South Australian ecologist creates vegetation regeneration program to reduce bushfire risk

17 May 2020

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AUSTRALIA – The ecologist from the University of South Australia says grass is a crucial — and often overlooked — part of any ecosystem, particularly when it comes to mitigating bushfire risk.

“Ninety-seven per cent of the biodiversity on earth is in the top 10 centimetres of soil,” she said.

“If we ignore the soil, then we don’t get the whole system functioning.”

With that ethos, she has embarked on a “pilot regeneration program” on her 70-acre property, which was devastated by the summer’s Cudlee Creek bushfire.

“People think ‘Oh. We’ll plant trees and everything else will follow’ … Well, it doesn’t necessarily happen that way.

“The longer-term recovery is based on getting these habitats to work in an energetic relationship.”

‘A recipe for recovery’

Grass seeds, biochar and an oatmeal sludge spiked with “puffball” fungi is all it takes to plant native grasses, Ms Gibbs said.

“Biochar is black gold for restoration, we need this stuff,” Ms Gibbs said.

Biochar is the by-product of burnt plant matter; rich in carbon, and abundant after a bushfire.

That acts as a fertiliser, while the oatmeal is a substrate — the “stuff that sticks the seeds on the soil”.

It sounds simple, but getting native grasses to grow is another story.

According to Andrew Fairney, ecologist and chief executive of environmental charity Seeding Natives, most people find sowing native grasses too hard and time-consuming.

“Site preparation is 95 per cent of the work. You need to remove the weeds,” he said.

“Fire obviously burns a lot of the weed seed so it brings you down to a clean slate to start ecological restoration.”

Weed control programs are preferable to removing topsoil, but it can take up to three years to completely eradicate weed seed from a site.

“For that reason, as far as we know, there’s nobody else in South Australia doing ground-up restoration, starting with sowing a native grassland, and then building it from there,” Mr Fairney said.

Mitigating bushfire risk

The major benefit of native grasslands is their low fuel load, which acts as a bushfire risk mitigator.

The ‘fuel load’ per hectare of native grassland is about two to five tonnes, compared to 10 to 25 tonnes per hectare of exotic grassland.

“That’s a huge difference when it comes to being able to protect a site,” Mr Fairney said.

Due to changing land management principles, Mr Fairney estimated the Adelaide Hills and Mount Lofty ranges have lost 99 per cent of the grasses that were there prior to colonisation.

“Aboriginal people used to manage the land as an open grassy woodland, and it was managed with fire,” he said.

“Now that we’ve stopped fire, and the ecosystem has changed, it has a very high fuel load … so when a fire does come through it ends up being catastrophic.”

Grassroots regeneration

Ms Gibbs and Mr Fairney both said there needs to be a community approach to bushfire regeneration.

“Getting people to do restoration is the necessary ingredient, because you cannot pay enough money to a commercial outfit to restore what’s needed,” Ms Gibbs said.

Part of her pilot program involves community plots, where anyone who wants to help can plant native grass seeds and monitor their progress.

“Every man, woman and child who thinks laterally are able to do this … we need everyone,” she said.

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