Australian native forests – are they valuable ecosystems and habitats for wildlife; or bushfire fuel hazards to be burned, before they burn?

 

Blue Mountains wet schlerophyl forest

© Photo by Henry Gold, wilderness photographer

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Bushfire Management’s root problems

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1. Bushfire Management which recognises wildlife habitat as an asset worth protecting makes the fire fighting task immensely complex. So moreover the more simplistic and cost saving rationale of ‘protecting life and property’ holds sway, where no thought is given to the conservation values or to the habitat needs of wildlife. The inculcated and unquestioned bushfire management attitude that native forests are the cause of bushfires, rather than being victims of bushfires, belies one of the three key root problems of why bushfire management is failing. Ignitions left to burn in inaccessible terrain time again have proved be devastating not just for nature and wildlife, but consequentially for human life and property. Wildfire does not discriminate.
2. Bushfire Management across Australia is so poorly equipped to detect and suppress ignitions when they do occur, that out of frustration, fear has been inculcated to encourage all native forests be dismissed as bushfire hazards and ‘prescribed burned’ as a precaution. Across the New South Wales Rural Fure Service, the term is quite unequivocal – ‘Hazard Reduction‘ . Broadscale hazard reduction, euphemistically labelled ‘strategic burns‘ or deceptively ‘ecological burns‘ and has become the greatest wildlife threatening process across Australia driving wildlife extinctions.’
3. Both the localised and regional impacts of bushfire and hazard reduction upon wildlife ecology are not fully understood by the relevant sciences – ecology, biology and zoology. Fire ecology is still an emerging field. The Precautionary Principle is well acknowledged across these earth sciences, yet continues to be dismissed by bushfire management. They know not what they do, but I do not forgive them.

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Australia’s record of wildlife extinctions are the worst of any country in the past two hundred years.

‘Of the forty mammal species known to have vanished in the world in the last 200 years, almost half have been Australian. Our continent has the worst record of mammal extinctions, with over 65 mammal species having vanished in the last 50 000 years.’ [Chris Johnson, James Cook University, 2006]

 

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‘Australia leads the world in mammal extinctions. Over the last two hundred years 22 mammal species have become extinct, and over 100 are now on the threatened and endangered species list, compiled as part of the federal government’s Environment Protection and Biodiversity Conservation Act.’ [Professor Iain Gordon, research scientist in CSIRO’s new Biodiversity Theme, 2009.]

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Uncontrolled bushfires, broadscale and frequent hazard reduction, and land clearing are the key drivers causing Australia’s remaining wildlife to disappear. Once habitat is destroyed, the landscape becomes favourable to feral predators which kill the remaining unprotected fauna. Thousands of hectares of Australia’s native forests are being burnt every year and are becoming sterile park lands devoid of undergrowth habitat. Wave after wave of habitat threats continue to undermine the layers of resilience of native fauna, until fauna simply have no defences left and populations become reduced to one local extinction after another.

James Woodford in his article ‘The dangers of fighting fire with fire‘ in the Sydney Morning Herald, 8th September 2008, incitefully observed:

‘Fighting fires with fear is a depressing annual event and easy sport on slow news days. Usually the debate fails to ask two crucial questions: does hazard reduction really do anything to save homes, and what’s the cost to native plants and animals caught in burn offs? What we do know is a lot of precious wild places are set on fire, in large part to keep happy those householders whose kitchen windows look out on gum trees.

Hazard reduction burning is flying scientifically blind. Much hazard reduction is performed to create a false sense of security rather than to reduce fire risks, and the effect on wildlife is virtually unknown. An annual bum conducted each year on Montague Island, near Narooma on the NSW far South Coast has become a ritual in which countless animals,including nesting penguins, are roasted.

The sooner we acknowledge this the sooner we can get on with the job of working out whether there is anything we can do to manage fires better. We need to know whether hazard reduction can be done without sending our wildlife down a path of firestick extinctions.’

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‘Koalas may be extinct in seven years’

[Source: Sydney Morning Herald, 20070411]

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‘Extreme drought, ferocious bushfires and urban development could make koalas extinct within seven years, environmentalists are warning. Alarms about the demise of the iconic and peculiar animal, which sleeps about 20 hours a day and eats only the leaves of the eucalyptus tree, have been raised before.

But Deborah Tabart, chief executive officer of the Australia Koala Foundation, believes the animal’s plight is as bad as she has seen it in her 20 years as a koala advocate.

“In South-East Queensland we had them listed as a vulnerable species which could go to extinction within 10 years. That could now be seven years,” she said. “The koala’s future is obviously bleak.”

South-East Queensland has the strongest koala populations in the vast country, meaning extinction in this area spells disaster for the future of the species, said Tabart.

The biggest threat is the loss of habitat due to road building and development on Australia’s east coast – traditional koala country. The joke, said Tabart, is that koalas enjoy good real estate and are often pushed out of their habitat by farming or development.

“I’ve driven pretty much the whole country and I just see environmental vandalism and destruction everywhere I go,” she said. “It’s a very sorry tale. There are [koala] management problems all over the country.”

Massive bushfires which raged in the country’s south for weeks during the summer, burning a million hectares of land, would also have killed thousands of koalas.’

[Read More]

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‘A Bushfire action plan which protects people, property and nature’

[Source: The wilderness Society, 20090219, http://www.wilderness.org.au/campaigns/forests/bushfire-action-plan]

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In the immediate aftermath of the devastating Victorian Bushfires of 2009, The Wilderness Society, in response to bushfire management’s quick blaming of the native forests for the bushfires; drafted a ‘Bushfire Action Plan‘ that sought to recognise the need to protect nature along with people and their property.

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‘Bushfire remains one of the most complex and difficult aspects of our environment to deal with. Climate change is expected to make things even tougher, with increases in the number of high fire danger days and the number of people and houses at risk increasing with the tree/sea change phenomenon.

With the onset of climate change, mega-bushfires that burn massive areas are expected to occur more often.

A joint CSIRO and Bureau of Meteorology study of the impact of climate change in bushfires found parts of Victoria faced up to 65% more days of extreme fire risk by 2020, and 230% more by mid-century.

Yet clearly we have a lot to learn and the Royal Commission will set a new agenda for land and fire management, prevention and response. Many challenges will remain but some aspects seem clear. We need more money and support for fire fighters if we are to successfully protect life, property and the environment. Two key areas are the early detection of fires including the use of aerial surveillance and remote sensing especially in remote areas, increasing rapid response capacity including more “Elvis” helicopters to fight bushfires as soon as they start.

The outstanding work of firefighters on the front line needs to be backed up with the best available knowledge, planning and resources to ensure operations are as effective as possible in protecting people, property and nature. There is an urgent need to increase investment in these areas and rapidly establish scientific underpinning to fire management, as well as properly resourcing implementation and fire operations.
We also need more information for government and community about how to deliver fire management in a way that also protects the natural environment and our unique wildlife.

