Tasmanian Times

The individual has always had to struggle to keep from being overwhelmed by the tribe. If you try it, you will be lonely often, and sometimes frightened. No price is too high for the privilege of owning yourself. ~ Friedrich Nietzsche

The individual has always had to struggle to keep from being overwhelmed by the tribe. If you try it, you will be lonely often, and sometimes frightened. No price is too high for the privilege of owning yourself. ~ Friedrich Nietzsche

Economy

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

Eastern quolls – small, fleet-footed and ferocious – are one of Australia’s few surviving marsupial predators1. They were once so common in southeast Australia that when Europeans arrived the quolls were reportedly hyperabundant2.

But by the 1960s they were extinct on the mainland, driven down by a combination of disease, poisoning, persecution and predation3.

Despite their mainland demise, eastern quolls continued to thrive in Tasmania – until recently. Across Tasmania, quoll numbers declined by more than 50% in the 10 years to 2009 and show no sign of recovery4.

Recognising this worrying decline, the quolls have recently been listed as endangered internationally5 and in Australia6. This is a stark reminder of how quickly a common species can plunge towards extinction.

But the quolls can still recover, as long as we act now while we still have an opportunity. In research published in Wildlife Research7, I looked at what caused the decline, and how we can help.

Change in the weather

Several factors coincided with the decline, but after five years of investigation8 I found that a period of unfavourable weather9 was the most likely explanation.

Eastern quolls prefer areas with low rainfall and cold winters10. But an 18-month period of warm winters and higher seasonal rainfall during 2002-03 resulted in most of Tasmania becoming unsuitable for eastern quolls. This rapidly drove their numbers down. In fact, the amount of environmentally suitable habitat in this period was lower than at any other time during the previous 60 years.

With the frequency of extreme weather events predicted to increase11 over coming decades, the future for eastern quolls looks uncertain.

image
Eastern quoll numbers declined as unfavourable weather conditions reduced the amount of environmentally suitable habitat across Tasmania (grey shading). Fancourt et al (2015)

The predator pit

Interestingly, while weather conditions have since improved, eastern quolls have not recovered. With their numbers pushed so low, the remaining small populations can no longer breed faster than other threats kill them off. Historically, when quoll numbers were higher, they could cope with these threats.

Quolls are now trapped in what ecologists call a “predator pit”12. Predators, cars, poison and a range of other threats are killing quolls as quickly as they can reproduce.

So population growth is in limbo – not because any threats have increased, but because small populations don’t have the capacity to outpace those same threats anymore.

So population growth is in limbo – not because any threats have increased, but because small populations don’t have the capacity to outpace those same threats anymore.

Contrary to earlier predictions, feral cat numbers in Tasmania have not increased13 following declines in the Tasmanian devil population. Quoll populations could previously cope with the loss of a few quolls (mainly juveniles) to cats. However, that same number of quolls killed by cats is now potentially enough to wipe out any population growth, preventing the species’ recovery.

image
While feral cat numbers have not increased in Tasmania, cat predation of juvenile quolls could still be preventing their population from recovering. Bronwyn Fancourt

Numbers game

The key factor preventing quoll recovery is their current small population. Quoll numbers need a boost, increasing reproductive capacity so that they can once again outpace the threats they are facing. This could be done by supplementing small, surviving populations in Tasmanian with quolls from captive-breeding colonies, insurance populations or the wild population on Bruny Island (which is doing better than mainland Tasmania).

Reducing feral cat numbers at key sites in early summer could also help reduce predation as juvenile quolls enter the population14. That would potentially increase juvenile survival and allow quoll populations to grow and recover.

image
Increasing survival rates of juvenile quolls in the wild is key to helping the species recover. Bronwyn Fancourt

Should quolls be reintroduced to the mainland?

Since word of the eastern quolls’ plight has spread, there has been increasing talk of reintroducing them to Australia’s mainland, where they disappeared more than 50 years ago. Such proposals are often well-intentioned and could potentially help restore some mainland ecosystems.

However, this could actually serve to drive wild populations in Tasmania closer to extinction, making the species’ recovery more difficult.

With only small populations persisting in the wild, removing only one or two individuals from a population could be enough to render that population functionally extinct – and once a population is functionally extinct it is on the path to total extinction.

Similarly, using quolls from captive colonies and insurance populations for mainland reintroductions further removes valuable quolls that could be used to repopulate and recover wild populations in Tasmania.

