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.




Read more:
I’m searching firegrounds for surviving Kangaroo Island Micro-trapdoor spiders. 6 months on, I’m yet to find any


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.




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


The Conversation


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.

The 50 beautiful Australian plants at greatest risk of extinction — and how to save them


Caley’s grevillea (Grevillea caleyi) occurs in Sydney. It needs fire to germinate but burns are hard to carry out near urban areas.
Tony Auld, Author provided

Jennifer Silcock, The University of Queensland; Jaana Dielenberg, Charles Darwin University; Roderick John Fensham, The University of Queensland, and Teghan Collingwood, The University of QueenslandAs far as odds go, things don’t look promising for the slender-nerved acacia (Acacia leptoneura), a spiky plant with classic yellow-ball wattle flowers. With most of its habitat in Western Australia’s wheat belt cleared for agriculture, it was considered extinct for more than 160 years.

Now, just two plants are known in the world, and they’re not even in the same place. This species is among many Australian plants that have come perilously close to extinction.

To help prevent the loss of any native plant species, we’ve assembled a massive evidence base for more than 750 plants listed as critically endangered or endangered. Of these, we’ve identified the 50 at greatest risk of extinction.

The good news is for most of these imperilled plants, we already have the knowledge and techniques needed to conserve them. We’ve devised an action plan that’s relatively easy to implement, but requires long-term funding and commitment.

What’s driving the loss?

There are 1,384 plant species and subspecies listed as threatened at a national level. Twelve Australian plant species are considered probably extinct and a further 21 species possibly extinct, while 206 are officially listed as critically endangered.

Yellow wattle
Two known plants of slender nerved acacia (Acacia leptoneura) remain, about 1 kilometre apart. Propagation attempts have been unsuccessful and the genetic diversity is probably very low.
Joel Collins, Author provided

Australian plants were used, managed and celebrated by Australia’s First Nations people for at least 60,000 years, but since European colonisation, they’ve been beset by a range of threats.

Land clearing, the introduction of alien plants, animals, diseases, and interruptions to ecological processes such as fire patterns and flooding have taken a heavy toll on many species. This is particularly the case in the more densely populated eastern and southern parts of the continent.

Close-up of yellow flower
Ironstone pixie mop (Petrophile latericola) occurs on a soil type that’s been heavily cleared for agriculture, and is suspected to be susceptible to an introduced root-rot fungus. In 2020 fewer than 200 plants remained, in poor condition.
Andrew Crawford, Author provided

Things aren’t improving. Scientists recently compiled long-term monitoring of more than 100 threatened plant species at 600 sites nationally. And they found populations had declined on average by 72% between 1995 and 2017.

This is a very steep rate of decline, much greater than for threatened mammal or bird populations.




Read more:
Australia-first research reveals staggering loss of threatened plants over 20 years


On the brink

Many species listed as threatened aren’t receiving targeted conservation action or even baseline monitoring, so an important first step in preventing extinctions was identifying the species at greatest risk.

To find the top 50, we looked at the evidence: all available published and unpublished information and expert surveys of over 120 botanists and land managers.
They’re targeted by our Action Plan for Australia’s Imperilled Plants.

Action Plan for Australia’s Imperilled Plants.

Thirty of the species in the plan have fewer than 50 mature individual plants remaining.

And 33 are known only from a single location, such as the Grampians pincushion-lily (Borya mirabilis), which occurs on one rocky outcrop in Victoria. This means the entire population could be destroyed by a single event, such as a major bushfire.

A dead-looking gum tree on agricultural land
About 2,000 Morrisby’s gums were growing in the early 1990s, but by 2016 fewer than 50 remained. Climate change and damage from insects and animals threaten those left. Protecting trees with fencing has led to new seedlings.
Magali Wright, Author provided
Fewer than 10 lax leek-orchids (Prasophyllum laxum) remain. Declines are ongoing due to drought and wildfire, and the South Australian species only occurs on private property not managed for conservation. Proposed recovery actions include habitat protection and establishing the orchid and its mycorrhizal fungi in conservation reserves.
Shane Graves, Author provided
Fewer than 15 woods well spyridium (Spyridium fontis-woodii) shrubs remain on a single roadside in South Australia. Research into threats and germination requirements is urgently needed, plus translocation to conservation reserves.
Daniel Duval/South Australian Seed Conservation Centre, Author provided

So how can we protect them?

Some of the common management actions we’ve proposed include:

  • preventing further loss of species’ habitat. This is the most important action required at a national scale
  • regularly monitoring populations to better understand how species respond to threats and management actions
  • safely trialling appropriate fire management regimes, such as burning in areas where fires have been suppressed
  • investing in disease research and management, to combat the threat of phytophthora (root-rot fungus) and myrtle rust, which damages leaves
  • propagating and moving species to establish plants at new sites, to boost the size of wild populations, or to increase genetic diversity
  • protecting plants from grazing and browsing animals, such as feral goats and rabbits, and sometimes from native animals such as kangaroos.
Once common, the dwarf spider-orchid (Caladenia pumila) wasn’t seen for over 80 years until two individual plants were found. Despite intensive management, no natural recruitment has occurred. Propagation attempts have successfully produced 100 seedlings and 11 mature plants from seed. This photo shows botanist Marc Freestone hand-pollinating dwarf spider-orchids.
Marc Freestone, Author provided
Only 21 mature plants of Gillingarra grevillea (Grevillea sp. Gillingarra) remain on a disturbed, weedy rail reserve in southwestern WA. Half the population was destroyed in 2011 due to railway maintenance and flooding. Habitat protection and restoration, and translocations to conservation reserves are needed to ensure its survival.
Andrew Crawford, Author provided

Another common issue is lack of recruitment, meaning there’s no young plants coming up to replace the old ones when they die. Sometimes this is because the processes that triggered these plants to flower, release seed or germinate are no longer occurring. This can include things like fire of a particular intensity or the right season.