Fuel reduction burning has an important place in the fire management toolbox, and we support its place in scientifically underpinned fire management for the protection of life, property and the environment.

The issue of fuel reduction burning often dominates the fire debate, as if it is the only fire management tool. But it’s important to remember that this is only one tool in fire management, and not the silver bullet that will fire proof the landscape.

Environmental groups want to see the science that supports the current fuel reduction program, including a scientific justification for so-called hazard reduction burns in specific areas and the scientific justification for the route and extent of fire break establishment. Environmental groups are particularly concerned about the lack of impact assessment of these programs on biodiversity, particularly given their uncertain benefits to reduce the extent, frequency and severity of fire.

Views on these measures tend towards two extremes. One extreme is that we should fuel reduction burn all forest areas every 20 years and carve out thousands of kilometres of fire breaks, the other is that all our forests are wilderness areas which should just be allowed to burn and not manage our forests for fire at all.

For the Australian bush to be healthy and to protect people, property and nature we need a scientifically based balance between these extremes.

Fire management is not ‘one size fits all’ when it comes to the Australian bush. It needs to be targeted and specific, because we know that different kinds of bush respond differently to fire and therefore need different management. For native plants and animals to survive, fire management needs to promote “good” fire at the right time of year, of the right type and size. And that varies with vegetation type and resident native animals. Grasslands will require more frequent fires compared with forests, while areas such as rainforest will need to be protected from fire altogether.

That’s why we need good ecological science informing fire management, which has come a long way in understanding what’s best for native plants, but we need a better understanding of what fire management is best for protecting wildlife and avoiding extinctions. Its critical that scientists, fire agencies and governments work together to understand how to best manage fire to protect habitat for endangered wildlife, because no one wants fire management to lead to extinctions.

Of course, the protection of life & property needs to come first in fire management – but we can do that while also protecting nature and wildlife. A balanced approach is to prioritise the protection of life and property in areas close to farms and townships, and to prioritise fire management for the environment in remote areas and national parks.

A continuation of the expansion in knowledge, resources and support for fire management and community preparedness will best ensure the protection of life, property and the environment into the future…

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We have developed a 6-point plan to reduce the bushfire risk and help protect people, property, wildlife and their habitat.

1. Improve aerial surveillance to detect bushfires as soon as they start.
2. Ramp up hi-tech, quick response capability, including more ‘Elvis’ helicopters to fight bushfires as soon as they ignite.
3. More research into fire behaviour and the impact of fire on wildlife and their habitat.
4. Around towns and urban areas – prioritise the protection of life and property with fuel reduction and fire break management plans.
5. In remote areas and National Parks – prioritise the protection of wildlife and their habitat through scientifically-based fire management plans.
6. Make native forests resistant to mega-fires by protecting old-growth forests, rainforests and water catchments from woodchipping and moving logging into existing plantations.

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Critique of Roger Underwood’s Criticism of TWS ‘6-Point Plan‘

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On 12th February 2009, Roger Underwood, a former rural firefighter and a forestry industry employee in Western Australia, had his article published in The Australian newspaper criticising the above recommendations of The Wilderness Society (TWS).

Regrettably, rather than offering constructive criticism and proposing counter arguments with supportive evidence, Underwood instead dismisses the Wilderness Society’s contribution, but disappointingly with empty rhetoric. Underwood states upfront:

“the trouble with the society’s action plan to reduce the risk of bushfires is that it won’t work.“

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The Wilderness Society’s six-point action plan aims to counter the current bushfire management strategy that relies upon hazard reduction burning and the ecological damage this is causing – ‘destroying nature’, ‘pushing wildlife closer to extinction’, ‘increasing the fire risk to people and properties by making areas more fire prone’.

Underwood claims that statistics exist showing no massive increase in prescribed burning, but in fact that prescribed burning has declined. Yet Underwood fails to provide nor even reference any such statistics. He fails to recognise that both bushfires and prescribed burning collectively cause adverse impacts on wildlife. If all burning of native vegetation, however caused, is included in the assessment, then would statistics indeed show an increasing trend in the natural area affected by fire in Australia?

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‘Burn it before it burns’ Theory

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Underwood questions the wildlife extinction problem without any basis. He then adopts the ”old chestnut‘ theory of blaming the threat to wildlife on ‘killer bushfires‘. ‘Killer bushfires’ (the firestorm threat) has become the default justification by bushfire management for its policy of prescribed burning. This is the ‘Burn it before it burns!‘ defeatist attitude. If one burns the bush, there will be no bush to burn. Underwood’s claim that ‘killer bushfires’ are a “consequence of insufficient prescribed burning” is a self-serving slippery slope fallacy. If nature is an asset of value to be protected, then it is defeatist to damage it to prevent it from damage. The history of so-called ‘controlled burns‘ have an infamous reputation of getting out of control and becoming wildfires. If the attitude of burning as much of the bush as possible to avoid uncontrolled wildfire, then then paradoxically the implied incentive is to let controlled burns burn as much as possible to minimise the risk of unexpected fires in the same area.

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In respect to each of The Wilderness Society’s (TWS) Six Point Plan, one counters Underwood’s responses as follows:

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1: Improve aerial surveillance to detect bushfires as soon as they start

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Underwood supports aerial detection as “a first-rate resource and a comprehensive system” but says that it can fail completely under hot, unstable atmospheric conditions and when there are very high winds. However, fire towers and aircraft are not the means of bushfire surveillance today. Low orbiting geostationary satellites with infrared and high resolution cameras can now spot individual cars in real time and through cloud and smoke. Satellites are not affected by atmospheric conditions such as high winds or hot temperatures. Modis-Fire is one company that specialises in such satellite technologies.

In addition, the CSIRO, with the Department of Defence and Geoscience Australia, has developed an internet-based satellite mapping system called ‘Sentinel Hotspots‘. Sentinel Hotspots gives emergency service managers access to the latest fire location information using satellite data. Fire fighting organisations across Australia have used this new strategic management tool, since it was launched in 2002, to identify and zoom in on fire hotspots. [Read More]

In 2003, an article in the International Journal of Wildland Fire entitled ‘Feasibility of forest-fire smoke detection using lidar‘ extolled the virtues of forest fire detection by smoke sensing with single-wavelength lidar.

Such technologies are available if the political will was met with appropriate investment. Such technologies could be available to a military-controlled national body, but unlikely to be available to volunteer members of the public. It all depends on the standard of performance Australians expect from bushfire management.

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2: Ramp up hi-tech, quick response capability, including more ‘Elvis’ helicopters to fight bushfires as soon as they ignite.

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Underwood dismisses aerial fire-bombing as a “dream” that “has never succeeded in Australia, and not even in the US” and “next to useless“.

