Thats strange.

I just read the on-line abstract for this paper and it makes no mention of the Mercurys’ claim of a non-environmental link! Perhaps someone has supplied an advance copy of the full text of the manuscript for the Mercury’s benefit - how kind.  Its interesting that these claims are based on empirical methodologies (geographic distribution) and not on conventional epidemiological methods. I hope Mr Wade looked carefully at the ANOVA analysis of variation in their geographic distribution to confirm the correlation!

The last time this type of simple “geographic distribution” approach was used (aka. Dr. Scammell), the science was roundly criticised by the government (and others) - how attitudes change (with apparent results)!  I look forward to the Mercury’s advance publication of any real science on this topic (based on clinical and statistically valid analyses).

Mercury seems to have a similarly harmful effect on both humans and truth.

Even the article didn’t claim that the original mutation couldn’t have been triggered by some anthropogenic substance.

John Hayward

There’s an interesting article from October 2005 at:
http://www.cdu.edu.au/ser/KillerCombo.html
Which hints that the population may crash to remnant levels when DFTD may disappear from circulation.

The thing that should be raised then is how to ensure that the devil population can settle into a safe state. Land clearing and logging displaces animal populations and alters structure. Are these activities driving diseased animals into healthy populations where perhaps the increased populations raises conflict and interaction between devils?  Will land clearing and logging remove the habitat for remnant populations before we know that those areas will stay disease free?

Another possibility, although remote, is an extinction vortex. The DFTD, coupled with landclearing and logging, may culminate in a wild population so reduced they can’t find each other to mate.

Habitat loss from landclearing and logging may not be a direct cause of DFTD but I think they contribute to the pressure on the devils.

Similarly, chemicals used in logging and agriculture may not be a direct cause of DFTD, but animals carrying a toxic load usually have reduced fitness and maybe, they can’t resist and kill off the cancerous cells as they appear.

Anything to lull the Tasmanian public into yet another false sense of security.

“new research paper ‘suggests’....
“the paper says the disease appears to be infectious, rather than a condition ‘directly’ brought about by local “human-induced modification of the environment or associated land use practices”.

No-one is arguing that the disease is DIRECTLY sourced from environmental degradation and pollution.  But viruses and bacteria and cancers take hold when the immune system of living organisms is damaged by a toxic and unfriendly environment.

Who’s Rohan Wade?

This article was a bit strange considering that this week’s ‘The Weekend Australian’ ( July 1-2, 2006) had an article about Clare Hawkins’ work, ( page 10). 

This is a ‘sister’ newspaper to ‘The Mercury’ & yet the article was completely different in its reporting. 

‘The Australian’ reported that she had shown that the devil populations had collapsed & refered to an earlier report about DFTD’s transmission. 

It also said that, “Several leading scientists believe DFTD was most likely triggered when a single devil or group of devils came into contact with carcinogenic chemicals, several of which have been used in farming & forestry.  Devils were the victims of deliberate poisoning in the 1990’s in the Mt William region, where DFTD first appeared in 1996.

Dr Hawkins’s research shows the Mt William devil population has since been reduced to a quarter of its size.” 

So how can ‘The Mercury’ report such a different story from the same information?

It is all about good news stories; the fox evidence presented lately has a different slant to some of the facts I personally know about and I am amazed how one eyed and biased it has become of late.

I heard one report the other day that the devils had been decimated most in the areas of the most fox sightings, what crap, and what foxes?

I agree that the Mercury article was a confused and irrelevant one, since the fact that the presence of the disease in individual devils (as it spreads) is not caused by each devil’s exposure to chemicals like 1080 is now generally conceded by even the stupidest and most biased participants in the debate.  The Mercury’s desperation to continue to waste column inches on recycled claims and unremarkable statements in the devil debate suggests that Tasmania is one big permanent slow news day. 

Nevertheless to compare the methods used to reach the conclusion mentioned with Scammell’s exercise in correlation-spotting, as Magnus does, is incorrect.  This is because Scammell was attempting to prove causation, which is different from attempting to disprove it.  For an attempted disproof a single counterexample is often quite sufficient.

