Climate change is testing the resilience of native plants to fire, from ash forests to gymea lilies

One year following the 2019/20 fires, this forest has been slow to recover.
Rachael Nolan, CC BY-NC-ND

Rachael Helene Nolan, Western Sydney University; Andrea Leigh, University of Technology Sydney; Mark Ooi, UNSW; Ross Bradstock, University of Wollongong; Tim Curran, Lincoln University, New Zealand; Tom Fairman, The University of Melbourne, and Víctor Resco de Dios, Universitat de LleidaGreen shoots emerging from black tree trunks is an iconic image in the days following bushfires, thanks to the remarkable ability of many native plants to survive even the most intense flames.

But in recent years, the length, frequency and intensity of Australian bushfire seasons have increased, and will worsen further under climate change. Droughts and heatwaves are also projected to increase, and climate change may also affect the incidence of pest insect outbreaks, although this is difficult to predict.

How will our ecosystems cope with this combination of threats? In our recently published paper, we looked to answer this exact question — and the news isn’t good.

We found while many plants are really good at withstanding certain types of fire, the combination of drought, heatwaves and pest insects may push many fire-adapted plants to the brink in the future. The devastating Black Summer fires gave us a taste of this future.

Examples of fire-adapted plants: prolific flowering of pink flannel flowers (upper left), new foliage resprouting on geebung (upper right), seed release from a banksia cone (lower left), and an old man banksia seedling (lower right).
Rachael Nolan

What happens when fires become more frequent?

Ash forests are one of the most iconic in Australia, home to some of the tallest flowering plants on Earth. When severe fire occurs in these forests, the mature trees are killed and the forest regenerates entirely from the seed that falls from the dead canopy.

These regrowing trees, however, do not produce seed reliably until they’re 15 years old. This means if fire occurs again during this period, the trees will not regenerate, and the ash forest will collapse.

This would have serious consequences for the carbon stored in these trees, and the habitat these forests provide for animals.

Southeast Australia has experienced multiple fires since 2003, which means there’s a large area of regrowing ash forests across the landscape, especially in Victoria.

The Black Summer bushfires burned parts of these young forests, and nearly 10,000 football fields of ash forest was at risk of collapse. Thankfully, approximately half of this area was recovered through an artificial seeding program.

Ash to ashes: On the left, unburned ash forest in the Central Highlands of Victoria; on the right, ash forest which has been burned by a number of high severity bushfires in Alpine National Park. Without intervention, this area will no longer be dominated by ash and will transition to shrub or grassland.
T Fairman

What happens when fire seasons get longer?

Longer fire seasons means there’s a greater chance species will burn at a time of year that’s outside the historical norm. This can have devastating consequences for plant populations.

For example, out-of-season fires, such as in winter, can delay maturation of the Woronora beard-heath compared to summer fires, because of their seasonal requirements for releasing and germinating seeds. This means the species needs longer fire-free intervals when fires occur out of season.

The iconic gymea lily, a post-fire flowering species, is another plant under similar threat. New research showed when fires occur outside summer, the gymea lily didn’t flower as much and changed its seed chemistry.

While this resprouting species might persist in the short term, consistent out-of-season fires could have long-term impacts by reducing its reproduction and, therefore, population size.

Out-of-season fires could have long-term impacts on gymea lilies.
Shutterstock

When drought and heatwaves get more severe

In the lead up to the Black Summer fires, eastern Australia experienced the hottest and driest year on record. The drought and associated heatwaves triggered widespread canopy die-off.

Extremes of drought and heat can directly kill plants. And this increase in dead vegetation may increase the intensity of fires.

Another problem is that by coping with drought and heat stress, plants may deplete their stored energy reserves, which are vital for resprouting new leaves following fire. Depletion of energy reserves may result in a phenomenon called “resprouting exhaustion syndrome”, where fire-adapted plants no longer have the reserves to regenerate new leaves after fire.

Therefore, fire can deliver the final blow to resprouting plants already suffering from drought and heat stress.

Drought stressed eucalypt forest in 2019.
Rachael Nolan

Drought and heatwaves could also be a big problem for seeds. Many species rely on fire-triggered seed germination to survive following fire, such as many species of wattles, banksias and some eucalypts.

But drought and heat stress may reduce the number of seeds that get released, because they limit flowering and seed development in the lead up to bushfires, or trigger plants to release seeds prematurely.

For example, in Australian fire-prone ecosystems, temperatures between 40℃ and 100℃ are required to break the dormancy of seeds stored in soil and trigger germination. But during heatwaves, soil temperatures can be high enough to break these temperature thresholds. This means seeds could be released before the fire, and they won’t be available to germinate after the fire hits.

Heatwaves can also reduce the quality of seeds by deforming their DNA. This could reduce the success of seed germination after fire.

Burnt banksia — Many native plants, such as banksia, rely on fire to germinate their seeds.
Shutterstock

What about insects? The growth of new foliage following fire or drought is tasty to insects. If pest insect outbreaks occur after fire, they may remove all the leaves of recovering plants. This additional stress may push plants over their limit, resulting in their death.

This phenomenon has more typically been obverved in eucalypts following drought, where repeated defoliation (leaf loss) by pest insects triggered dieback in recovering trees.

When threats pile up

We expect many vegetation communities will remain resilient in the short-term, including most eucalpyt species.

But even in these resilient forests, we expect to see some changes in the types of species present in certain areas and changes to the structure of vegetation (such as the size of trees).

Resprouting eucalypts, one year on following the 2019-2020 bushfires.
Rachael Nolan

As climate change progresses, many fire-prone ecosystems will be pushed beyond their historical limits. Our new research is only the beginning — how plants will respond is still highly uncertain, and more research is needed to untangle the interacting effects of fire, drought, heatwaves and pest insects.

We need to rapidly reduce carbon emissions before testing the limits of our ecosystems to recover from fire.