Well, it seems Underwood is contradicted by the recent decisions of Australia State Governments across Australia’s eastern seaboard to charter not just one Erikson Aircrane but three. Not only was Elvis contracted from the United States in Summer 2010 to Victoria, “Elvis” was based in Essendon, ‘Marty‘ was based in Gippsland and ‘Elsie‘ was based in Ballarat. Clearly, the Victorian State Government considers the cost of these three aircraft justifiably cost-effective in offering quick response capability to fight bushfires.

Dedicated Fire Fighting Erikson Aircrane ‘Elsie‘ based in Ballarat, Victoria during the 2010 Summer

© Photo ABC Ballarat http://www.abc.net.au/local/audio/2010/12/22/3099609.htm

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In South Australia, the Country Fire Service (CFS) believes in the philosophy of hitting a fire ‘hard and fast’.

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‘CFS volunteers and aerial firefighting aircraft are responded within minutes of a bushfire being reported and as many resources as possible are deployed to keep the fire small and reduce the chance of it getting out of control. It is not widely known that South Australia has a world class initial attack strategy of aerial firefighting. The value of a rapid aerial firefighting approach has been supported by Bushfire Cooperative Research Centre research. In their 2009 report titled ‘The cost-effectiveness of aerial fire fighting in Australia, the Research Centre wrote the following in their summary

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The results of the analysis show that the use of ground resources with initial aerial support is the most economically efficient approach to fire suppression. Aircraft are economically efficient where they are able to reach and knock down a fire well before the ground crew arrives. This buys time for the ground forces to arrive and complete the containment. Rapid deployment of aerial suppression resources is important. This advantage is much greater in remote or otherwise inaccessible terrain. Where other suppression resources are unable to reach the fire event within a reasonable time period, sole use of aircraft is economically justified.’

 

[http://www.bushfirecrc.com.au/research/downloads/The-Cost-Effectiveness-of-Aerial-Fire-Fighting-in-Australia.pdf].

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Underwood claims that: “Elvis-type aircranes cost a fortune, burn massive amounts of fossil fuel, use gigalitres of precious water and are ineffective in stopping the run of a crown fire that is throwing spot fires. Water bombers do good work protecting houses from small grass fires. But against a big, hot forest fire and during night-time they are next to useless.”

Underwood conveys a sense of dogged reliance in traditional fire truck centric thinking as if to preserve an old firie culture of ‘we know best‘ and ‘nothing is going to change our thinking‘ mindset. May be it is out of petty envy wherein many volunteer firies can command trucks but wouldn’t have a clue flying helicopters and so would feel sidelined.

Well, since the 2009 Victorian Bushfires, more than A$50 million worth of new initiatives have been introduced or are under development.

“Further changes are likely to be introduced as the Royal Commission, which was established to investigate the Black Saturday disaster, is ongoing. Aerial firefighting is set to be addressed by the commission. Among new initiatives in Victoria is a A$10 million trial of a very large air tanker (VLAT) – the first-ever such experiment in the country. On 14 December, a McDonnell Douglas DC-10-30 Super Tanker, leased from US company 10 Tanker Air Carrier, arrived in Melbourne. Australian regulator, the Civil Aviation Safety Authority, and underwent final compliance assessment to allow it to enter service in January.”

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[Source : http://www.flightglobal.com/articles/2010/02/09/338056/australia-puts-firefighting-tankers-to-the-test.html]

Underwood may well dismiss aerial suppression technology as ‘razzle-dazzle‘, but he is right to state that such investment requires governments to put more resources into research and into monitoring bushfire outcomes, including the environmental impacts of large, high-intensity bushfires and continuous feedback to management systems from real-world experience out in the forest.’

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3: More research into fire behaviour and the impact of fire on wildlife and their habitat

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While Underwood claims that he supports more research into fire behaviour and fire impacts, he is dismissive of the conclusions of much of the research already done, but offers no explanation. This seems an internal contradiction. What are the conclusions of the research?

Underwood claims the conclusions do not support the Wilderness Society’s agenda. How so? What is TWS agenda?

Underwood conveys an unsubstantiated bias against the Wilderness Society, only offering an ad hominem fallacious argument – attacking the messenger, not the argument.

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The science on fire ecology is still emerging. The Wilderness Society validly states above that ‘bushfire remains one of the most complex and difficult aspects of our environment to deal with‘, that ‘there is an urgent need to increase investment in these areas and rapidly establish scientific underpinning to fire management, as well as properly resourcing implementation and fire operations‘ and ‘the lack of impact assessment of these programs on biodiversity, particularly given their uncertain benefits to reduce the extent, frequency and severity of fire‘.

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4: Around towns and urban areas – prioritise the protection of life and property with fuel reduction and fire break management plans.

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Underwood here perceives an inconsistency in TWS Action Plan – suggesting its support for fuel reduction around urban areas contradicts its claim that fuel reduction makes the burned areas “more fire prone”. However, this action item is about prioritising fuel reduction on a localised basis around the immediate areas where life and property are located.

Whereas broadscale hazard reduction that is carried out many miles from human settlements has become a new strategy of bushfire management. The excuse used is euphemistically termed a ‘strategic burn‘ or even an ‘ecological burn‘ in the name of encouraging biodiversity. Except that the practice seems to be a leftover habit from the Vietnam War in which helicopters are used to drop incendiaries indiscriminately into remote areas without any care for the consequences.

A so-called ‘ecological burn‘ of Mt Cloudmaker

This was conducted by helicopter incendiary by NSW National Parks and Wildlife Service (DECCW)

in the remote Krungle Bungle Range of the Blue Mountains World Heritage Area

(Photo by editor from Hargraves Lookout, Shipley Plateau, 20080405 , free in public domain)

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A recent example is the ‘strategic burn’ authorised and executed by the NSW Department of Environment, Climate Change and Water (DECCW) in the Blue Mountains World Heritage Area on 12th May 2010. Some 2500 hectares of remote wilderness was deliberately set alight around Massif Ridge, some 12 kilometres south of the town of Woodford in wild inaccessible forested area of the World Heritage Area. The excuse was to reduce the available ‘fuel’ (native vegetation) for potential future wildfires. [>Read More: ‘National Parks burning biodiversity‘ ]

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5: In remote areas and National Parks – prioritise the protection of wildlife and their habitat through scientifically-based fire management plans.

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Underwood contends another stock standard industry claim that where native forests have been protected, they have naturally accumulated fuel loads in which sooner or later an uncontrollable landscape-level fire occurs. So his anthropocentric theory runs that is humanity’s responsibility not to let nature be nature, but to control nature and so to burn the bush before it burns. This theory is premised on the defeatist approach that in the event of a bushfire, bushfire management is not in a position to detect and suppress it.

And so Underwood, poses the standard industry response of “more frequent planned burning under mild conditions“. He assumes that leaving the overstorey and the soil intact will ensures a diversity of habitat for wildlife. Yet Underwood is not a zoologist and has no understanding of the vital role that dense ground vegetation provides to Australia’s native ground dwelling mammals (e.g.the Long-footed Potoroo, Spotted-tailed quoll, Eastern Pygmy Possum, the Petrogale penicillata, Broad-toothed Rat, Bolam’s Mouse, the Smoky Mouse, the Eastern Chestnut Mouse, the Long-nosed Bandicoot), as well as nexting birds, flightless birds, amphibians and reptiles.

