Nick Mooney took the time to extensively document his views and insights ( HERE ) and I welcome his contribution and critique of my arguments ( HERE ) A as well as the forthright and good-natured manner in which he made them.
There are some key aspects we agree on and others we don’t, yet this is the expected nature of constructive debate about controversial issues.
It is appropriate that I clarify some issues and provide answers to the questions that Nick asked of me.
Firstly, to a non-scientific but nonetheless very relevant issue.
Nick discussed the pantheon of sceptics involved in the long running discussion about Tasmanian foxes. It seems that we both support healthy scepticism; yet missing in both our contributions is a recognition that one size does not fit all. We need to distinguish between two oft confused words that betray clearly different motivations: Critic: One who forms and expresses judgments of the merits, faults, value, or truth of a matter, and Sceptic: One who instinctively or habitually doubts, questions, or disagrees with assertions or generally accepted conclusions.
Criticism does not automatically become scepticism because you do not like it or agree with it. If anyone can point to where current data, information, conclusions and approach is not consistent or easily reconciled with scientific knowledge or logic, they are not sceptics. It can easily appear pejorative to dismiss them as such.
Sceptics are often created not born; sometimes due to the nature and quality of the information provided. Scepticism can be a barometer of sorts; storms of disagreement build over time and rarely for no reason.
We encourage scepticism by maintaining counterintuitive or conflicting positions and not quickly admitting to errors or uncertainty. Replacing yesterday’s “factual” version of events with another without clear explanation or retraction is another way. Rampant speculation is the original organic fertiliser of scepticism. Straight questions are best addressed with straight answers.
Of course, science is very hard to do without accurate information. If we don’t have good quality data, we should freely admit that we can’t draw clear scientific conclusions. There is no shame in this.
I asked a straight question about the widely reported fact that the Tasmanian fox population was established by the intentional release of fox cubs by known persons in the late 1990’s. The Tasmanian Police believed that this was not a credible as early as 2001 ( HERE ). My question was this:
“…did this happen and most importantly, where did it happen”?
Firstly, let’s give some context to this question. In Nature in 2002 Nick was quoted as saying: “The information that the authorities have received leaves no doubt that foxes were deliberately brought into Tasmania” ( HERE ). Other documents stated that the police had confirmed the smuggling of three litters of fox cubs ( HERE ). But in subsequent police documents it was apparent that this was far from the case ( HERE ). However, the same circumstances were still cited at an international scientific conference in 2007 by key Fox Program and Invasive Animals CRC members who cite and affirm that foxes were released and were clearly the founding population for foxes in Tasmania in 1999/2000 “These foxes are believed to have been part of, or the progeny of, a deliberate introduction of an unknown number of foxes to the island around 1999/2000” ( HERE ). The original event has been communicated in Tasmanian Government public briefings and Parliamentary Hansard again as fact as recently as 2009.
These statements are either accurate or they are not. This was and remains the elephant in the living room ( HERE ).
Nick’s reply to my question was:
“Everyone I have discussed the issue with acknowledges the reports of an introduction of several litters of foxes in about 2001 (Clive’s elephant in the room) are unproven. With respect Clive, I suggest you talk to senior people in and around the fox program and check for yourself; the issue has long moved to the evidence appearing since that time”.
The point is I had asked senior people too; Minister O’Byrne was the first cab off the rank. I reminded him that the event was reported to be factual by his predecessor; David Llewellyn. I specifically asked with reference to the Tasmanian Police reports that conflicted with this claim and if it was still considered to be a credible founding event for the Tasmanian fox population. This is what Minister O’Byrne replied on 1st September 2010:
But the event had clearly been used to justify the presence of foxes in Tasmania with great certitude (see above links). The abovementioned documents cite Tasmanian Government staff and information as their source. It was also the first time that I had heard that it was a serious contention that foxes may have been established in Tasmania for perhaps more than 100 years. Interestingly too was the statement that possible events that we knew nothing about were a “common sense” means by which foxes may have become established.
It was honestly not clear to me what was being said as this new position departed from the previously well documented one concerning recent introductions. I wrote back to seek further clarification. I assumed that the reply meant the Minister was now in agreement with the Tasmanian Police that the original scenario was not credible. But his reply on 22nd October 2010 suggested that I had distorting his intent and original comments when paraphrasing this conclusion. He went on to say:
Strangely it now seemed that the Minister was saying that the once factual event, was now unproven and only alleged, but not dismissed and might be credible but just one of many possible (proven and alleged) founding events. Although it was no less than the imperative to act, at the same time it is was now not the actual line of inquiry used to believe that foxes were introduced to Tasmania. Most interesting was his first sentence that began with; “To be clear…...”.