Rachael Helene Nolan, Postdoctoral research fellow, Western Sydney University; Andrea Leigh, Associate Professor, Faculty of Science, University of Technology Sydney; Mark Ooi, Senior Research Fellow, UNSW; Ross Bradstock, Emeritus professor, University of Wollongong; Tim Curran, Associate Professor of Ecology, Lincoln University, New Zealand; Tom Fairman, Future Fire Risk Analyst, The University of Melbourne, and Víctor Resco de Dios, Profesor de Incendios y Cambio Global en PVCF-Agrotecnio, Universitat de Lleida

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Smoke from the Black Summer fires created an algal bloom bigger than Australia in the Southern Ocean

Christina Schallenberg, University of Tasmania; Jakob Weis, University of Tasmania; Joan Llort, Barcelona Supercomputing Center-Centro Nacional de Supercomputación (BSC-CNS); Peter Strutton, University of Tasmania, and Weiyi Tang, Princeton UniversityIn 2019 and 2020, bushfires razed more than 18 million hectares of land in Australia. For weeks, smoke choked major cities, leading to almost 450 deaths, and even circumnavigated the southern hemisphere.

As the aerosols billowed across the oceans many thousands of kilometres away from the fires, microscopic marine algae called phytoplankton had an unexpected windfall: they received a boost of iron.

Our research, published today in Nature, found this caused phytoplankton concentrations to double between New Zealand and South America, until the bloom area became bigger than Australia. And it lasted for four months.

This enormous, unprecedented algal bloom could have profound implications for carbon dioxide levels in the atmosphere and for the marine ecosystem. But so far, the impact is still unclear.

Meanwhile, in another paper published alongside ours in Nature today, researchers from The Netherlands found the amount of carbon dioxide emitted by the fires that summer was more than double previous estimates.

Absorbing 680 million tonnes of carbon dioxide

Iron fertilises phytoplankton and helps them grow, in the same way nutrients added in soil help vegetables grow. And like plants on land, phytoplankton photosynthesise — they absorb CO₂ as they grow and produce oxygen for fish and other marine creatures.

Bushfire smoke is an aerosol made up of many different chemicals, including iron.
Shutterstock

We used satellite data to estimate that for phytoplankton to grow as much as they did in the Southern Ocean, they would have absorbed 680 million tonnes of CO₂. This means the phytoplankton absorbed roughly the same amount of CO₂ as released by the bushfires, according to the latest estimates released today.

The Dutch researchers found the bushfires released 715 million tonnes of CO₂ (or ranging 517–867 million tonnes) between November 2019 and January 2020. This surpasses Australia’s normal annual fire and fossil fuel emissions by 80%.

To put this into perspective, Australia’s anthropogenic CO₂ emissions in 2019 were much less, at 520 million tonnes.

Phytoplankton can have dramatic effects on climate

But that doesn’t mean the phytoplankton growth absorbed the bushfire’s CO₂ emissions permanently. Whether phytoplankton growth extracts and keeps CO₂ from the atmosphere depends on their fate.

If they sink to the deep ocean, then this represents a carbon sink for decades or even centuries — or even longer if phytoplankton are stored in ocean sediments.

But if they’re mostly eaten and decomposed near the ocean’s surface, then all that CO₂ they consumed comes straight back out, with no net effect on the carbon balance in the atmosphere.

Himawari satellite image showing the January aerosol plume stretching over the South Pacific.
Himawari-8, Author provided

In fact, phytoplankton have very likely played a role on millennial time scales in keeping atmospheric CO₂ concentrations down, and can affect the global climate in the long term.

For example, a 2014 study suggests iron-containing dust billowing over the Southern Ocean caused increased phytoplankton productivity, which contributed to reducing atmospheric CO₂ by about 100 parts per million. And this helped transition the planet to ice ages.

Phytoplankton blooms can also have a big impact on the marine ecosystem as they make excellent food for some marine creatures.

For example, more phytoplankton means more food for zooplankton that feed on phytoplankton, with effects up the food chain. It’s also worth noting this huge bloom occurred at a time of year when phytoplankton are usually in decline in this part of the ocean.

But whether there were any long-lasting effects from the bushfire-fuelled phytoplankton on the climate or ecosystem is unclear, because we still don’t know where they ended up.

Using revolutionary data

The link between fire aerosols and the increase in phytoplankton demonstrated in our study is particularly relevant given the intense fire activity around the globe.

Droughts and warming under global climate change are expected to increase the frequency and intensity of wildfires, and the impacts to land-based ecosystems, such as habitat loss and air pollution, will be dramatic. But as we now know, wildfires can also affect marine life thousands of kilometres away from land.

A robotic float being deployed on board the CSIRO RV Investigator.
Jakob Weiss, Author provided

Previous models have predicted the iron-fertilising effect of bushfire aerosols, but this is the first time we’ve observed and demonstrated the connection at a large-scale.

Our study is mainly based on satellite data and observations from robotic floats that roam the oceans and collect data autonomously. These robotic floats are revolutionising our understanding of chemical cycling, oxygen variability and ocean acidification.

During the bushfire period, our smoke tracers reached concentrations at least 300% higher than what had ever been observed in the 22-year satellite record for the region.

Interestingly, you wouldn’t be able to observe the resulting phytoplankton growth in a true-colour satellite image. We instead used more sensitive ocean colour sensors on satellites to estimate phytoplankton concentrations.

So what’s next?

Of course, we need more research to determine the fate of the phytoplankton. But we also need more research to better predict when and where aerosol deposition (such as bushfire smoke) will boost phytoplankton growth.

For example, the Tasman Sea — between Australia and New Zealand — showed only mildly higher phytoplankton concentrations during the bushfire period, even though the smoke cloud was strongest there.

Was this because nutrients other than iron were lacking, or because there was less deposition? Or perhaps because the smoke didn’t stick around for as long?

Whatever the reason, it’s clear this is only the beginning of exciting new lines of research that link forests, wildfires, phytoplankton growth and Earth’s climate.

