Tasmanian Devils Not On The "Verge of Extinction"

This extinction talk is all a bit of a yawn really.  (Image credit: www.waynemaclean.com)

Late last year, fifteen Tasmanian devils were released on Maria Island, an action that had been in the pipeline for many years.  You can watch cute footage of their cautious emergence into their new environment here.
Devil populations statewide are being ravaged by Devil Facial Tumour Disease (warning: link contains some remarkably ugly and potentially distressing images), a very unusual contagious cancer spread when animals bite each other during fights, that was first photographed in the north-east of Tasmania in 1996.   The Save the Tasmanian Devil website noted:

"As at February 2011, there has been an 84% decline in average sightings of devils across Tasmania during the annual spotlight surveys. In the north-east region, where signs of DFTD were first reported, there has been a 96% decline of average sightings."

A figure of 91% reduction in spotlighting results has been given in some recent media reports.



Note that any such figure is not necessarily a fully fair reflection of the decline in the population, since unroaded areas in the west of the state are among the areas that the disease is taking the longest to reach and having the least known impact.  Nonetheless, the impact on the species has been severe, with estimates of the population crashing from well over 100,000 individuals to low tens of thousands.  (See the IUCN page for a detailed if five-years-dated account of some of the past and recent estimates, while the STTD FAQ provides further slightly dated estimates.)  The September 2012 issue of Devil News gives the net decline at 80%. 

Despite the species' rapid decline it is not an extremely rare animal and there are areas of the state where it remains common.  I saw several of them, including one that I believe to have been the most dimwitted mammal that has never joined Resistance, at one site in the central north myself in late 2011.  A frequent occurrence on Tasmanian Times is to see some deep green type who's desperate to protect their favourite forest patch from logging point out that it is home to Many 100% Certified DFTD-Free Devils!

Yet this piece in the Australian by the normally fairly restrained Matthew Denholm started with the blaring of sirens for a species supposedly on the precipice:

"AS experts warn the Tasmanian devil is on the verge of extinction in the wild, one of the nation's most ambitious species translocations has begun to create a "devil island" refuge."


The article provides no evidence that any expert has warned any such thing.  The nearest it gets is two words from the Save the Tasmanian Devil Program co-ordinator, Dr Howell Williams:

"He warned extinction of the devil was "highly likely" if the disease was left to run its course."

No indication of timeframe was given.

Alas, Denholm's is not an isolated instance of this particular species of fast-spreading media hype. For instance, CNN's recent list of ten last great wilderness areas included reference to "the near-extinct Tasmanian devil."

Reasons To Be Less Fearful

If any expert did warn of any such thing as the species being "on the verge of extinction in the wild", they would be wrong, or lying.   Seventeen years after the disease was first recorded (and probably more than that since it first happened) the disease is yet to even cause any confirmed local extinctions in the areas where it is most severe (although numbers in many places have been trashed to very low levels from which they have shown no signs yet of rebounding).  And yet there are still people about who are willing to project statewide extinction in the wild in the near future.

There are still areas of the state the disease has probably not even reached yet, and when it reaches those areas it will take its time to cause similar declines to those seen in the north-east - if it even causes decline at such a rate in such areas at all.  To project statewide extinction in the wild even within 20 years under such circumstances is clearly fanciful.

Then there's the question of whether the disease will even trash all populations as quickly and as nastily it has in the north-east.   In fact, there are already signs that it probably won't.  A very well-studied population at West Pencil Pine (near Cradle Mountain) has shown much smaller and slower impact of the disease in the first four years than elsewhere (example scientific paper here), although the September 2012 issue of Devil News reports, alas, that infection rates there have recently increased.  A massive scientific research effort, now generating papers at the rate of dozens per year, is focused on a range of aspects of the disease, including trying to explain what genetic factors and behaviours make some devils more likely to get the disease than others, tracking the evolution of the disease and the devil in response to it, and trying to determine possibilities and causes of resistance in particular devils.

