If you’ve been following the bushfire crisis on social media and elsewhere, you may have seen reports of benevolent wombats herding other animals to shelter into their fire-proof burrows.
These stories went quickly viral – probably reflecting the appetite for good news after the horrors of the bushfire crisis. However the accounts are not entirely accurate.
Wombats do not heroically round up helpless animals during a bushfire and lead them to safety. But wombats do help other animals in a different way – even if it’s not their intention.
Wombats can emerge as accidental heroes during a bushfire, by providing a safe refuge underground for other wildlife.
Wombat warrens – networks of interconnecting burrows – are large and complex, and considerably shielded from the above-ground environment. Small mammals are known to use wombat burrows to survive an inferno.
What’s more, temperatures deep within burrows are very stable compared to surface temperatures, with daily temperature fluctuations of less than 1℃, compared to 24℃ on the surface.
This thermal buffering would help a great deal during intense fires, and you can understand why other species would want access to these safe havens.
The wombat sharehouse
By placing camera traps outside 34 wombat burrows, a 2015 study showed a surprising variety of animals using southern hairy-nosed wombat burrows. Researchers observed ten other species, six of which used them on multiple occasions.
The intruders ranged from rock wallabies and bettongs to skinks and birds. Little penguins were recorded using burrows 27 times, while the black-footed rock wallaby was observed using wombat burrows more often than wombats – nearly 2,000 visits in eight weeks! They were even observed using the burrows to specifically avoid birds of prey.
They spend a few nights sleeping in one burrow, before moving onto another.
Since each wombat has multiple burrows, many can be vacant within a home range, and abandoned burrows are common in some areas. A 2007 study showed that even among “active” burrows (those with signs of recent use), only one in three are actually occupied by a wombat at any given time.
This means, at times, other species may not need to share burrows with wombats at all. It’s vacant real estate.
So how might a wombat react to an uninvited guest? This is difficult to know, and likely depends on who’s visiting. Wombats prefer not to share burrows with other wombats, although burrow sharing can be common when wombat populations are very high in one place.
In her book Wombats, Barbara Triggs recalls a fox being chased from a burrow by an angry wombat. Meanwhile, the crushed skulls of foxes and dogs in wombat burrows suggest not all intruders are welcome.
That a suite of species use wombat burrows suggests wombats may not notice or care about squatters – so long as they don’t pose a threat. But more research is needed on the fascinating interactions that take place in wombat burrows, particularly during fire.
The battle is not over
While empirical studies are needed, the available evidence suggests wombats may well provide an important refuge for other wildlife during fire.
In any case, it’s important to recognise that surviving fire is only half the battle.
Wombats and their house guests face a medley of challenges post-fire – not least avoiding predators in a barren landscape and eking out a living in a landscape with scarce food.
Right now, ENSO is not active, and a very strong positive IOD event – the strongest since 1997 – has just ended. Positive IOD events typically result in below average winter-spring rainfall over southern and central Australia, and are often associated with more severe bushfire conditions.
There has also been a marked warming of the atmosphere over Antarctica, known as sudden stratospheric warming. This has led to a weakening of the polar vortex, resulting in more negative conditions in the Southern Annular Mode – essentially the north-south movement of the westerly wind belt that loops around Antarctica.
New Australian research has found weakening and warming of the stratospheric polar vortex over Antarctica significantly increases the chances of hot and dry extremes, including more severe fire weather conditions across subtropical eastern Australia than is normal for spring-early summer.
These factors have combined to bake the landscape dry, even transforming usually wet sub-tropical rainforests into available fuel for this season’s catastrophic bushfire conditions.
How climate influenced past Australian bushfires
Historically, the most severe Australian bushfire seasons and droughts occurred when the Indian Ocean Dipole combined with El Niño to reinforce dry conditions. Both these climate drivers influence Australian rainfall and soil moisture, with the driest conditions over the southeast, but more broadly across most of the country (with the notable exception of coastal NSW).
As Australia’s climate continues to warm, a range of scientific sources suggest some established relationships between the historical drivers of Australian climate and their impact on rainfall and temperature may be breaking down.
For example, Australia’s hottest years on record were historically associated with El Niño events, in line with global temperature trends. However, global warming means even traditionally cooler La Niña years are now warmer than many El Niño years of the past. This suggests natural variability may be increasingly swamped by human influences on the climate.
