Do foxes exist in Tasmania?

ABC – RN Breakfast – 28 July, 2011 8.23 am

Do foxes exist in Tasmania?

Professor Chris Johnson from the University of Tasmania has responded to suggestions there are no foxes in Tasmania, saying there is plenty of evidence to prove their presence over the years. On RN Breakfast earlier this week [Tuesday 26 July], Veterinary Pathologist, Dr David Obendorf cast doubt on their existence. Tasmania’s Fox Eradication Program and its effectiveness have been criticised.

Transcript here: http://www.abc.net.au/rn/breakfast/stories/2011/3279766.htm

Interviewer Marius Benson: And you are with ABC Radio National Breakfast program; Marius Benson with you. Earlier this week we heard criticism from… of Tasmania’s Fox Eradication Program; its 3 million dollar annual price tag and also criticism of its effectiveness. Veterinary pathologist, Dr David Obendorf said the program, which had been running since 2002, had in all that time failed to find a single fox. In fact Dr Obendorf cast doubt as to whether there actually are any foxes in Tasmania.

David Obendorf: ‘No foxes have been trapped, shot, spot-lit, poisoned by the program. The difficulty has been the reliability of the original threat assessment back in 2001, and subsequently the credibility of the evidence produced and the claims of fox sightings across the length and breath of Tasmania. It’s somewhat analogous to the sort of thylacine sighting reports that ahhm…Tasmania (Umm) has been notorious for as well.

Marius Benson: Tasmanian veterinary pathologist, Dr David Obendorf speaking on the program earlier this week. Well not everyone agrees, far from it. Chris Johnson is professor of wildlife conservation with the University of Tasmania. He says there’s quite good evidence that foxes exist in the island state and says that the eradication effort is absolutely vital. Chris Johnson joins us this morning from Hobart. Chris Johnson, welcome to radio national Breakfast.

Chris Johnson: Hello, Marius.

Marius Benson: Chris we’ve been having this debate for nearly a decade and no-one can agree if foxes exist in Tasmania or not.

Chris Johnson: Oh, I think the evidence is really convincing. And the fox taskforce has done a very good job in accumulating that evidence over about the last ten years. And, and what is shows is that clearly we’ve got a small population of foxes in Tasmania. Numbers are low but there quite widely spread and they occur in pretty much all of the environments in Tasmanian where you expect foxes to flourish. And if we stand back and do nothing; that’s what will happen, we’ll have a big population that will cause massive environmental impacts.

Marius Benson: So there are foxes in Tasmania, but is it true that there’s never been a carcass found?

Chris Johnson: There have been several; I think four. Ahhm…the… the conclusion that foxes are here is based of physical evidence and the most convincing, and I think undisputable physical evidence, is the discovery of fox scats – that is poos – that are conclusively identified as ‘fox’ using DNA. And since 1998 there have been about 57 of those. Ahhm… and the DNA analysis has been able to confirm at least 15 different individuals; no doubt there are more than that, including males and females. So what we can take from that is clear evidence that there is a small – probably breeding – population of foxes in Tasmania. Ahhm… it’s actually possible that the total population could be still less than 100. And in that case, ahhm… very few people are going to see a fox . so it’s actually, if you don’t see them you can disbelieve their existence. But the evidence is really strong and at that population level, eradication is possible.

Marius Benson: So 100 foxes… it’s difficult to eliminate. If you’ve only got 100 in the whole of Tasmania, it’s going to be hard to isolate, identify and eliminate those few, isn’t it?

Chris Johnson: Ah, indeed. Exact… and, and the more so because there… that number of foxes, if that’s correct, and we can’t be certain. Ahhm… but that number is spread over quite a large area. Ahhm… what we need is a fairly… is a systematic campaign ahhm… to move through the areas where foxes may be present and ahhm… and, and … (pause)… use ahhm… poison baiting, as is being done now, to try eliminate those local populations. And if that’s done on a kind of rolling front, it can prevent the re-establishment of populations behind the front. And…

Marius Benson: Might just 100 foxes be the irreducible minimium. I mean looking for 100 foxes in somewhere the size of Tasmania makes needles in haystack easy to find.

Chris Johnson: Exactly, but you don’t have to find every fox. I think that’s, that’s the important point. And if we focus on actually producing a fox- on demand – ahhm… we’re going to go round in circles because that’s impossible. Ahhm… what, what we want to do is ahh… cover that population with a control method that is likely to be effective, when foxes are at low density. And then do…

Marius Benson: Do you think Tasmania… sorry.

Chris Johnson: Sorry and then do follow up to confirm absence.

Marius Benson: Do you think Tasmania will ever be utterly fox-free?

Chris Johnson: It… it’s possible. It may not happen because this is a big challenge. Ahhm… it’s very, very difficult to eliminate populations of pest animals once they’re established. And the time to do it is very soon are initial establishment; when the population is small. Ahhm… now, so… the stakes are really high here because, ahhm… if this is not done in this case, I, I’m in no doubt that we’ll have a large, firmly established population of foxes in Tasmania for all time and it’s almost impossible to calculate the cost of that economically and environmentally. But with a well planned control operation that’s implemented now, then eradication is possible. And that should be the aim.

Marius Benson: Chris Johnson, thank you very much.

Chris Johnson: Thank you.

Marius Benson: And Chris Johnson is professor of wildlife conservation with the University of Tasmania.