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Environmental Influence

Krebs Lecture 2020: landscape transformation and ecosystem collapse

The map of ecologist David Lindenmayer’s childhood was inked by epic family drives, criss-crossing the east and south of Australia as they drove to Adelaide, Melbourne or central Queensland.

“There was no radio in the car, and there’s only so much ‘I Spy’ you can play!” he says. “So I had to find other ways to amuse myself.”

Young David’s gaze turned outwards, towards the landscape flying past the car windows. Patterns in forest and field began to emerge, and his thoughts soon turned to how nature’s elements fitted so intriguingly together – intricate, interlocking puzzle pieces making up the whole world.

These thoughts seeded David’s distinguished career as a landscape ecologist and conservation biologist.

He has devoted his 37-year body of large-scale, long-term research to the long game of exploring how landscapes – and biodiversity in particular – respond to interventions and change, such as logging and fire.

“For this kind of research to be meaningful, it needs to be conducted over a long time, and it needs good data,” he says. “Two disturbances in a landscape can happen a long way apart and still be linked in their consequences.”

David’s research has been conducted across diverse areas ranging from heathlands in coastal New South Wales, to the wetlands of Tumut and the wet forests of Victoria.

“We are now at the point of starting to see how things interact, the consequences of which are very important – we’re talking about the relationships between climate change and logging and fire, and how these things affect systems in the long run.”

The Professor at the Australian National University’s Fenner School of Environment and Society is the headliner at the Krebs Lecture 2020: From Landscape Transformation to Ecosystem Collapse, at the University of Canberra on 18 February. His talk will highlight some of the important interactions mentioned, and explore the truths and complexities underlying the devastation fire has wreaked on the country in recent months.

“When it comes to the fires, climate change is important – and has exacerbated the situation we are finding ourselves in – but the history of forest management is equally important,” he says.

“One of the unexpected interactions we have discovered is that when wet forests – such as mountain ash – are logged and regrown, they become very prone to fire,” David says.

“This is in spite of the biomass being cut – and one reason for this is that a lot of dry debris is left behind after logging, which can potentially become fuel. We’ve seen evidence of that in the Gippsland fires and southeast NSW throughout this bushfire season.

“This gives rise to a cycle where the regrown, young forests burn again and again and remain trapped as young forests, which just aren’t resilient to fire – so the systems are just much more fire-prone than they should be.”

Moving forward, David says that any undisturbed native forests should be left untouched.

“Those places that have been burnt should be left to recover on their own, which will take time.”

He is appalled that post-fire salvage logging has been suggested as a solution to deal with the bushfires.

“There’s a big push from the logging industry for this, but it would inflict a double disturbance on the land, and as I mentioned, logged forests are always more fire-prone so this would increase overall fire risks,” David says.

“Timber should be sourced only from plantations, and not from native forests. A plantation is much more defendable from fire than a native forest. And plantation trees are planted to have a comparatively higher turnover – they reach crop maturity every 20 years or so, versus a native forest with trees of between 80 and 100 years old.”

As Australia looks to weather the here and now, David knows that many people are also looking to the future with trepidation.

“People are right to be concerned,” he says. “Insights into how ecosystems work only come to light over time, and much of what we’re seeing now is the result of poor interventions and changes made over years.

“Consider this: 20 years ago, if you grew up in Gippsland, you might have seen a bumper sticker saying ‘Alpine grazing reduced blazing’,” David says. “They were part of an argument that grazing cows on the grasslands would reduce fire risks. But since those cows weren’t grazing in the treetops, what actually happened was that all the grass they ate was soon replaced by shrubs – which were more fire-prone, and raised the fire risks for the area!”

“I have hundreds of examples, of stories like this, where decisions were rooted in populist pseudo-science – this is why sensible policy decisions must be based on scientific data and not an oversimplified, ‘shock jock’ approach.”

And what can the everyday citizen do to support these sensible decisions and progressive actions?

“Stay informed and engage with your democracy,” David says. “We publish about 60 studies a year, and every time I have new results, I write a cover letter and send the study to the government. Even if you’re not a scientist, you can keep abreast of the science and write letters to politicians.”

“Let them know how the people feel, because a democratic government relies on the people’s support.”

And there’s no time to waste. Change must be made now. Or it will be a very different – and much bleaker – view out that car window, for coming generations.

Words by Suzanne Lazaroo, photo by Madeleine Wood

The Krebs Lecture 2020: From Landscape Transformation to Ecosystem Collapse is on 18 February. Click here to register for the free event.

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