Similarly in Tasmania, the 2016 fires destroyed large areas of ancient Gondwanan forest, triggering a cascade of changes through the entire ecosystem.
Strikingly, the current catastrophic bushfires are occurring in the absence of El Niño conditions typically associated with severe bushfires in the past.
The notorious Ash Wednesday fires that devastated parts of south-eastern Australia in February 1983 occurred during one of the most intense El Niño events on record. Some 75 people were killed across the country’s south-east, and more than 2,000 homes were lost.
Ash Wednesday was also preceded by a positive Indian Ocean Dipole event. Together with the El Niño, this created a “double whammy” of drought conditions which provided the climatic backdrop for the fires.
Similarly, the 1994 Sydney fires were also influenced by a combination of El Niño and positive IOD conditions.
However the current drought is affecting areas such as coastal NSW which have not historically been influenced by positive IOD and El Niño events. This suggests other drivers are at play.
Perhaps most alarmingly, this summer’s bushfire crisis also differs from the past in the spread and extent of landscape burned. More so than during Victoria’s Ash Wednesday or Black Saturday, this season’s fires have burned large swathes of the country. In some cases, fires merged to form unprecedented “mega fires”. It is sobering to consider what might happen to the Australian landscape the next time an El Niño hits.
Of course it will take time before researchers can pinpoint the full extent to which climate change influenced the current drought and associated bushfires.
But it is already clear to experts that natural variability and human influences on the climate system are now interacting to generate extremes that may have no parallel in Australian history.
What this means for bushfire danger
As with land and sea temperatures, Australia has seen rising trends in fire danger indices in recent decades.
In particular, the annual accumulated Forest Fire Danger Index (FFDI) – which takes into account drought, recent rain, air temperature, relative humidity and wind speed – has increased in eastern and southern Australia.
The bushfire season has become longer and more intense. In fact, the extraordinary conditions experienced during Victoria’s Black Saturday fires in February 2009 later prompted the creation of a new “catastrophic” fire rating, represented by a FFDI of 100 or greater.
On September 6 last year – less than a week out from winter – severe bushfires burned across Queensland and NSW. In most affected areas, daily FFDI values that day (pictured in the bottom right of the graphic below) were higher than anything observed so early in the season since records began in 1950. Astoundingly, a FDDI of 174 was recorded at Murrurundi Gap in the Hunter region of NSW.
In the past, Australia only had to contend with natural climate variability. Now, our entire weather and climate systems are being altered and amplified by human activity. Climate change is making extreme events even more severe, resulting in unprecedented conditions that are rewriting our nation’s history.
It will take time to understand the exact contribution of each climatic factor in the bushfire season of 2019–2020. However one thing is certain: unless there are global reductions in greenhouse gas emissions, temperatures will continue to rise, increasing the risk that catastrophic bushfire conditions become Australia’s “new normal”.
The scale and speed of the current bushfire crisis has caught many people off-guard, including biodiversity scientists. People are scrambling to estimate the long-term effects. It is certain that many animal species will be pushed to the brink of extinction, but how many?
One recent article suggested 20 to 100, but this estimate mostly considers large, well-known species (especially mammals and birds).
A far greater number of smaller creatures such as insects, snails and worms will also be imperilled. They make up the bulk of biodiversity and are the little rivets holding ecosystems together.
But we have scant data on how many species of small creatures have been wiped out in the fires, and detailed surveys comparing populations before and after the fires will not be forthcoming. So how can we come to grips with this silent catastrophe?
Using the information that is available, I calculate that at least 700 animal species have had their populations decimated – and that’s only counting the insects.
This may sound like an implausibly large figure, but the calculation is a simple one. I’ll explain it below, and show you how to make your own extinction estimate with only a few clicks of a calculator.
Using insects to estimate true extinction numbers
More than three-quarters of the known animal species on Earth are insects. To get a handle on the true extent of animal extinctions, insects are a good place to start.
My estimate that 700 insect species are at critical risk involves extrapolating from the information we have about the catastrophic effect of the fires on mammals.
We can work this out using only two numbers: A, how many mammal species are being pushed towards extinction, and B, how many insect species there are for each mammal species.
To get a “best case” estimate, I use the most conservative estimates for A and B below, but jot down your own numbers.
How many mammals are critically affected?