The eastern quoll’s persistence in Tasmania decades after it disappeared from the mainland suggests Tasmania is a far safer place for eastern quolls and offers them the best chance to recover. Removing them from a relatively safe place and reintroducing them to high-risk mainland sites filled with dingoes, foxes and toxic fox baits could actually hinder, not help, their recovery. For example, while baiting foxes may reduce the threat from foxes, it takes less than half of one fox bait to kill an adult female eastern quoll.

Mainland reintroductions should definitely be a goal in the longer term. But given the dangerously low numbers in Tasmania, we shouldn’t take Tasmanian quolls for high-risk mainland reintroductions until the Tasmanian population is safe. Once numbers in the wild have recovered, wild-sourced Tasmanian quolls could be reintroduced to mainland sites without putting wild populations at risk.

It’s time to act

Australia’s declining species face a slippery slope towards extinction. The key to recovery is understanding why the species declined, then acting while there is still time.

Australia’s history is littered with examples where delays and inaction prevented small populations from recovering, with some species now lost forever15. The eastern quolls’ fate is not yet sealed. But we have to act now.

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*Bronwyn Fancourt, above, recently completed a PhD in wildlife ecology and threatened species conservation at the University of Tasmania, in Hobart. Since 2010, her research has focussed on the decline of the eastern quoll in Tasmania and investigating the likely causes of the decline. This research involved extensive investigations into the impacts of climate change, disease and predator interactions on eastern quoll populations.

Refs:

1. https://theconversation.com/quolls-are-in-danger-of-going-the-way-of-tasmanian-tigers-27744
2. http://www.publish.csiro.au/zo/ZO14029
3. http://www.publish.csiro.au/wr/WR15188
4. http://www.publish.csiro.au/am/AM13004
5. http://www.iucnredlist.org/details/6296/0
6. http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=333#top
7. http://www.publish.csiro.au/wr/WR15188
8. http://www.publish.csiro.au/wr/WR15188
9. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0129420
10. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0129420
11. https://www.researchgate.net/publication/236116527_Climate_Futures_for_Tasmania_Extreme_Events_Technical_Report
12. http://www.publish.csiro.au/wr/WR15188
13. https://theconversation.com/can-tassie-devils-control-feral-cats-the-devil-is-in-the-detail-37151
14. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0119303
15. http://onlinelibrary.wiley.com/doi/10.1111/j.1755-263X.2012.00239.x/full

First published on The Conversation HERE

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17 Comments

17 Comments

  1. john hayward

    October 8, 2016 at 2:28 pm

    #13, Jack. How would you gather any empirical evidence on a purely hypothetical interaction between foxes and devils in a state which devotes so little attention to environmental matters?

    The state govt confined its fox eradication to bombarding the state with 1080. If Jack is the same Jack we know so well, I can understand his concern that even the notional kudos for thwarting the fox invasion be reserved for his crowd alone.

    John Hayward

  2. Ian Rist

    October 7, 2016 at 9:57 pm

    Re # 12 and #14 Devils kill foxes?…. pure speculation, never been witnessed or proven. It was propaganda used during the great money grab.

    I have been around Tassie devils all my life and for ten years observing them almost every night. They are cowards and any fox would put them to flight any day. Even a small Jack Russell terrier can bluff the biggest Devil.

    It would be a very stupid and suicidal Devil that ventured near a fox den, let alone entering a fox den.

    Anyway there have never been any fox dens found in Tasmania period.

  3. spikey

    October 7, 2016 at 4:43 pm

    I saw a truck labelled sodium fluoroacetate driving up huon rd a few days ago.
    I wondered where it was going, it seemed a large container for something i thought required relatively low doses for toxicity.
    Perhaps it was mostly empty.
    I presume it was headed to the council depot.

  4. Ian Rist

    October 7, 2016 at 2:39 pm

    Claiming 1080 is species specific is only one of the false claims put out by the supporters of 1080 poison.
    1080 is not species specific at all, it works around the metabolism rate of each individual animal/species and the ability then of the 1080 toxin to shut down the bait takers krebs cycle and therefor deprive the bait takers ability to convert food into energy, simply put it starves the bait consumers vital organs.
    The Eastern Quoll has a LD50 of only 3.7 m/g 1080 per kilogram of body weight. Tasmanian fox baits contained 3 m/g of pure 1080. This puts all juvenile and female Quolls at lethal dose risk.
    The average weight of a female Eastern Quoll is only 800 grams.
    The Spotted-tailed Quoll is at higher risk with a very low 1.85 m/g per kilogram of body weight.
    There is much evidence from cameras at 1080 bait locations recorded on the Tasmanian Parliament Hansard of Quolls visiting and excavating 1080 baits at 1080 fox bait poison locations.
    It would appear no-one was listening.