Unfortunately, for some plants we don’t yet know what triggers are required, and further research is essential to establish this.

Now we need the political will

Our plan is for anyone involved in threatened flora management, including federal, state, territory and local government groups, First Nations, environment and community conservation groups, and anyone with one of these plants on their land.

The Border Ranges lined fern (Antrophyum austroqueenslandicum) and its habitat are exceedingly rare. It’s threatened by drought and climate change, and fewer than 50 plants remain in NSW. If the threat of illegal collection can be controlled, the species would benefit from re-introduction to Queensland’s Lamington National Park.
Lui Weber, Author provided

Plants make Australian landscapes unique — over 90% of our plant species are found nowhere else in the world. They’re also the backbone of our ecosystems, creating the rich and varied habitats for our iconic fauna to live in. Plants underpin and enrich our lives every day.

Now we have an effective plan to conserve the Australian plants at the greatest risk of extinction. What’s needed is the political will and resourcing to act in time.




Read more:
Undocumented plant extinctions are a big problem in Australia – here’s why they go unnoticed


The Conversation


Jennifer Silcock, Post-doctoral research fellow, The University of Queensland; Jaana Dielenberg, University Fellow, Charles Darwin University; Roderick John Fensham, Associate Professor of Biological Sciences, The University of Queensland, and Teghan Collingwood, Research Technician, 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


Shutterstock

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.




Read more:
The government has pledged over $800m to fight natural disasters. It could be revolutionary — if done right


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.




Read more:
Australia, you have unfinished business. It’s time to let our ‘fire people’ care for this land


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.




Read more:
As bushfire and holiday seasons converge, it may be time to say goodbye to the typical Australian summer holiday


The Conversation


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.

Phantom of the forest: after 100 years in hiding, I rediscovered the rare cloaked bee in Australia


James B. Dorey, Flinders University

It’s not often you get to cast your eyes on a creature feared to be long-gone.

Perhaps that’s why my recent rediscovery of the native bee species Pharohylaeus lactiferus is so exciting — especially after it spent a century eluding researchers.

But how did it stay out of sight for so long?

A creature overshadowed

Australia is home to 1654 named species of native bee. Unfortunately, these are often overshadowed in the eyes of public by the widespread and invasive European honeybee.

Scientific research on Australian native bees is lagging, compared to many other nations.

With this in mind, it may not be surprising to learn some native species can go unnoticed for many years. Although, when it’s the only representative of a whole genus, one might start to worry about losing something special.

In this case the genus is Pharohylaeus, where “pharo” means “cloaked”, as these bees’ first three abdominal segments overlay the others to resemble a cloak.

I found the cloaked bee P. lactiferus during a major east coast sampling effort of more than 225 unique sites. The discovery, and what I learnt from it, helped me find more specimens at two additional sites.

It also made me wonder why P. lactiferus had been missing for so long. Is it naturally rare, hard to find, or perhaps threatened?




Read more:
We taught bees a simple number language – and they got it


Taxonomic trouble

Many Australian bees are very difficult to identify to a species level. In fact, some might be nearly impossible.

However, P. lactiferus is a relatively distinct black and white masked bee. Masked bees are those from the subfamily Hylaeinae, named so because they often have striking, bright facial patterns on an otherwise dark face.

With this distinctive appearance, identification issues weren’t a contributor to the mystery of P. lactiferus.

Seeing red

Still, despite having sampled extensively across sites and flowering plant species, I only found P. lactiferus on two types of plant: the firewheel tree and the Illawarra flame tree — both of which boast exuberant red flowers.

_Brachychiton acerifolius_ flowers.
The Illawarra flame tree (Brachychiton acerifolius).
James Dorey, Author provided

Bees generally don’t see shades of red, so such plants are usually pollinated by birds. It could be that bee researchers tend to avoid sampling these red flowering plant species for this reason.

Then again, bee vision and bee perception are not always the same. And bees are also guided by their keen sense of smell.

Habitat specialisation

So far, I’ve only found P. lactiferus within about 200 metres of one major vegetation subgroup, which is tropical or sub-tropical rainforest.

The first specimens I collected were in Atherton, Queensland. I later found more in Kuranda and Eungella. Some of these specimens are now stored in the South Australian Museum.

The habitat specialisation of P. lactiferus may suggest it has an above-average level of vulnerability to disturbances, particularly if it needs a strict set of requirements to make it through its entire life-cycle.

It is one of myriad bee species that nest in narrow, wooden hollows. Some bees such as Amphylaeus morosus dig these themselves and may require specific plant species to make their nest in.

Others such as Exoneurella tridentata need to use holes made by weevil larvae in two particular tree species: western myall and bullock bush.

Rainforests are also notoriously hard to sample. If a bee species spends much of its time in the high canopy, finding it would be difficult.

That said, two early collectors managed to find six specimens of P. lactiferus between 1900 and 1923. So its rarity doesn’t necessarily come down to it being a canopy-dweller.




Read more:
The mystery of the blue flower: nature’s rare colour owes its existence to bee vision


Potential threats

We know in the bioregions where P. lactiferus has been found that rainforests have undergone both habitat destruction and fragmentation since European colonisation. This threat hasn’t abated and Queensland is still a land-clearing hotspot.

We also know these rainforests burnt across Queensland every year between 1988 and 2016. The 2019-20 black summer megafires burnt nearly double the area of any previous year.

For some bee species this may not be a problem. But for a species that potentially requires specific foods, habitats and even other species, it could mean local extinction.

Only so many populations of a single species can disappear, before there are none left.

Where does this leave us?

P. lactiferus persists, which is wonderful. Unfortunately, we can’t yet say whether or not it is threatened.

To determine this confidently would require a robust, extensive and targeted survey regime.