So, just what were the proven founding event(s) (which is the proper scientific term - not one I just made up) that the Minister alluded to? Well, he didn’t say.
Also hard to comprehend was that if it was the key alleged incident that was the imperative for ‘action’, real action seemed to gestate for quite a few years. For it was either 3-6 years, depending on the earliest and latest dates you choose to believe, before any comprehensive fox baiting began (The original founding event was originally reported to have happened in 1997, although 1999 and 2000 are have also sometimes mentioned in various correspondence).
So, has the considered view now changed to one entertaining that foxes had been in Tasmania for perhaps a century? What is the evidence for this?
Confused, I next asked the chairman of the Fox Eradication Program’s Technical Advisory Panel and his reply blew my mind as it seemed to be quite a different view. Dr Saunders told me that he was presently sticking to this recent history of fox release as opposed to any long-term theory. This began as his starting premise in the review he co-authored in 2006 ( HERE ).
In a recent ABC interview ( shown in the recent Stateline program HERE ), the previous Minister yet again presented this original scenario as credible – and held that the Tasmanian Police were in error. This seems to starkly contrast with a theory of long-term fox establishment. But no one has revealed just how the Tasmania Police got it wrong, if in fact they did.
Consequently, the answer to my simple question is anything but simple, logical or even consistent. There seems to be two broad views about how foxes established in Tasmania (long term versus a recent one). Perhaps even a third view suggests that it is common sense that events we do not know of might have been responsible.
Some eight years back I assisted the ABC to organize a re-enactment of this original founding event at my laboratory using a captive fox (shown in the recent Stateline program ( HERE ). Since then I have never been informed that I was acting from information (provided by the Tasmanian Government) that would later be considered so passé, unfashionable and so crude that it would be the equivalent of wearing brown polyester track-suit pants to a poolside cocktail party and lobbing Polly Waffles into the deep end.
The nature of the founding event is nebulous and a conspicuously absent key piece of knowledge. Should you believe we need to eradicate foxes in Tasmania, or even if you want to believe it is still possible, you should be deeply concerned about this – it is not a sideshow or a small oversight. Here’s why.
Nipping a fox incursion in the bud in a place the size of Tasmania happens very shortly after the actual incursion, not 10, 50 or 100 or years later. In his report back in 2003 Dr Jack Kinnear suggested three years as a time limit to achieve eradication ( HERE ). Analysis of the potential need for fox eradication (and I have provided a link to one key paper already ( HERE ) have long held that you need to identify the location of the incursion (the founding event) and be able to detect these foxes and monitor the success of your control efforts – which should be up to the task. Ultimately you need to measure fox abundance and distribution at low density ( HERE ). If you can’t do these things, you cannot eradicate anything but public money and the patience of people attempting to explain this. Yet another barrage of “yes, but look what is at stake” as a homily in response becomes incredibly tiresome; because we all accept that the motivation may well be noble, but it does nothing to address the really important things that count 10 (or 100+) years later; the methods applied, measurement of success and overall achievability of eradication, or even if it is necessary at all. Parroting the mother of all motherhood statements does nothing practical when we desperately need practical magic; the equivalent of a fox being pulled from a hat.
Consequently this elephant in the living room is now so old it has grown tusks. But it is not yet ready to carry itself to the elephant’s graveyard.
However I certainly see the point that Nick is making with his Pearl Harbor war reminiscence and Precautionary Principle analogy there within – that the US had prior warning of the attack but did not act from appropriate precaution. But one thing did seem to sink the analogy quicker than the Arizona after a direct torpedo hit though. Ten years after the attack, you’d reckon they would be clear that the attack had actually happened and how. Following Nick’s analogy, ten years later we’d all be stunned by the sudden revelation that the Japanese had been hiding in Pearl Harbor for over 100 years before the surprise attack got underway. This might raise some bushy eyebrows among historians and no doubt some would be asking as I; where is your evidence and what happened to your prior certainty?
The Precautionary Principle demands action in the absence of better evidence. There is absolutely no need to doubt the merits of this to begin with – it is sensible and a part of good risk management. But as I argued before, after 10 years we can, should and must have better evidence about the nature of fox populations in Tasmania as actions dictated only by precaution will always be inferior to those based upon knowledge. The Precautionary Principle is not a replacement for knowledge after 10 years or a mantra to chant as an excuse for a lack of knowledge-based actions. Moreover it should never be a green light for rampant speculation.
The key is to test that which is testable rather than endlessly debating that which is not. Testing is what science is actually good at and this is what I would like to see happen.