Christina Schallenberg, Research Fellow, University of Tasmania; Jakob Weis, Ph.D. student, University of Tasmania; Joan Llort, Oceanógrafo , Barcelona Supercomputing Center-Centro Nacional de Supercomputación (BSC-CNS); Peter Strutton, Professor, Institute for Marine and Antarctic Studies, University of Tasmania, and Weiyi Tang, Postdoc in Biogeochemistry, Princeton University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Some animals have excellent tricks to evade bushfire. But flames might be reaching more animals naive to the dangers

Dale Nimmo, Charles Sturt University; Alex Carthey, Macquarie University; Chris J Jolly, Charles Sturt University, and Daniel T. Blumstein, University of California, Los AngelesThe new report by the Intergovernmental Panel on Climate Change paints a sobering picture of the warming climate in coming decades. Among the projections is an increase in fire weather, which will expose Earth’s landscapes to more large and intense megafires.

In our paper, published today in Global Change Biology, we considered what this fiery future might mean for the planet’s wildlife. We argue a lot can be learned by looking at how wildlife responds to a very different threat: predators.

Australia has seen the brutal consequences that occur when native wildlife is exposed to introduced predators. Australian animals have not evolved alongside introduced predators, such as cats and foxes, and some are what scientists call “predator naive” — they simply aren’t equipped with the evolutionary instincts to detect and respond to introduced predators before it’s too late.

Now, let’s take that idea and apply it to fires. Some animals have evolved excellent tricks to detect when a bushfire is nearby. But some areas where infernos were once rare are growing increasingly bushfire-prone, thanks to climate change. The wildlife in these spots may not have the evolutionary know-how to detect a fire before it’s too late.

Just as being “predator naive” has decimated Australian wildlife, will being “fire naive” wreak havoc on our native species?

Behaviour forged in fire

A growing list of studies show the tricks animals from fire-prone areas use to survive the flames.

Sleepy lizards have been shown to panic at the smell of burnt pastry, reed frogs leap away from the crackling sounds of fire, and bats and marsupials wake from torpor after smelling smoke.

And one study found that, when exposed to smoke, Mediterranean lizards from fire-prone areas reacted more strongly than Mediterranean lizards from areas where fire was rare.

These studies show some animals can recognise the threat of fire, and behave in a way that increases their chance of survival. Those that can are more likely to live through fire and pass on those abilities to their offspring.

That’s where the parallels between fire and predation become striking — and potentially worrying.

Reading the cues

It’s well known predators and prey are in an ongoing evolutionary race to outmanoeuvre one another.

One tool prey draw upon to avoid becoming predator food is to recognise cues — such as smells, sights and sounds — that indicate a predator is lurking nearby. Once they do, prey can change their behaviour to minimise the risk of becoming dinner.

Research showed the Mediterranean skink can smell a fire. — Research has shown the Mediterranean skink can smell a fire.
By Balles2601 / Wikimedia Commons / CC BY-SA 4.0, CC BY-SA 4.0, CC BY

Decades of research has shown that when prey evolve alongside a predator, they can become highly adept at recognising their predator’s cues, such as a scent markings or territorial calls.

But what about animals that haven’t evolved alongside these lethal threats?

When a new predator enters an ecosystem, prey that have not evolved with it can be naive to its cues. They might fail to recognise the threat implied by the new predator’s scents, signs, or sounds, placing them at substantial risk.

This “predator naivety” helps explain why introduced predators are global drivers of extinction. Naive prey just don’t hear, smell, or see them coming.

Which species are ‘fire naive’?

Research on how animals respond to fire cues has focused on animals from fire-prone regions, probably because that’s where you’d expect to find the strongest responses. But more research is needed about animals from regions that rarely burn.

Do these animals also recognise the cues of fire as an approaching lethal threat?

Do they have finely tuned behaviours that help them survive fire?

Are they “fire naive”?

We don’t know. And that’s a worry because recent changes in global fire activity, triggered by a warming and drying climate, are seeing fires enter ecosystems long regarded as “fire-free”.

If they are naive to fire, species in these ecosystems might be more at risk than previously thought.

The search for fire naivety

We urge researchers around the world to assess fire naivety of animals, particularly in areas experiencing a change in their fire regimes, such as from rare to frequent fire or increased fire severity.

Evidence suggests recognition of predator cues is at least partly genetic. It will be important to determine whether the capacity to recognise and respond to fire also has a genetic basis.

If those behaviours can be passed on from one generation to the next, then perhaps we could take fire-savvy individuals from fire-prone areas and place them into fire naive populations, in the hope their favourable behaviours will spread rapidly via genes passed onto their offspring. Scientists call this “targeted gene flow”.

As the world continues to warm and megafires rage across the globe, we will need all the knowledge and tools at our disposal to help avoid an acceleration of Earth’s biodiversity crisis.

Dale Nimmo, Associate Professor in Ecology, Charles Sturt University; Alex Carthey, Macquarie University Research Fellow, Macquarie University; Chris J Jolly, Postdoctoral Research Fellow, Charles Sturt University, and Daniel T. Blumstein, Professor in the Department of Ecology and Evolutionary Biology and the Institute of the Environment and Sustainability, University of California, Los Angeles

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Native forest logging makes bushfires worse – and to say otherwise ignores the facts

Philip Zylstra, University of Wollongong; Grant Wardell-Johnson, Curtin University; James Watson, The University of Queensland, and Michelle Ward, The University of QueenslandThe Black Summer bushfires burned far more temperate forest than any other fire season recorded in Australia. The disaster was clearly a climate change event; however, other human activities also had consequences.

Taking timber from forests dramatically changes their structure, making them more vulnerable to bushfires. And, crucially for the Black Summer bushfires, logged forests are more likely to burn out of control.

Naturally, the drivers of the fires were widely debated during and after the disaster. Research published earlier this month, for example, claimed native forest logging did not make the fires worse.

We believe these findings are too narrowly focused and in fact, misleading. They overlook a vast body of evidence that crown fire – the most extreme type of bushfire behaviour, in which tree canopies burn – is more likely in logged native forests.

Logged forest — The authors say logging increases the risk of intense crown fires.
Australian National University

Crown fires vs scorch

The Black Summer fires occurred in the 2019-20 bushfire season and burned vast swathes of Australia’s southeast. In some cases, fire spread through forests with no recorded fire, including some of the last remnants of ancient Gondwanan rainforests.