We may not be able to undertake such a regime for all 1654 of the named bee species in Australia. But perhaps we could make that effort for the country’s only cloaked bee.The Conversation

James B. Dorey, PhD Candidate, Flinders University

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

Predators, prey and moonlight singing: how phases of the Moon affect native wildlife



Wes Mountain/The Conversation, CC BY-ND

Euan Ritchie, Deakin University; Courtney Marneweck, Clemson University , and Grant Linley, Charles Sturt University

Humans have long been inspired and transfixed by the Moon, and as we’re discovering, moonlight can also change the behaviour of Australian wildlife.

A collection of recently published research has illuminated how certain behaviours of animals – including potoroos, wallabies and quolls – change with variation in ambient light, phases of the Moon and cloud cover.




Read more:
How big is the Moon? Let me compare …


One study found small mammals were more active on cloudy nights. Another found variation in moonlight led to differing amounts of species captured in non-lethal traps. And a study on willie wagtails found males just love singing on a full moon.

These findings are interesting from a natural history perspective. But they’ll also help ecologists and conservation scientists better locate and study nocturnal animals, and learn how artificial light pollution is likely changing where animals can live and how they behave.

Moonlit predator-prey games of hide and seek

Most of Australia’s mammals are nocturnal, and some smaller species are thought to use the cover of darkness to avoid the attention of hungry predators. However, there’s much we don’t know about such relationships, especially because it can be difficult to study these interactions in the wild.

Eastern barred bandicoots became more active on darker nights.
Simon Gorta

In the relatively diverse mammal community at Mt Rothwell, Victoria, we examined how variation in ambient light affected species’ activity, and how this might influence species interactions. Mt Rothwell is a fenced conservation reserve free of feral cats and foxes, and with minimal light pollution.

Over two years, we surveyed the responses of predator and prey species to different light levels from full, half and new moon phases.




Read more:
One little bandicoot can dig up an elephant’s worth of soil a year – and our ecosystem loves it


Potential prey species in our study included eastern barred and southern brown bandicoots, long-nosed potoroos, brushtailed rock-wallabies, and brushtail and common ringtail possums. Eastern and spotted-tailed quolls are their potential predators.

Just as we predicted, we found that while there does appear to be relationships between cloud cover, Moon phase and mammal activity, these interactions depend on the sizes and types of mammals involved.

Spotted tail quoll
The spotted-tailed quoll, a meat-eating marsupial, hunts smaller prey at night.
Shutterstock

Both predators and prey generally increased their activity in darker conditions.
Smaller, prey species increased their activity when cloud cover was higher, and predators increased their activity during the half and new moon phases.

This suggests their deadly game of hide and seek might intensify on darker nights. And prey might have to trade off foraging time to reduce their chances of becoming the evening meal.

What happens in the wild?

It’s important to acknowledge that studies in sanctuaries such as Mt Rothwell might not always reflect well what goes on in the wild, including in areas where introduced predators, such as feral cats and red foxes, are found.

Another recent study, this time of small mammals in the wilds of Victoria’s Mallee region, sheds further light on the situation. The authors tested if variation in weather and Moon phase affected the numbers of five small mammal species – Bolam’s mouse, common dunnart, house mouse, southern ningaui, and western pygmy possum – captured in pitfall traps.

Ningauis are less likely to be caught in ecological surveys with increasing moonlight.
Kristian Bell

Pitfall traps are long fences small animals can’t climb over or through, so follow along the side until they fall into a bucket dug in the ground. Ecologists typically use these traps to capture and measure animals and then return them to the wild, unharmed.




Read more:
Eastern quolls edge closer to extinction – but it’s not too late to save them


At more than 260 sites and over more than 50,000 trap nights, they found wind speed, temperature and moonlight influenced which species were caught and in what numbers.

For example, captures of a small native rodent, Bolam’s mouse, and carnivorous marsupial, southern ningaui, decreased with more moonlight, whereas captures of pygmy possums were higher with more moonlight.

Variation in the moon phase and associated light can change how active mammals are.
Aaron Greenville

Moonlight songbird serenades

Research from last month has shown even species normally active by day may change their behaviour and activity by night.

It’s not uncommon to hear bird song by night, including the quintessentially Aussie warbling of magpies. Using bioacoustic recorders and song detection software, these researchers show the willie wagtail – another of Australia’s most recogisable and loved birds – is also a nighttime singer, particularly during the breeding season.

While both male and female wagtails sing by day, it is the males that are most vocal by night. And it seems the males aren’t afraid of a little stage-lighting either, singing more with increasing moonlight, with performances peaking during full moons.

While characteristically playful by day, male willie wagtails can really turn on a vocal performance by night.
Jim Bendon/Flickr

This work provides insight into the importance and potential role of nocturnal song for birds, such as mate attraction or territory defence, and helps us to better understand these behaviours more generally.

Moonlight affects wildlife conservation

These studies, and others, can help inform wildlife conservation, as practically speaking, ecological surveys must consider the relative brightness of nights during which work occurred.

Depending on when and where we venture out to collect information about species, and what methods we use (camera traps, spotlighting, and non-lethal trapping) we might have higher or lower chances of detecting certain species. And this might affect our insights into species and ecosystems, and how we manage them.

Artificial lighting can change the behaviour of wildlife.
Kenny Louie

As dark skies become rarer in many places around the world, it also begs a big question. To what extent is all the artificial light pollution in our cities and peri-urban areas affecting wildlife and ecosystems?




Read more:
Turn off the porch light: 6 easy ways to stop light pollution from harming our wildlife


Pipistrelle bats, for example, will be roughly half as active around well-lit bridges than unlit bridges. They’ll also keep further away from well-lit bridges, and fly faster when near them.