A recent Time article lists four mammal species that will be severely impacted: the long-footed potoroo, the greater glider, the Kangaroo Island dunnart, and the black-tailed dusky antechinus. The eventual number could be much greater (e.g the Hastings River mouse, the silver-headed antechinus), but let’s use this most optimistic (lowest) figure (A = 4).
Make your own estimate of this number A. How many mammal species do you think would be pushed close to extinction by these bushfires?
We can expect that for every mammal species that is severely affected there will be a huge number of insect species that suffer a similar fate. To estimate exactly how many, we need an idea of insect biodiversity, relative to mammals.
How many insect species are out there, for each mammal species?
So there are at least 185 insect species for every single land mammal species (B = 185). If the current bushfires have burnt enough habitat to devastate 4 mammal species, they have probably taken out around 185 × 4 = 740 insect species in total. Along with many species of other invertebrates such as spiders, snails, and worms.
For your own value for B, use your preferred estimate for the number of insect species on earth and divide it by 5,400 (the number of land mammal species).
One recent study suggests there are at least 5.5 million species of insects, giving a value of B of around 1,000. But there is reason to suspect the real number could be much greater.
My “best case” values of A = 4 and B = 185 indicate at least 740 insect species alone are being imperilled by the bushfires. The total number of animal species impacted is obviously much bigger than insects alone.
Feel free to perform your own calculations. Derive your values for A and B as above. Your estimate for the number of insect species at grave risk of extinction is simply A × B.
Post your estimate and your values for A and B please (and how you got those numbers if you wish) in the Comments section and compare with others. We can then see what the wisdom of the crowd tells us about the likely number of affected species.
The above calculations are a hasty estimate of the magnitude of the current biodiversity crisis, done on the fly (figuratively and literally). Technically speaking, we are using mammals as surrogates or proxies for insects.
To improve these estimates in the near future, we can try to get more exact and realistic estimates of A and B.
Additionally, the model itself is very simplistic and can be refined. For example, if the average insect is more susceptible to fire than the average mammal, our extinction estimates need to be revised upwards.
Also, there might be an unusually high (or low) ratio of insect species compared to mammal species in fire-affected regions. Our model assumes these areas have the global average – whatever that value is!
And most obviously, we need to consider terrestrial life apart from insects – land snails, spiders, worms, and plants too – and add their numbers in our extinction tally.
Nevertheless, even though we know this model gives a huge underestimate, we can still use it to get an absolute lower limit on the magnitude of the unfolding biodiversity crisis.
This “best case” is still very sad. There is a strong argument that these unprecedented bushfires could cause one of biggest extinction events in the modern era. And these infernos will burn for a while longer yet.
When heavy rainfall eventually extinguishes the flames ravaging south-east Australia, another ecological threat will arise. Sediment, ash and debris washing into our waterways, particularly in the Murray-Darling Basin, may decimate aquatic life.
We’ve seen this before. Following 2003 bushfires in Victoria’s alpine region, water filled with sediment and debris (known as sediment slugs) flowed into rivers and lakes, heavily reducing fish populations. We’ll likely see it again after this season’s bushfire emergency.
Large areas of northeast Victoria have been burnt. While this region accounts only for 2% of Murray-Darling Basin’s entire land area, water flowing in from northeast Victorian streams (also known as in-flow) contributes 38% of overall in-flows into the Murray-Darling Basin.
Immediately following the bushfires, we expect to see an increase in streamflow when it rains, because burnt soil repels, not absorbs, water.
When vast amounts of carbon are present in a waterway, such as when carbon-loaded sediments and debris wash in, bacteria rapidly consumes the water’s oxygen. The remaining oxygen levels can fall below what most invertebrates and fishcan tolerate.
These high sediment loads can also suffocate aquatic animals with a fine layer of silt which coats their gills and other breathing structures.
Habitats are also at risk. When sediment is suspended in the river and light can’t penetrate, suitable fish habitat is diminished. The murkier water also means there’s less opportunity for aquatic plants and algae to photosynthesise (turn sunshine to energy).
What’s more, many of Australia’s waterbugs, the keystone of river food webs, need pools with litter and debris for cover. They rely on slime on the surface of rocks and snags that contain algae, fungi and bacteria for food.
But heavy rain following fire can lead to pools and the spaces between cobbles to fill with silt, causing the waterbugs to starve and lose their homes.