Eastern Quoll – Dasyurus viverrinus – EXTINCT on mainland Australia

© Photo by Andrea Little http://www.mtrothwell.com.au/gallery.html

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Underwood’s view reflects the simplistic misguided view of biodiversity of most of Australia’s bushfire management – that the presence of trees and regrowth of fire-tolerant plants equates to biodiversity.

Can Underwood name one species of Australian fauna that is fire tolerant?

Underwood misinterprets the text of TWS which advocates an holistic fire management system, not as a silver bullet or ‘one-size-fits- all’ convenient panacea that pretends to fire proof the landscape. The only guarantee of ‘one-size-fits- all’ hazard recution is a sterile forest devoid of biodiversity and causing local species extinctions. TWS argues for a scientifically-based and balance approach recognising that some forest ecosystems like rainforests are most definitively fire-intolerant.

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6: Make native forests resistant to mega-fires by protecting old-growth forests, rainforests and water catchments from woodchipping and moving logging into existing plantations

Underwood challenges this last item stating there is no evidence that old growth forest is less likely to burn than the regrowth forests. This is false. Australian native forests that regrow after fire are those that are fire-resistant. Typically, these genus (Eucalypt and Acacia) regrow quickly and become dense mono-cultures. If a fire passes through again, the fire is often more intense and devastating. Old growth forests, rainforests and riparian vegetation around water catchments tend to be moist and so less prone to bushfires.

But this sixth item is not about the relative propensity of old growth forests to burn more readily than regrowth forests, so Underwood’s argument is a distracting red herring. TWS’ aim here is more about placing a higher value on old growth and rainforests due to their greater biodiversity and due to their increasing scarcity. Clearly, TWS is ideologically opposed to woodchipping and logging of old growth forests and rainforests. Logging operations typically involve follow up deliberate burning and such fires have frequently got out of control. Underwood’s needling criticism of TWS for having a lack of knowledge of fire physics or bushfire experience is a typical defensive criticism leveled at anyone who dares to challenge bushfire management. Conversely, if Underwood has the prerequisite knowledge of fire physics or bushfire experience, he is not very forthcoming except to defend the status quo of bushfire management.

The recent bushfire results are demonstrating that bushfire management is increasingly unable to cope with bushfire catastrophes nor meet the expectations of the public to protect life, property and nature.

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Further Reading:

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[1] ‘Studies of the ground-dwelling mammals of eucalypt forests in south-eastern New South Wales: the species, their abundance and distribution‘ by PC Catling and RJ Burt, CSIRO, 1994, http://www.publish.csiro.au/paper/WR9940219.htm

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[2] ‘Australia’s Mammal Extinctions – A 50,000-Year History‘, by Chris Johnson, 2006, James Cook University, North Queensland. http://www.cambridge.org/aus/catalogue/catalogue.asp?isbn=9780521686600

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[3] ‘Solving Australia’s mammal extinction crisis‘, (2009) by Professor Iain Gordon, research scientist in CSIRO’s new Biodiversity Theme, ABC Science programme. He chaired a symposium on Australia’s mammal extinction crisis at the 10th International Congress of Ecology in Brisbane August 2009. http://www.abc.net.au/science/articles/2009/09/02/2674674.htm

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[4] ‘Koalas may be extinct in seven years‘ , Sydney Morning Herald, 20070411, http://www.smh.com.au/news/environment/koalas-may-be-extinct-in-seven-years/2007/04/11/1175971155875.html

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[5] ‘A Bushfire action plan which protects people, property and nature‘, The Wilderness Society, 20090219, http://www.wilderness.org.au/campaigns/forests/bushfire-action-plan

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[6] ‘Manage bush better so climate won’t matter‘, by Roger Underwood (ex-firefighter), The Australian newspaper, 20090212, http://www.theaustralian.com.au/news/manage-bush-better-so-climate-wont-matter/story-e6frg73o-1111118824093

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[7] ‘Locating bushfires as they happen‘, CSIRO – Sentinel Hotspots, http://www.csiro.au/solutions/Sentinel.html

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[8] ‘Modis-Fire’ satellite bushfire detection, http://modis-fire.umd.edu/Active_Fire_Products.html

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[9] ‘Elsie’s first day on the job, Ballarat’s fire fighting helicopter‘, by Prue Bentley (ABC TV Ballarat), 20101222, http://www.abc.net.au/local/audio/2010/12/22/3099609.htm

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[10] ‘South Australia – Country Fire Service – Factors that influence aircraft selection‘ – http://www.cfs.sa.gov.au/site/about_us/aerial_firefighting/aircraft_selection.jsp

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[11] ‘Australia puts firefighting tankers to the test‘, Fight Global 20090209, http://www.flightglobal.com/articles/2010/02/09/338056/australia-puts-firefighting-tankers-to-the-test.html

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[12] ‘Bushfire-CRC – Aviation content’, http://www.bushfirecrc.com/category/bushfiretopic/aviation.

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[13] ‘Towards New Information Tools for Understanding Bushfire Risk at the Urban Interface‘, 2004, R. Blanchi, J. Leonard, D. Maughan, Bushfire-CRC, CSIRO Manufacturing & Infrastructure Technology, Bushfire Research. [Read full report]

[end of article]

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by Editor 20100810.

The following article appeared on ABC Television in Tasmania (Australia), Friday 16th July 2010.

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‘Scientists are concerned about a decline in eastern quoll numbers in Tasmania.

The eastern quoll is a carnivorous marsupial and is sometimes known as a native cat.

Scientists predicted quoll numbers would rise as the tasmanian devil population was decimated by the facial tumour disease.

But spotlighting survey work has shown numbers have fallen by half.

University of Tasmania honours student, Bronwyn Fancourt, is now doing more detailed survey work but says initial results are concerning.

“We really need to protect these guys because we don’t want to see them end up as another thylacine,” she said.

Blood samples and measurements will be taken for further research into why the species is in decline.’

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Further reading on the plight of Quolls in Tasmania:

[The following article was extracted from the Tasmanian Times of 15th May 2010, by Nick Mooney, Richmond (Tasmania), ^http://www.tasmaniantimes.com/index.php/article/cynical-dismissal-of-substantial-material-evidence ].

‘Cynical dismissal of substantial material evidence‘

[This article was extracted from the Hobart Mercury of 16-July 2010, by Charkes Waterhouse, http://www.themercury.com.au/article/2010/07/16/159131_tasmania-news.html ].

‘Another native Tasmanian species is under threat, with the population of eastern quolls falling around the state.

The decline has alarmed experts as the eastern quoll was expected to thrive to fill the void left by falling numbers of disease-ravaged Tasmanian devils.