Accordingly, scat DNA data is presently the only tangible way to provide irrefutable evidence of the presence and distribution of foxes in Tasmania – or otherwise ( HERE ). This is because scat DNA data and procedures are potentially testable, auditable and verifiable and can tell you much about a potential fox population. But this will not be the case until valid doubts about the quality, adequacy and interpretation of these data are addressed ( HERE ). It is great to read that Nick gives some limited support to this position. It is my hope that everyone will see that there is much to be gained and nothing to loose – other than confusion, anxiety and a lot of scepticism. I seriously doubt that any committed Fox Program worker would want otherwise.
I don’t doubt Nick’s summary of fox introductions in the distant past in Tasmania. It is nonetheless interesting that although many people (including scientists in peer reviewed papers) assume that that mainland fox populations arose from numerous releases by hunting clubs from the 1850s onwards, there is relatively little evidence to support this, although a wide range of individual foxes were indeed released. Two large and planned releases of groups of foxes in the 1870s, one near Ballarat and another near Melbourne, were far more likely to be the actual founding events for the mainland population. Have a read ( HERE ). We will never know for sure, however it might help you understand why I am interested in confirming founding events based upon the release of groups of foxes, rather than individual releases.
Let’s cut to the evidence that Nick says has allowed the Tasmania Fox Program to move on. Nick suggests that in I have missed an elephant in the living room; I may well have – that living room is getting crowded.
Ultimately Nick might be proven correct that it was more than a coincidence when fox evidence in Tasmania started to pop up that it coincided with a decline in devil numbers due to devil facial tumour disease (DFTD). But invisible elephants are not my bag! Speculation is not science as correlation is not causation. In reality there is very little hard scientific evidence that I know of to support a relationship between these events as something we know – it is an untestable and at best a hypothesis in Tasmania at present. As I tried to explain, this is where Ockham’s razor helps; it cuts out more complex and speculative hypotheses that are inconsistent with the known biological constraints.
So let’s use it.
There are two broad ways to look at the current data, depending upon the brand of Ockham’s razor you use. I want to show why, based upon a reasoned argument, that the scat DNA data is odd, unexpected and its interpretation unclear. So if you would like references for anything in the following paragraphs that I claim we know, I am happy to provide them, but some will be found in my previous article ( HERE ).
So here we go, first to what we know and then to my shave down to what I think are reasonable conclusions (breath in, brace yourself and read).
Ockham’s Single-Bladed Knowledge Razor (a cruel and boring cut, time after time):
We know that foxes have a 51-53 day pregnancy (it varies by a few days more sometimes) and know pretty precisely when in the year that they breed as day length and a ‘hormonal clock’ control their breeding. We know that the majority of foxes in the population don’t normally live past 1.5 - 2 years of age. We know that they establish a breeding den before the birth of cubs, as we know that cubs (usually 4-6 are born and survive to emerge from the den). They rarely emerge from dens before 4 weeks or age but we know that they can remain dependent upon lactation for some time (about 6 weeks) and maternal care and the security of the maternal range for many weeks more. We know that the male fox or non-breeding females have a role in providing food to the newly born cubs because we know cubs cannot control their body temperature for the first 2-3 weeks and need a well insulated breeding den and the vixen. We know it would be an exceptionally precocious fox that decided to disperse until 12 weeks old. We know that this fundamental reproductive biology is unlikely to change either, as much of it is hardwired by day length, hormones and having a fox brain – its reproductive behavior and physiology would not be shifted easily, if at all. All this allows us to deductively conclude that breeding foxes (a reasonable assumption is two adults and then four cubs and juveniles later on) are in one place for at minimum of three and most likely four months of the year, if not much longer. We also know that for foxes to be in Tasmania after 10-100+ years, they must have bred (ie. they are an established population) with many breeding dens being used.
Therefore we can draw this together as a deductive conclusion and suggest what we should be finding from the DNA evidence:
1. At least during one third of a year, if scat DNA detection methods were sensitive enough and of adequate discrimination to find foxes, clusters of scats should be produced and repeat sampling of individual foxes (genotypes) is to be expected;
2. If scats cannot be found in a way that shows clusters and repeat individual foxes (genotypes) it is a clear implication that if we can’t find their scats we can’t eradicate the foxes;
3. There is another possible conclusion that there is an unknown error in the scat DNA procedures or field practice and they are not there at all (or at least not over such a wide distribution).