This is bad news for fish too. Any bug-eating fish that manage to avoid dying from a lack of oxygen can be faced with an immediate food shortage.
We saw this in 2003 after the sediment slug penetrated the Ovens River in the north east Murray catchment. Researchers observed dead fish, stressed fish gulping at the water surface and freshwater crayfish walking out of the stream.
Bushfires can increase the amount of nutrients in streams 100 fold. The effects can persist for several years before nutrient levels return to pre-fire conditions.
More nutrients in the water might sound like a good thing, but when there’s too much (especially nitrogen and phosphorous), coupled with warm temperatures, they can lead to excessive growth of blue-green algae. This algae can be toxic to both people and animals and often closes down recreational waters.
Large parts of the upper Murray River catchment above Lake Hume has burnt, risking increases to nutrient loads within the lake and causing blue-green algae blooms which may flow downstream. This can impact communities from Albury all the way to the mouth of the Murray River in South Australia.
Some aquatic species are already teetering on the edge of their preferred temperature as stream temperatures rise from climate change. In places where bushfires have burnt all the way to the stream edge, decimating vegetation that provided shade, there’ll be less resistance to temperature changes, and fewer cold places for aquatic life to hide.
But while we can expect an increase in stream flow from water-repellent burnt soil, we know from previous bushfires that, in the long-term, stream flow will drop.
This is because in the upper catchments, regenerating younger forests use more water than the older forests they replace from evapotranspiration (when plants release water vapour into the surrounding atmosphere, and evaporation from the surrounding land surface).
It’s particularly troubling for the Murray-Darling Basin, where large areas are already enduring ongoing drought. Bushfires may exacerbate existing dry conditions.
So what can we do?
We need to act as soon as possible. Understandably, priorities lie in removing the immediate and ongoing bushfire threat. But following that, we must improve sediment and erosion control to prevent debris being washed into water bodies in fire-affected areas.
One of the first things we can do is to restore areas used for bushfire control lines and minimise the movement of soil along access tracks used for bushfire suppression. This can be achieved using sediment barriers and other erosion control measures in high risk areas.
Longer-term, we can re-establish vegetation along waterways to help buffer temperature extremes and sediment loads entering streams.
It’s also important to introduce strategic water quality monitoring programs that incorporate real-time sensing technology, providing an early warning system for poor water quality. This can help guide the management of our rivers and reservoirs in the years to come.
While our current focus is on putting the fires out, as it should be, it’s important to start thinking about the future and how to protect our waterways. Because inevitably, it will rain again.
But when it comes to climate policy, there are three possible scenarios in the aftermath of the crisis: everything magically changes for the better, everything stays the same or something different happens.
What these three scenarios look like
Everything magically changes for the better would look like this: Morrison announces the crisis has transformed his previous token admission of a link between bushfires and climate change into a revelation of the reality of global warming, with consequential policy change.
As logical and desirable as this seems, it is unlikely, not least because of Morrison’s character and personal beliefs.
Everything stays the same has a powerful impetus behind it. Morrison does not want policy change any more than his likely successor in the event of leadership change, Peter Dutton.
Government-friendly journalists and commentators at News Corp and 2GB show no sign of changing tack either, so even if the government wanted to shift its policy, the media environment makes it difficult to do so. The forces of inertia are powerful.
Then there is the slim hope that something different happens. This scenario relies on all three of Australia’s main political groupings – the LNP, Labor and the Greens – realising they each face their own distinct climate policy challenge and rising to it.
Avoiding the appearance of a backflip
Opinion polls are not done over the summer holiday period, meaning the LNP has yet to see the impact of the bushfires on their public standing.
When polling resumes, Liberal and National MPs will understand the impact, and they won’t like it. Morrison and others will likely urge party members to hold their course since the next election is years away and a dozen other issues could distract attention from climate policy between now and then.
This tactic can prevail for some time but is not strategically sustainable: firestorms like those in the summer of 2020 will not be the last.
The emerging LNP argument that inadequate hazard reduction burns are to blame for the current crisis is risible. The Australian who has emerged with the most credibility from the bushfires – NSW Rural Fire Service Commissioner Shane Fitzsimmons – rejects it out of hand.
The LNP’s challenge, then, is to realise its current position won’t hold strategically and to transition to better policy ahead of that becoming obvious, managing the optics to avoid the appearance of a backflip.