The University of Tasmania and the Department of Primary Industries, Parks, Water and Environment will investigate the extent of the falling population.

DPIPWE threatened species zoologist Clare Hawkins said the study would provide scientific data on the status of the species.

She said annual spotlighting information suggested the population of the eastern quoll had declined.

“It does appear quite complicated as at the same time there are areas of the state, such as Bruny Island, where landowners are reporting they have never seen so many eastern quolls,” she said.

“It may be that in some areas of the state they remain in high numbers, whereas other parts of Tasmania have had declines, or it may be that in some areas they are coming into closer contact with the urban environment making them more observed, which could be masking an overall decline.”

University of Tasmania zoology honours student Bronwyn Fancourt said a systematic survey would provide scientific information on the wild population, building on information about population changes and showing whether there were areas where increases or decreases had occurred.

“Tasmania is the last stronghold for the eastern quoll as it is now presumed extinct on mainland Australia, which highlights the importance of having scientific data on what the population is doing,” Ms Fancourt said.

She said the survey was taking place through a trap-and-release program at various sites.

Information from this program and any other data collected could help an understanding of possible contributory factors if the quolls were in decline.

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‘Foxes, quolls, devils and 1080‘

[This article is extracted from the Tasmanian Times, 24-Nov-2006, by wildlife biologist Nick Mooney,^ http://tasmaniantimes.com/index.php?/article/nick2/].

Assessing the Risks

When assessing the risks of 1080 fox baiting to individuals or populations of any particular species a number of things should be taken into account, including:

• The physiological sensitivity of the species to 1080 poison (depends on many things principal amongst them the historic exposure of the species to 1080 as it occurs in Australian plants), something that can be experimentally measured.

• How many baits the species might find (depends on the sensory abilities of the animal, how, where and the number of baits placed in a given area — the landscape density).

• How many baits the species might eat within a certain period. To cause death, a lethal dose has to be ingested in a certain time — usually within 2 days because sub lethal doses of 1080 are metabolised. Dried meat baits are too hard for many species to do more than mouth and nibble but many species can eat other baits such as Foxoff (eg non toxic bait trials — Belcher 1998 and DPIW data). There is evidence some species can detect 1080 in baits and avoid eating them (eg the spotted-tailed quoll in Foxoff baits, Kortner et al 2003).

• How much 1080 is left in baits when they are eaten (if they are decomposing, 1080 will have also degraded to a comparable degree).

• The likelihood of the species digesting baits (many carnivores and omnivores regurgitate food containing significant amounts of 1080. There are past records of devils regurgitating 1080-laced food in captive trials).

• The age and health of the individual eating the bait or carcasses of poisoned animals (smaller individuals of a species likely have higher metabolisms and consequent usual higher sensitivity to 1080 and healthy individuals likely have more resistance to 1080)

• The size of individuals in the population at baiting (size effects metabolism and consequent susceptibility to 1080. Individuals of the same species might be different in size in different populations, eg devils on the east coast of Tasmania are much larger than west coast individuals, and there may be many small juveniles just after breeding).

• How the species’ range and abundance overlaps with 1080 baiting (the proportion of the species that might be exposed to baiting).

Physiological sensitivity

The level of physiological sensitivity of a species to 1080 is usually described as the species’ LD50 – that is the mg of 1080 ingested per kg of animal during a very short period that will kill 50% of the individuals exposed (LD = Lethal Dose). Most of the research on LD50s for Australian animals and the potential impacts of 1080 was done on captive animals decades ago by Dr John McIlroy, then at CSIRO, and published in various issues of Australian Wildlife Research (eg McIlroy, 1981a, 1981b and 1981c) and he still gives occasional advice on the matter to DPIW. It is doubtful if this work could ever be substantially expanded or repeated because it involves lethal testing.

LD50s for some Tasmanian animals of obvious interest as potential non-target consumers of fox baits (mainly dried kangaroo meat but also some Foxoff meat compound) are

We see that kg-for-kg, red foxes are over 13 times as sensitive to 1080 as are spotted-tailed quolls and 30 times as sensitive as devils. The LD50 for spotted-tailed quolls is lower than might be expected considering those for its relatives, the eastern quoll and Tasmanian devil. McIlroy has expressed the opinion the small sample size and temperatures the results were obtained under may have given a too low result. This is born up by most mainland research that shows little effect of fox and wild dog baiting on spotted-tailed quolls (eg Kortner et al 2003).

Persistence of 1080 in baits

In the field, 1080 breaks down by microbe and fungal activity. Meat baits as used in Tasmania are about 120g of fresh kangaroo meat, each dosed with 3mg of 1080 dried hard to about 40g for storage then use (eg Saunders et al 1995). By the time they are set (buried) some 1080 is already broken down and on average they then only contain 2.7mg – a 10% loss. Once buried, degradation of 1080 accelerates, the rate depending on soil conditions (particularly moisture and temperature) and consequent baits degradation. Such degradation of 1080 is well known (eg Saunders et al 2000).

Tasmanian 1080 fox dried meat baits have been tested after different times in the ground in field conditions and on average after 2 days in the ground only 43.3% of 1080 remained, after 5 days there was 28.2% left, after 10 days 19.7% and after 15 days 11.6%. However, there was considerable variation even between neighbouring baits; some in wet places have much less 1080 residue and some in dry places much more than the average.

Number of baits needed to put individuals at risk

Considering the sensitivity of spotted-tailed quolls, devils and foxes to 1080 and degradation of 1080 in buried baits we can calculate how many baits buried for various times need to be eaten by different sized spotted-tailed quolls, devils and foxes within 2 days to have a 50% chance of being killed.

We see below that a very small spotted-tailed quoll will consume an LD50 if it eats most of one freshly layed bait but that same animal would have to eat at least 5 baits within 2 days once they had been in the ground for two weeks to be at similar risk. Similarly a very large spotted-tailed quoll would have to eat more than 4 freshly layed baits to be at risk but more than 30 after two weeks in the ground.

We see below that even a very small devil (probably not even weaned) needs to eat more than 3 freshly layed baits within 2 days to reach an LD50 and large devils need to eat very many baits in a short period to reach an LD50.

We see that foxes are extremely susceptible to 1080 baiting and in many circumstances need less than 1 bait to reach an LD50.

The chances of individuals finding enough baits in a short enough period to be at risk

Extensive testing with foxes on mainland Australia clearly shows they can find baits immediately they are buried; initial take is often high and usually continues until baits and/or foxes are greatly reduced (eg Saunders et al 1995). Limited testing with Foxoff and fresh meat baits with captive and wild spotted-tailed quolls in NSW showed they could detect buried baits but trials only identified this species as taking 2 of 7 baits taken after 3-4 weeks buried adjacent to a spotted-tailed latrine in the wild (Belcher 1998); results consistent with Tasmanian observations considering time buried and that baits were replaced exactly where taken (see below).

