Koalas are the face of Australian tourism. What now after the fires?



Koalas have long featured in tourism ads, including this new one from Tourism Australia. Amid our bushfire crisis, this digital ad has been ‘paused’.
Tourism Australia

Kevin Markwell, Southern Cross University

In 1936, The Evening News in Rockhampton wrote:

The time has arrived when Australians must decide whether or not they will accept responsibility for the perpetuation of the koala […]

It seems extraordinary that this animal which is so greatly admired, not only by overseas visitors, but by Australians, is being allowed to suffer extinction.

The preservation of the koala was not talked about so much in environmentalist terms: instead, the koala was seen as a crucial icon of Australian identity and tourism.

The earliest picture postcard featuring a koala I have found was postmarked 1903, and it has been a mainstay of tourism advertising ever since.

A 1903 postcard featuring a ‘native bear’.
Author provided, Author provided

In the latest ad from Tourism Australia, the koala has been recruited, once again, to market Australia, starring alongside Kylie Minogue, chilling in a graceful eucalyptus on Sydney Harbour.

But amid Australia’s ongoing bush fire crisis, airing of the digital ad has been “paused”.

Up to 30% of the koala population from the NSW mid-north coast is expected to be lost in the fires, alongside 50% of the koalas on Kangaroo Island – the last remaining wild population not infected by deadly chlamydia.

Eighty four years on from the Evening News’ story, we are still talking about the possible extinction of koalas, our national tourism icon.

The creation of an icon

Koalas were exhibited at Melbourne Zoo from 1861 and at Taronga Zoo from 1914. But at the same time, koalas were hunted ruthlessly for fur throughout much of the 19th century. This practice only came to a halt at the end of the 1920s.

The original 1933 publication of Blinky Bill.
Trove

By the 1930s, three koala-themed wildlife parks – the Koala Park in Pennant Hills, Sydney, Lone Pine Koala Park on the Brisbane River and the Adelaide Snake Park and Koala Farm – had opened for business.

1933 saw the publication of Dorothy Wall’s Blinky Bill. Zoologist Ellis Troughton’s book Furred Animals of Australia (1931) and natural historian Charles Barrett, with Koala: The Story of the Native Bear (1937), also influenced public attitudes towards the native animal.

In 1934, the Sydney Morning Herald called the koala “Australia’s national pet”.

Perhaps most famously, it was the star of a Qantas advertising campaign from 1967 to 1992.

A 1981 Qantas advertisement, published in American magazines.
Qantas

The loss of a tourism icon

A 2014 study suggests koala tourism could now be worth as much as A$3.2 billion to the Australian economy and account for up to 30,000 jobs.

In 2020, Australia has 68 zoos and wildlife parks exhibiting just under 900 koalas. A photograph with a koala is a must-have souvenir for many international tourists.

But it is impossible to look at Kylie hanging out with her koala mates without bringing to mind the shocking images of badly burned koalas and other wildlife as the devastating wild fires destroy millions of hectares of bushland habitat.

The plump, relaxed, pampered koalas in the Tourism Australia ad are far removed from the horrific realities of fire. These catastrophic fires have compounded the threatening processes that already affect koala populations: habitat destruction and fragmentation, disease, car accidents and dog attack.

Recent research has shown koalas are also vulnerable to climate change through changes in the nutritional status of eucalyptus leaves, excessively hot temperatures and these canopy-destroying wildfires.




Read more:
Koalas are feeling the heat, and we need to make some tough choices to save our furry friends


A life beyond extinction?

Australians have clearly shown they are willing to take action to protect the animal, with the GoFundMe campaign to raise funds for the Port Macquarie Koala Hospital raising almost A$2 million.

The outpouring of emotion and financial support reflects the strong connection that Australians feel for the koala, formed out of the interplay of the animal’s baby-like features and its multitude of representations in popular culture, including, of course, tourism marketing.