I totally agree with Nick, much of this is about detection probability (of confirmed fox scats) and it is not encouraging that the probability of detecting fox scats by dogs and people looks low over very large areas. But it should not be a major surprise to anyone either as scat DNA was never intended as a method of fox detection, it is best for measuring fox abundance once you know you have an established population at a particular area. People confuse methods of detection with those suited to measuring population size; they are chalk and cheese. The sensitivity or resolution of fox detection in Tasmania is based upon sightings and detector dogs. DNA validation allows you to discriminate, well, fox ‘shit from clay’ and is not a magic way to find fox scats or even foxes. This technology is not yet a rapid turnaround detection test; it takes a long time from sample collection to results and is presently not what is ideally needed.
Now, even if we speculate or find that some unknown Tasmanian animal (Poophilus tasmaniensis) loves a diet of fox poo and vacuums up the evidence before it can be found or if we assume that fox scats are difficult to discover in the Tasmanian landscape (because maybe they decompose rapidly for some mysterious reason), this does not change conclusion 1 and 2.
It is not possible to conclude that these data describe a low density and not-yet-established fox population, especially if you already suspect that your sample collection rate is low, skewed or does not reflect an expected pattern. Therefore you’re in a weak position to propose that such data describes the reality of fox populations in Tasmania and then use it as a basis to propose further speculation; i.e. to move on with it. Hence, my suggestion that we need to review these data ( HERE ).
So, let’s look at what I think Nick’s brand of Ockham’s Razor is doing for his shave (hold onto your chair).
Ockham’s Multi-Bladed Speculation Razor (with lubricating strip, inconvenient fact ejector in exciting theoretical packet):
We know that DFTD has caused a population crash in Tasmanian devil populations. We can speculate that the appearance of fox physical evidence in Tasmania is causally linked to their population decline. We can further speculate or hypothesise that Tasmanian devils might have been suppressing Tasmanian fox populations although we have no direct evidence for this (and very little in the way of implied or inductive evidence despite it being almost media lore since at least 2001). We can be pretty sure that Tasmanian devil numbers had increased in the decades before their crash. But we might speculate, on the basis that (eg.) as devils may have sometimes eaten thylacine cubs in unattended dens or that they are effective carrion eaters, they might compete effectively with foxes (that are actually opportunistic predators). We further speculate and extrapolate they will be an effective form of fox biological control or enough of an influence to suppress fox populations from growing - based on recent theoretical work on how some predators may interact. We can further speculate that this may have happened with foxes and Tasmanian devils for maybe 10 or perhaps 100+ years and also speculate that the sparse scat DNA data indicates a low abundance of foxes in Tasmania and speculate that this fits the retrieval of very few fox bodies. For this all to be plausible we must assume that the scat DNA technique is infallible and speculate there is no error (ie 100 per cent accuracy). We must dismiss odd data that does not fit (such as finding a fox scat on Bruny Island) and speculate about the reason for either a potential data error or continued failure to find foxes by other means. To do this we must fully embrace speculation that foxes behave differently in Tasmania. Importantly we are forced to speculate that fox reproductive biology would be fundamentally changed and speculate they move around a lot, even in the breeding season. This would account for the lack of repeat genotypes, scat clusters and wide distribution of the positive scat samples. To do this we must in turn largely ignore the implication of the newest speculation; that they have been actually established for 100+ years and have a low-density population over a wide area (this would be an established population that breeds and has colonised a large area, maybe as the distribution map suggests?).
Thereafter, we can draw all this together as three speculative conclusions that say;
1. The scat DNA data reflects a widely distributed population of foxes at low abundance;
2. Foxes have been there for perhaps 100 years or more; suppressed by the Tasmanian devil and are only now seen because DFTD has removed a lot of devils;
3. Scat data only looks abnormal because fox reproductive behaviour in Tasmania is abnormal and we cannot expect otherwise because no one knows how foxes behave in Tasmania. This is why there are no clusters and repeat genotypes [ie. There is no error in the scat DNA data at all].
Personally I don’t like the Ockham’s Speculation Razor because you have to shave without a net of knowns and upon a tightrope of speculation – and early in the morning before a coffee this is dangerous. There is not a chain of knowns to build a deductive conclusion upon and you don’t strengthen a position based upon speculation by building in more speculation. Usually to accept one speculative claim you must accept another, then another. In fact this makes it less likely according to Ockham’s razor to explain the uncorroborated scat DNA data.
It would be totally unfair to put words into Nick’s mouth or attempt to belittle ideas that are constrained by a lack of data or just because they remain hypothetical and untestable. Nick is alluding to the theoretical framework of some very sound work in his arguments. Indeed it is possible that devils might have some impact suppressing fox populations, but at present it is untestable. In the United Kingdom we know that fox populations grow when badger populations are reduced – but badgers do not limit foxes such that foxes cannot be observed or their populations measured. Devils have certainly had only a marginal impact upon the Tasmanian feral cat population for instance, if any, yet their decline might assist feral cat populations to grow. But no one really knows if this is the case with foxes or what has happened, if anything – mainly because we can’t accurately detect and measure fox populations in Tasmania anyway.