The challenge for Labor and the Greens
Labor is benefiting from leader Anthony Albanese’s call for “an adult conversation” in Australia about climate policy. He is astutely citing British Tories like the late Margaret Thatcher and current Prime Minister Boris Johnson, who long ago accepted and acted upon the climate science the Morrison government viscerally rejects.
Labor’s homework now is to reconcile the views and interests of members and supporters prioritising climate policy over mining jobs, and vice versa.
This can and must be done if Labor is to build a coalition of support big enough to win office and then enact the climate and other policies the current firestorms make so urgent.
The Greens, meanwhile, need to have an internal conversation about whether they want to continue making perfect policy the enemy of the good – leaving Australia with no emissions trading system (ETS) at all, for example, because they would not vote for one that did not meet their every demand – or join in efforts to begin on the path to better policy.
Central to that conversation must be a realisation their current strategy isn’t working – the LNP keeps returning to power.
A possible way forward
There is an obvious point the LNP, Labor and Greens might momentarily agree upon to move policy forward. It is the ETS proposed by Liberal Prime Minister John Howard in 2007.
Howard saw climate change coming. In late 2006, he established a prime ministerial task group on emissions trading chaired by the secretary of his Department of Prime Minister and Cabinet, Peter Shergold.
The Shergold Report, released in May 2007, said “emissions trading should be preferred to a carbon tax” and among the various kinds possible, a national “cap and trade” ETS was best.
This will be a world-class emissions trading system more comprehensive, more rigorously grounded in economics and with better governance than anything in Europe.
Implementing an emissions trading scheme and setting a long-term goal for reducing emissions will be the most momentous economic decisions Australia will take in the next decade.
This emissions trading system must be built to last. It needs to last not five or 10 years, it needs to last the whole of the 21st century if Australia is to meet our global responsibilities and further build our economic prosperity.
Howard positioned the LNP as the party Australians could trust to implement an ETS in a way that gives “firms and families” the ability to “plan for the future with confidence”.
His authorship – and his framing of his ETS as an act of economic responsibility –provides a fig leaf Morrison can now use to move the LNP to a credible, sustainable and politically viable climate policy position.
“Something different” has to start somewhere. If Morrison can deploy the cunning he showed winning the 2019 election by drawing on Howard’s deep well of credibility within the LNP to implement the plan himself and then inviting – daring – Labor and the Greens to back him, it would be a signal political achievement.
And if Morrison doesn’t want to, Labor, the Greens, independent MPs and conscientious LNP MPs should vote together to turn Howard’s ETS into law right away. With political will, “something different” can start now.
Updates to add that the latest Newspoll, released late Sunday, shows Morrison’s standing has taken a massive hit over the bushfires, dropping nine percentage points as preferred prime minister from 48% to 39% since the last poll in early December. Opposition leader Anthony Albanese stood at 43% – a massive reversal of Morrison’s 14 percentage point lead over the Labor leader in early December.
Smoke from this season’s bushfires has turned the sun red, the moon orange and the sky an insipid grey. It has obscured iconic views tourists flock to see. Far more than an aesthetic problem, it has forced business shutdowns, triggered health problems and kept children indoors for weeks.
City dwellers in southeast Australia have been forced to take a crash course in the finer points of air pollution. We’ve learned about the dangers of inhaling tiny PM2.5 particles (those 2.5 microns or fewer in diameter). We’ve learned that only a close-fitting P2 mask will do much to protect us.
Still, we wear disposable paper masks and hold handkerchiefs to our faces, hoping any amount of filtering is helpful.
Even for an historian of air pollution like me, this situation is a shock. It is not the first time Australia’s major cities have been shrouded in bushfire smoke. But the terrible air quality is unmatched in terms of severity, duration and extent.
Historically, air pollution from smoke was considered outside human control and not subject to regulation. But these bushfires are clearly linked to global warming, for which government, corporations and individuals are responsible. It’s time to rethink the way we protect air quality.
The history of smoke
In recent weeks, apps such as AirVisual have confirmed what we city dwellers can already see and smell: since the fires on the north coast of NSW began in late October, our air quality has plummeted.
The New South Wales government’s Air Quality Index data has shown that since late October, days when the index was higher than 100 – signalling exposure is unhealthy – have outnumbered clear days in Sydney, Newcastle and the Illawarra.