Sadly, it is more than likely the koala will go on serving the national interest through its role in tourism even if it was to tragically go extinct in the wild.

The Tourism Tasmania logo features the extinct thylacine.

Most koala tourism is based on experiences with captive koalas. And extinction hasn’t been a problem elsewhere: Tasmanian Tourism uses a stylised image of the thylacine in its logo.

The long term survival of the koala ultimately rests with governments and their policies on forest clearing, fire management and climate change.

If future tourists to Australia are to experience the koala in the wild, it is imperative that governments act now to strengthen the protection of the species and most crucially, its habitat.The Conversation

Kevin Markwell, Professor in Tourism, Southern Cross University

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

To save koalas from fire, we need to start putting their genetic material on ice



Over the coming months, koalas will depend on wildlife hospitals to recover from the effects of unprecedented bushfires.
Lachlan G. Howell , Author provided

Ryan R. Witt, University of Newcastle; Chad T. Beranek, University of Newcastle; John Clulow, University of Newcastle; John Rodger, University of Newcastle; Lachlan G. Howell, University of Newcastle, and Robert Scanlon, University of Newcastle

Thousands of koalas may have died in fires burning through New South Wales but expert evidence to a state parliamentary inquiry on Monday said we are unlikely to ever know the real numbers.

Unprecedented fires have burned through millions of hectares of forest, including koala habitat and rainforests untouched by fire for thousands of years.




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The devastation won’t stop once the fires are out. Koala populations that survive the fires could be cut off from each other, lowering their genetic diversity and threatening their long-term survival.

To protect Australia’s iconic koalas we need to start freezing their genetic material. With more investment in the fast-developing field of cryogenics, koala hospitals could start taking samples from their patients, creating a vital lifeline for the species as a whole.

Koala-threatening fires are getting worse

Fire seasons are starting earlier, lasting longer and becoming more intense, made worse by climate change.

This season, there is an above-average risk of serious fires across an extensive range of koala habitat on Australia’s east coast.

Left, Australian seasonal bushfire outlook for the upcoming bushfire season. Right, the comparative koala distribution from January 2017 to 2019.
Bushfire and Natural Hazard CRC/Atlas of Living Australia

Experts at the NSW inquiry estimated about 2,000 koalas may have died in fires already this year, and the destruction of habitat means further population declines are inevitable. With areas not usually threatened by fires now at risk, we need new plans for future conservation.

Koalas are highly vulnerable to fire. The heat burns their paws and fur, and the superheated air can cause internal damage to their lungs. The canopy of eucalypt forests is their only refuge, but offers no protection during high-intensity bushfires.

Beyond this direct threat, when large numbers of koalas are killed or badly injured, the genetic diversity of their local populations shrinks.

Over the coming months, koalas will depend heavily on wildlife hospitals for rehabilitation and recovery after fires.

Small, fragmented groups of koalas living in habitat on the edge of urban areas, such as the coastal areas of Port Macquarie and Port Stephens, are particularly at risk.

Port Stephens experienced several fires in 2018 that burned thousands of hectares of koala habitat. This followed a similarly catastrophic fire season five years earlier.

If these events continue at the same rate – or, as predicted by climate modelling, become more intense and more frequent – we may lose sources of koala genetic diversity that cannot be replaced.




Read more:
Koalas sniff out juicy leaves and break down eucalypt toxins – it’s in their genome


Sudden reductions in population size can cause genetic bottlenecks that lead to inbreeding. Eventually this reduces reproductive fitness and makes extinction more probable.

Take, for example, a koala population like that of Port Macquarie, between 1,000 and 2,000 individuals. We estimate that losing 350 koalas from this group would increase inbreeding by 20-50%. It would take five to ten years for the population to recover, assuming no further fires in that time.

While many volunteers and professionals do fantastic work to help koalas survive fire, we have no strategy for safeguarding genetic diversity and reducing the risk of inbreeding.