When it comes to Tasmanian wildlife I am happy to doff my cap to Nick and others who are quite rightly discussing and investigating all manner of possibilities such as this. But claims that are not based upon any direct observations or a sound and testable premise are speculation. It is no crime to speculate of course, its even good fun, and the untestable is not necessarily untrue. Some or even most of it might be correct. But all the same, it is a big gamble to inject speculation into public debate if it is mistaken for scientific knowledge; especially when it is used to explain odd-looking data that has as yet not been rigorously tested and reviewed.
Perhaps in the future this speculation will be shown to be insightful, predictive and intuitive – and I am not being flippant. It may well reveal that Nick Mooney and others beat the scientific house and called it as it was. One day, Clive Marks may have to kneel and kiss the bronze big toe of Nick’s statue at Pearl Harbour, next to the monument to the Precautionary Principle (the other one being in Baghdad).
But just what appears to be the perfect partner and justification for speculation? That’s right, flop out the good old Precautionary Principle that suggests we don’t need true knowledge nor indeed do we have the time to generate it. Yet after 10 years this wears thin and speculation is no longer helpful or able to resolve issues that require knowledge. We should always freely admit speculation and hypothesis to be the more shrivelled organ of scientific debate. In the hall of media mirrors it is too easy for such arguments not well endowed with facts to seem more impressive than they actually are. It is not always the fault of the person who proposes new ideas as much as it is the manner in which speculation is reported as fact.
Evidence-based decisions should be the hallmark of good wildlife management. Acting from precaution and speculation after 10 years, is not where we should want to be.
Presently, coming up with a wide range of speculative hypotheses is much less urgent than a focus upon developing absolute confirmation that the scat DNA data is telling us what many may believe it is. After all, this is the fundamental question and the nub upon which everything hangs. Proposing convenient scenarios that require the re-definition of known breeding biology of foxes to fit the current scat DNA data is not addressing this need; the cart is well before the horse in this case – in fact the horse needs binoculars to even sight the cart, so far down the road has it been dragged.
Nick correctly suggests, “other fox experts (who) say they don’t know what foxes with a dearth of neighbors would do”. True enough too in a general sense, but extremely unlikely when it comes to their reproductive biology. To offer another reason for why clusters of scats are not found and repeat genotypes (and breeding dens, cubs and prints for that matter), especially during these four months requires a more robust argument, because there are most certainly some things we can be pretty sure that foxes are doing.
We should reject that the wide distribution of fox scats and lack of individual genotypes can be explained by a small population of non-breeding foxes bouncing about Tasmania like long-lived vulpine pin-balls all year long – as some people have seriously claimed. We should also reject notions that if foxes have indeed been in Tasmania for more than 100 years are not established as a breeding population – how can this be the case? This makes no logical sense, nor does the explanation I received on 22nd October 2010 that sounded more like a script from a new film “Ghostbusters meets Yes Minister”:
Spirits and ghosts may well form a presence, but breeding foxes form a population – and an established population even at low density no less, even if they have been in Tasmania for 10 years and certainly for 100+ years. Just how hard they would be to eradicate is another issue altogether that requires knowledge to go along with all this well-meaning belief and hope.
Remember – central to the issue is if we can’t find them we can’t eradicate them. Furthermore, if the founding event is nebulous and we seriously consider that foxes have been in Tasmania for 100+ years, they are clearly an established population.
Presence is a dubious term that describes an impossible scenario that is inconsistent with other claims. A twilight fence-sitting definition of presence is hardly credible, and it blows oxygen onto the fires of scepticism. It is scientific navel lint. There is either a population of foxes or none at all.
But let’s get away from shavers and spirits and instead take a look at Nick’s new baby in the bath water.
For the record, no Nick, I would never advocate tossing babies and bathwater out together. But neither should we stand and clutch the baby tub for a decade and speculate, telling everyone (again!) how valuable babies are. We all sort of get that. We need to know if the baby is actually in the bath before we decide to do something or not. Is it a baby or perhaps just a ghostly presence of one? Was the baby ever put in the bathwater to begin with - or was it bathed in an alleged, unproven but credible manner; all at the same time? Maybe it has been there for 10 years, but yet again perhaps 100+. Maybe babies behave very differently in Tasmania and that’s why you can never tell?
