with each plant species and soil type reacting differently to being burnt. Some ecosystems, such as Australian alpine areas, have not adapted to frequent fire and can be very slow to recover.

Working alongside a national team of researchers and industry experts, University of Southern Queensland (UniSQ) ecologist Dr Christina Birnbaum is studying the impact of wildfires on the health of Tasmania’s alpine plant species and their associated soils.

As part of the project, Dr Birnbaum has received two soil samples from the Tasmanian Wilderness World Heritage Area, one taken from a site burned in 2016 and the other from a site burned in 1961, as provided by Dr Anita Wild (Wild Ecology Pty Ltd).

Dr Birnbaum said soil degradation following wildfire in alpine areas was well documented.

“In this experiment, we will plant alpine seeds into these different soils under controlled conditions,” Dr Birnbaum said.

“We will then look at how well the plants are germinating, how well they grow in the glasshouse and if there is a difference in growth in historically burnt soils compared to more recently burnt soils and control treatments.

“We will also study the below-ground effects – the presence of bacteria and fungi in the soil, and whether there is any difference between the plant samples in how they respond to different soils.

“This will be an exploration as currently there isn’t much research on the effects of fire on plants and their soil microbial communities in the alpine regions of Australia.”

Dr Birnbaum said while wildfires were a catalyst for renewal and regeneration, they sometimes disrupted the plant and soil microbial communities which had evolved over millennia.

“Different wildfires burn vegetation at different intensities, depending on the scale of the fire,” she said.

“We are only beginning to understand how time since fire affects plant-soil interactions.

“Emerging research suggests that there are temporal changes in soil fungal communities, with high fire frequencies increasing soil fungal plant pathogens and lowering the abundance of symbiotic, plant beneficial, soil fungal communities.”

Findings from this experiment will be used to assist future ecological restoration programs.

It is hoped that natural soil microbial processes may help to facilitate natural recovery and germination of plant species, making alpine restoration more cost-effective and applicable to more areas to speed up recovery.

“If we want to restore these ecosystems, say after a fire, or if there was a disturbance or weed invasion, it’s important to understand the role fire plays (in germination) and in disrupting plant-soil interactions,” Dr Birnbaum said.

Learn more about research at the University of Southern Queensland.

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