    Another false claim was that you never find 1080 poisoned foxes…absolute rubbish.
    I have heard and seen the poor foxes up at Yea and Seymour (Vic.) after taking a 1080 bait, squealing and crying in agony and wandering about staggering into things until some kind Samaritan shot them and put them out of their agony.

    A totally inhumane poison by anyone’s standards.

  5. Jack

    October 7, 2016 at 2:31 pm

    #12

    “The Tasmanian Devil is the ideal mammal to control the fox numbers by devouring the young in their dens……”

    Ted, can I please know where you have found the evidence to justify this statement? For instance, has this ever been documented? My understanding is that this was pure speculation that originated with Tim Flannery some years back. But perhaps you have some other source?

  6. Ted Mead

    October 7, 2016 at 12:23 pm

    There is no doubt there is a correlation between the loss of Eastern Quoll numbers and the rampant distribution of 1080 through the fox eradication program.

    Any lamebrain scientist should know that the placing of 1080 in the ground would be easy target for the foraging habits of Quolls.

    The dumping of 1080 was never going to eradicate foxes. In my opinion foxes were only likely to be controlled through predation. The Tasmanian Devil is the ideal mammal to control the fox numbers by devouring the young in their dens, and no young inevitably means no adults.

    It is of no coincidence that fox sighting numbers have arisen at the same time the Devil population has been decimated.

    1080 has no role in sound ecological management, but unfortunately there are many who have been hoodwinked into believing that the laying of this toxic substance is merely species specific.

  7. Ian Rist

    October 7, 2016 at 11:15 am

    Re # 10 “Or perhaps it is just the money”
    Three things I would say, money, excuse to keep 1080 on the agenda and egos.
    Egos being a bigger contender than some might think.
    I pleaded with them fourteen years ago “stop using 1080 meat baits for non-existent foxes and I will get off your backs”…well they didn’t and look where it has got them now.

    Interesting to note that on the mainland the biggest users of 1080 Foxoff baits before they went belly up was Timbercorp (from 1999-2008) and Great Southern…any clues there ?

  8. Got Me a Fox

    October 7, 2016 at 12:51 am

    It is beyond belief that they laid 1080 for non-existent foxes, when animals such as quolls and devils would obviously die from the baits.

    The program must be run by fools. Or perhaps it is just about the money …

  9. Ian Rist

    October 5, 2016 at 11:01 pm

    Climate change my fat auntie… when I lived at Blessington there were a lot of Eastern Quolls, in fact some nights when spotlighting feral cats I would see thirty to forty Quolls.

    The temperature extremes there have to be experienced to be believed, from minus 5 degrees centigrade to minus 7 degrees centigrade in winter to 30c degrees plus in summer. So simply put I do not agree with the climate change theory.

    What I did notice on adjoining properties after 1080 fox baiting was a sudden and dramatic decline in Eastern Quoll numbers.

    Eastern Quolls are excellent excavators, at certain times of the years they survive on excavating corbie grubs. My guess is they excavated a lot of 1080 fox baits also ……..

    Beautiful little creatures are Quolls, we had a number that lived around the Lodge and in the close by big logs that were left from the early pioneering days. Even though they can be quite feisty I never had any problems with them around the pheasant,partridge and quail. We loved to have them around for the visitors.

    Talking about visitors we had once staying with us at the Game Farm the Baroness and Baron von Stauffenberg from Germany. Grandson of von Stauffenberg of the bomb under Hitlers chair fame. One night whilst having a Bar-b-que a mother Quoll came to check out the smells and had 4-5 baby Quolls on her back, the Baroness was ecstatic and filmed the whole event. I didn’t think much more about it until some months later I received a letter from the Baroness to say the highlight of their trip to Oceania was the Quoll and her babies at the Bar-b-que.

  10. spikey

    October 5, 2016 at 9:43 pm

    Can someone please tell me
    what thresholds in a warm wet event
    cause such drastic demise
    of an opportunistic omnivore
    who lives from mountaintop
    to sea level
    and on islands

    And all evidence of past warm wet events causing population decline?

    How are they dying?
    Drowning related heatstroke?
    Starvation over a warm wet period?
    Orange bellied parrot Flu?
    Increased definitely introduced sugar gliders?

    Primary poisioning by forestry, farming and misguided fox hunters?
    Secondary poisoning by forestry, farming and rat poisoners?
    Habitat destruction?