Enough already! We need to test what is testable and find out. The best way is to independently review that scat DNA data, audit that chain of evidence and have transparent standards. It does not mean doing more of the same thing.
The evidence for a fox founding event in Tasmania is murky. It invites speculation and endemic scepticism. Why don’t we at least admit this and banish prevarication? Moving on is good advice, but not with a no-fault divorce from past facts without retraction or clarification either. Moving on is good if science can brought to bare on this problem and test something testable and conclude something irrefutable – one way or the other. It’s strange looking data, just what is it telling us? Lets not speculate endlessly about it either, let’s find out.
Let’s also not confuse valid criticism with skepticism or dismiss those who want clarification as sceptics. Weasel words, changing facts, failure to separate knowledge from speculation and institutional agendas have damaged reasoned and sound debate and public unity in Tasmania over this issue. Ultimately it is the lack of quality information that is the main problem; it demeans and patronises a concerned and confused public to say otherwise. A tsunami of press releases and sometimes-incorrect media vinaigrettes is no replacement for communicating good and careful science. Let’s banish spin-doctors from science; let them take their own ghostly presence back to their pseudoscientific underworld to confuse whatever sorry creatures live there.
Here are the answers to some of Nick’s main questions. I hope you forgive me taking out some specific statements and questions for the sake of clarity.
Question 1: Why have I assumed that foxes boarded at Webb Dock and not some other location?
Answer: Because your own Tasmanian Government documents, reports and other information say so and it has been the established line of public information and reported widely in the media without modification, challenge or retraction. It was the basis of why a fox control program was initiated at Webb Dock, largely at the behest of the Tasmanian Government.
Question 2: But how high are the stakes? Not the 40 million bucks Clive reports.
Answer: There are many published figures on the cost of the program. How about $56 million as used by the Fairfax press for instance ( HERE ) or a proposed $50 million ( HERE )? I took the $40 million from a publication, as it was one of the most conservative in recent times. Again, none of the published figures have been corrected, revised or challenged to my knowledge. I rang some journalists who confirmed that they got their various figures from Tasmanian or Commonwealth Government staff.
Question 3: Clive discusses the likelihood of a den being in Burnie if anywhere, and suggests it either does not exist or searchers are incompetent. He might be right but why Burnie?
Answer: Nick, you are a co-author on a 2007 paper at an international conference that refers to the 2003 Burnie fox and says “These foxes are believed to have been part of, or the progeny of, a deliberate introduction of an unknown number of foxes to the island around 1999/2000” HERE. It also comes from Tasmanian Government documents that propose Burnie as a possible founding event; public information given by the task force specific to problems associated with detecting foxes in Burnie; prior media speculation that foxes were established via Burnie and other foxes that came into the port; speculation after the 2003 that the new Burnie fox was part of a local population or additional incursion; lack of any clarification, moderation, correction or alternative view etc.
Question 4: Nick asks if I or anyone has experience in detecting foxes at the low abundance they are attempting.
Answer: Without avoiding this straight question, it has an implied assumption within it which may or may not be correct. The first question to ask is if your data is definitely telling you that you actually have a low fox abundance or if this an artifact of the field procedure and test? You probably base you conclusion of low abundance mainly upon scat DNA results that you admit most likely suffer from the inability of dogs and people to find scats. As I suggested in my article ( HERE ) these data suggest to me that you have a much larger fox population if indeed they are accurate. So large that you will never eradicate them!. This is partly why I consider it to be odd and worth looking at very closely. And I hope we find error.
Are there better approaches for detecting low densities of foxes? The answer is yes, there are and it is not scat DNA (a technique for measuring abundance). There are more promising technologies appropriate to the job of detecting foxes over large areas that have been partially tested and look very promising. I have even tried to interest your Minister in these with no success. The people who own and developed the enabling technology did not do so to find foxes and have more lucrative commercial interests to protect. They have no interest in spilling their beans to government committees who are unlikely to be fluent in physics and scary maths anyway – their language. Bureaucratic structures often stand in the way of innovation because they want it done their way, by their committees that reflect their vested interests and their laborious processes - rather than the way the innovator requires it. Many people are willing to help, but not everyone is overjoyed with the prospect of working with government committees. Your Minister seems unwilling to accommodate these concerns.
Statement 1: In his argument about scientific uncertainty, Nick seems to confuse a statistical convention with science itself and/or even what I termed irrefutable evidence.
