They’re small, furry and adorably cute, but you wouldn’t want them for a pet.
The Eastern Quoll is a bite-sized ball of attitude, and they are under threat.
Researcher and eastern quoll expert Bronwyn Fancourt said the population has potentially reached a precipice, where it can no longer breed faster than it is being killed.
Ms Fancourt said research has shown a massive population decline in the 10 years to 2009, from which the species has not yet recovered.
“When we calculated it ... they declined by just over 50 per cent across the state and it hasn't increased since; it doesn't appear to have continued to decline but it doesn't appear to have recovered,” Ms Fancourt said.
One of just a few carnivorous marsupials the eastern quoll is now extinct on mainland Australia, Tasmania is the last stronghold.
Its plight may be less well known than the Tasmanian devil, but the quoll is federally listed as vulnerable, and earlier this year was listed as endangered by the International Union for Conservation of Nature.
Ms Fancourt’s research has shown weather played a key factor in the significant drop in eastern quoll numbers.
“We looked at where quolls occurred and when they occurred there and then we looked at the weather in the 12 months and three years prior to the observation, so we actually worked out what were the conditions that are favourable for them and which ones are not favourable,” she said.
“Rather than saying, ‘Okay they were found here in Launceston, the average rainfall in Launceston is 400mm a year, that's obviously the rainfall levels that they prefer or they wouldn’t be existing here’, we actually went back and looked at the weather just prior to when that animal was observed there, because an animal that lives three years doesn't care what the 50 year average rainfall is in an area.”
What this approach found was during 2002 to 2003 there was a significant decline in suitable weather conditions for the quolls, which prefer cold winters and low rainfall, that resulted in a contraction of the population, lasting about 18 months.
“Now thats enough for these guys to not breed for a year or two, these things only live for three years so you’ve lost two generations, the numbers crashed,” she said.
This has resulted in what is known as the ‘predator pit’, where the animals can’t breed faster than they are being killed off.
“Previously they were able to cope with cats killing a few juveniles and a bit of road kill and a few things like that, but it wouldn't really have an overall impact on the population. When you’ve got some other factor that pushes their population down really quickly, suddenly that same level of cat predation and road kill that they could cope with before is enough to take out the next generation,” Ms Fancourt said.
“So for them to actually increase the population size is next to impossible because things are removing them as fast as they can reproduce.”
Devils at Cradle director Wade Anthony has been monitoring the activity and proliferation of carnivorous marsupials, including the eastern quoll, near Cradle Mountain and in the Vale of Belvoir for several years.
“We’ve got a pretty good handle on quoll populations; we have seen some fluctuations in numbers but this could be due to weather patterns and things like that, I guess there are some boom bust breeding periods that depend on things like weather and food,” he said.
Mr Anthony said his program has observed healthy populations in the area, where quoll sightings are common.
Ms Fancourt said there are still some remaining pockets in Tasmania with healthy populations, but overall the picture isn’t so rosy.
“I guess the perception is people in those areas see lots of them around and still think that that’s the case right across the state, but we’ve surveyed now probably over 17 different sites around the state and whilst there’s a couple that are okay, the overwhelming majority of them have declined by big numbers,” she said.
If you suddenly begin to see the little spotted critters all over the place in the next few months, don’t get too excited either.
“Now it’s right at the time of year when people are going to see more quolls than ever because they breed in May/June, they have them in the pouch July/August they’re actually now starting to emerge over November/December from their den,” Ms Fancourt said.
“You’ll suddenly see this massive increase in juveniles over summer and everyone will go, ‘But they're everywhere’ but we know that in a normal year the majority of them won’t even survive to may the next year to breed so you’ll suddenly see this plague of quolls for the next month or two but the majority of them won’t actually survive.”
Mr Anthony has established a networked eastern quoll breeding program at Devils at Cradle, which ensures the genetic diversity of their breeding population.
“The insurance population is vital to ensure you have source animals there that can be used for conservation in the wild, it’s absolutely imperative,” Mr Anthony said.
Ms Fancourt said breeding programs like this provide insurance populations and she would like to see active management to introduce them into the wild in an effort to begin recovering wild populations.
“My preference would be to see some management intervention, we’ve got a few captive breeders around the place and to use those animals to try and repopulate those sites,” she said.
Ms Fancourt adds there is a push to reintroduce the species to the mainland, but she thinks these efforts would be better directed in Tasmania, where the species has proven itself to be better adapted.
“The concern is if they (the eastern quoll) persisted in Tasmania and went extinct on the mainland that suggests Tasmania is a much safer environment for them, so my preference would be to see those captive breeders repopulate the wild populations in Tasmania before they go and try ad book them into a high risk environment like the mainland,” she said.