    1080 back in town?
    Incredible
    I smell a rat

  11. Pete Godfrey

    October 4, 2016 at 8:21 pm

    #5 Ivo thanks for that article, it certainly makes it much easier to counter the argument that we have had foisted upon us for years. That argument being that 1080 only affects the target species blah blah.
    It is strange how the New Zealand 1080 kills birds, insects and everything else but ours from what we have been told only affects wallabies and possums.
    Once again thanks for the link. It will come in very useful.

  12. DPIPWE friend

    October 4, 2016 at 4:34 pm

    Hey Ivo (#5). Look on the bright side! At least if quolls take the poison carrot baits then there is less available for the exclusively vegetarian protected species potoroos, bettongs, wombats, bandicoots, new Holland mice and various birds and assorted other rare opportunistic feeders! Hence less chance of slowly but steadily endangering the future for these important and iconic species!

  13. Ivo Edwards

    October 4, 2016 at 11:35 am

    Mmm – here is a nice photo! Tasty carrots being eaten by an eastern quoll! http://newsroom.macleay.net/eastern-quoll-returned-to-the-australian-mainland/ Hope it can distinguish between the orange ones and the flavour enhanced green ones?

    Note from the latest issue of Game Tracks, page 17, that 1080 use using carrots has gone up significantly in Tasmania in the past few months. This reflects a dramatic easing of restrictions on its use for browser pest control.

  14. Reynard O'Brien

    October 4, 2016 at 10:33 am

    As most working wildlife professionals should know the key wildlife conservation efforts should be focused on maintaining the remaining habitat/biota of these delightful creatures.

    Or maybe not. Perhaps it could be argued that if enough DNA samples from the few remaining animals are gathered and stored at the deep freeze locker next to the wine fridge at the university of New South Wales all will be fine. Future science will repopulate regenerated Tassie bush with cloned super quolls. Why stop there? Imagine the playful eco-experience Red Chinese Communist tourists could have with Thylacoleo (Thylacoleo carnifexbrought) back from extinction. In the interim Huonville diesel tax suckers in partnership with National Parks & Wildlife Service can clear fell, incinerate, bulldoze, reseed with foreign species, poison, fumigate, flood with fungicide, poison and incinerate again for good measure.

  15. Ivo Edwards

    October 3, 2016 at 1:51 pm

    Hi Bronwyn – good to have someone actually doing something about the plight of the eastern quolls! Pity you weren’t supported by the Tasmanian government in your attempt to save the last of them?

    Regarding your evidence that the disastrous collapse in numbers occurred about 2002 – 03 due to unfavourable climate lasting just a couple of years. Could you please explain how this might have happened? i.e. supposedly the quolls didn’t just succumb directly to the weather?. Presumably the essential cause would have been lack of prey in a critical period (most likely winter?) which was itself weather related? Did you find evidence of lack of food in a specific period as contributing to the decline?

    You sensibly listed controlling feral cats in a critical period when juvenile quolls are dispersing after weaning in early summer as a possible helpful measure. I would suggest that additional measures are also needed! Possibly artificially providing food via feeders would be a good approach? After all, we are inundated with plague proportions of wallabies which landowners are struggling to control. Why not feed some of these to quolls via preserved meat in dedicated feeders at critical times of the year? Another possible helpful measure might be provision of snug and secure artificial dens for breeding?

    If the government can successfully eradicate foxes in Tasmania by cutting edge science and brilliant scientists, then surely it can come up with the science to save the eastern quoll from a slow and lingering extinction?

  16. john hayward

    October 3, 2016 at 11:53 am

    Eastern quolls seem to be one of those creatures not equipped to deal with the environmental changes delivered by H sapiens.

    Warm winters will only increase, there does not look to be much regulation of the pesticides used on their insect prey, and you have to wonder if the climate change might encourage the persistence of toxo.

    I also wonder if Bronwyn has noticed any impacts from the seeming increase in ST quoll populations with the demise of devils.

    John hayward

  17. Ian Rist

    October 3, 2016 at 10:45 am

    “while baiting foxes may reduce the threat from foxes, it takes less than half of one fox bait to kill an adult female eastern quoll.”

    Tasmania, with only fabricated and hoaxed ‘evidence’ of foxes went ahead and laid in excess of 350,000 toxic 3 m/g 1080 meat based ‘fox’ baits in the last fourteen years…and we are asking why Eastern Quoll populations have crashed in the last ten years? Not to mention the plight of the Tasmanian Devil, another Tasmanian carnivore in serious trouble.
    What mentality would condone this stupidity?
    About the same mentality as the Government of the day putting a bounty on the Thylacine.

    Ony in Taz-mania.
    Persons must be held accountable for this tragedy.

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