Research on take of fox baits without 1080 was undertaken with an isolated, island population of devils (no quolls or foxes present). Initial take was very low (a few % per night) but escalated once baits began to rot, to the point where most baits were taken after 3 weeks. These results were mirrored in places with devils and spotted-tailed quolls, devils and eastern quolls and eastern quolls alone; there are no places exclusively with spotted-tailed quolls in Tasmania. If baits were replaced in a hole where a previous bait had rotted then re-take could be immediate but if placed in a new hole take was very low. Devils in particular would sometimes deeply excavate holes in which baits had rotted.

It seems devils and quolls are not well equipped to find buried baits until they rot or are otherwise smelly (or replaced); probably there has been no need in their evolution. On the other hand, foxes and dogs evolved under conditions of extremely harsh winters where caching and recovering food (or raiding others’ caches) was fundamental to survival. Therefore, these canids are ‘professionals’ at finding buried food (eg Saunders et al 1995, Twigg et al 2000). This does not mean that other species cannot find any buried baits or might even be exposed accidentally (eg during echidna excavations) but it is a clear trend.

There has been considerable questioning of what animals have taken the thousands of baits of the nearly 80,000 sofar set in Tasmania. Checking baits daily allows a reasonable judgment of what might have taken them and in the early days of baiting (2002/3) when daily checks were undertaken about 20 baits were recorded as taken in typical fox style (as seen else where in Australia). Once baiting expanded and baits were only checked at recovery such judgments of take could rarely be made; hence the experiments reported here. If baits were recovered 2-3 weeks after burial few were missing but if it was 3 weeks or more most might be – it seemed a simple fact of rotting and then being found.

In operational fox baiting in Tasmania, baits are buried at a landscape density of 5-10/km2. The number of baits in an animal’s home range can also be considered and how much competition there might be for baits. A large devil might have 100 baits in its home range but that home range would likely be shared by 10-30 other devils plus quolls (and possibly foxes). Thus, the baits available per individual are comparatively few.

The chances of individuals eating enough baits in a short enough period to be at risk

Although they can easily eat soft baits, test have shown that small or even medium sized spotted-tailed quolls and very small devils do not (probably can not) eat very dry and hard baits and it is not until they are independent that they are likely to be under enough nutritional pressure and are strong enough to eat such. Tests on captive mainland Australian spotted-tailed quolls support these results (Belcher 2000).

What actually happens in the field?

Considerable research has been done on effects of 1080 fox baiting on spotted-tailed quolls on mainland Australia (eg Kortner ET al 2003). In Tasmania, experimental 1080 baiting was not carried out but rather, research waited until an operational baiting occurred in an area with enough spotted-tailed quolls to usefully study (near Wynyard).

Although there were too few quolls in the study sites area (and a comparative control site with no baiting) to have statistically robust comparisons of numbers before and after baiting we found individual spotted-tailed quolls similarly persisted in both areas through and after baiting. Importantly, there were breeding females (with pouch young) and free ranging juveniles present in both sites after baiting; there was no identifiable difference between baited and non-baited sites. This work will be repeated as opportunity presents.

In the northern midlands where the effects of 1080 fox baiting on devils was being studied, there was also a ‘background’ population of spotted-tailed quolls. Trapping after a prolonged baiting period showed all elements of a normal devil population in place – breeders and juveniles with no apparent drop in density. Perhaps most interestingly, in the months after this research a substantial drop in numbers of devils due to Devil Facial Tumour Disease occurred and in another 6 months numbers of spotted-tailed quoll seemed to have measurably increased (probably due to decreased competition and predation from the fewer devils) and has stayed high with an apparently normal mix of breeders and juveniles. DFTD it seems has absolutely overwhelming effects (even if indirect) compared to fox baiting.

In an area in which Foxoff meat compound baits were operationally used extensive capture-mark-recapture studies were done of large local populations of Tasmanian bettongs Bettongia giamardi and brushtail possums Truchosaurus vulpecula, two species likely to eat these baits. Very few Foxoff baits were taken and there was no difference in population change between the baited site and a control site.

These Tasmanian ‘pilot’ studies suggest there is little if any damage to local populations of spotted-tailed quoll, Tasmanian devils, Tasmanian bettongs or brushtail possum from 1080 fox baiting in Tasmania as is known to have severe effects on fox populations on mainland Australia (eg Saunders et al 1995).

State-wide Effects

A final check can be made by looking at what proportion of Tasmania’s spotted-tailed quoll and devil population might be exposed to 1080 fox baiting. Sofar, 1080 fox baiting has only touched the fringe of Tasmania’s core spotted-tailed quoll habitat and perhaps less than 2-3% of Tasmania’s spotted-tailed quolls have been in baited areas. Similarly perhaps 5% of Tasmania’s devils have been in baited areas. These areas and percentages may increase by half with planned fox baiting but, even then the reality is little or no effect on a small proportion of the State’s populations of these important species.

References

1. Belcher, C. (1998). Susceptibility of the tiger quoll, Dasyurus maculatus, and the eastern quoll D. viverrinus, to 1080-poisoned baits in control programmes for vertebrate pests in eastern Australia. Wildlife Research 25, 33-40.
2. Belcher, C. (2000). The ecology of the Tiger Quoll Dasyurus maculatus, in south-eastern Australia. Unpublished PhD thesis, Deakin Uni.
3. Kortner, G., Gresser, S. and B. Harden (2003). Does fox baiting threaten the spotted-tailed quoll, Dasyurus maculatus? Wildlife Research 30, 111-118.
4. McIlroy, J. C. (1981a). The sensitivity of Australian mammals to 1080 poison. 1. Intraspecific variation and factors effecting acute toxicity. Australian Wildlife Research 8, 369-383.
5. McIlroy, J. C. (1981b). The sensitivity of Australian mammals to 1080 poison. 11. Marsupial and eutherian carnivores. Australian Wildlife Research 8, 385-399.
6. McIlroy, J.C. (1981). The sensitivity of Australian animals to 1080 poison.1X. Comparisons between the major groups of animals, and the potential danger non-target species face from 1080 poisoning campaigns. Australian wildlife Research 13, 39-48.
7. Saunders, G., McLeod, S. and B. Kay (2000). Degradation of sodium monoflouroacetate (1080) in buried fox baits. Wildlife Research 27, 129-135.
8. Twigg, L., Eldridge, S., Edwards, G., Shakeshaft, B., dePeru, N. and N. Adams (2000). The longevity and efficacy of 1080 meat baits used for dingo control in central Australia). Wildlife Research 27, 473-481.

Other Useful Reading

Kinnear, J.E. (2003). Eradicating the fox in Tasmania: A review of the Fox Free Tasmania Program. Unpublished report to DPIWE, Hobart.
Saunders, G., Coman, B., Kinnear, J. and M. Braysher (1995). Managing vertebrate pests: Foxes. Australian Government Printing Service, Canberra
Saunders, G., Lane, C., Harris, S. and C. Dickman (2006). Foxes in Tasmania: A Report on the Incursion of an Invasive Species. IACRC, Canberra.