But we can take a lesson from botanical gardens, which routinely freeze genetic material for seed banks. Freezing koala sperm, eggs and embryos could offer a way to preserve genetic diversity ahead of further population crashes.




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Artificial reproduction is in its infancy

Artificial reproduction for koalas – and marsupials generally – is developing quickly. Scientists have used freshly collected sperm to artificially inseminate zoo koalas, which resulted in the birth of live young.

However, the technology does not yet exist to freeze, store and then use koala sex cells. Components of this process do exist, but there is no complete system for marsupials.

If that capacity existed, koala hospitals could easily and inexpensively begin collecting genetic samples from their patients.

Although NSW has invested significantly in koala conservation in recent years, we argue that future funding should also support applied research to make this technology a reality for not only koalas but other marsupials.

Koalas and many other native species are exceptionally unprotected in this new era of record-breaking fires. We need to start planning and investing in long-term conservation solutions and new research-based technologies that provide a last line of defence against the possibility of permanent extinction.The Conversation

Ryan R. Witt, Conjoint Lecturer | Conservation Biology Research Group, University of Newcastle; Chad T. Beranek, PhD candidate, University of Newcastle; John Clulow, Associate Professor, University of Newcastle; John Rodger, Emeritus Professor, University of Newcastle & CEO FAUNA Research Alliance, University of Newcastle; Lachlan G. Howell, PhD Candidate | Conservation Biology Research Group, University of Newcastle, and Robert Scanlon, PhD Candidate in Restoration Ecology, University of Newcastle

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

The Blinky Bill effect: when gum trees are cut down, where do the koalas go?


Kita Ashman, Deakin University

In the past two decades there has been an unprecedented increase in the area of blue gum (Eucalyptus globulus) plantations in southern Australia. In southwest Victoria alone, some additional 80,000 hectares of commercial blue gum have been planted.

This expansion has significantly increased the habitat available for koalas. In fact, my research, published in the journal Landscape and Urban Planning, has found there are more koalas in plantations than in surrounding native habitat.




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More koalas may seem like a good thing, but perversely this could ultimately harm their welfare (and the welfare of other native animals and plants), and disrupt the plantation industry.

Blinky Bill had to leave his home after the trees were bulldozed.

Plantations

Koalas are protected in Victoria, so when plantation managers harvest the mature trees they must have a permit and a koala management plan. These plans focus on locating koalas, ensuring that the trees koalas are sitting in at harvest are not felled, and post-harvest surveys to find any injured koalas.

However, these plans don’t consider where the koalas go after the plantation has been cut down, and what effects their movement has on the landscape and surrounding native vegetation.

A recently harvested blue gum plantation showing remnant trees left due to koalas.
Author provided

To work out how factors such as plantation cover affect koala populations, my colleagues and I surveyed 72 sites across southwest Victoria. We found more koalas in plantations than in blocks of native vegetation or in native roadside vegetation.

We then spatially modelled koala numbers for the region, and found several high-priority areas for population management, as well as significant conservation habitat for koalas and other wildlife in the region that overlap with high koala population densities.




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Our mapping predicted high koala numbers in the southeast, where there are important remnant bushland areas such as Kurtonitj Indigenous Protected Area and Mount Napier State Park. This highlights the importance of considering the overall landscape when establishing and harvesting plantations, and the arrangement of plantations near remnant forest.

Harvest rates in much of southwest Victoria are set to increase. This may result in increased koala numbers in the native vegetation surrounding harvested sites, which could then put pressure on food trees in remnant forests.

Local landholders are already seeing the effect of more koalas on native vegetation. Many trees on private land or beside roads are being stripped of leaves.

Canopy defoliation of remnant trees due to increased numbers of koalas in south-west Victoria.
Author provided

More koalas are also likely to mean more injuries or other welfare issues. As plantations have a responsibility to avoid these, koala injuries could threaten the future of one of the main industries in this region. More than 4,000 people are directly employed in the regional forestry industry, with a further 4,500 in associated service industries.