This means artificial light might reduce the amount and connectivity of habitat available to some bat species in urban areas. This, in turn could affect their populations.

Research is underway around the world, examining the conservation significance of such issues in more detail, but it’s another timely reminder of the profound ways in which we influence the environments we share with other species.


We would like to acknowledge Yvette Pauligk, who contributed to our published work at Mt Rothwell, and that the traditional custodians of this land are the Wathaurong people of the Kulin nation.The Conversation

Euan Ritchie, Associate Professor in Wildlife Ecology and Conservation, Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University; Courtney Marneweck, Postdoctoral Researcher in Carnivore Ecology, Clemson University , and Grant Linley, PhD Candidate, Charles Sturt University

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

Don’t count your fish before they hatch: experts react to plans to release 2 million fish into the Murray Darling



Dean Lewins/AAP

Lee Baumgartner, Charles Sturt University; Jamin Forbes, Charles Sturt University, and Katie Doyle, Charles Sturt University

The New South Wales government plans to release two million native fish into rivers of the Murray-Darling Basin, in the largest breeding program of its kind in the state. But as the river system recovers from a string of mass fish deaths, caution is needed.

Having suitable breeding fish does not always guarantee millions of healthy offspring for restocking. And even if millions of young fish are released into the wild, increased fish populations in the long term are not assured.

For stocking to be successful, fish must be released into good quality water, with suitable habitat and lots of food. But these conditions have been quite rare in Murray Darling rivers over the past three years.

We research the impact of human activity on fish and aquatic systems and have studied many Australian fish restocking programs. So let’s take a closer look at the NSW government’s plans.

A mass fish kill at Menindee in northern NSW in January 2019 depleted Fisk stocks.
AAP

Success stories

According to the Sydney Morning Herald, the NSW restocking program involves releasing juvenile Murray cod, golden perch and silver perch into the Darling River downstream of Brewarrina, in northwestern NSW.

Other areas including the Lachlan, Murrumbidgee, Macquarie and Murray Rivers will reportedly also be restocked. These species and regions were among the hardest hit by recent fish kills.

Fish restocking is used worldwide to boost species after events such as fish kills, help threatened species recover, and increase populations of recreational fishing species.

Since the 1970s in the Murray-Darling river system, millions of fish have been bred in government and private hatcheries in spring each year. Young fish, called fingerlings, are usually released in the following summer and autumn.




Read more:
Australia, it’s time to talk about our water emergency


There have been success stories. For example, the endangered trout cod was restocked into the Ovens and Murrumbidgee Rivers between 1997 and 2006. Prior to the restocking program, the species was locally extinct. It’s now re-established in the Murrumbidgee River and no longer requires stocking to maintain the population.

In response to fish kills in 2010, the Edward-Wakool river system was restocked to help fish recover when natural spawning was expected to be low. And the threatened Murray hardyhead is now increasing in numbers thanks to a successful stocking program in the Lower Darling.

After recent fish kills in the Murray Darling, breeding fish known as “broodstock” were rescued from the river and taken to government and private hatcheries. Eventually, it was expected the rescued fish and their offspring would restock the rivers.

A Murray hardyhead after environment agencies transplanted a population of the endangered native fish.
North Central Catchment Management Authority

Words of caution

Fish hatchery managers rarely count their fish before they hatch. It’s quite a challenge to ensure adult fish develop viable eggs that are then fertilised at high rates.

Once hatched, larvae must be transported to ponds containing the right amount of plankton for food. The larvae must then avoid predatory birds, be kept free from disease, and grow at the right temperatures.




Read more:
Last summer’s fish carnage sparked public outrage. Here’s what has happened since


When it comes to releasing the fish into the wild, careful decisions must be made about how many fish to release, where and when. Factors such as water temperature, pH and dissolved oxygen levels must be carefully assessed.

Introducing hatchery-reared fish into the wild does not always deliver dramatic improvements in fish numbers. Poor water quality, lack of food and slow adaptation to the wild can reduce survival rates.

In some parts of the Murray-Darling, restocking is likely to have slowed the decline in native fish numbers, although it has not stopped it altogether.

Address the root cause

Fish stocking decisions are sometimes motivated by economic reasons, such as boosting species sought by anglers who pay licence fees and support tourist industries. But stocking programs must also consider the underlying reasons for declining fish populations.

Swan Hill, home to a larger-than-life replica of the Murray cod, is just one river community that relies on anglers for tourism.
Flickr

Aside from poor water quality, fish in the Murray Darling are threatened by being sucked into irrigation systems, cold water pollution from dams, dams and weirs blocking migration paths and invasive fish species. These factors must be addressed alongside restocking.

Fish should not be released into areas with unsuitable habitat or water quality. The Darling River fish kills were caused by low oxygen levels, associated with drought and water extraction. These conditions could rapidly return if we have another hot, dry summer.

Stocking rivers with young fish is only one step. They must then grow to adults and successfully breed. So the restocking program must consider the entire fish life cycle, and be coupled with good river management.

The Murray Darling Basin Authority’s Native Fish Recovery Strategy includes management actions such as improving fish passage, delivering environmental flows, improving habitat, controlling invasive species and fish harvest restrictions. Funding the strategy’s implementation is a key next step.

Looking ahead

After recent rains, parts of the Murray Darling river system are now flowing for the first time in years. But some locals say the flows are only a trickle and more rain is urgently needed.

Higher than average rainfall is predicted between July and September. This will be needed for restocked fish to thrive. If the rain does not arrive, and other measures are not taken to improve the system’s health, then the restocking plans may be futile.