Nick Mooney is a wildlife biologist with DPIW and has been working with Tasmanian wildlife for more than 30 years. Amongst other hats, he pioneered Tasmanian rehabilitation and conservation of raptors including eagles in forestry, has monitored reports of Thylacines and foxes, helped with responses to newly discovered diseases, whale strandings and oil spills and developed practical conservation of devils and innovative wildlife tourism. Most recently he kicked off the response to Devil facial Tumour Disease and has been giving advice for the response to recent evidence of foxes in Tasmania. Nick is assessing the potential ecological effects of DFTD, foxes and cats; he sees the biggest ecological threat as establishment of foxes because of DFTD, a process that could cause the ultimate long term threat to devils (his favourite animal).

Nick Mooney

There has been a recent spate of public concern over the effect that 1080 baiting targeting the red fox Vulpes vulpes in Tasmania might have on the spotted-tailed quoll Dasyurus maculatus and the Tasmanian devil Sarcophilus harrisii.

Considerable research has been done on that quoll species on mainland Australia, studies augmented by work in Tasmania on both it and devils.

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‘Foxes, quolls, devils and 1080 #2‘

[This article is extracted from the Tasmanian Times, 27-Nov-2006, by David Obendorf,^ http://tasmaniantimes.com/index.php?/article/obis1/].

AS NICK MOONEY states: ‘Most of the research on lethal dose to 50% (LD50) for Australian animals and the potential impacts of 1080 was done on captive animals decades ago by John McIlroy, then at CSIRO, and published in various issues of Australian Wildlife Research. It is doubtful if this work could ever be substantially expanded or repeated because it involves lethal testing.’  (Foxes, quolls, devils and 1080)

With DPIW poised to embark on a decade-long $56 million dollar fox eradication campaign using 1080 meat baits as the principle eradication tool, I believe there are several very good reasons why 1080 testing of non-target Tasmanian species exposed to these baits must now be repeated. For Tasmanian wildlife authorities to rely solely on this unrepeated toxicological data would be reckless.
John McIlroy commenced his work on the sensitivity of Australian animals to the poison 1080 (Sodium Fluoroacetate) a quarter of a century ago. John was a research scientist working at the CSIRO Division of Wildlife Research at Gunghalin near Canberra. During the period from 1980-86 he conducted a series of dose-response experiments to assess the sensitivity of 1080 on a representative range of Australian animals, covering species in all the main vertebrate taxa. He published 9 scientific papers in this series; 7 as the sole author and 2 in collaboration with others.

In documenting his research findings, John was careful to firstly prepare the theoretical and statistical ground work on which this series of experimentally-based toxicity would be based (McIlroy 1981a).

“In toxicological work the sensitivity of different [species of] animals to a poison is usually expressed as the LD50 or median lethal dose, a statistical estimate of the dose — in milligrams of poison per kilogram body weight, that will kill 50%  of a large population.

The LD50 of a poison and its 95% confidence limits are only an indication of the values that might be expected from repeated trials on the same strain of animals under the same experimental conditions.”

In applying the LD50 values to a test poison, McIlroy states:

“The necessity for such a standardised procedure has been questioned … [as] statistically significant differences in LD50 values (up to 3.2 fold) within and between laboratories, related to differences in experimental procedure, …  [but] these were not great enough to change the interpretation of the relative hazards of the test chemical involved. However, because I was concerned with a controversial poison [1080] and its toxicity to a variety of wild animals, I felt it was important to assess the effects that differences in experimental procedure might have on LD50 values of 1080 and, if necessary, design a procedure to minimize such sources of variation.” (McIlroy 1981a)

In his second paper detailing the results of his experimental studies on marsupials and placental mammals, John began on a cautionary note:

“The effect that these [1080] poisoning campaigns are having on non-target or native animal populations is not known, despite occasional reports of individuals of these species being found dead or ‘vanishing’ from areas in which 1080 has been used.” (McIlroy 1981b).

Targeting dingoes

McIlroy was very considered in any reliance of these experimentally derived LD50 values:

“In reality many factors are involved in determining whether an individual or what proportion of a population may be killed by a [1080] poisoning campaign. The preceding theoretical analysis involved mean body weights of only small samples of animals, LD50s obtained under specific experimental conditions, and a particular concentration of 1080 in each bait plus the assumptions about bait intake by free-living species. All are likely to vary in different field situations, altering the risk each individual carnivore faces.”

Based on 1080 baiting campaigns targeting dingoes (& wild dogs), John McIlroy made some thoughtful recommendations when deciding on the most effective bait size and quantity of 1080 per bait for maximal kill of target species and minimal impact to non-target (native) species.

“The data on [1080] sensitivities do provide fundamental information for the planning of dingo-poisoning operations. For example, if the aim is to obtain maximal control with minimum dose it would be best to plan the baiting on the basis of a LD100 based on twice the upper confidence limit of the LD50 and the weight of the heaviest specimen reported. In contrast, to assess the hazard to a non-target species, calculations might be best based on the lower confidence limit of the LD50, or some other lower figure, and either the mean weight or much lower body weights of, for instance, immature animals.”

McIlroy went on to do a theoretical calculation to show this point for dingoes (the target carnivore) and spotted-tail quolls (a non-target carnivore).

“The heaviest individual [dingo] caught in the Eastern Highlands was 25 kg. Thus if the LD100 is assumed to be approximately twice the upper confidence limit of the LD50 (i.e. 0.3mg/kg BW), it would be necessary to get 7.5 mg of 1080 into a dog of this size to kill it. Similar calculations for tiger cats [spotted-tail quolls], using twice the lower confidence limit of the LD50 (i.e. 2.56 mg/kg BW) and taking the mean body weight of 2.8 kg, indicate that 7.17 mg of 1080 is a lethal dose for [this species].

Applying McIlroy’s precautionary recommendation to the mean body weight for immature spotted-tail quolls of 1.1 kg, only 2.8 mg of 1080 is a lethal dose.

Obtain a lethal dose

The same theoretical calculation and logic can be applied can be applied to 1080 poisoning campaigns targeting foxes.

For an extreme body weight fox of 6 kg and applying an LD100 that is approximately twice the upper confidence limit of the LD50 (i.e. 0.26mg/kg BW), it would be necessary to get a fox to consume 1.56 mg of 1080 to kill it (not 3 mg of 1080 per bait). If each dried kangaroo meat (DKM) baits contained this amount of 1080, one bait would kill all foxes less than 6 kg. When applying McIlroy’s precautionary calculation to a mean body weight for immature quolls, such animals would need to ingest at least two baits to obtain a lethal dose.