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The bigger picture

To meet this challenge, we argue management plans need to consider the larger landscape. What native forest is near a plantation? Where are the koalas likely to go after the harvest? How might they affect other native species?

A female koala being released in Bessiebelle, south-west Victoria, after undergoing a health check.
Esther Wong, Author provided

Such plans could include some areas of plantations set aside for koala habitat, harvesting plans that consider adjacent habitat that koalas may move into, or increasing areas of native food trees. These would all benefit other wildlife in the area, as well as koalas.

Currently, there is something of a negative feedback loop in southwest Victoria. When plantations are established koalas move in and reproduce. When plantations are later harvested, the koalas move into surrounding areas. As a result, populations can rapidly increase in some areas, affecting native trees and creating welfare issues for the forest industry.




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Victorian koalas are eating themselves out of house and home


We have seen the devastating effects high density koala populations can have on native forests in places like Cape Otway, which saw mass starvation and widespread forest death in 2013 and 2014. Current state regulations could disrupt the forestry industry, especially with koala numbers increasing in plantations but with no plan to really manage koala numbers in southwest Victoria in sight.The Conversation

Kita Ashman, PhD candidate in koala conservation, Deakin University

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

A virus is attacking koalas’ genes. But their DNA is fighting back


Keith Chappell, The University of Queensland

A virus that infects koalas is steadily integrating itself into their DNA, ensuring that it is passed down from generation to generation. But the koala genome is defending itself, revealing that DNA has its own immune system to shut down invaders.

The virus, called koala retrovirus (KoRV), is linked to weakened immunity, cancer, and chlamydia infection in koalas. All retroviruses hijack the DNA in some cells of their host’s body, but not all of them manage to be transmitted to the host’s offspring.

Your DNA is 8% virus

Over the millions of years of evolutionary history, retroviruses have at one time or another made their way into the genomes of all species of vertebrates that we have studied.

We know about these ancient infections because retroviruses sometimes infect the animal’s sperm or egg cells, which means the virus incorporates its own DNA sequences into the genome that is passed from generation to generation.




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These viral sequences can contribute to disease, but have also been “co-opted” by the host animals for processes that are essential to normal development. As much as 8% of the human genome is made up of the remnants of infectious viruses.

While we know that retroviruses have frequently appeared during evolutionary history, we don’t know much about how retroviral sequences infiltrate sperm and egg cells, or how these cells react.

Catching a retrovirus in the act

Almost all known retrovirus genome invasions happened millions of years ago. However, KoRV is a recently identified exception. The virus spreads between individuals, but is also infecting sperm and egg cells, so many koalas are born with this pathogen as part of their genome.

My colleagues and I at the University of Queensland are collaborating with scientists from the University of Massachusetts Medical School to analyse how koala sperm and egg cells respond to KoRV-A infection.

Our findings, published today in Cell, suggest these cells mount a novel “innate genome immune response” to viral infection, which may help control the spread of infectious KoRV.

Within this project, the team analysed DNA and RNA from different tissue samples from deceased wild koalas from South East Queensland. (Like DNA, RNA also contains genetic information about the koalas – but it is also what KoRV’s own genome is made of.)

The team specifically looked for short sequences of RNA, between 23 and 35 nucleotides long, known as PIWI Interacting RNAs (piRNAs). Clusters of piRNA sequences are retained within the genome and serve as a kind of memory bank of undesirable sequences – signatures of invading viruses – to be targeted.

An immune system for the genome

Based on our new findings, we suggest that there is a specialised immune system to defend against retroviral genome invasion. Like the ordinary immune system, this one includes an innate response – a sort of general-purpose defence against attackers – and an adaptive response, which learns to recognise specific pathogens and take them down.

At the early stages of egg or sperm infection, the altered DNA sequence results in a “molecular pattern” that is recognised by an innate genome immune system, which stops the activity of the virus and starts producing signature piRNA sequences to recognise the invader.