Response: We do not need 95% or 99% confidence that the earth revolves around the sun. No one puts a probability on wombats and Tasmanian devils existing in Tasmania either. Nor 10 years down the track should we need to use belief or probability to discuss the presence or absence of breeding populations of foxes in Tasmania. It’s one of those is or is not type of things! Dr Jack Kinnear warned of the absolutely need to clarify this in his report back in 2003. He was spot on! It is a very different thing to opportunistically collect foxes reported by the public compared to showing that your control program is effectively killing foxes. To my knowledge, this has not been done on a single occasion.
One of my key points seemed to be a little confused in Nick’s essay and perhaps because I had not explained it well enough. Irrefutable evidence is not that which invites endlessly debate over that which can never be tested for its veracity, especially retrospectively. Science is actually very concerned with testing things and is pretty useless when it can’t. For example, it is certainly not Nick’s fault that two of the most significant fox bodies were recovered and subject to belated claims of being moved from the assumed site of death and their origin involves convoluted and/or anonymous justifications. But it does degrade their value as evidence. It is simply not possible to retrospectively test the veracity of this physical evidence (i.e. bodies, skull etc) or relate them to the current status of a putative fox population under these conditions. You’re not a sceptic if you don’t see this evidence as irrefutable, your simply being logically critical – and you have every justification to be critical of those who maintain otherwise. Equally, this criticism does not disprove the existence of foxes in Tasmania; this should not be forgotten for one moment. Yet I wince at Nick’s implied suggestion that we should assume validity of evidence until it is disproved. Perhaps to begin with you cannot afford not to, but 10 years later this is a license to speculate rabidly with no burden of proof on those who make claims – some evidence and claims can never be tested to an agreed conclusion. That is why we need that which is testable!
Statement 2: Nick suggests “good science requires the rational assessment of evidence and casting a wide net to put new records in context”. Response: Well, not really Nick. Good science tests data and evidence using the scientific method in a way that explanations can be drawn, errors known and knowledge created. Science is not good with the untestable. Wide nets are great for fishing for speculative sardines but science is not open to changing context that someone believes is rational versus another’s idea of what is not – i.e. opinion. Testable (empiricism) is at its heart. This is the entire point – eventually it must be testable and conclusions should be consistent with valid and tested data.
One practical example of the pitfalls of not understanding this distinction can perhaps be seen in a statement when Nick says that that “There actually has been an apparent fox-positive scat recorded at a bait dig. Collection protocols were not fully followed so it was not listed as definitely ‘fox-positive’ and therefore not publicly reported”. But just why would you say there has been an apparent fox scat if the protocols were not followed? It’s like saying that when I did not use the correct methods in an experiment and generated some unreliable data it should be enough to show my critics that I have proved something. This cannot be reconciled with the scientific method, it is not science, knowledge has not been created and it is wrong to say otherwise.
Statement 3: Nick maintains that it would be difficult to distinguish a fox den from that of a Tasmanian devil den. Response: I reject this. Overwhelmingly foxes (as fox cubs and juveniles) are most easily detected by spotlight searches during the known period of the breeding season over a period of two to three months. This is a proven method and is usually how you find the den – not by trawling through the bush in the day. Incidentally, foxes breed at a time that does not correspond with the Tasmanian devil breeding season. For quite some time in the fox-breeding season, dens do stink of fox and it is unmistakable – outside of the breeding season foxes rarely shelter in breeding dens however. Also unmistakable is the amounts of cub scats that surround the dens sites and cached food; hard to miss in the first weeks after their emergence from the den. There is a flattened area where cubs are fed that is quite characteristic of foxes. Tracks of cubs and adults are also abundant and if you rake soil in front of the suspected dens and you can easily distinguish fox tracks from devils. Breeding den location is the single greatest opportunity to find foxes in any area by direct observation as you have a locally much higher density of foxes at their focus, especially as cubs and juveniles are naïve and it is not at all uncommon that they walk towards the spotlight! I don’t doubt that there would be 1000s of fox shooters who have experienced this as well on the mainland. I have scooped up many wild cubs with my hands using this technique. I’m interested in your observation that fox and devil dens are the same size, because there is a vast range of natal den habitats and strategies used by foxes and the den entrance differs markedly – regionally and worldwide. Foxes seem to be very good at picking locations to provide security for cubs given the risks of any particular environment – including predators.
Statement 4: Nick counters my call for having field procedures to assure the standard of scat DNA evidence and the credibility of data by saying “Such lack of ultimate surety applies to virtually every aspect of science”.