Tragically, the fires directly killed 33 people, while an estimated 417 died due to the effects of smoke inhalation. A possible three billion vertebrate animals perished and the risk of species extinctions dramatically increased.

Much of the forest that burned during Black Summer experienced crown fires. These fires burn through the canopies of trees, as well as the undergrowth. They are the most extreme form of fire behaviour and are virtually impossible to control.

Crown fires pulse with such intense heat they can form thunderstorms which generate lightning and destructive winds. This sends burning bark streamers tens of kilometres ahead of the fire, spreading it further. The Black Summer bushfires included at least 18 such storms.

Various forest industry reports have recognised logging makes bushfires harder to control.

And to our knowledge, every empirical analysis so far shows logging eucalypt forests makes them far more likely to experience crown fire. The studies include:

A 2009 paper suggesting changes in forest structure and moisture make severe fire more likely in logging regrowth compared to undisturbed forest
2012 research concluding the probability of crown fires was higher in recently logged areas than in areas logged decades before
A 2013 study that showed the likelihood of crown fire halved as forests aged after a certain point
2014 findings that crown fire in the Black Saturday fires likely peaked in regrowth and fell in mature forests
2018 research into the 2003 Australian Alps fires, which found the same increase in the likelihood of crown fire during regrowth as was measured following logging.

The findings of these studies are represented in the image below. The lines a, b and c refer to the 2013, 2014 and 2018 studies respectively.

Graph showing the likelihood of crown fire relative to years since logging or fire — Author supplied

Crown fires take lives

The presence of crown fire is a key consideration in fire supression, because crown fires are very hard to control.

However, the study released last week – which argued that logging did not worsen the Black Summer fires – focused on crown “scorch”. Crown scorch is very different to crown fire. It is not a measure of how difficult it is to contain the fire, because even quite small flames can scorch a drought-stressed canopy.

Forestry studies tend to focus more on crown scorch, which damages timber and is far more common than crown fires.

But the question of whether logging made crown scorch worse is not relevant to whether a fire was uncontrollable, and thus was able to destroy homes and lives.

Importantly, when the study said logging had a very small influence on scorch, this was referring to the average scorch over the whole fire area, not just places that had been logged. That’s like asking how a drought in the small town of Mudgee affects the national rainfall total: it may not play a large role overall, but it’s pretty important to Mudgee.

The study examined trees in previously logged areas, or areas that had been logged and burned by fires of any source. It found they were as likely to scorch on the mildest bushfire days as trees in undisturbed forests on bad days. These results simply add to the body of evidence that logging increases fire damage.

Timber plantation after fire — Forestry industry studies tend to focus on crown scorch.
Richard Wainwright/AAP

Managing forests for all

Research shows forests became dramatically less likely to burn when they mature after a few decades. Mature forests are also less likely to carry fire into the tree tops.

For example during the Black Saturday fires in 2009, the Kilmore East fire north of Melbourne consumed all before it as a crown fire. Then it reached the old, unlogged mountain ash forests on Mount Disappointment and dropped to the ground, spreading as a slow surface fire.

The trees were scorched. But they were too tall to ignite, and instead blocked the high winds and slowed the fire down. Meanwhile, logged ash forests drove flames high into the canopy.

Despite decades of opportunity to show otherwise, the only story for eucalypt forests remains this: logging increases the impact of bushfires. This fact should inform forest management decisions on how to reduce future fire risk.

We need timber, but it must be produced in ways that don’t endanger human lives or the environment.

Philip Zylstra, Adjunct Associate Professor at Curtin University, Honorary Fellow at University of Wollongong, University of Wollongong; Grant Wardell-Johnson, Associate Professor, Environmental Biology, Curtin University; James Watson, Professor, The University of Queensland, and Michelle Ward, PhD Candidate, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

New research finds native forest logging did not worsen the Black Summer bushfires

David Bowman, University of TasmaniaThe Black Summer bushfires shocked the world and generated enormous global media interest. Fire scientists like myself found themselves filling a role not unlike sport commentators, explaining the unfolding drama in real time.

Scientists who engaged with the media during the crisis straddled two competing imperatives. First was their duty to share their knowledge with the community while knowing their understanding is imperfect. Second was the ethical obligation to rigorously test hypotheses against data analysis and peer review – the results of which could only be known long after the fires were out.

One area where this tension emerged was around the influential idea that logging exacerbated the bushfire disaster. During the fire crisis and in the months afterwards, some scientists suggested logging profoundly affected the fires’ severity and frequency. There were associated calls to cease native forestry and shift wood production to plantations.

But there is no scientific consensus about the possible effects of logging on fire risk. In fact, research by myself and colleagues, published in Nature Ecology and Evolution today, shows logging had little if any effect on the Black Summer bushfires. Rather, the disaster’s huge extent and severity were more likely due to unprecedented drought and sustained hot, windy weather.

These findings are significant for several reasons. Getting to the bottom of the bushfires’ cause is essential for sustainable forest management. And, more importantly, our research confirms the devastating role climate change played in the Black Summer fires.

Firefighters recover after battling blazes at Kangaroo Island on 10 January 2019.
David Mariuz/AAP

Looking for patterns

Our research focused on 7 million hectares of mostly eucalyptus forests, from the subtropics to temperate zones, which burned between August 2019 and March 2020.

There is some evidence to suggest logged areas are more flammable that unlogged forests. Proponents of this view say logging regimes make the remaining forests hotter and drier, and leave debris on the ground that increases the fuel load.

In our research, we wanted to determine:

the relative roles logging and other factors such as climate played in fires that destroyed or completely scorched forest canopies
whether plantations are more vulnerable to canopy scorch than native forests.

To do so, we used landscape ecology techniques that could compare very large areas with different patterns of land use and fire severity. We sampled 32% of the area burnt in three regions spanning the geographic range of the fires.

firefighters run past fire — The research used landscape ecology techniques to compare large areas.
Shutterstock

What we found

Fire intensity is classified according to the vertical layer of vegetation burnt. A scorched tree canopy suggests the most intense type of fire, where the heat extended from the ground to the treetops.