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The innate immune response works until a memory of the genome invader is created and a sequence-specific adaptive response kicks in.

We propose a framework through which a sequence from an invading retrovirus can first have its genes “silenced”, and then through targeted processes it eventually becomes an integral part of the host genome.

This “genome immune system” changes our understanding of what shapes the genomes of all animals. No more can we view the genome as a defenceless entity governed purely by natural selection – it fights back.The Conversation

Keith Chappell, Senior Research Fellow, School of Chemistry and Molecular Biosciences, The University of Queensland

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

Koala-detecting dogs sniff out flaws in Australia’s threatened species protection



Maya the detection dog was part of a team sniffing out koalas.
Marie Colibri/USC

Romane H. Cristescu, University of the Sunshine Coast; Anthony Schultz, University of the Sunshine Coast; Celine Frere, University of the Sunshine Coast; David Schoeman, University of the Sunshine Coast, and Kylie Scales, University of the Sunshine Coast

In a country like Australia – a wealthy, economically and politically stable nation with multiple environmental laws and comparatively effective governance – the public could be forgiven for assuming that environmental laws are effective in protecting threatened species.

But our new research, published recently in Animal Conservation, used koala-detecting dogs to find vulnerable koalas in places developers assumed they wouldn’t live. This highlights the flaws of environmental protections that prioritise efficiency over accuracy.

The dog squad: from left to right, Baxter, Billie-Jean, Bear, Charlie and Maya sniffed out vulnerable koalas to see how many are living in areas due to be developed in Queensland.
Author provided

Environmental impact assessments

Every new infrastructure project must carry out an Environmental Impact Assessment (EIA) to see whether it will affect a threatened species. If this is the case, the logical next step is to try to avoid this by redesigning the project.

But this rarely happens in reality, as we saw recently for the endangered black-throated finch.




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More often, when the EIA suggests an unavoidable impact the response is to identify mitigation and compensation measures, often in the form of “offsets”. These are swathes of comparable habitat assumed to “compensate” the impacted species for the habitat lost to the development.

To take koalas as an example, developers building houses might be required to buy and secure land to compensate for lost habitat. Or a new road might need fencing and underpasses to allow koalas safe passage across (or under) roads.

Koalas can be found in many environments, from the bush to cities.
Detection Dogs for Conservation, University of the Sunshine Coast

These steps are defined in environmental regulations, and depend on the results from the original EIA.




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An issue of assumptions

With koala numbers still declining, we investigated whether current survey guidelines for EIA were indeed adequate.




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For an EIA to be effective, it is fundamental the environmental impact of a future development can be accurately anticipated and therefore appropriately managed. This relies, as a first step, on quantifying how the project will affect threatened species through ecological surveys of presence and extent of threatened species within the project’s footprint.

There are government guidelines to prescribe how these ecological surveys are performed. Every project has time and budget constraints, and therefore survey guidelines seek efficiency in accurately determining species’ presence.

Dr Romane Cristescu performing a koala survey with detection dog Maya.
Marie Colibri

As such, the Australian guidelines recommend focusing survey effort where there is the highest chance of finding a species of concern for the project. This sounded very logical – until we started testing the underlying assumptions.

We used a very accurate survey method – detection dogs – to locate koala droppings, and therefore identify koala habitat, in the entire footprint of proposed projects across Queensland. We did not target our efforts in areas we expected to be successful – therefore leaving out the bias of other surveys.

Unpredictable koalas

We found koalas did not always behave as one would expect. Targeting effort to certain areas, the “likely” koala habitat, to try increase efficiency risked missing koala hotspots.

In particular, the landscape koalas use is intensely modified by human activity. Koalas, like us, love living on the coast and in rich alluvial plains. That means we unexpectedly found them right in the middle of urban areas, along roads that – because they have the final remaining trees in dense agricultural landscapes – are now (counterintuitively) acting as corridors.