Response: No Nick, not in the least. For example, when you give any pathology sample at the doctor, as millions of samples are generated each year, there are established protocols and standards that ensure that your results are extremely unlikely to be in error as the chain of custody, analysis and reporting is standardized and auditable. The same for veterinary pathology or even if you give a DNA sample from a racehorse or dog. I used a pathology service to generate scientific data for a fox project and have little doubt of its reliability ( HERE ). The police have much tighter standards for collecting DNA at crime scenes of course. Standards are maintained to meet the magnitude of the conclusions and claims that you may need to make. The conclusions that are made based on scat DNA are clearly important to the Program. I’m asking nothing more than assurance of adequate standards that are appropriate and no more onerous than those used every day. But I have been told by the current Minister:
Boy o boy Nick. The day my doctor tells me that their pathology or any other science-based service or standard is robust because a technical committee reports to a management committee is the day I take out health insurance in North Korea! As I pointed out, we have a Standards Authority and International Standards Organisation (ISO) that thousands of laboratories and field practices involving sample collection and data generation must abide by and this is how we have confidence in their reliability. Why should this Program be any different given the magnitude of the claims and implications coming from scat DNA data?
Statement 5: Nick makes a range of comments about the use and limitations of sightings such as “…if foxes were indisputably in Tasmania I bet the suspicion over sighting reports would evaporate and any old report would likely be accepted by the public”.
Response: I maintain that sightings are the least useful form of evidence as you cannot test their reliability – again, it is in stark contrast to scat DNA where you eventually can. Sightings must be taken on faith, although I have not advocated ignoring them – they may well be right, but we can’t test this. They have obviously never lead to any confirmed evidence of thylacines nor UFOs for that matter! Unfortunately, they enhance perceptions that as sightings accumulate the more likely it is that something must be there. Public sightings rarely if ever pull a species from extinction, place a new record of a species on another continent or unilaterally confirm exotic species incursions. In some situations where some animals are abundant, people are better primed with familiarity and know what the animals look like because they have seen them over many years. For example, if you ask a Melbournian if they have brushtail possums in their backyard it is likely that many have seen them and will be able to give you some useful information. However, circulate a false report of an exotic grey squirrel incursion in Melbourne, describe this species with breathlessly urgency, and sit back and wait for the avalanche of squirrel sightings to flood in as mistaken brushtail possum sightings. If we ask a public that is totally naïve to discriminate a particular cryptic animal, almost certainly we will get many mistaken identifications. For instance, thousands or reports of thylacines on the mainland are likely to be foxes with mange. Can you imagine how these reports would increase should it be suggested that a few credible thylacine sightings have been made and that we are certain that they exist in Victoria? But would this suddenly make them retrospectively useful and justify an emphasis on sightings? No.
Statement 6: Finally, to take one of Nick’s first comments last where he defends the “colourful reactions” of some persons and the invidious position of public servants.
Response: I totally encourage scientific debate without restriction and have written on this topic in respect of state government organizations ( Download: Galileos_dilemma.pdf ). But science cannot afford to be about berating critics and dismissing valid criticism for scepticism. Science is about playing and testing the facts and always will be for anyone interested in scientific integrity. People (and as far as I am aware you have never done so) who hit back and pillory critics, especially when they are not independent from the issue and present flawed arguments do not contribute to scientific debate. There is especially no excuse for this when you represent a public scientific organization. It’s a slippery slope to excuse poor ethics in this regard. I think we should always allow for and expect a bit more color from members of the public and demand higher standards of conduct from professionals and public institutions. They should be mindful of setting an example in this regard and never lord it over members of the public. I consider this to be more than just good manners. It’s even pretty consistent with the spirit of Article 19 of the Universal Declaration of Human Rights:
Everyone has the right to freedom of opinion and expression; this right includes freedom to hold opinions without interference and to seek, receive and impart information and ideas through any media and regardless of frontiers.
The issue is one of proportionality; “everyone” sure. But an individual is brave to stand against a large organization and representatives of public interests should never use the status of a public organization to diminish and belittle them; communicating facts should be enough. It is all too easy to reduce the willingness of other members of the public to express similar views by doing so - perhaps the very intention? Even if we may not agree with all or some of what members of the public might say, protecting their right to say it takes absolute priority. It’s also a simple schoolyard lesson; tit for tat is rarely productive and if your arguments are good science, why fear you’re critics?
In respect of Nick’s comments on Public Servants, they represent a government organization and their personal views and speculation on a range of matters are sometimes not nearly as important as the policy of the organization concerned – it says so in many Public Service Acts.
Dr Clive A Marks is the director of Nocturnal Wildlife Research Pty Ltd and was the head of the Victorian government’s Vertebrate Pest Research Department for over a decade. He has published widely on aspects of fox biology and control in independently peer-reviewed science journals.
First published: 2010-11-29 04:00 am
The Fox that wasn’t there?