There's also the question of whether the disease will even cause the extinction in the wild of the species at all.  Precedents for extinction of a species from disease often involve species with small populations already vulnerable for that reason, often as a result of a host of other problems.  A species of land snail (Partula turgida) became the first species known to have snuffed it in this manner.  After the species was rendered extinct in the wild by an exotic predatory snail, the species' few surviving captive individuals were wiped out by a parasite.  Chytrid fungus is strongly believed to have wiped out many lost species of amphibians, but documented cases of mammals becoming even locally extinct as a result of diseases are, thus far, very rare.  The loss of two native rat species from Christmas Island has recently been pinned on a disease many decades after it happened, but populations on very small islands are especially prone to extinctions generally.

Some scientists are not exactly helping the media to get it right.  Two common problems are rampant speculation and sloppy paraphrasing of the work of others, the latter being an astonishingly frequent problem in peer-reviewed research of many kinds, even when every other aspect of a paper may be excellent.  As an example of the latter, the just-released and otherwise important Siddle et al (2013) paper (here) states:

"It is predicted that the rapid spread of DFTD will cause extinction of Tasmanian devils in the wild (22)."

(22) turns out to be this 2007 McCallum et al paper.

But the McCallum et al paper only projects "local extinction" in "the population with the best longitudinal data" (Freycinet) and even that projection is somewhat hesitant, being "sensitive to the estimate of the latent period, which is poorly known".  The paper does claim "a strong possibility of extinction of the Tasmanian devil due to the disease over a timeframe of perhaps 25-35 years", but declaring extinction a "strong possibility" is not the same as predicting extinction, and in any case the statewide extinction "strong possibility" claim in the McCallum et al paper is not backed by any specific analysis in that paper at all (unlike the Freycinet-specific projection, for which analysis is supplied).

Another McCallum et al paper released in 2009 and co-authored by many of the leading Tasmanian DFTD researchers provides much more detailed analysis (explicitly superceding the 2007 paper) but still goes only so far as to declare, for instance, that extinction in the wild is "a real possibility" and that its findings "lend considerable weight to concerns that this host-specific pathogen will cause the extinction of the Tasmanian devil."

ABC TV News, as I work on this article, came through with popular reports of numerous positive signs that will be deeply distressing to activists who specialise in trumping up this species' predicament for political gain, although we will have to see what form these take as they appear in published research.  Stabilising populations in disease-ravaged areas, increased proportions of devils in diseased-ravaged areas reaching 3 years or more of age, examples of apparent remission in particular devils.  (It also discussed speculative prospects for a vaccine based on a new discovery about why the devils' immune systems do not recognise the tumours.)  (I can't find this item online yet; if I do I'll post a link to it.)

Everybody Knows That The Plague Is Coming

All that is not to deny that DFTD has some sort of potential to eliminate the species from the wild eventually.  Normally wildlife diseases don't do this, because as the target species becomes rare as a result of the disease, the disease becomes less able to spread and cannot wipe out its host before it gets rid of itself.  One exception, irrelevant in this case, occurs if the disease has multiple hosts and a common species acts as a "reservoir".  Another, which may well be relevant, occurs if the disease has what is called a "frequency-dependent" transmission mode that allows it to continue to spread even as numbers of a species become very low.  Sexually-transmitted diseases are often examples of this, because no matter how rare an infected species becomes, it has to mate to reproduce, so there will always be opportunities for the disease to keep spreading.  The argument is that DFTD, spread by direct contact between devils, may well continue to spread as long as devils keep directly contacting each other, and hence its dynamics may be very similar to those of a sexually-transmitted disease.   This is backed by data (eg the McCallum 2009 paper mentioned above) showing that the infection rate has remained quite high even in areas where the disease has already trashed the population to 10% of its previous level. 

