NEWS

Endangered Possums Have A Dating Site

It's already saved a population of pygmy possums.

25/10/2017 11:04 SAST | Updated 27/10/2017 10:58 SAST
The mountain pygmy possum is so rare that until 1966 it was thought to be extinct.
The University of Melbourne

ewAustralia holds the dubious honour of world leader when it comes to driving animals to extinction, but a group of Victorian researchers have hit on a new breeding strategy they hope will reverse the trend and help save our unique wildlife.

The 'dating' program has already helped rebuild a dwindling population of mountain pygmy possums in Victoria, and now it's being trialed on a species of bandicoot extinct in the wild on the Australian mainland.

It's been as successful as we could have hoped for."

The University of Melbourne's Dr Andrew Weeks is leading the program and said the technique could also prove beneficial for koalas, Tassie devils and the critically endangered Leadbeater's possum.

"This approach of genetic rescue actually can work in just about any different threatened species that now exists in a fragmented distribution -- whether it be fish, frogs or plants," he told HuffPost Australia.

So how does it work?

Getty Images/iStockphoto
Koala populations are rapidly declining due to logging, domestic dog attacks and bush fires.

The breeding program targets endangered animals that live in small groups isolated from others of their species over time, Dr Weeks explained.

It started in 2011 with the mountain pygmy possum -- a species so rare that until 1966 it was thought to be extinct.

The Mount Buller ski resort in eastern Victoria is one of just three places in Australia where the critically endangered animal still lives in the wild, but by 2006 there was only a handful of the possums left.

Destruction of their native habitat and attacks from foxes, cats and other invasive species had devastated the population, but even the restoration of their habitat and control of predators by the land managers of the ski resort failed to see the population recover.

Australia: Leading The World On Extinction

  • A third of all mammals driven to extinction worldwide in the past 500 years have been in Australia;

  • Only four places in the world have had more animal and plant species become extinct;

  • 818 Australian animals are critically endangered, endangered or vulnerable;

  • Eastern Australia holds the ignoble title of being the only major deforestation front in the developed world. Rates of clearing rival those of Borneo, New Guinea and the Amazon;

  • Land clearing in Australia has gained pace in recent years. Almost 400,000 hectares of forests were logged just in Queensland in 2015-16

The mountain pygmy possums had been isolated from a neighbouring population 100 km away on Mount Hotham for thousands of years, resulting in inbreeding. And as with humans, too much interbreeding is bad news for the possums, leading to less genetic diversity and animals that were smaller, weaker and less adaptable to changes in climate and habitat.

"All of the genetic variations which enable species to be able to adapt to changing environments had been lost from the population," Dr Weeks explained.

This meant that instead of raising four babies annually, each possum was only having an average of 2.6 young each year.

University of Melbourne
The mountain pygmy possum is the only marsupial in Australia which hibernates during the winter.

To combat this, in 2011 six healthy male mountain pygmy possums were taken from Mount Hotham and introduced to the shrinking group at Mount Buller during breeding season, and the results were almost immediate: by 2013, the population had increased by 50 percent.

"Subsequently for the next three years there was a 50 percent increase in population size each year," Dr Weeks said.

"So now there's actually more possums on that mountain than there were back in 1996 when we first discovered it."

"It's been as successful as we could have hoped for."

Now, the same technique is being trialed with eastern barred bandicoots -- a species of bandicoot which is still common in parts of Tasmania, but has all but been wiped out on the Australian mainland.

A small captive breeding program to rescue the Victorian eastern barred bandicoot from extinction involved just 19 original animals, resulting in a 40 percent loss of genetic diversity.

Since February, a captive breeding program using five bandicoots brought to Victoria from Tasmania has seen 19 baby bandicoots born in captivity -- and already they showed signs of being healthier and stronger.

"They're actually larger than the Victorian eastern barred bandicoot and their development time appears to be quicker..larger individuals end up being more fit, because they're a bit tougher, they can handle conditions a little bit better and the males are often more successful at mating," Dr Weeks said.

"So, all the signs are looking very, very positive for this program being successful as well."

University of Melbourne
Since Februry, 19 baby eastern barred bandicoots have been born through the genetic rescue program.

Now, Dr Weeks and colleague Professor Ary Hoffmann are looking to other species which might benefit from the intervention.

And Dr Weeks believes the program could also help animals in southern Australia adapt to climate change.

"Let's say you had populations of a particular species that were at more northern latitudes (of Australia). You can bring some of those genes from the northern latitudes to the more southern latitudes," he explained.

"That increases the genetic variation that is found within the population, but also brings in traits that have already been selected for -- e.g. traits that can handle a warmer climate -- so when the climate warms those genes are already present within the population and they're able to come into effect and be selected for."

WWF Living Forests Report 2015
Eastern Australia is one of the world's 11 major deforestation fronts -- and its threatening dozens of our native species.

But Dr Weeks warns that strengthening an animal's genetics alone won't save species that are being devastated by deforestation, a warming climate and invasive animals like foxes, cats and domestic dogs.

"We can fix the genetics -- which is something often overlooked in a lot of conservation programs to date -- but you also have to correct the thing that has led to the decline of those populations in the first place.

"That is critical for any genetic rescue."

The findings of the genetic rescue program were published on Friday in the journal Nature Communications.