‘Peter Lemon Tree’ was found alone, sick and weighing just 1.1 kilograms. Without the warmth and protection of his mother’s pouch, he was lucky to be alive.
Thankfully, a local wildlife rescuer scooped Peter up from the side of a busy main road in Lemon Tree Passage. Peter is now a happy resident of Port Stephens Koala Hospital – where his rescuer, Paul, is one of the many volunteers. Just shy of one year old, the little trooper has already suffered a myriad of health problems – eye disease, chlamydia, cancer, and diabetes.
While illness has been Peter’s biggest enemy, disease is just one of the threats that koalas face. Peter Lemon Tree’s young age spared him from the firing line of one of the ‘worst wildlife disasters in modern history’ – the 2019/2020 Australian bushfires. An estimated 61,000 koalas were caught in the path of the blaze, and more than 5,000 died. Now the fate of koalas lies in our hands. Literally. A New South Wales parliamentary inquiry found koalas in the state would be extinct by 2050 unless there is urgent human intervention.
Disastrous events like this are a brutal reminder that we desperately need a long-term solution to ‘insure’ the survival of koalas. Luckily for our furry friends, a team of University of Newcastle researchers are working on exactly that.
Could freezing koala sperm save the species?
Banking on IVF technology
Scientists are proposing to freeze koala sperm and then tweak existing reproductive technologies, like human IVF, to boost dwindling koala populations and inject much-needed genetic diversity.
Their model reveals this would help captive breeding programs to retain genetic diversity, and cut the costs currently required to deliver these programs (a win-win!).
Co-author of the study and conservation scientist at the University of Newcastle, Dr Ryan Witt, said while there is a biobank of non-living tissues for the koala, it does not include sex cells.
“We currently have no way to bring back koalas if the population dies, or to preserve their genetics,” Dr Witt says.
“Biobanking, if developed for the koala, would offer a solution to store or “bank” live koala genetics by freezing sex cells such as sperm. The frozen sperm can then be used to impregnate female koalas in breed-for-release programs, using assisted reproductive technology.”
While the technology is not yet optimised for koalas, it is widely used in the agriculture industry to breed livestock and has also helped millions of parents around the world to conceive.
Dr Ryan Witt (left) and Dr Lachlan Howell at Port Stephens Koala Hospital with Peter Lemon Tree. Commercial veterinary charges for Peters treatment, if applied, are calculated to be more than $70,000 since his admission.
A fraction of the cost
IVF for koalas… sounds expensive, right? Surprisingly not. Dr Witt and his colleague, Dr Lachlan Howell, have crunched the numbers and found that integrating biobanking and assisted reproduction would actually reduce captive koala breeding costs – by five times!
Dr Witt points out the huge cost saving is thanks to a much smaller koala colony needed.
“To reach the genetic target, you would need 223 koalas in a conventional captive program. By contrast, adding assisted reproduction means you’d only have to keep 17 koalas,” he explains.
Dr Lachlan Howell, who is the lead author of the study, has spent years developing and analysing this model for various endangered animals as part of his PhD project at the University of Newcastle. But he believes it offers the koala the most promise.
“The beauty of applying assisted reproductive technologies to the koala population is that much of the foundation has already been laid, much of the infrastructure is already in place,” Dr Howell says.
Their model identifies 16 wildlife hospitals and zoos across Australia that could act as nodes to collect koala sperm and help integrate assisted reproduction – one of them being Peter Lemon Tree’s home: Port Stephens Koala Hospital. These facilities are well equipped to care for koalas, the Hospital even has an incubator crib donated from John Hunter Hospital NICU!
More good news for the koala (at last!) – scientists aren’t starting from scratch with the research and tech to make this plan a reality. They can leverage the fertility tools used in both humans and livestock.
To date, 34 koala joeys have been born using artificial insemination in tame zoo koalas. These joeys, however, came from fresh or chilled sperm, not frozen.
“The hurdle is trying to freeze sperm and make use of it. All that is needed now is more research and funding to tweak existing assisted reproduction technologies so that we can cryopreserve koala sperm, just like we do for humans,” Dr Howell says.
The model identifies 16 wildlife hospitals and zoos across Australia that could act as nodes to collect koala sperm and help integrate assisted reproduction.