We found several predictors of canopy damage. First, completely scorched canopy, or canopy consumed by fire, typically occurred across connected swathes of bushland. This most likely reflected instances where the fire made a “run”, driven by localised winds.

Extreme weather fire conditions were the next most important predictor of canopy damage. The drought had created vast areas of tinder-dry forests. Temperatures during the fire season were hot and westerly winds were strong.

Southeast Australia’s climate has changed, making such extreme fire weather more frequent, prolonged and severe.

Logging activity in the last 25 years consistently ranked “low” as a driver of fire severity. This makes sense for several reasons.

As noted above, fire conditions were extraordinarily extreme. And there was mismatch between the massive area burnt and the comparatively small areas commercially logged in the last 25 years (4.5% in eastern Victoria, 5.3% in southern NSW and 7.8% in northern NSW).

Fire severity is also related to landscape features: fire on ridges is generally worse than in sheltered valleys.

Our research also found timber plantations were as prone to severe fire as native forestry areas. In NSW (the worst-affected state) one-quarter of plantations burned – than 70% severely. This counteracts the suggestion using plantations, rather than logging native forest, can avoid purported fire hazards.

plantation forest divided by road — Plantation forests were found to be highly flammable.
Shutterstock

A challenge awaits

Our findings are deeply concerning. They signal there is no quick fix to the ongoing fire crisis afflicting Australia and other flammable landscapes.

The crisis is being driven by relentless climate change. Terrifyingly, it has the potential to turn forests from critical stores of carbon into volatile sources of carbon emissions released when vegetation burns.

Under a rapidly warming and drying climate, fuel loads are likely to become less important in determining fire extent and severity. This will make it increasingly difficult, if not impossible, to lower fuel loads in a way that will limit bushfire severity.

A massive challenge awaits. We must find socially and environmentally acceptable ways to make forests more resilient to fire while the also produce sustainable timber products, store carbon, provide water and protect biodiversity.

The next step is a real-world evaluation of management options. One idea worth exploring is whether the fire resistance of native forests can be improved in specific areas by altering tree density, vegetation structure or fuel loads, while sustaining biodiversity and amenity.

Commercial forestry could potentially do this, with significant innovation and willingness to let go of current practices.

Through collective effort, I’m confident we can sustainably manage of forests and fire. Our study is but a small step in a much bigger, zig-zagging journey of discovery.

forest regenerating after fire — Forests must become fire-resilient while performing other functions.
Shutterstock

David Bowman, Professor of Pyrogeography and Fire Science, University of Tasmania

This article is republished from The Conversation under a Creative Commons license. Read the original article.

‘We know our community better than they do’: why local knowledge is key to disaster recovery in Gippsland

Celeste Young, Victoria University and Roger Jones, Victoria UniversityOvercoming the odds is second nature to the Gippsland community. The people in this region have seen it all — fires, floods, droughts and extreme weather. And every time, these capable, resourceful and independent communities bounce back.

However, recovery from bushfires of the 2019/2020 Black Summer followed by the COVID-19 pandemic has been different.

Even before these events, we were researching vulnerability to natural hazards, risk ownership and diversity and inclusion nationally as part of our work with the Bushfire and Natural Hazards Cooperative Research Centre.

Through a mix of interviews, focus groups and surveys, we sought insights about communities, how they recover after disaster and what factors have the greatest impact. We focused on community strengths and how to build on them.

Our recently released report, Growing the seeds: recovery, strength and capability in Gippsland communities, highlights that recovery is often non-linear. It’s not just the damage to infrastructure, houses, environment and farmland that makes recovery difficult; the emotional and physical toll is often gruelling as well.

The report identifies several opportunities for change, including the need for a long-term plan (five years minimum) for building community emergency management capability in the region — well before the next disaster strikes.

Our research highlights recovery is often non-linear, an observation well supported by other research in this field.
Growing the seeds report.

A brutal time

The 2019–20 fires damaged over half of the East Gippsland Shire, an area of over
1.16 million hectares. Over 400 dwellings and businesses were lost and four people lost their lives. Areas like Mallacoota were at acute risk. In some areas, communities were under threat for weeks and evacuated repeatedly, exhausting them before the recovery process began.

Then, the pandemic hit, disrupting the established pattern of recovery where people get together to make sense of what has happened and start to rebuild their communities. One person describe the timing as “brutal”. Another said:

When the fires happened, you had a couple of amazing people who stepped up, opened the hall, and everyone was coming in, and they started doing Friday night dinners and everyone was there. There were 200-odd people every Friday night and then COVID ended it.

Via online community consultations, interviews and focus groups, we asked community members to identify strengths that supported recovery and opportunities for change.

We also surveyed 614 people during October 2020 in fire-affected regions of Victoria and New South Wales, with 31% of respondents coming from Victoria and 69% from NSW.

When asked what strengths their community showed following the bushfires, they included generosity and kindness (69%), resilience (61%) and active volunteering (59%).

Growing the seeds report., Author provided

When asked to identify the main challenges since the bushfire, COVID was named as the main challenge (49%), followed by damage to the environment (39%), anxiety (31%) and overall fatigue (26%).

The combination of bushfires and the pandemic also created economic risks and disrupted supply chains. Small businesses make up 98% of the local economy, and many are heavily reliant on tourism.

Recovering through community strength and capability

Many of the strengths needed to drive recovery and resilience are already at the heart of these communities. These capabilities are more diverse and widespread than is often assumed.

There is considerable wealth and capacity in some areas, but also a high level of social and economic vulnerability, with some living hand-to-mouth.

There is significant local knowledge of risk management and recovery, which is often overlooked by experts coming in from outside. As one person told us:

You’ve got bureaucracy coming in from Melbourne who think that we’re just a bunch of country bumpkins who don’t quite know what we’re doing, yet we know our community better than they do.

Volunteer and informal economies are significant and underpin community resilience. Yet formal recovery strategies don’t target these areas very well; some people in the informal economy found they did not qualify for economic or business support at all.

The JobSeeker and JobKeeper programs helped maintain employment (albeit at levels of productivity that were lower than in the past). JobKeeper has now ended but support is still needed to boost productivity and help the local economy recover.

