The impact of fire on fauna

There is extensive knowledge of how plants respond to fire, but little on how fauna respond. Michael Clarke says blanket recommendations of how much land should be burned as hazard reduction are made without any knowledge of how fauna will respond in local areas. He says more work is being done monitoring fauna and studying long-term changes in response to fire.


Michael Clarke: I had been studying a population of crescent honeyeaters which lived at Wilson’s Promontory. I had colour-marked individuals, and a prescribed burn, escaped, and I returned to a study site where all the animals were now gone, and I felt a profound grief actually. I could not recognise a site I had spent seven years and had mapped on a 20-metre grid and I didn’t know where I was standing on that grid, and it was silent except for a few tree creepers calling.

Robyn Williams: Michael Clarke. No, not that one. He is Professor of Zoology at Latrobe University, and he’s been studying what happens to animals during the fires we shall get in a long hot Australian summer.

Did you expect the fire to reach that zone?

Michael Clarke: Yes, I did. There was extraordinary weather and the fire took off and was most unexpected, but the conditions were horrific, and what was meant to be about a 40-hectare burn burnt about 6,000. Really regrettable, a really tough situation, but as a biologist it made me then question why were we prescribe burning, what do we know about fire, or what the impact of fire on fauna?

Robyn Williams: It’s quite surprising sometimes to see out of that kind of holocaust animals emerging as if somehow they have survived.

Michael Clarke: Absolute surprises. So, to watch crimson rosellas flocking to a burnt piece of forest, grab a messmate seed cap and throw their heads back and scoff the seeds like they were taking shots. They were completely onto this food source that had been made available via the fire.

Robyn Williams: How do they know?

Michael Clarke: That’s a really good question. It’s a rare event, it’s fairly catastrophic and those who survive are obviously those with certain attributes. I don’t know, to be perfectly frank, but it is astonishing watching what will recover. How do the tree creepers, who are now in the forest, a few weeks after the fire, eating cooked insects in amongst the bark fissures know that this is okay? Other birds are decimated.

Robyn Williams: Well, we’ve studied lots to do with plants after fire and indeed the effect of smoke on their germination, some famous work from Western Australia. What about the animals? How are you following up their survival techniques?

Michael Clarke: I’ve got a range of studies going because I believe passionately that zoologists have been missing in action in regard to studying the impact of fire on fauna. As you say, our knowledge is really good for plants, and we know certain plants require fire. Our knowledge of the wildlife and how it responds to fire is a much weaker, and there are much bigger knowledge gaps.

In a park as prominent as Wilson’s Promontory, one of our icon parks in Victoria, mine was the only systematic bird data available that had pre-fire surveys that we could say what used to live here, how long will it take to come back, is it catastrophic that this has happened at this site? And so I’ve personally started a long-term study to watch the recovery of fauna at that site. And we’ve gone on in the mallee and the box ironbark forests and in the foothill forests with my colleague Andrew Bennett from Deakin University, doing very large-scale examinations of the impact of fire on fauna.

Robyn Williams: What have you found so far?

Michael Clarke: We’ve found that there are a number of wildlife that require particular time-since-fire age classes of forest and that require resources that take very long periods to develop, and that’s particularly concerning when our prescribed burning recommendations are often built around how long will it be until this plant is capable to replace itself with seed. And so you can look at a Banksia and say, okay, it’s going to take 15 years before that Banksia will set seed and will require a fire to germinate that seed, and on you go.

Well, some of our animals are requiring hollows in trees, and the tree may well have developed its seed after 15, 20 years, but the hollow won’t be there for 50 to 100 years. So simply designing our prescriptions around the plants is not going to deliver the needs of the fauna, and we need to understand the needs of the fauna if we are to manage them sensibly.

Robyn Williams: And what about hiding from fire itself? Have you teased out what seems to be a miraculous survival?

Michael Clarke: Only from anecdotes that people have shared with us after the Black Saturday fire, in particular people sharing creek beds with lyrebirds, of seeing kangaroos go down wombat burrows during the fire, intimate knowledge of the landscape that surprises us, and said where did that knowledge come from, what drives them to use those kinds of resources which they would never utilise in their normal daily lives. The selective pressures for that, again, just leaves you shaking your head. How did they know to do that?

Robyn Williams: And of course with a change of weather coming…well, without being too pessimistic, were going to have to know lots more than we did before if many of the fauna are going to survive some of the hot times promising.

Michael Clarke: Yes, the prescriptions are very worrying, that large intense fires are likely to increase in many parts of Australia under the current climate scenarios, and that becomes incumbent upon us to have a deeper knowledge of what we can or can’t do in the face of those changes. And so the more we can inform policymakers about the likely consequences of their action or inaction in regards to planning for fire the better. That’s why I’m so keen to get a better knowledge of fauna.

Robyn Williams: You mentioned Deakin University. Of course there is work going on in Tasmania and, from some of the people in Tasmania, in the Northern Territory. Is there much overall, as you’d expect in a country like this?

Michael Clarke: It’s increased dramatically in the last decade, so there is great work being done in South Australia and in Western Australia. The zoologists I guess are starting to pick up their pace. I think in the last decade we’ve seen some terrific work done from the University of Wollongong, Adelaide, ANU, and there’s quite a camaraderie amongst the zoologists and the ecologists working on fire now, that we are starting to understand it at a landscape scale where we hadn’t in the past.

Robyn Williams: I’d imagine in California and, who knows, in Colorado as well, various places where the fires have broken out famously, there should be work going on as well?

Michael Clarke: Yes, there’s international work, but our systems are different, even from the west coast of Australia to the east, and it is a detailed local knowledge that becomes important. One of the regrettable outcomes of the Bushfires Royal Commission in Victoria were prescriptions that have been applied state-wide to all habitats. As an expert witness at the Royal Commission I was really quite disappointed that blanket recommendations came across that seemed to ignore those differences between ecosystems.

Robyn Williams: What would you like to have seen?

Michael Clarke: I would have liked to have seen an informed bottom-up approach where people went from region to region and said what’s the appropriate fire regime in this locality, rather than a state-wide target of ‘we will burn 5% of public land every year’.

Robyn Williams: And do you think that might happen eventually?

Michael Clarke: I live in hope. The person, Neil Comrie, who has been asked to look at the implementation of the Bushfire Royal Commission recommendations has questioned the blanket 5% ruling, and he’s taken it from the risk perspective, that burning 5% of public land every year is not necessarily going to achieve the risk reduction to human life and property that the Royal Commission was after, and may indeed do ecological harm.

Robyn Williams: Going back to that fire, has your study site recovered?

Michael Clarke: It has, and it’s remarkable and astonishing as a biologist to watch what comes back. It’s completely revegetated. The bird list is 100% of what it was before, 70% of abundance. So, absolutely astonishing, I don’t know where they’ve come from in many cases, but it’s a privilege to watch that and watch the vegetation change over time, and I happen to be in a profession where I have the luxury of watching this. During my holidays. I go down each year and survey 70 sites every spring and summer.

Robyn Williams: The bush recovers, spectacularly, with help. Michael Clarke is Professor of Zoology at La Trobe University.

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