Read more:
We wrote the report for the minister on fish deaths in the lower Darling – here’s why it could happen again


The Conversation


Lee Baumgartner, Professor of Fisheries and River Management, Institute for Land, Water, and Society, Charles Sturt University; Jamin Forbes, Freshwater Ecologist, Charles Sturt University, and Katie Doyle, Freshwater Ecologist, Charles Sturt University

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

NSW has approved Snowy 2.0. Here are six reasons why that’s a bad move



Lucas Coch/AAP

Bruce Mountain, Victoria University and Mark Lintermans, University of Canberra

The controversial Snowy 2.0 project has mounted a major hurdle after the New South Wales government today announced approval for its main works.

The pumped hydro venture in southern NSW will pump water uphill into dams and release it when electricity demand is high. The federal government says it will act as a giant battery, backing up intermittent energy from by wind and solar.

We and others have criticised the project on several grounds. Here are six reasons we think Snowy 2.0 should be shelved.

1. It’s really expensive

The federal government announced the Snowy 2.0 project without a market assessment, cost-benefit analysis or indeed even a feasibility study.

When former Prime Minister Malcolm Turnbull unveiled the Snowy expansion in March 2017, he said it would cost A$2 billion and be commissioned by 2021. This was revised upwards several times and in April last year, Snowy Hydro awarded a A$5.1 billion contract for partial construction.

Snowy Hydro has not costed the transmission upgrades on which the project depends. TransGrid, owner of the grid in NSW, has identified options including extensions to Sydney with indicative costs up to A$1.9 billion. Massive extensions south, to Melbourne, will also be required but this has not been costed.

The Tumut 3 scheme, with which Snowy 2.0 will share a dam.
Snowy Hydro Ltd

2. It will increase greenhouse gas emissions

Both Snowy Hydro Ltd and its owner, the federal government, say the project will help expand renewable electricity generation. But it won’t work that way. For at least the next couple of decades, analysis suggests Snowy 2.0 will store coal-fired electricity, not renewable electricity.

Snowy Hydro says it will pump the water when a lot of wind and solar energy is being produced (and therefore when wholesale electricity prices are low).




Read more:
Snowy 2.0 is a wolf in sheep’s clothing – it will push carbon emissions up, not down


But wind and solar farms produce electricity whenever the resource is available. This will happen irrespective of whether Snowy 2.0 is producing or consuming energy.

When Snowy 2.0 pumps water uphill to its upper reservoir, it adds to demand on the electricity system. For the next couple of decades at least, coal-fired electricity generators – the next cheapest form of electricity after renewables – will provide Snowy 2.0’s power. Snowy Hydro has denied these claims.

Khancoban Dam, part of the soon-to-be expanded Snowy Hydro scheme.
Snowy Hydro Ltd

3. It will deliver a fraction of the energy benefits promised

Snowy 2.0 is supposed to store renewable energy for when it is needed. Snowy Hydro says the project could generate electricity at its full 2,000 megawatt capacity for 175 hours – or about a week.

But the maximum additional pumped hydro capacity Snowy 2.0 can create, in theory, is less than half this. The reasons are technical, and you can read more here.

It comes down to a) the amount of time and electricity required to replenish the dam at the top of the system, and b) the fact that for Snowy 2.0 to operate at full capacity, dams used by the existing hydro project will have to be emptied. This will result in “lost” water and by extension, lost electricity production.



The Conversation, CC BY-ND

4. Native fish may be pushed to extinction

Snowy 2.0 involves building a giant tunnel to connect two water storages – the Tantangara and Talbingo reservoirs. By extension, the project will also connect the rivers and creeks connected to these reservoirs.

A small, critically endangered native fish, the stocky galaxias, lives in a creek upstream of Tantangara. This is the last known population of the species.

The stocky galaxias.
Hugh Allan

An invasive native fish, the climbing galaxias, lives in the Talbingo reservoir. Water pumped from Talbingo will likely transfer this fish to Tantangara.

From here, the climbing galaxias’ capacity to climb wet vertical surfaces would enable it to reach upstream creeks and compete for food with, and prey on, stocky galaxias – probably pushing it into extinction.

Snowy 2.0 is also likely to spread two other problematic species – redfin perch and eastern gambusia – through the headwaters of the Murrumbidgee, Snowy and Murray rivers.




Read more:
Snowy 2.0 threatens to pollute our rivers and wipe out native fish


5. It’s a pollution risk

Snowy Hydro says its environmental impact statement addresses fish transfer impacts, and potentially serious water quality issues.

Four million tonnes of rock excavated to build Snowy 2.0 would be dumped into the two reservoirs. The rock will contain potential acid-forming minerals and other harmful substances, which threaten to pollute water storages and rivers downstream.

When the first stage of the Snowy Hydro project was built, comparable rocks were dumped in the Tooma River catchment. Research in 2006 suggested the dump was associated with eradication of almost all fish from the Tooma River downstream after rainfall.

Snowy 2.0 threatens to pollute pristine Snowy Mountains rivers.
Schopier/Wikimedia

6. Other options were not explored

Many competing alternatives can provide storage far more flexibly for a fraction of Snowy 2.0’s price tag. These alternatives would also have far fewer environmental impacts or development risks, in most cases none of the transmission costs and all could be built much more quickly.

Expert analysis in 2017 identified 22,000 potential pumped hydro energy storage sites across Australia.

Other alternatives include chemical batteries, encouraging demand to follow supply, gas or diesel generators, and re-orienting more solar capacity to capture the sun from the east or west, not just mainly the north.

Where to now?

The federal government, which owns Snowy Hydro, is yet to approve the main works.

Given the many objections to the project and how much has changed since it was proposed, we strongly believe it should be put on hold, and scrutinised by independent experts. There’s too much at stake to get this wrong.




Read more:
Five gifs that explain how pumped hydro actually works


The Conversation


Bruce Mountain, Director, Victoria Energy Policy Centre, Victoria University and Mark Lintermans, Associate professor, University of Canberra

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

National parks are for native wildlife, not feral horses: federal court




Don Driscoll, Deakin University and Dick Williams, Charles Darwin University

Today, the federal court ruled feral horses can be removed from the Victorian high country.