None of this guarantees that the disease will actually eliminate devils from the wild - it just establishes a possibility, subject to numerous ifs and buts - the species may evolve responses, there may be areas in which devils are already largely resistant, and so on.  And nor does it tell us, with any real accuracy, how long extinction might actually take if it happens.

But the disease is continuing to spread.  The map below (source) shows records pre-2011 in red and 2011-mid 2012 records in green.  While it may not have covered the whole state as quickly as predicted, the general pattern is that it will reach any given area eventually - it is only a matter of time.

This disease spread pattern is important as concerns two aspects of the debate.

Firstly, it is extremely common to see green activists tout the presence of Tasmanian devils, as typically shown by automatic camera images, as arguments that a certain area should be reserved or should not be logged.  But whether an area is reserved and whether it is logged do not seem to have much to do with the spread of this disease - it doesn't read maps and then stop at reserve boundaries, and indeed it has spread freely and devastatingly through National Parks already, even in the absence of disturbance of any kind within their boundaries.   Therefore, the use of devils - even disease-free ones - as an argument for reserving a given area from logging is illogical.  Reservation does not significantly protect devil populations from the threatening factor that is affecting the species.

If the disease really has what it takes to wipe the species out in the wild, then whether this bit of habitat or that is protected in the short term is irrelevant.  I'm reminded of the Artilleryman in HG Wells' War of the Worlds referring to an ineffective defensive method as "bows and arrows against the lightning".

Secondly, the green dots in the state's north-west more or less ring the frequently contentious area often known as the "Tarkine".  This area, consisting largely of uninhabited rainforest and buttongrass and including many areas with high wilderness values (not that wilderness values necessarily demonstrate any other kind) is repeatedly described as the species' last disease-free home.  A typical example is here and unfortunately it is not just activists like GetUp, or Green politicians, who make these claims, but plenty of journalists accept them without sufficient checking.

Problems with the claim that the Tarkine is the devil's last disease free stronghold include:
1. Large areas of the south-west of the state have no mapped records of DFTD.  While this does not mean DFTD is absent from these areas, which are difficult to survey because of access issues, it does mean that the claim that there is no substantial disease-free area outside the Tarkine is unproven and may very well be false. 

2. It is far from clear that "the Tarkine" really is disease-free.  Indeed the Greens themselves have reported images of a possibly diseased devil, filmed by activist group Code Green, at a proposed Tarkine mining site, although a filmed-only record is inconclusive.

3. Even if the Tarkine is disease-free at present, or very nearly so, the rate of spread of the disease in the past provides no basis for belief it will remain so for very long, no matter what management is imposed.

Of course, impacts on specimens and populations of Tasmanian devils as a result of broad-scale open-cut mining and associated roading, or for that matter logging, may well occur, and disturbance may speed up the spread of the disease slightly in some areas (though parts of the Tarkine are already riddled with old logging roads).  But ultimately, the question is whether DFTD is capable of wiping the devil off the map.  If it is capable, it can do so irrespective of fiddling over the trivial portion of the Tarkine or the state as a whole to be roaded or mined.  If it is not capable, then the species just isn't at risk.

The idea that "saving" the Tasmanian Devil is a valid key argument for reserving land is easily shown up by the following question, which activists should be asked whenever they use the devil as an argument:

If Devil Facial Tumour Disease runs through the area after it is protected and kills all the devils in it, will you then support the area's reserve status being cancelled?

Of course they won't, because a certain kind of activist is only interested in the instrumental use of scientific arguments to advance goals and doesn't actually care whether those arguments are valid.  Very widespread threatened-listed species - devils, Tasmanian wedge-tailed eagles, grey goshawks, masked owls, spotted-tailed quolls etc - what I call "landscape threatened species" - are especially useful for arguments of this type because they are present in so many areas that are subject to logging and other impacts.  My own experience in having a snail that is widespread and fairly common in the north-east wet forests chucked off the threatened species list - because it is widespread and fairly common - showed that it is precisely these kinds of species that are most valuable to activist propaganda.  Apart from orange-bellied parrots, species that are genuinely teetering on the brink very rarely rate a mention in propaganda because they are useless to it.