We also found:

government and some supporting agencies often lacked knowledge about the cultural, physical and social structures of different communities
some policies had perverse effects (for example, the HomeBuilder grant resulted in a lack of available builders)
programs and communication were often not tailored and did not accommodate the diverse needs of communities or specific cohorts within them
a lack of clarity as to what role the community have in response and recovery, and what risks they are responsible for
short-term allocation of resources and funding sometimes created an environment of uncertainty; for example, some participants raised concerns vulnerable community members may at risk when contracts for certain programs ran out, as the service offered would either cease or be led by a new contract-holder. As one person told us:

You can’t just bring someone in now and go, ‘Here you go, you take over all my people’, because the relationships and the trust that you build over this time, it’s not something you can hand over to someone else.

Knowing community strengths and supporting them

Recovery processes will never be perfect and we can also no longer assume communities will have time to recover from one disaster before the next arrives. As one person said:

People are suffering collective trauma, which creates anxiety and irritability. So, it is going to be difficult to move forward and I believe [name removed] will be a really changed place, this is something that will echo up and down along all fire-ravaged communities.

In natural hazard prone areas like Gippsland, it’s crucial to know what strengths already exist in the community so they can be harnessed when disaster hits. In other words, we need to find ways to support and grow community capabilities.

Listening to communities

It’s crucial communities, governments and the emergency services have a shared understanding of what the priorities are after a disaster and what can be realistically achieved.

A database of community capabilities would support more effective planning, policy-making and program development, as would a longer term collaborative project to identify and develop community capability.

Through listening to these communities we can learn from their experiences and support the development of community-led pathways to recovery.

If this article has raised issues for you, or if you’re concerned about someone
you know, call Lifeline on 13 11 14. This story is part of a series The Conversation is running on the nexus between disaster, disadvantage and resilience. You can read the rest of the stories here.

Celeste Young, Collaborative Research Fellow, Sustainable Industries and Liveable Cities (ISILC), Victoria University and Roger Jones, Professorial Research Fellow, Victoria University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

A staggering 1.8 million hectares burned in ‘high-severity’ fires during Australia’s Black Summer

Ross Bradstock, University of Wollongong; Hamish Clarke, University of Wollongong; Luke Collins, La Trobe University; Michael Clarke, La Trobe University; Rachael Helene Nolan, Western Sydney University, and Trent Penman, The University of MelbourneIn the aftermath of Australia’s devastating Black Summer fires, research has begun to clarify the role of climate change.

We already know climate change contributed to the record-breaking drought and fire weather conditions, leading to the bushfires’ unprecedented range across Australia.

Our new research looks at whether bushfires are becoming more “severe” (an indicator of how intensely the vegetation burned) as a result of climate change.

Our findings were unexpected, as we learned the proportion of high-severity fires generally hasn’t increased in recent decades. However, the sheer breadth of the Black Summer fires meant an unprecedented 1.8 million hectares across southeast Australia were exposed to high-severity fires. This has dire consequences for the people and wildlife who call the forests home.

What is fire severity?

Two measurements in fire science are pertinent to our research: fire severity and fire intensity.

Fire severity refers to how high the flames and the plume of hot air reach, as measured by the resulting damage to vegetation (vertical profile of scorch and consumption of leaves and twigs). Fire intensity refers to the energy released from the fire — how hot and destructive the flames are.

Scientists can estimate severity using using satellite imagery, by contrasting differences in the cover and condition of vegetation before and after fires.

In forests, “high-severity” fires occur when the crowns of dominant trees are fully burnt or scorched. High-severity fires are lethal to tree-dwelling mammals in forests, such as possums, gliders and koalas. They also pose a big risk to nearby homes and buildings.

“Low-severity” fires, on the other hand, may be confined to the leaf litter and ground cover plants beneath the forest canopy, and can even leave entirely unburnt patches in forests.

Are high severity fires becoming more common?

To determine if high-severity bushfires are becoming more common, we looked at satellite data for bushfires from 1988 to 2020. The data covered more than 130,000 square kilometres of forest, woodland and shrubland ecosystems in southeast Australia.

If fires were becoming more intense in recent decades, we would have expected the proportion of vegetation subjected to high-severity fire to have increased.

Instead, we found the average proportion of high-severity wildfire remained constant in dry forest — the dominant vegetation across this region. There was, however, evidence of an increase in the average proportion of high-severity fire in wet forests and rainforests, along with woodlands.

Nonetheless, the main conclusion was clear: across the bulk of the study area, the average proportion of high-severity fires has not changed in recent decades, despite an increase in the area burned during the Black Summer bushfires.

Why the Black Summer bushfires were exceptional

While the proportion of high-severity fires hasn’t changed, the enormous range of the 2019-2020 bushfires meant 44% of the total area burned by high-severity fire since 1988 occurred in that one summer alone.

This means 1.8 million hectares of the forest and woodland regions of southeastern Australia — an enormous proportion — was exposed to intense and severe fire. In this regard, the Black Summer bushfires were exceptional.

As Australians remember all too clearly, this had a devastating effect on the environment. An estimated three billion animals were killed or displaced, vulnerable rainforests burned and 3,000 homes were destroyed.

A firefighter runs through a burning forest — Firestorms could become more common under a changing climate.
AAP Image/Dean Lewins

The 2019-20 fire season also involved a record number of “firestorms”, particularly during the latter part of the season in January and early February. This occurs when fires create their own weather.

These fires can burn at exceptional intensity. And research from 2019 indicates such firestorms could become more common under climate change.

This means we can’t rule out a future change in the proportion of bushfires that burn at the highest levels of intensity and severity.

Ecosystems in jeopardy

The results of our study underline one of the likely consequences of future climate change.

The sheer scale of the area burned in the 2019-20 fire season exceeded not only historical records for forested ecosystems of southern Australia, but also outstripped projections for the late 21st century under strong scenarios of climate change.

As bushfires become larger in the future, the area exposed to intense and severe fires is likely to increase commensurately. As a result, the future of our wetter forest types, which have not evolved to cope with frequent and severe fires, is in jeopardy.