The case was brought by the Australian Brumby Alliance against the Victorian Government in 2018. Since then, the strategic management plan for feral horses has been shelved, allowing feral horse numbers to increase without control.

In the northern area of Kosciuszko National Park numbers jumped from an estimated 3,255 in 2014 to 15,687 in 2019, in the absence of any management.




Read more:
Double trouble as feral horse numbers gallop past 25,000 in the Australian Alps


Expanding numbers of feral horses roaming the Australian Alps – which are listed as a national heritage site – threaten the alp’s ecosystems, soils and unique species. More feral horses is also an animal welfare issue, as horses face starvation during droughts and have been hit by cars in Kosciuszko.

Feral horses cause extensive damage to fragile ecosystems.
Shutterstock

The ruling is a victory for national parks, which can once again be managed to protect native Australian ecosystems and species. But it stands in stark contrast to the NSW government’s controversial legal protection of feral horses.

Taken to court

The Victorian Government’s strategic action plan, released in 2017, was to remove all horses from the Bogong High Plains, where around 100 horses caused cumulative damage to sensitive alpine ecosystems.

The plan also aimed to trap horses in the eastern Victorian alps, but at a rate so low it was unlikely to make a dent in horse numbers.

Not satisfied with retaining thousands of horses in the eastern alps, in 2018, the Australian Brumby Alliance took out a court injunction to stop horse removal from the Bogong High Plains and prevent substantial reduction in horse numbers in the eastern alps.

High stakes

Twenty-five thousand feral horses in Australia’s alpine parks have damaged peat wetlands listed as threatened under federal and state legislation. Recovery will take decades to centuries.

Feral horses have also eliminated multiple populations of the native broad toothed rat and are a threat to other native species like the corroboree frog and mountain pygmy possum.

And habitat degradation and loss caused by feral horses is officially listed as a threatening process in Victoria and NSW.

Feral horse damage to a swampy area as they trample over important wetlands.
Meg McKone, Author provided

If the court had ruled in favour of the Australian Brumby Alliance’s case, it would have locked in escalating threats to the environment, including threatening already endangered species such as the alpine she-oak skink.

It would also have given at least informal legitimacy to NSW legislation that protects feral horses in Kosciuszko National Park.




Read more:
Passing the brumby bill is a backward step for environmental protection in Australia


And possibly most damaging, it could have emboldened claims by brumby groups that feral horses should take priority over conservation in other contentious horse hotspots, such as Barmah, Oxley Wild Rivers, Blue Mountains, Guy Fawkes and Barrington Tops National Parks.

Feral horses have eliminated broad toothed mouse populations in the Alps.
Ken Green, Author provided

A matter of cultural heritage

The Australian Brumby Alliance argued removing horses from the alps would compromise its heritage value. They claimed feral horses are part of that heritage, including part of the mountain vistas, the pioneering heritage and myths and legends such as the Man from Snowy River.

The counterpoint from Parks Victoria was that it’s possible to remove horses from the alps while protecting the area’s cultural heritage.

It would be like taking cattle out of the high country, but nevertheless recognising pioneering exploits by preserving cattlemen’s huts.

These high plains will now be protected from feral horses.
Don Driscoll, Author provided

So what did Judge O’Bryan make of this? In a nutshell, the Australian Brumby Alliance did not have a legal hoof to stand on.

He rejected the Australian Brumby Alliance’s argument the Bogong High Plains horse population was likely to be genetically different from other feral horse populations in a way relevant to the case, and rejected claims feral horses could be beneficial to alpine ecosystems.

Judge O’Bryan also rejected the contention that the brumbies are part of the National Heritage values of the Australian Alps and accepted the evidence that feral horses cause substantial environmental damage.

The ruling acknowledged Parks Victoria’s strategic plan to control feral horses was consistent with legal obligations under the Convention on Biological Diversity, the federal EPBC (Environment Protection and Biodiversity Conservation) Act and the state’s Flora and Fauna Guarantee Act.

National parks for nature

Laws and the management of protected areas that reduce their integrity are a global concern. A 2017 study found one-third of Australia’s protected areas had been downgraded, reduced in size or had protection removed to make way for tourism ventures and other developments, like Snowy 2.0 in Kosciuszko National Park.

Kosciusko has faced the brunt of recent downgrading, notably where the NSW government voted to legally protect feral horses in 2018.

This unilateral decision has caused substantial concern for Victoria and the ACT as they face ongoing risks of feral horse incursions from NSW into their own protected areas.

The Australian Brumby Alliance’s court case threatened similar downgrading for Victoria’s alpine parks. However, state, federal and international laws, that place obligations on Australian governments to conserve native species and ecosystems in protected areas, have helped restore sensible park management.

Protecting natural heritage

Toyay’s federal court ruling upholds the right of state agencies to carry out their legal obligations. And it meets the general expectations of Australian society that our national parks exist to conserve native Australian ecosystems and species, particularly as extinction rates in Australia continue at unprecedented rates.




Read more:
Feral cat cull: why the 2 million target is on scientifically shaky ground


It also reflects the intent of nature conservation laws. National parks are for conserving our natural heritage, the product of millions of years of evolution on this continent.

Brumby advocates concerned about recent European heritage in Australia can protect horses outside of national parks, an approach pioneered successfully in South Australia.The Conversation

Don Driscoll, Professor in Terrestrial Ecology, Deakin University and Dick Williams, Adjunct Professorial Fellow, Research Institute for the Environment and Livelihoods, Charles Darwin University

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

Snowy 2.0 threatens to pollute our rivers and wipe out native fish



Schopier/Wikimedia

John Harris, UNSW and Mark Lintermans, University of Canberra

The federal government’s Snowy 2.0 energy venture is controversial for many reasons, but one has largely escaped public attention. The project threatens to devastate aquatic life by introducing predators and polluting important rivers. It may even push one fish species to extinction.