Ultimately, I think those who are using the devil as a primary argument for reserving any area of land from impacts need to get a better argument.  That includes those scientists involved with devil research who have chosen (unwisely in my view) to lend their hands to the anti-Tarkine-mining case.  In the case of the Tarkine, if the best argument an activist can find against proposed open-cut mines that could potentially destroy square kilometres of land is the possible impact on Tasmanian devils, then either they're not trying very hard or else they've got nothing.

In Praise Of The Program

Recently I expressed reservations about another very expensive Tasmanian wildlife program, the hamfisted attempt to "eradicate" foxes which may or may not be actually still present. (Are Foxes Widespread In Tasmania?)  The Save the Tasmanian Devil Program poses similar questions, because it too is a massive vertebrate-research program focused on issues associated with a single species, and premised on a threat that may not turn out to require human intervention after all.  Massive spending on a very small number of vertebrate conservation issues, while other biota generally receive relatively little (and in cases grossly inadequate) funding is unfortunately a well-worn path in Tasmanian nature conservation.  A recent review of threatened-species recovery spending found the devil to be among the most hideously expensive species to recover, in terms of bang-for-buck, out there.  It might therefore be expected I'd begrudge the funding spent on Tasmanian devils.

I don't.  I think the work that's being done on this species, despite its vast expense, is excellent research and that the efforts involved in investigating and trying to react to such a novel disease will develop research skills that are likely to be useful in managing other wildlife diseases or impacts in the future.  And I think the disease itself is of great intrinsic and evolutionary scientific interest even if it turns out that only a single species is ever affected by anything like it.  It is quite a contrast to the fox program which has produced hardly any formally published research (and what it has produced has been rather questionable.)

Bet Offer

I am so confident of my position that the risks of quick extinction are being overstated, that I am willing to bet $1000, indexed for inflation, that Tasmanian Devils will not be extinct in the wild as of 2045 AD.  (Hope I'll still be around to collect my winnings at age 73!) The other side of the bet must, of course, publicly identify themselves, provide contact details, and publicly agree to pay me their side of the sum should the species not become extinct in the wild in this time.   I'm willing to negotiate about verification terms, to load the odds in the other side's favour, or to have the wagers in the form of donations to charities, or anything else that might credibly get one of the doomsayers on this issue to put up a stake and put their money where their mouth is.

I've made this or similar bet offers on Tasmanian Times in the past without success.  TT is, of course, a home of idiocy regarding this species at almost all times it is mentioned.  In particular, although it is absolutely clear the disease spreads contagiously from devil to devil rather than new infections being caused by environmental factors, and although there will probably never be any way of knowing what (if anything) triggered the first case(s), there are many posters there who are utterly determined to pin the blame for the disease entirely on their pet obsession, forestry.

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Update 20 July: Shree Decision

This week the Federal Court annulled former Environment Minister Tony Burke's approval of the Shree Minerals Nelson Bay River open-cut mine. The decision, on grounds connected to the Tasmanian devil, was widely perceived as a victory for the species, but as usual the great bulk of commentary on the matter failed the fundamental test of carefully reading the actual judgement.

Holler For A Marshall, Again?

I was a bit surprised, and not entirely impressed, by the appointment of Justice Shane Marshall to hear this case, because Justice Marshall has what might be called "form".  He was the judge who delivered the original Wielangta judgement, in which he found that logging in the Wielangta area in south-eastern Tasmania violated the federal Environment Protection and Biodiversity Conservation Act by failing to adequately "protect" the wedge-tailed eagle, swift parrot and broad-toothed stag beetle. 