So, as the area exposed to intense fires is likely to increase in the future, we’ll see major challenges to the long-term viability of our forested ecosystems, the services they provide and the people who reside in and around them.

Ross Bradstock, Emeritus professor, University of Wollongong; Hamish Clarke, Research Fellow, University of Wollongong; Luke Collins, Research scientist, La Trobe University; Michael Clarke, Emeritus professor, La Trobe University; Rachael Helene Nolan, Postdoctoral research fellow, Western Sydney University, and Trent Penman, Professor, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bushfire/Wildfire Storms

5 remarkable stories of flora and fauna in the aftermath of Australia’s horror bushfire season

hamiltonphillipa/iNaturalist, CC BY-NC-SA

Will Cornwell, UNSW; Casey Kirchhoff, UNSW, and Mark Ooi, UNSW

Around one year ago, Australia’s Black Summer bushfire season ended, leaving more than 8 million hectares across south-east Australia a mix of charcoal, ash and smoke. An estimated three billion animals were killed or displaced, not including invertebrates.

The impact of the fires on biodiversity was too vast for professional scientists alone to collect data. So in the face of this massive challenge, we set up a community (citizen) science project through the iNaturalist website to help paint a more complete picture of which species are bouncing back — and which are not.

Almost 400 community scientists living near or travelling across the firegrounds have recorded their observations of flora and fauna in the aftermath, from finding fresh wombat droppings in blackened forests, to hearing the croaks of healthy tree frogs in a dam choked with debris and ash.

Each observation is a story of survival against the odds, or of tragedy. Here are five we consider particularly remarkable.

Greater gliders after Australia’s largest ever fire

The Gospers Mountain fire in New South Wales was the biggest forest fire in Australian history, razing an area seven times the size of Singapore. This meant there nothing in history scientists could draw from to predict the animals’ response.

So it came as a huge surprise when a community scientist observed greater gliders deep within the heart of the Gospers Mountain firegrounds in Wollemi National Park, far from unburned habitat. Greater gliders are listed as “vulnerable” under national environment law. They’re nocturnal and live in hollow-bearing trees.

A greater glider with shining eyes at night — A citizen scientist snapped this photo of a greater glider in the heart of the the Gospers Mountain firegrounds.
Mike Letnic/iNaturalist, CC BY-NC

How gliders survived the fire is still unknown. Could they have hidden in deep hollows of trees where the temperature is relatively cooler while the fire front passed? And what would they have eaten afterwards? Greater gliders usually feed on young leaves and flowers, but these foods are very rare in the post-fire environment.

Finding these gliders shows how there’s still so much to learn about the resilience of species in the face of even the most devastating fires, especially as bushfires are forecast to become more frequent.

Rare pink flowers burnishing the firegrounds

The giant scale of the 2019-20 fires means post-fire flowering is on display in grand and gorgeous fashion. This is a feature of many native plant species which need fire to stimulate growth.

Excitingly, community scientists recorded a long-dormant species, the pink flannel flower (Actinotus forsythii), that’s now turning vast areas of the Blue Mountains pink.

Pink flannel flowers are bushfire ephemerals, which means their seeds only germinate after fire.
Margaret Sky/iNaturalist, CC BY-NC

Pink flannel flowers are not considered threatened, but they are very rarely seen.

Individuals of this species spend most of their life as a seed in the soil. Seeds require a chemical found in bushfire smoke, and the right seasonal temperatures, to germinate.

Rediscovering the midge orchid

Much of Australia’s amazing biodiversity is extremely local. Some species, particularly plants, exist only in a single valley or ridge. The Black Summer fires destroyed the entire range of 100 Australian plant species, incinerating the above-ground parts of every individual. How well a species regenerates after fire determines whether it recovers, or is rendered extinct.

The midge orchid.
Nick Lambert/iNaturalist, CC BY-NC

One of these is a species of midge orchid, which grows in a small area of Gibraltar Range National Park, NSW.

All of the midge orchid’s known sites are thought to have burned in late 2019. The species fate was unknown until two separate community scientists photographed it at five sites in January 2021, showing its recovery.

Like many of Australia’s terrestrial orchids, this species has an underground tuber (storage organ) which may have helped part of it avoid the flames’ lethal heat.

Don’t forget about insects

Despite their incredible diversity and tremendous value to society, insects tend to be the forgotten victims of bushfires and other environmental disasters.

Many trillions of invertebrates would have been killed in the fires of last summer. A common sight during and after the bushfire season was a deposit of dead insects washed ashore. Some died from the flames and heat, while others died having drowned trying to escape.

Dead insects washed up on the beach was a common sight in the fire aftermath.
BlueBowerStudio/iNaturalist, CC BY-NC

One dead insect deposit — one of hundreds that washed up near Bermagui, NSW on Christmas Eve — included a range of species that have critical interactions with other organisms.

This includes orchid dupe wasps (Lissopimpla excelsa), the only known pollinator of the orchid genus Cryptostylis. Transverse ladybirds (Coccinella transversalis), an important predator of agricultural pests such as aphids, also washed up. As did metallic shield bugs (Scutiphora pedicellata), spectacular iridescent jewel bugs that come in green and blue hues.

Some insects died from the flames and heat, while others died having drowned trying to escape the flames.
BlueBowerStudio/iNaturalist, CC BY-NC

The unlikely survival of the Kaputar slug

Creatures such as kangaroos or birds have a chance to flee bushfires, but smaller, less mobile species such as native slugs and snails have a much tougher time of surviving.

The 2019-2020 bushfire season significantly threatened the brilliantly coloured Mount Kaputar pink slug, found only on the slopes of Mount Kaputar, NSW. When fires ripped through the national park in October and November 2019, conservationists feared the slug may have been entirely wiped out.

But park ranger surveys in January 2020 found at least 60 individuals managed to survive, likely by sheltering in damp rock crevices. Community scientists have spotted more individuals since then, such as the one pictured here found in September 2020.

But the slug isn’t out of the woods yet, and more monitoring is required to ensure the population is not declining.

