From the Frontline: Burn-off policy impact

Researchers warn that burn-off policies on public land could be contributing to extinctions; high-school students can now conduct university-based lab experiments by remote control; and a new Australian-designed radar system is being used to detect solar flares. Cathal O'Connell reports.

Back-burning, as shown here near Mount Beauty in Victoria, Australia, may keep some species away. – Aaron Francis/Getty Images

With summer comes long lazy evenings and the sweet smell of fresh-cut grass. But for many Australians the season can also bring an orange glow in the sky, smoke plumes, and the taste of ash.

Fires are a feature of Australian ecology and many native plants have evolved to deal with it, erupting anew from a blackened landscape. Yet the impacts of fire are much longer-lasting than previously believed according to a large study co-led by zoologist Michael Clarke at La Trobe University.

The team discovered that some species can only survive in areas that have not burned for decades, and that has significant implications for current “planned burn” policies that aim to reduce the latent fuel for summer bushfires by burning off in spring and autumn.

The research ran for almost a decade and involved the work of seven PhD students who surveyed 840 sites in the semi-arid Mallee region where South Australia, Victoria and New South Wales meet. The sites were chosen for their different fire histories and cover an area the size of Belgium. “It’s been a massive effort,” says Clarke.

The landscape is dominated by mallee trees, a type of eucalypt that grows multiple stems rather than a single trunk.

“Mallee are really strange trees,” says Clarke. They have a huge underground root system and when they get burnt the old stems die and new ones sprout. They don’t form annual growth rings, and so are difficult to age. As part of the study Clarke’s team developed a new method to age the trees, by measuring the diameters of the stems. Using this information they could date the time since the last fire at each site to create a record going back over 100 years. They also performed an extensive survey of the populations of birds, reptiles, mammals, termites, scorpions and plants at all sites. “What was fascinating was that those animal and plant communities were still changing a century after the last fire occurred,” says Clarke. The reason is that the habitats for some species take a long time to recover after a fire.

Frequent fires can devastate the nesting sites of the endangered Mallee emu-wren. – John Barkla 2012

Some birds, such as the endangered Mallee emu-wren, build their nests in clumps of spinifex – the spiky grass that grows beneath the mallee trees. These habitats can be devastated by too-frequent burning.

Other animals, including parrots, possums and lizards, need tree hollows in which to live. These hollows don’t begin to form until the trees are 40 years old. “That’s much longer than people thought,” says Clarke.

The state of Victoria has a policy of burning 5% of all public land each year to stem the build-up of fuel. “That equates to every area being burnt once every 20 years,” says Clarke. “It’s just never going to get to an age where it can support those creatures.”

Clarke has high hopes for a more nuanced, risk-based burn-off policy now being developed, which would target burning for fuel reduction in locations where it was most likely to reduce risk to life and property. Remote bushland would be left in a more natural state, and allowed to recover more fully between burns.

Remote-control physics

High-school students can now conduct university-based lab experiments by remote control.

Watch any teenager immersed in their smartphone and it’s clear how much kids love technology. But they’re not so keen on science. A 2012 report by the Office of the Chief Scientist of Australia showed only 51% of students were enrolling in science subjects for Years 11 and 12, and that the number was declining.

In response Anna Davis, then President of the Australian Science Teachers Association, emphasised the importance of students participating in hands-on experiments rather than watching a teacher in a classroom. “We’ve got a lot of students who are sitting back being spectators, not being actively engaged,” she said.

But labs are expensive and many schools don’t have the resources for student experiments. La Trobe University physicists have responded by developing a world-first initiative that provides schools across the country with remote access to university equipment.

They have built an online platform, dubbed FARLabs (Freely-Accessible Remote Laboratories), through which students can operate physics experiments housed at the university.

“It’s all real. That’s why students love it,” says David Hoxley, a lecturer in physics and the leader of the project.

“They press a button and something, here in Melbourne, moves in response. At the same time they are doing practical experiments, obtaining live data.” The experiments on offer include activities using radioactive materials, as well as investigating solar energy, weather and optics.

“They can even run the equipment from their smartphones,” Hoxley says. The platform was recently awarded an international S-Lab award in innovative education, presented by Britain’s Institute of Science and Technology.

“It’s really a continuation of our philosophy for hands-on education,” Hoxley says, adding that La Trobe undergraduates get access to a range of high-level research equipment, including the $200 million Australian Synchrotron.

The TIGER-3 digital radar system is the most sophisticated of its kind. – LaTrobe university

Space-weather radar

A new Australian-designed radar system is being used to detect solar flares.

It looks like a line of towering flagpoles tied down by guywires. In fact, it’s the most sophisticated radar of its kind in the world, 10 times more sensitive than its nearest rival. Designed and built by La Trobe University researchers, the TIGER-3 digital radar is being used to study space weather, including the solar flares that can knock out satellites and even cause blackouts at ground level.

Radar is best known for its use in detecting aircraft, but it can be used to observe any kind of moving structure, says Emma Bland, a space physicist at La Trobe. “We look at the ionosphere, from about 70 to 600 kilometres in altitude,” she says, describing the veil of charged particles that surround our planet. “If there’s a big disturbance from the Sun, such as a solar flare, we often see that signature really clearly in the radar data.”

Several atmospheric research groups around the world, including the British Antarctic Survey, based at Cambridge, have recently bought the radar design from La Trobe. Eddie Custovic, an electronics engineer at the university, is not surprised. “We completely redesigned the concept of this radar, making it entirely digital”, he says. The redesign improves resolution and extends range. “It’s by far the best in the world for ionospheric research.”

These stories were sponsored by La Trobe University.

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