That judgement was overturned by the Full Bench, which held that Justice Marshall had misinterpreted a key clause in the Regional Forest Agreement and as a result spent most of the case barking up trees.  The following commentary by the Full Bench is especially scathing:

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103 Our conclusion on s 38 of the Act makes it unnecessary to examine the grounds of appeal disputing the primary judge’s findings about the degree of protection provided by CAR to the three species. This aspect of the case at first instance occupied most of the 33 sitting days, together with views. In the events that have happened, a great deal of time and much expense has been devoted to investigating matters that have turned out not be determinative of any relevant issues. These include issues 1, 3 to 7 and 9(b). If there was any issue at all that was appropriate for preliminary determination, it was that turning on s 38. Instead many far-ranging issues were, in our view, wastefully explored.

104 Courts have frequently stressed the caution that must be taken in deciding whether to determine separate questions and issues lest this course leads to increased cost and delay. No caution was on display in this case.
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In a way it's a pity the Full Bench took such a consistently economical approach to disposing of the judgement as they did, because had they not done so it's quite possible other aspects of Justice Marshall's original findings - such as his extraction of a radical definition of "protect" from various international treaties Australia had signed up to - would have been tested.  This has led to claims that these aspects of the original case were accepted by the Full Bench, when in fact the Full Bench declined to even examine them.

The Shree Decision

In the current case (full decision here) the approval of a Shree Minerals magnetite and hematite mine was set aside for what is ultimately a process-based reason.  S 139(2) of the EPBC Act requires that in considering an action that is expected to significantly impact on a federally listed threatened species, "the Minister must, in deciding whether to so approve the taking of the action, have regard to any approved conservation advice for the species or community."

"Approved conservation advice" refers to a particular document approved by the Minister (or a predecessor) that contains information about why the species is threatened and what, if anything, could be done about its status.

In this case the advice was approved by Peter Garrett in 2009, and included the claim that there was "modelling that indicates that there is a strong possibility that the Tasmanian Devil will be extinct within a timeframe of approximately 25-35 years, if trends in DFTD spread and population decline continue".  As noted above, this actually isn't really true. Rather, a modeller claimed there was a strong possibility of statewide extinction in a paper that modelled regional extinction.

But whether the advice is true or not, the law seems to require the Minister to consider it.  And Justice Marshall found that Minister Burke did not "have regard to" the approved conservation advice for this species, as it was not provided to the Minister as a briefing.  Although the Minister considered most of the matters contained in the approved advice, some were not contained elsewhere in the briefings provided, or referred to in the Minister's decision.

So this opens up the possibility that the Minister didn't consider official government statements on the species that, if considered, might have led to a different decision, even if some of the content was misleading (a matter not explored by the case).  It's highly likely that considering the advice would have made no difference and possible that had the Minister referred to it he would have dismissed parts of it.  But since it didn't happen, we don't know.  And there is nothing whatsoever in the decision that prevents the Government from now revising the decision, without the previous procedural error, but with exactly the same result.  It could therefore be a pyrrhic victory for the Tarkine National Coalition.

On the other hand, it gives activists a second bite of the cherry in terms of attempting to pressure the Government to not grant the approval.  The Tasmanian Devil based objections had no scientific merit the first time around, and hopefully activists will read the judgement carefully enough to realise that they need to get a better case because they won't win this one that way again.  More likely, however, they will stick with the case they have and just hope that the times favour them and the Government buckles.

The TNC's other claims 

The TNC's other challenges to the decision all failed.  The TNC had the cheek to claim the decision condition requiring the developer to donate money to Tasmanian devil conservation was unauthorised under law.  Fortunately, this was found to be false, as such conditions are often good solutions to cases where a very lucrative development presents only minor hazards to a listed threatened species.

Secondly the TNC failed to show that the decision was inconsistent with the Convention on Biological Diversity "by approving an action that threatens the survival of the “in-situ” wild population of the Tasmanian devil, purportedly on the basis that this damage would be mitigated or repaired by Condition 14, which is an “ex-situ” measure."  The judge found the obvious: that ex-situ measures like captive breeding projects were capable of contributing to conservation of species in the wild.