This koala was found in a built-up area not captured by traditional surveys.
Detection Dogs for Conservation, University of the Sunshine Coast



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Assumptions about where koalas live can massively underestimate the impact of new infrastructure. In one case study, the habitat defined by recommended survey methods was about 50 times smaller than the size of the habitat actually affected.

If surveys miss or underestimate koala habitat while attempting to measure development impact, then we cannot expect to adequately avoid, mitigate or compensate the damage. If the first step fails, the rest of the process is fatally compromised. And this is bad news for koalas, among many other threatened species.

All parts of the landscape are important

What is needed is a paradigm shift. In a world where humans have affected every ecosystem on Earth, we cannot focus on protecting only pristine, high-quality areas for our threatened species. We can no longer afford to rely on assumptions.

This might seem like a big, and therefore expensive, ask. Yet ecosystems are a common resource owned by all of us, and those who seek to exploit these commons should bear the cost of demonstrating they understand (and therefore can mitigate) their impact.

The alternative is to risk society having to shoulder the environmental debt, as we have seen with abandoned mines.




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The burden of proof should squarely reside with the proponent of a project to study thoroughly the project impact.

A koala found in the wild while performing an Environmental Impact Assessment.
Detection Dogs for Conservation, University of the Sunshine Coast

This is where the issue lies – proponents of projects are under time and budget constraints that push them to look for efficiencies. In this tug of war, the main losers tend to be the threatened species. We argue that this cannot continue, because for many threatened species, there is no longer much room for mistakes.

The environmental regulations that define survey requirements need to prioritise accuracy over efficiency.

A review of Australian’s primary environmental law, the Environment Protection and Biodiversity Conservation Act is due to begin by October this year. We call on the government to use this opportunity to ensure threatened species are truly protected during development.


The authors would like to gratefully acknowledge the contribution of Dr David Dique and Russell L. Miller to this research and the two original papers this piece is based upon (feature paper and response).The Conversation

Romane H. Cristescu, Posdoc in Ecology, University of the Sunshine Coast; Anthony Schultz, PhD Candidate, University of the Sunshine Coast; Celine Frere, Senior lecturer, University of the Sunshine Coast; David Schoeman, Professor of Global-Change Ecology, University of the Sunshine Coast, and Kylie Scales, Senior lecturer, University of the Sunshine Coast

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

What does a koala’s nose know? A bit about food, and a lot about making friends


Ben Moore, Western Sydney University and Edward Narayan, Western Sydney University

The koala’s nose is distinctive – it’s a big black leathery rectangle in the middle of a round, grey face that’s surprisingly soft to the touch. And every koala nose is unique.

A study of 108 wild koalas found distinctive patterns of pigmentation around the nostrils allowed observers on the ground to reliably recognise individual animals, even when they’re in the trees.




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A report claims koalas are ‘functionally extinct’ – but what does that mean?


But more importantly for the koala, the nose is an important connection between this iconic marsupial and the world it lives in, from sniffing out toxins to saying hello.

And it starts right at birth. The tiny newborn koala, despite weighing only half a gram, already has the ability to smell and feel its way towards the milky scent of the pouch and its mother’s teats.

A koala’s nose knows how to sniff out toxins

Koalas, famously, spend most of their time sleeping or resting. When they’re not sleeping or resting, they are mostly feeding or moving between trees. In both of these activities – or in other words, for most of their waking hours – they follow their nose.

Koalas nearly always smell their food carefully before eating. So many koala experts were surprised to learn recently that koalas don’t have particularly many genes for olfactory receptors – the receptors found on nerve cells in the nasal cavity for detecting different smells.




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Koalas sniff out juicy leaves and break down eucalypt toxins – it’s in their genome


This matches up with anatomical observations that also suggest that among marsupials, the koala’s sense of smell is probably relatively poor, partly as a result of features associated with conserving water.