Bright pink slug — A community scientist spotted this rare slug in firegrounds.
Taylor/iNaturalist, CC BY-NC

Continuing this work

While community scientists have been documenting amazing stories of recovery all across Australia, there are still many species which haven’t been observed since the fires. Many more have been observed only at a single site.

The Snowy River westringia (Westringia cremnophila), for instance, is a rare flowering shrub found on cliffs in Snowy River National Park, Victoria. No one has reported observing it since the fire.

So far these community scientist observations have contributed to one scientific paper, and three more documenting the ability for species to recover post-fire are in process.

Recovery from Black Summer is likely to take decades, and preparing a body of scientific data on post-fire recovery is vital to inform conservation efforts after this and future fires. We need more observations to continue this important work.

Will Cornwell, Associate Professor in Ecology and Evolution, UNSW; Casey Kirchhoff, PhD Candidate, UNSW, and Mark Ooi, Senior Research Fellow, UNSW

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Fires bring home climate-driven urgency of rethinking where we live – and how

Barbara Norman, University of Canberra; Peter Newman, Curtin University, and Will Steffen, Australian National University

As we were still recovering from last summer’s fires in southeast Australia, the southwest fires brought in 2021. Both were far more intense fires than seen before, driven by deep drying, extreme heat and powerful winds. It’s a harsh reminder that climate change is going to bounce us up and down with increased frequency.

We have published a new research paper in the journal Nature, titled Apocalypse Now: Australian Bushfires and the Future of Urban Settlements. It was put together as the fires were raging in the east, and comes out as Perth residents are still reeling from the devastating fires in the west this month.

Both sides of Australia have now learnt hard lessons.

What have we learned?

1. Bushfires have become more frequent and more intense

The 2019-2020 Black Summer bushfires were unprecedented in their scale and were fuelled by unprecedented climatic conditions.

The fires burned about 21% of eastern Australia’s temperate broad-leafed (mainly eucalypt) forests. That’s more than ten times the annual average of about 2%, even in extreme fire seasons.

Individual fires were also massive in size. For example, the Gospers Mountain fire near Sydney burned more than 500,000 hectares. This made it the largest individual fire ever recorded in Australia.

2. Climate change is creating unprecedented conditions

The preceding climatic conditions were also unprecedented. 2019 was Australia’s hottest year on record. The average maximum temperature was 2.09°C above the baseline and 0.5°C higher than the previous record.

Australia also experienced its driest year on record in 2019. Rainfall was about 40% below average across the continent.

Climate change played a strong role in driving these weather records.

3. It’s a global problem

Modelling by the Intergovernmental Panel on Climate Change (IPCC) shows if the world goes past the 2°C rise on average and moves towards 3°C, the world is likely to lose most of the forests in dry climate areas like ours.

The southwestern region of Australia has been drying for 40 years, linked to climate change. In recent years, the Perth region has depended on desalinating seawater for about half of the water supply to more than 2 million residents.

perth desalination plant — Perth’s rainfall has fallen dramatically for decades and the city now relies very heavily on desalination for its water supply.
Callistemon/Wikimedia Commons, CC BY-SA

The bushfires have become more intense over the past decade. Similar patterns are found in California and other areas with a Mediterranean climate.

4. The global community is watching

State and federal governments must commit to net-zero emissions targets. These would signal to industry and communities that there is a diminishing future for fossil fuels and encourage investment in a renewable future.

The fires strikingly remind people that we remain a global climate laggard. This will soon spread to our trade discussions and ability to raise finance for nation-building infrastructure and major projects.

5. Our settlements will need to change

The most vulnerable parts of our cities are in the urban fringes where there is substantial scattered development set in bush. Such homes are going to be increasingly vulnerable. As a result, owners will find insurance harder to secure.

Consolidating the city will need to start by reviewing such lifestyle zonings to reduce risk to communities. Rural areas and coastal settlements also will need a new model based on new green technology infrastructure, new building materials and new ways of living together rather than living in forest hideaways.

6. Indigenous fire management needs to be applied to all bush

Indigenous fire techniques are beginning to be developed and adapted with local communities after the fires last summer. These are needed around our cities and in urban bushland, as well as in forests and rangelands across our country.

If we don’t begin to adopt such “cool burn” approaches, then we face the prospect of losing our forests, even those in and around our cities.

What must we do to make this happen?

Key elements include:

regional urban centres make the transition to renewable energy
urban design becomes responsive to climate through retrofitting programs and consolidating settlements
settlements retreat from areas of high climate risk, working with affected communities to identify options
community climate action plans get funded, including climate change adaption, climate-sensitive urban design and heat reduction though urban green spaces
embed action on climate change (mitigation and adaptation) through a national investment program, in partnership with the states, to review urban planning processes.

This is a crisis that needs strong leadership of the type shown in the COVID response. That means working together, fostering innovation and investing in creating and building more climate-adapted communities.

This article is part of a series The Conversation is running on the nexus between disaster, disadvantage and resilience. You can read the rest of the series here.

Barbara Norman, Chair of Urban & Regional Planning and Director of Canberra Urban & Regional Futures, University of Canberra; Peter Newman, Professor of Sustainability, Curtin University, and Will Steffen, Emeritus Professor, Fenner School of Environment & Society, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

What happens when fires become more frequent?

What happens when fire seasons get longer?

When drought and heatwaves get more severe

When threats pile up

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Absorbing 680 million tonnes of carbon dioxide

Phytoplankton can have dramatic effects on climate

Using revolutionary data

So what’s next?

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Behaviour forged in fire

Reading the cues

Which species are ‘fire naive’?

The search for fire naivety

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Crown fires vs scorch

Crown fires take lives

Managing forests for all

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Looking for patterns

What we found

A challenge awaits

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A brutal time

Recovering through community strength and capability

Knowing community strengths and supporting them

Listening to communities

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What is fire severity?

Are high severity fires becoming more common?

Why the Black Summer bushfires were exceptional

Ecosystems in jeopardy

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Greater gliders after Australia’s largest ever fire

Rare pink flowers burnishing the firegrounds

Rediscovering the midge orchid

Don’t forget about insects

The unlikely survival of the Kaputar slug

Continuing this work

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What have we learned?

What must we do to make this happen?

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