Index readings above 2,550 have been recorded in Sydney, while the Monash monitoring site in Canberra reached a choking 5,185 at 8pm on New Year’s Day.
Bushfire smoke has affected the cities of NSW and the Australian Capital Territory in the past. In late January 1926, when Canberra was just emerging as a city, a thick haze of smoke sat over the site. Fires came within metres of Yarralumla, the residence which, the following year, would become home to the Governor-General.
In several years in the mid 1930s, bushfires burning to the north of Sydney left the city air thick with smoke. In October 1936, bushfire smoke forced a motor liner arriving from Hong Kong to warily enter the harbour sounding its siren, because it was invisible to signallers on South Head.
A New Zealand pilot, flying into Sydney from Longreach the following month, had to fly blind in “great clouds of dense smoke” covering much of NSW. In 1939, Canberra was covered by what visiting writer HG Wells described as a “streaming smoke curtain”.
In the summer of 1944, Sydney was again enveloped in a smoke haze, this time from fires in the Blue Mountains and (later Royal) National Park in November. Photographs published at the time show the Sydney Harbour Bridge barely visible through dust and smoke at midday. The ongoing fires were blamed for an increase in diseases of the ears, nose and throat, and for cases of influenza and pneumonia, leading to a shortage of hospital beds.
In November 1951, all of NSW was said to be blacked out by bushfire smoke. In Sydney on the worst days, records show all four of the city’s airfields were closed because of “smoke-fog”.
A hazy legal framework
In each of these episodes, bushfire smoke disrupted transport, commerce, health and the enjoyment of the urban environment. But even as other forms of air pollution began to be regulated, smoke from bushfires escaped legislative attention.
What was understood as air pollution were the unwanted byproducts of industrial processes, whereas bushfire smoke was viewed as natural.
In NSW in 1866, an act based on British legislation restricted smoke from mills, distilleries and gas works. Further limitations on smoke production in built-up areas were included in later acts governing public health (1902), motor traffic (1909) and local government (1919).
After World War II Newcastle, the site of the country’s largest concentration of coal-burning heavy industry, began to pay closer attention to managing air quality. This pioneering work was given added urgency after 4,000 people died in heavy London smog in 1952.
In 1958, a NSW parliamentary committee delivered a report into smoke abatement. It did not mention recent issues with bushfire smoke, and also dismissed the impact of domestically produced smoke. The subsequent 1961 Clean Air Act focused on air pollution from industry, transport and power generation.
Air pollution legislation continued to evolve in following decades, targeting motor vehicle emissions in the 1970s, backyard burning of waste in the 1980s, and wood fires used to heat homes in the 1990s.
These measures have been successful. A 2006 study found that between 1998 and 2003, on the limited occasions when standards for PM10 in six Australian cities were exceeded, the main sources were not industry or transport, but dust storms and bushfires (with the exception of Launceston, where heating fires were the main contributor).
Today, bushfire smoke is excluded from air quality regulations, despite its obvious role in pollution. It is still considered natural, and beyond human control.
As the Australian National University’s Tom Griffiths has written, the current fires in some ways repeat patterns of the past. But “the smoke is worse, more widespread and more enduring”.
When Australia begins the recovery from these fires, our business-as-usual approach requires a rethink. Measures to protect air quality should be a major part of this.
It is time that corporations, governments and societies which contribute to global heating be held to account for more frequent, intense and widespread bushfires, and the smoke which billows from them.
Images of desperate, singed koalas in blackened landscapes have come to symbolise the damage to nature this bushfire season. Such imagery has catalysed global concern, but the toll on biodiversity is much more pervasive.
Until the fires stop burning, we won’t know the full extent of the environmental damage. But these fires have significantly increased the extinction risk for many threatened species.
We estimate most of the range and population of between 20 and 100 threatened species will have been burnt. Such species include the long-footed potoroo, Kangaroo Island’s glossy black-cockatoo and the Spring midge orchid.
The fires are exceptional: way beyond normal in their extent, severity and timing. The human and property losses have been enormous. But nature has also suffered profoundly. We must urgently staunch and recover from the environmental losses, and do what it takes to avoid future catastrophes.