The scenarios raised by Jon Sumby seem extremely remote to me.  Even if the devil loses 90% of its population to this disease, it will still be a commoner animal than the spotted-tailed quoll (for instance), a species that only narrowly qualifies for listing as threatened.

The quote given by Christopher Purcell is interesting.  It is amazing that given the massive furore over all kinds of unlikely forestry related triggers for the disease, virtually no attention has been given to the possibility that deliberate poisoning of the devil itself by landowners could have been the culprit.  Of course, we don’t know, and I suspect we never will.

The following link (from the publishers) gives the abstract and the free download of some research that may may be interesting.

‘In natural biological communities the disappearance of one species can have knock-on effects causing extinction of further species from the food web.’

It comes from OIKOS, the journal of the Nordic Ecological Society.

http://www.blackwell-synergy.com/doi/abs/10.1111/j.0030-1299.2005.13493.x

“For an attempted disproof a single counterexample is often quite sufficient”. Indeed Kevin - a most novel approach to population based statistical analyses. You can fool all of the people some of the time Kevin….. This is the type of “new science” that the people at FT just love.  I think the rest of us will just stick with the old fashioned ways of T-squared, Chi Squared Tests, and analysis of variance.

By the way Kevin - perhaps you can help me with my problem in the area of the Phylum Mollusca (excuse my tardy taxonomy) - I put some snail bait on the vege patch last week but saw a few live snails there today! So was my snail baiting exercise just a figment of my imagination?

Dr Kevin Bonham raises an interesting point about the possibility of “...landowners…” being involved in the deliberate poisonings of devils in the Mt William region.  My question is, why would “...landowners…” deliberately poison devils?  I thought devils lived off carion only; am i wrong?  What possible reasons would “...landowners…” have to commit such crimes?  And we are talking about crimes here.

Which brings me too my next question.  If it was “...landowners…” involved in the poisonings, why hasn’t that been investigated by the police?  Surely there aren’t that many “...landowners…” in the immediate area.  By finding the culprits of these hideous crimes, perhaps the scientists might be told what chemicals were involved.

We must remember though, that “...landowners…” is a broad definition that encompasses companies as well as individuals.

Forsooth, in a mind where logic cannot stand alone, conspiracy fills nicely the space left by doubt.

Magnus, a common cause of snails failing to succumb to snail bait (apart from incorrect application) is that some snail baits function by causing death through dehydration; however if a snail having consumed snail bait manages to access enough moisture quickly enough, it may live.  For this reason snail bait is less effective in heavy rain conditions.

My comment was not about “population based statistical analyses”; it was simply about the presence of the disease in areas not affected by and well away from areas affected by (insert suspected agent here) confirming that the disease is not directly caused by (insert suspected agent here) each time it appears, irrespective of whether (insert suspected agent here) triggered the initial appearance of the disease.

Thank you for your on the informative lesson on the survival instincts of snails Kevin. ‘A dunce peg tests’ is by the way the offical anagram for ‘suspected agent’ as far as the whole conspiracy theory goes.

The poison used in the far NE Tasmania on properties adjacent to Mt William National Park was Phosdrin (TM) - a very high toxicity, newer generation organpophosphate - the active constituent is Mevinphos. Its lethality to mammals and birds is well known.

Mevinphos had very restricted and prescribed applications in horticulture but was used illegally to kill protected wildlife in this area in the late 1980s and early 1990s. The then PWS ranger, Mr Steve Cronin estimated up to 800 Tasmanian devils died as a result of exposure to carcasses laced with this poison.

In answer to Christopher Purcell’s question regarding investigation of this matter; yes it should be possible to determine from the State Agricultural & Veterinary Chemical Registrar who was authorised to purchase and use this potent chemical at these times. Has it been done? I don’t believe so.

If you inspect the publicly available scientific literature on this chemical, it is listed as a ‘genotoxic’ and capable of causing mutogenic changes to genomic material in test organisms.

Mevinphos has been withdrawn from registration in most first world countries including Australia. Does anyone know (or care) if there are still old supplies of this rugged chemical in Tasmania?