The environmental impact statement for the taxpayer-funded project is almost 10,000 pages long. Yet it fails to resolve critical problems, and in one case seeks legal exemptions to enable Snowy 2.0 to wreak environmental damage.

The New South Wales government is soon expected to grant the project environmental approval. This process should be suspended, and independent experts should urgently review the project’s environmental credentials.

Native fish extinctions

Snowy Hydro Limited, a Commonwealth-owned corporation, is behind the Snowy 2.0 project in the Kosciuszko National Park in southern NSW. It involves building a giant tunnel to connect two water storages – the Tantangara and Talbingo reservoirs. By extension, the project will also connect the rivers and creeks connected to these reservoirs.

A small, critically endangered native fish, the stocky galaxias, lives in a creek upstream of Tantangara. This is the last known population of the species.




Read more:
Snowy 2.0 is a wolf in sheep’s clothing – it will push carbon emissions up, not down


An invasive native fish, the climbing galaxias, lives in the Talbingo reservoir (it was introduced from coastal streams when the original Snowy project was built). Water pumped from Talbingo will likely transfer this fish to Tantangara.

From here, the climbing galaxias’ capacity to climb wet vertical surfaces would enable it to reach upstream creeks and compete for food with, and prey on, stocky galaxias – probably pushing it into extinction.

The stocky galaxias.
Hugh Allan

Snowy Hydro has applied for an exemption under NSW biosecurity legislation to permit the transfer of the climbing galaxias and two other fish species: the alien, noxious redfin perch and eastern gambusia.

Redfin perch compete for food with other species and produce many offspring. They are voracious, carnivorous predators, known to prey on smaller fish.

Redfin perch also allow the establishment of a fatal fish disease – epizootic haematopoietic necrosis virus – or EHN. This disease kills the endangered native Macquarie perch, the population of which below Tantangara is one of very few remaining.

If Snowy 2.0 is granted approval, it is likely to spread these problematic species through the headwaters of the Murrumbidgee, Snowy and Murray rivers.

The climbing galaxias, which threatens the native stocky galaxias.
Stella McQueen/Wikimedia

Acid and asbestos pollution

Four million tonnes of rock excavated to build Snowy 2.0 would be dumped into the two reservoirs. Snowy Hydro has not assessed the pollution risks this creates. The rock will contain potential acid-forming minerals and a form of asbestos, which threaten to pollute water storages and rivers downstream.

When the first stage of the Snowy Hydro project was built, comparable rocks were dumped in the Tooma River catchment. Research in 2006 suggested the dump was associated with eradication of almost all fish from the Tooma River downstream after rainfall.




Read more:
Snowy 2.0 will not produce nearly as much electricity as claimed. We must hit the pause button


Addressing the problems

The environmental impact statement either ignores, or pays inadequate attention to, these environmental problems.

For example, installing large-scale screens at water inlets would be the best way to prevent fish transfer from Talbingo Dam, but Snowy Hydro has dismissed it as too costly.

Snowy Hydro instead proposes a dubious second-rate measure: screens to filter pumped flows leaving Tantangara reservoir, and building a barrier in the stream below the stocky galaxias habitat.

The best and cheapest way to prevent damage from alien species is stopping the populations from establishing. Trying to control or eradicate pest species once they’re established is far more difficult and costly.



The Conversation, CC BY-ND

We believe the measures proposed by Snowy Hydro are impractical. It would be very difficult to maintain a screen fine and large enough to prevent fish eggs and larvae moving out of Tantangara reservoir and such screens would be totally ineffective at preventing the spread of EHN virus.

A six metre-high waterfall downstream of the stocky galaxias habitat currently protects the critically endangered species from other invasive species threats. But climbing galaxias have an extraordinary ability to ascend wet surfaces. They would easily climb the waterfall, and possibly the proposed creek barrier as well.

Such an engineered barrier has never been constructed in Australia. We are informed that in New Zealand, the barriers have not been fully effective and often require design adjustments.




Read more:
The government’s electricity shortlist rightly features pumped hydro (and wrongly includes coal)


Even if the barrier protected the stocky galaxias at this location, efforts to establish populations in other unprotected regional streams would be severely hampered by the spread of climbing galaxias.

Preventing redfin and EHN from entering the Murrumbidgee River downstream of Tantangara depends on the reservoir never spilling. The reservoir has spilled twice since construction in the 1960s, and would operate at much higher water levels when Snowy 2.0 was operating. Despite this, Snowy Hydro says it has “high confidence in being able to avoid spill”.

If dumped spoil pollutes the two reservoirs and Murrumbidgee and Tumut rivers, this would also have potentially profound ecological impacts. These have not been critically assessed, nor effective prevention methods identified.

The Tumut 3 scheme, part of the existing Snowy Hydro scheme.
Snowy Hydro Ltd

Looking to the future

Snowy 2.0 will likely make one critically endangered species extinct and threaten an important remaining population of another, as well as pollute freshwater habitats. As others have noted, the project is also questionable on other environmental and economic grounds.

These potential failures underscore the need to immediately halt Snowy 2.0, and subject it to independent expert scrutiny.


In response to the issues raised in this article, a spokesperson for Snowy Hydro said:

“Snowy Hydro’s EIS, supported by numerous reports from independent scientific experts, extensively address potential water quality and fish transfer impacts and the risk mitigation measures to be put in place. As the EIS is currently being assessed by the NSW Government we have no further comment.”