Frozen sperm injects fresh genetics
While captive breeding programs are a very powerful tool to help save koalas, they do face significant challenges of high costs and genetic diversity.
Dr Howell said genetic issues in koalas can lead to reproductive dysfunction and infertility. It’s no surprise these issues can also compromise survival, disease resistance, and the species’ ability to adapt to changing environmental conditions from climate change.
But there’s hope.
“Our modelling shows that supplementing frozen founder sperm into koala colonies using various assisted reproductive technologies could significantly reduce inbreeding.”
“We can reintroduce genetic variation into wild koala populations without having to relocate koalas.”
“By using frozen sperm, we can reintroduce genetic variation into wild koala populations without having to relocate koalas. In New South Wales for example, koala populations are declining rapidly in some locations so they would greatly benefit from the introduction of biobanked material from other unique populations to help manage genetic diversity," Dr Howell explains.
If cryopreservation is made possible for koalas, it opens the door to recover and biobank genetic material from koalas who may have died in bushfires or been hit by cars. Koalas like Peter Lemon Tree, who will need captive care for the rest of his life, would have the chance to contribute to the wild population gene pool.
The proof is in the pudding ferret
Feeling sceptical? Wondering if it’s just another model hinging on an if ? Time for a true (not crime) story…
It’s 1981 and we’re in North America. The black-footed ferret is thought to have been extinct for two years now. But in a remarkable plot twist, a small population – of only 18 ferrets – is discovered in Wyoming.
Luckily for the black-footed ferret, research is funded to freeze their sperm - despite scientists having no clue at the time how to use it for reproduction. After all, it’s not every day one must artificially inseminate a thought-to-be extinct black-footed ferret.
Twenty years later, scientists were able to impregnate some of the last remaining female ferrets using this frozen sperm. The donor male ferret was long-dead by this point but his sperm survived and thrived.
This was crucial to reintroduce genetic variation in the captive population, which over time suffered reproductive complications from inbreeding. Thousands of black-footed ferrets have since been born and released into the wild.
“In this case, researchers cryopreserved black-footed ferret sperm many years before they figured out how to use the sperm in assisted breeding. This may be the path we need to take to ensure the future of Australia’s much-loved koala,” Dr Howell says.
The black-footed ferret was once thought to be extinct. Image from Getty.
The conservation toolbox
It’s important to note, while cryopreservation of sperm paints a promising future for koalas, it’s not a silver bullet.
Koalas will continue to face threats and “we need to address the underlying drivers of koala decline,” Dr Howell says. “After all, what’s the point of breeding koalas for release if we’ve got nowhere to release them?”
Integrating assisted reproduction creates an opportunity to reduce the number of koalas needing to be in captivity, and in turn lowers costs.
“This would free up valuable conservation funding to support a greater number of species, or to support other koala conservation efforts such as habitat restoration,” Dr Howell added.
Port Stephens Koala Hospital volunteers, Jo and Paul with Peter Lemon Tree.
Peter Lemon Tree’s rescuer Paul, and his wife Jo are among 200+ volunteers at Port Stephens Koala Hospital who see first-hand the magnitude of threats koalas, and other endangered species face. From habitat loss and dog attacks to fires, road danger, and diseases. As part of his volunteer work, Paul maintains vegetation and food sources – for every koala in captivity 1000 trees are needed to offer a variety of leaves, while Jo coordinates the rescue team and looks after koalas in care.
“Once-upon-a-time koalas used to rule the east coast of Australia. It’s incredibly sad to realise that there’s not as many around anymore as what people think,” Jo says.
“I think this sort of research is essential because otherwise we will lose Australia’s koalas.”
Dr Lachlan Howell is an Honorary Associate Lecturer at the University of Newcastle, and a Postdoctoral Research Fellow with the Centre of Integrative Ecology at Deakin University. Dr Ryan Witt is a Postdoctoral Researcher with the University of Newcastle’s School of Environmental and Life Sciences. Co-authors from the University of Newcastle also include Emeritus Professor John Rodger, Shelby Ryan and Chad Beranek and Professor John Clulow.
The paper was published in the international journal, Animals, and is a joint study with Deakin University, Taronga Conservation Society Australia, the University of Newcastle, FAUNA Research Alliance, The University of Queensland, Macquarie University, and Port Stephens Koala Hospital.
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