Thirdly the TNC went so far as to claim the following:

"It is irrational, unreasonable or perverse to approve an action that may directly threaten or hasten the extinction of a species, on the basis that the damage or threat is ameliorated by requiring the proponent to contribute to establishing a captive population of the species, for reintroduction in the event the species does become extinct."

Justice Marshall correctly accepted that the Minister was within his right to conclude that "any residual significant impacts of the proposed action on Tasmanian devils are acceptable".  He also held that this objection, if upheld, would involve the court second-guessing the original decision, which is not a good idea unless the original decision is blatantly wrong.

In a sense the TNC might not be blamed for trying to win the case.  But had some of these challenges been successful they would have had a chilling effect on the range of options available to federal environment law in making decisions flexibly.  Given the kind of legislative reform that might have forced, the TNC should count themselves lucky that they failed.

Misreporting As Usual 

As an example of the kind of misreporting these cases seem to always generate, here's an ABC item:

"The Federal Court has thrown out the former Environment Minister Tony Burke's approval of the mine because he did not properly take into account the impact on the Tasmanian devil."

No; what Minister Burke did not properly take into account was a government document making general claims about the plight of the Tasmanian devil, that were not relevant to determining the impact on the devil of the present project.  The court found no fault with Minister Burke's assessment of the impacts on the devil, but did conclude that his decision-making process did not obey the required procedure.

Another piece of bad reporting is here by Andrew Darby in The Age:

"The last wild stronghold of cancer-free Tasmanian devils is in the Tarkine, but this official advice on the animal was not in decision briefs provided to the minister and he did not have a copy before him, the court heard."

Quite aside from the "last wild stronghold" line being probably piffle as discussed in the main article, this sentence provides the false impression that material related to the Tarkine's supposed status for the species was the "official advice" not provided to the Minister.  In fact it is not part of the official advice at all. 

To the extent that the decision ruled about conservation at all, it accepted the Minister's approach (not necessarily as correct, but at least as not unreasonable enough to overturn).    This wasn't a win on the science of the species or the science of the impacts - it was a win on a technicality.

It is often right that court cases are won on legal technicalities.  It is never right that those wins are passed off as something they are not.

Update 23 July: Darby Strikes Again

There is another report by Andrew Darby here that makes more out of this than it is worth, though this time the worst thing about the report is the title, which jumps to an unwarranted conclusion that the then Environment Minister Burke "ignored" risks to the species.  He may well have considered that the risks were real but not significant enough to not approve the project, or that they were real but adequately mitigated by the donation conditions.  It seems there is some strange definition of "ignore" popular among activists and certain media sources, in which if someone fails to agree that something is a conclusive objection to a development, then they are "ignoring" it. 

The image caption "Federal approvals of an iron ore mine was found to have ignored strong advice on dangers to Tasmanian devils" (hmmm, I'm not quite sure where to put the "[sic]" in that one) is still more nonsense.  The approval process was found to have not taken into account the approved conservation advice, but one can hardly ignore something one apparently hasn't even seen.  Furthermore, as stated above, the approved advice had nothing to do with the mine or dangers it supposedly posed.


If Darby's report actually stated what sort of things were in the conservation advice then perhaps this erroneous captioning would not have occurred.  But instead his report talks about the mining findings then goes on to referring to the approved conservation advice without making it clear they had nothing to do with each other.

For Scott Jordan to then draw the bow that the Minister was aware that an action that could increase the spread rate of the disease thus "condemning the Tasmanian devil to extinction in the wild" (his words not Darby's) is extremely melodramatic.  Even assuming the disease is capable of causing extinction in the wild of the species, the chance that one mine approval would make the difference to whether this happens or not is extremely low.