A previous version of this article incorrectly stated that water pumped from Tantangara will likely transfer fish to Talbingo. It should have said water pumped from Talbingo will likely transfer fish to Tantangara.The Conversation

John Harris, Adjunct Associate Professor, Centre for Ecosystem Science, UNSW and Mark Lintermans, Associate professor, University of Canberra

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

Yes, native plants can flourish after bushfire. But there’s only so much hardship they can tak



Bulbine lilies flowering and eucalypts resprouting after fire in the Victorian high country.
Heidi Zimmer

Lucy Commander, University of Western Australia and Heidi Zimmer, Southern Cross University

In a fire-blackened landscape, signs of life are everywhere. A riot of red and green leaves erupt from an otherwise dead-looking tree trunk, and the beginnings of wildflowers and grasses peek from the crunchy charcoal below.

Much Australian flora has evolved to cope with fire, recovering by re-sprouting or setting seed. However, some plants are sensitive to fire, especially when fires are frequent or intense, and these species need our help to recover.




Read more:
Some say we’ve seen bushfires worse than this before. But they’re ignoring a few key facts


After announcing a A$50 million wildlife and habitat recovery package, the Morrison government recently met with Australia’s leading wildlife experts to steer recovery efforts.

Encouraging native flora to bounce back from these unprecedented fires requires targeted funding and actions to conserve and restore plants and ecological communities, including seed banking.

How do plants naturally recover from fire?

Many plants from fire-prone ecosystems have evolved strategies to survive, and even thrive, with fire. Some resprout after fire, with green shoots bursting from blackened stems. For others, fire stimulates flowering.

Some species are able to resprout from blackened stems following a fire.
Lucy Commander, Author provided

Fire can also trigger seed germination of hundreds of species, as seeds respond to fire “cues” like heat and smoke.

Seeds may wait in woody fruits stored on the plant. The fruits’ hard capsules shield the seeds from the fire, but the heat opens the capsules, releasing seeds into the soil below.

We can capitalise on this natural recovery by not disturbing the soil where the seeds are scattered, not clearing “dead” plants which may resprout and provide shelter for remaining wildlife, including perches for birds who may bring in seeds.

We should also stop vegetation clearing, especially unburnt vegetation home to threatened species and communities.

Some species, like this Banksia, have woody fruits that protect the seeds, then open after fire to release them.
Lucy Commander, Author provided

When do we need to intervene?

While Australian plants and ecosystems have evolved to embrace bushfires, there’s only so much drought and fire they can take.

Many plants and ecosystems, including alpine and rainforest species, are not resilient to fire, especially if drought persists or they have been burnt too frequently. Too frequent fires deplete the seed bank and put recovery at risk.

Fires which are intense and severe will outright kill other plants, or the plants will be very slow to recover – taking years or decades to reach maturity again. We need comprehensive monitoring to detect which species are not returning, with systematic field surveys starting immediately, and continuing after the first rains to identify which species emerge from the soil.

Some ecosystems are adapted to fire, with trees resprouting and seeds germinating from the soil seed bank. Even so, fencing and weed control may be required.
Lucy Commander, Author provided

Invasive plants such as blackberry or veldt grass can also impede recovery after a fire by out-competing the natives. Feral herbivores – such as rabbits, goats and horses – can overgraze the native regrowth. So controlling the weeds and feral grazers with, for instance, temporary fencing and tree guards, is a priority post-fire.

And when ecosystems aren’t able to repair themselves, it’s up to us to intervene. For instance, land managers, supported by volunteer community groups, could sow seeds or plant seedlings in fire-affected areas. This act of restoring ecosystems can be an important healing process for those affected by the fires.

Do we have enough seeds?

But for that to happen, we need enough seeds to supply restoration efforts. With millions of hectares already burnt, few areas may be left for seed collection.

This means unburnt areas are at risk of over-collection from commercial and volunteer seed collectors. Stopping this from happening is possible, however. The agencies giving out permits for seed collection must record where seeds are being sourced and how much is collected. This ensures areas aren’t stripped of seeds, rendering them less resilient.




Read more:
The sweet relief of rain after bushfires threatens disaster for our rivers


Another, more controversial issue, is whether seeds should be collected locally (perhaps within 20km or within the catchment), or from somewhere much further away and more suited to a potential future climate.

And what should we do if we lose a population of a threatened plant species? Establishing a new population or replacing a lost one using translocation is one option. Similar to capture-and-release or zoo breeding programs for reintroduction of threatened animals, translocation refers to deliberately moving plants or seeds to a new location.

How can we better prepare for next time?

With potentially more unprecedented bushfire seasons in our future, it’s important land managers are prepared.

They need data on the distribution of species and the fire frequency, severity and season they can tolerate. A nationwide database could identify which species and ecosystems are most at risk, and could be incorporated into fire and restoration planning – including seed collecting – to ensure plant material is available if species fail to recover.




Read more:
‘Plant blindness’ is obscuring the extinction crisis for non-animal species


Botanic gardens have a special role to play as many already have conservation seed banks of threatened species, and their living collections provide additional genetic material. Across Australia there is already a network of seed banks collaborating through the Australian Seed Bank Partnership that collect, store and undertake research to better support plant conservation.

A restoration seed bank in Utah, USA. These banks hold huge amounts of seeds, but the Australian equivalents operate on a smaller scale.
Lucy Commander

However, restoration seed banks operate on a much larger scale than botanic gardens, and it’s important both approaches are conducted collaboratively. We need more ongoing investment in seed banks, particularly for threatened species and ecosystems least likely to recover from repeat fires like rainforests. Investment in skilled staff to run them is also critical, as well as national guidelines for seed use and training programs for staff and volunteers.

The recent bushfires will push many plant species to their limits. If we want to keep these species around – and the animals depend on them for food and habitat – we need to monitor their recovery and intervene where necessary.The Conversation

Lucy Commander, Adjunct Lecturer, University of Western Australia and Heidi Zimmer, Research associate, Southern Cross University

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