“From the viewpoint of trying to safeguard tiger cats [spotted-tail quolls]; therefore, it is obviously necessary to keep 1080 concentration in baits as low as possible.” (McIlroy 1981b)

One variable that McIlroy particularly commented on was the effect of ambient temperature on the sensitivity of 1080 poison. He was concerned that his experimental trials to set the LD50 for many native marsupials were carried out at about 22°C (in controlled environment rooms). He noted that in relation toxicity studies on the spotted-tail quolls, trials were conducted at 13°C where the LD50 was calculated at 1.85 mg/kg BW.

“… different ambient temperatures cause two to five fold differences in the susceptibility of mice and guinea pigs to 1080. Both species are susceptible at both low and high ambient temperatures than they are at medium temperatures. If similar responses occur amongst other, larger homeotherms, this might explain the relatively low LD50 for the tiger cat [spotted-tail quoll] compared to those for the other native cats [quolls]. The possibility exists, therefore, that if these trials had been carried out at 22°C [instead of 13°C], the LD50 would have been slightly higher than 1.85 mg/kg BW.

Ambient temperatures obviously vary considerably between field poisoning situations, both geographically and diurnally, so a LD50 obtained at 22°C, or a dose that will kill 50% of a population experiencing this ambient temperature, must be regarded as only a general value. Greater population mortality may be expected at much lower or higher environmental temperatures.” (McIlroy 1981b)

In relation to the most susceptible non-target marsupial carnivore, the spotted-tail quoll, 1080 baiting programs targeting foxes and wild dogs are still reliant on McIlroy’s highly qualified toxicology studies and LD50 calculations.

In obtaining his LD50 levels for each species, McIlroy orally dosed between 3 and 5 individuals at dose intervals of 1.26 in 4 distinct dose groupings. For spotted-tailed quoll he used 12 animals. The LD50 was calculated at 1.85 mg/kgm with 95% confidence intervals of 1.28 to 2.68 mg/kgm BW.

Other animals begin to vomit

Clinical observations were made on the experimentally poisoned animals.

“Most commonly, affected animals suddenly became hyper-excited, with rapid breathing, bouts of trembling and sometimes periodic circling within their cages. Again, some animals may then recover while other begin to vomit, convulse, or both. With some animals, particularly the eastern native and tiger cats [quolls] and Tasmanian devils, the first symptom is the sudden onset of vomiting.

Convulsions were triggered by disturbance, such as the opening of a door, sudden movement by an observer, or convulsion by a neighbouring animal. In rough order, these symptoms include: restlessness; increased hyperexcitability or response to stimuli; bouts of trembling; rapid, shallow breathing; incontinence[involuntary passing of urine and/or faeces] or diarrhoea; excessive salivation; twitching of the facial muscles; nystagmus (involuntary eyeball movement exposing the whites of the eyes)or bulging eyes with large (dilated) pupils and rapid blinking plus, in domestic cats, discharge of mucus from the eyes); slight lack of coordination or balance; abrupt bouts of vocalisation; and finally, sudden burst of violent activity such as racing around the cage, or biting the cage mesh or other objects. All affected animals then fall to the ground in a tetanic seizure, with hind limbs or all four limbs and sometimes the tail extended rigidly from their arched bodies. At other times the front feet are clasped together, clenched or used to scratch frantically at the cage walls. This tonic phase is then followed by a clonic phase in which the animals lie and kick and ‘paddle’ with the front legs and sometimes squeal, crawl around or bite at objects. During this phase the tongue and penis may be extruded, the eyes rolled back so that only the whites show and the teeth are ground together. Breathing is rapid but laboured, with some animals partly choking on their saliva. Finally such animals begin to relax, breathing more slowly and shallowly and lying quietly with the hind legs still extended but apparently semiparalysed (paresis).

From then on individual animals either: (1) gradually recover; (2) die shortly afterwards; (3) after a short or long delay (e.g. 5 min or 3-4 h) experience another one or two series of convulsions and then die shortly afterwards or eventually recover; (4) remain lying quietly, scarcely breathing or moving, until death up to 6 days later.

It is noteworthy that in McIlroy’s observations on carnivorous marsupials exposed to sub-lethal doses of 1080, he noted that animals that did not die but ‘remained weak for 2 or more days’. From this we can infer that the sub-lethal consequences of 1080 poisoning may therefore affect an animal’s ability to evade predation by other animals and affect their ability to find safe refuge.

McIlroy also makes the following observations:

“The pouch young of tammar wallabies are significantly more susceptible to 1080 than adults (P>0.01. The pouch young of brush-tailed possums and northern native cats, Dasyurus hallicatus, similarly appear to be more sensitive than adults. More pouch young pouch young possums than adults died at each dose level, although only their mothers were dosed with 1080; presumably the young ingested lethal amounts of 1080 in the milk. The eight pouch young of one northern native cat also died within 24 h after their mother received a non-lethal dose (84% of a LD50 )but the five pouch young of a tiger cat, Dasyurus maculatus, survived in similar circumstances (74% of a LD50 ). [There are] similar reports of young rats killed by milk from their poisoned mothers.” (McIlroy 1981).

Fox entry into Tasmania

Fox entry into Tasmania has ALWAYS been a biosecurity/biodiversity risk for Tasmania, yet it is remains unclear whether foxes have established breeding populations in Tasmania.

Despite the unsubstantiated stories of intentional introductions of foxes the most likely source of single-fox introductions into Tasmania has been slack and inadequate quarantine measures. In the decades of inadequate quarantine measures at our ports, any foxes that have arrived and escaped into Tasmania, the questions remains which locations have the highest frequency of receiving fox-risk materials?  Might these be the places where foxes might just get lucky and breed?

Over fifty years of 1080 use in Tasmania to control native herbivores like Bennett’s wallaby, Tasmanian pademelon and brush-tail possum coupled with the high sensitivity of red foxes to secondary 1080 poisoning (i.e. through eating a poisoned carcass) is rarely acknowledged.

Where will they ‘get lucky’ in the landscape? Closest to the farms & feedlots that have historically received container-loads of stock feed grain; agri-businesses that transport or deal with used farm equipment; freight forwarding depots. The highly reliable sighting reports of foxes in remote areas (where 1080 poisons have not been used) like the western Central Plateau or our National Parks must be the basis for intensive investigation. Maybe the remote camera used by the DFT team can be now deployed for fox studies.

It ALWAYS comes down to validating the risk assessment.

References:

1. McIlroy, JC (1981) The Sensitivity of Australian Animals to 1080 Poison I. Intraspecific variation and Factors affecting Acute Toxicity. Australian Wildlife Research 8, 369-383.
2. McIlroy, JC (1981) The Sensitivity of Australian Animals to 1080 Poison II. Marsupial and Eutherian Carnivores. Australian Wildlife Research 8, 385-399.

David Obendorf

With DPIW poised to embark on a decade-long $56 million dollar fox eradication campaign using 1080 meat baits as the principle eradication tool, I believe there are several very good reasons why 1080 testing of non-target Tasmanian species exposed to these baits must now be repeated. For Tasmanian wildlife authorities to rely solely on this unrepeated toxicological data would be reckless.

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