Gum leaves are chock full of natural plant toxins and other unpleasant chemicals, and koalas choose trees that minimise their exposure to the worst of these.

But most of the toxins that influence koala feeding are not volatile – they have no smell. It falls to the koala’s sense of taste (and genes for taste receptors are especially abundant in the koala genome) to make a final decision on whether a leaf is safe to eat.

Fortunately for the koala, the only-slightly-toxic compounds called terpenes (the invigorating scent of Eucalyptus oil) are highly volatile and offer a useful cue to the levels of other toxins in a leaf.

And one advantage of being a specialist feeder with a basic diet, is that there are relatively few odour cues to learn. It’s also fortunate the leaves koalas are checking out are right in front of their noses!

The koala’s nose might not only smell plant toxins, it may also play a minor role in detoxifying them.




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We know enzymes in our own noses can detoxify certain drugs, and in other specialist herbivores, such as woodrats, many of the same enzymes that detoxify natural plant toxins and drugs in the liver are also expressed in the lining of the nose.

These enzymes likely help stop the nose from becoming overwhelmed by odours and maintain sensitivity. Critically, they also protect the central nervous system, as nasal tissue is the only thing separating inhaled toxins from the brain.

A koala’s nose knows how to make friends

Sniffing out food is important, but it’s not the koala’s biggest forte. So why the big schnoz? The answer may lie with the importance of social communication.

Although the koala genome has relatively few olfactory receptors, it’s rich in vomeronasal receptors, which are expressed in cells in the nasal cavity that are sensitive to moisture-borne molecules like pheromones.

Koalas are generally solitary creatures, but that’s not to say they don’t know their neighbours. Along with the distinctive loud bellowing of male koalas during the breeding season, olfactory communication is what koalas use to find or avoid each other.

A male koala’s breeding season bellow. Video: Denise Dearing.

Koalas of both sexes often spend considerable time smelling the base and trunk of a tree before they decide whether to climb up or move on elsewhere. When they enter or leave a tree, koalas commonly dribble a stream of urine down the trunk, leaving a trail of chemicals that potentially reveal information about the koala’s sex, identity, dominance, relatedness to other koalas, readiness to mate, disease status and even what they’ve been eating.

But if koala urine is a book written in scent, the secretions of the male koala’s sternal gland are more like a barcode.

This gland is obvious as a yellow-brown stained patch of bare skin in the middle of male koalas’ chests, and offers a straightforward way to tell the sexes apart.

It secretes an oily mixture of fatty acids and other chemicals, which are then transformed into an even more complex chemical mixture by the unique bacterial community occupying each koala’s gland. The end result is a distinctive bouquet and an unmistakable badge of identity for each koala.

Nose kisses from a koala

Aside from these fascinating nasal abilities, there is one more thing that we love about the koala’s nose.

When wild koalas are brought into captivity, they continue to rely on their nose to learn about the strange new world around them – that includes their food and branches, but also the scientists and carers moving around them.




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They will pull anything of interest into smelling range, making them one of the few wild animals that will rub noses to say hello with humans and fellow koalas, even when barely acquainted!

But wild koalas are highly sensitive to human handling, which can generate sub-lethal stress through the stress hormone, cortisol.

Without question, the koala’s nose is fascinating and a marvel of evolution, but no matter how strong the temptation to touch it, please leave those koalas in peace!The Conversation

Ben Moore, Senior Lecturer in Ecology, Hawkesbury Institute for the Environment, Western Sydney University and Edward Narayan, Senior Lecturer in Animal Science, Western Sydney University

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

A report claims koalas are ‘functionally extinct’ – but what does that mean?



Koalas are facing serious threats in the wild.
Mathias Appel/Flickr

Christine Adams-Hosking, The University of Queensland

Today the Australian Koala Foundation announced they believe “there are no more than 80,000 koalas in Australia”, making the species “functionally extinct”.

While this number is dramatically lower than the most recent academic estimates, there’s no doubt koala numbers in many places are in steep decline.