The fire and its aftermath
One estimate last month put the the number of birds, mammals (other than bats) and reptiles affected by fire in New South Wales alone at 480 million. The toll has risen since.
Most will have been killed by the fires themselves, or due to a lack of food and shelter in the aftermath.
Some animals survive the immediate fire, perhaps by hiding under rocks or in burrows. But the ferocity and speed of these fires mean most will have perished.
One might think birds and other fast-moving animals can easily escape fires. But smoke and strong winds can badly disorient them, and mass bird deaths in severe bushfires are common.
We saw this in the current fire crisis, when dead birds including rainbow lorikeets and yellow-tailed black-cockatoos washed up on the beach at Mallacoota in Victoria.
Damage lasts decades
Fire impacts are deeply felt in the longer-term. Many habitat features needed by wildlife, such as tree and log hollows, nectar-bearing shrubs and a deep ground layer of fallen leaves, may not develop for decades.
Populations of plant and animal species found only in relatively small areas, which substantially overlap fire-affected areas, will be worst hit. Given the fires are continuing, the precise extent of this problem is still unknown.
We estimate most of the range and population of between 20 and 100 threatened species will have been burnt. The continued existence of such species was already tenuous. Their chances of survival are now much lower again.
For example, the long-footed potoroo exists in a very small range mostly in the forests of Victoria’s East Gippsland. It’s likely intense fires have burnt most of these areas.
Many threatened plants are also affected: in NSW, fires around Batemans Bay have burnt some of the few sites known for the threatened Spring midge orchid.
This time, it’s different
Fire has long been a feature of Australian environments, and many species and vegetation types have adapted to fire. But the current fires are in many cases beyond the limits of such adaptation.
The fires are also burning environments that typically go unburnt for centuries, including at least the perimeter of World Heritage rainforests of the Lamington Plateau in south-eastern Queensland. In these environments, recovery – if at all – will be painfully slow.
Many Australian animal species, particularly threatened birds, favour long-unburnt vegetation because these provide more complex vegetation structure and hollows. Such habitat is fast disappearing.
The shortening intervals between fires are also pushing some ecosystems beyond their limits of resilience. Some iconic Alpine Ash forests of Kosciuszko have experienced four fires in 20 or 30 years.
This has reduced a grand wet forest ecosystem, rich in wildlife, to a dry scrub far more flammable than the original forest. Such ecosystem collapse is all but impossible to reverse.
Fires also compound the impacts of other threats. Feral cats and foxes hunt more effectively in burnt landscapes and will inexorably pick off wildlife that may have survived the fire.
What does this mean for conservation?
In a matter of weeks, the fires have subverted decades of dedicated conservation efforts for many threatened species. As one example, most of the 48,000 hectares of forest reserves in East Gippsland established last year in response to the rapid decline of greater gliders has been burnt. This has further endangered the species and makes the remaining unburnt areas ever more critical.
Beyond counting the wildlife casualties, responses are needed to help environmental recovery. Priorities may differ among species and regions, but here is a general list:
quickly protect unburnt refuge patches in otherwise burnt landscapes
increase control efforts for pest animals and weeds that would magnify the impacts of these fires on wildlife
strategically establish captive breeding populations of some threatened animals and collect seeds of threatened plants
provide nest boxes and in special circumstances plant vegetation providing critical food resources
care for and rehabilitate injured wildlife and establish monitoring programs to chart a hoped-for recovery.
Some of these actions may be mere pinpricks in the extent of loss. But any useful action will make a small difference, and perhaps help alleviate the community’s profound sense of dismay at the damage wrought by these fires.
Governments, conservation groups and landholders must all play a role. Recovery actions should be thoughtfully coordinated, and form part of the broader social and economic post-fire recovery program.
Critically, we must also reduce the likelihood of similar catastrophes in future. Some have blamed the fires on national parks and a lack of hazard reduction burning. Skilful and fine-scale application of preventative burning does have merit. But such measures would not have stopped these fires, and the number of days suitable for such burning is diminishing.
Increasingly severe drought and extreme heat, associated with global warming, are the immediate causes of these wildfires and their ferocity. To prevent this fire-ravaged summer becoming the new normal, we must take drastic measures to tackle climate change.
A caption in an earlier version of this article said the glossy black cockatoo was extinct on the mainland. It was referring to the South Australian subspecies found on Kangaroo Island. The caption has been amended to clarify this.