It’s hard to say exactly how many koalas are still remaining in Queensland, New South Wales, Victoria, South Australia and the Australian Capital Territory, but they are highly vulnerable to threats including deforestation, disease and the effects of climate change.

Once a koala population falls below a critical point it can no longer produce the next generation, leading to extinction.




Read more:
Koalas sniff out juicy leaves and break down eucalypt toxins – it’s in their genome


What does ‘functionally extinct’ mean?

The term “functionally extinct” can describe a few perilous situations. In one case, it can refer to a species whose population has declined to the point where it can no longer play a significant role in their ecosystem. For example, it has been used to describe dingoes in places where they have become so reduced they have a negligible influence on the species they prey on.

Dingoes are top predators, and therefore can play a significant role in some ecosystems. Our innocuous, leaf-eating koala cannot be considered a top predator.

For millions of years koalas have been a key part of the health of our eucalyptus forests by eating upper leaves, and on the forest floor, their droppings contribute to important nutrient recycling. Their known fossil records date back approximately 30 million years so they may have once been a food source for megafauna carnivores.

Functionally extinct can also describe a population that is no longer viable. For example in Southport, Queensland, native oyster reef beds are functionally extinct because more than 99% of the habitat has been lost and there are no individuals left to reproduce.

Finally, functionally extinct can refer to a small population that, although still breeding, is suffering from inbreeding that can threaten its future viability. We know that at least some koala populations in urban areas are suffering in this way, and genetic studies on the Koala Coast, located 20kms south-east of Brisbane, show that the population is suffering from reduced genetic variation. In South East Queensland, koalas in some areas have experienced catastrophic declines




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We also know that koala populations in some inland regions of Queensland and New South Wales are affected by climate extremes such as severe droughts and heatwaves and have declined by as much as 80%.

Exhaustive multi-disciplinary koala research continues apace in an effort to find ways of protecting wild koala populations and ensuring that they remain viable now and into the future. Habitat loss, population dynamics, genetics, disease, diet and climate change are some key areas being studied.

How many koalas are there?

Koala researchers are often asked “how many koalas are in the wild?” It’s a hard question to answer. Koalas are not stationary, are patchily distributed throughout an extremely wide range encompassing urban and rural areas in four states and one territory, and are usually difficult to see.

To determine whether each population of koalas scattered across eastern Australia is functionally extinct would require a gargantuan effort.

Koalas are a key part of eucalyptus forests’ health.
Dave Hunt/Flickr, CC BY-NC-SA

In 2016, in an attempt to determine population trends for the koala within the four states, a panel of 15 koala experts used a structured, four-step question format to estimate bioregional population sizes of koalas, and changes in those sizes.

The estimated percentage of koala population loss in Queensland, New South Wales, Victoria and South Australia was 53%, 26%, 14% and 3%, respectively. The estimated total number of koalas for Australia was 329,000 (within a range of 144,000–605,000), with an estimated average decline of 24% over the past three generations and the next three generations.

Since May 2012, koalas have been listed as vulnerable in Queensland, New South Wales and the Australian Capital Territory because populations in these regions have declined significantly or are at risk of doing so.

In the southern states of Victoria and South Australia, koala populations vary widely from abundant to low or locally extinct. Although not currently listed as vulnerable, these koalas are also experiencing a range of serious threats, including low genetic diversity.

To date, the present “vulnerable” listing has not achieved any known positive results for koala populations in Queensland and New South Wales. In fact, recent research invariably shows the opposite.




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This is because the key threats to koalas remain, and are mostly increasing. The primary threat is habitat loss. Koala habitat (primarily eucalyptus woodlands and forests) continues to rapidly diminish, and unless it is protected, restored, and expanded, we will indeed see wild koala populations become “functionally extinct”. We know what comes after that.The Conversation

Christine Adams-Hosking, Honorary Research Fellow, The University of Queensland

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