Are there foxes in Tasmania? Follow the poop

Stephen Sarre, based at the University of Canberra in Australia, has made a career out of collecting and analyzing poop.

It’s a tough job, but someone’s got to do it. Part of his work is designed to answer a multi-million dollar question: Is Tasmania home to foxes, a pest that carries rabies and other diseases and can ravage local wildlife? According to the Australian news outlet ABCthe Tasmanian and Australian governments have spent $50 million (AUD) on hunting foxes on the island since 2001 — even though many have debated whether they are even there.

In 2012, after analyzing thousands of fecal samples, Sarre published a paper in the Journal of Applied Ecology which boldly claimed that “Foxes are now widespread in Tasmania.” But many outside researchers didn’t buy it, and quickly voiced their criticisms of the paper, namely that there may be problems with false positives and the methodology used to analyze the samples. Recently, the journal issued an expression of concern for the paper, citing an ongoing investigation into the allegations.

Here’s the expression of concern (paywalled, tsk tsk):

With this notice, Journal of Applied Ecology informs readers of an ongoing investigation to examine concerns regarding allegations about the independent collection of samples by the Department of Primary Industries, Parks, Water and Environment (Tasmania) that were subsequently used in the analysis of the data presented in the above paper first published online on 4 December 2012 in Wiley Online Library (, and in Volume 50, pp. 459–468. The Department of Primary Industries, Parks, Water and Environment (Tasmania) are conducting an investigation to examine the concerns. When the outcome of this investigation is reported to the Editors, the paper’s content will be reviewed in light of this information. This notice will be updated when the investigation is complete.

Foxes are now widespread in Tasmania: DNA detection defines the distribution of this rare but invasive carnivore” has been cited 18 times, according to Clarivate Analytics’ Web of Science.

For the past 16 years, experts have disagreed over whether foxes exist in Tasmania. The debate first heated up in 2001, when allegations surfaced that hunters had imported and released a dozen, more or less, foxes onto the island. According to several official police reports, the Tasmanian police began investigating the “alleged conspiracy to import foxes into Tasmania” in 2001 and found no evidence to substantiate the claim. Still, the government continued to invest millions trying to eradicate this allegedly present pest — including collecting and testing thousands of poop samples for fox DNA.

According to a 2011 report written by a member of the Fox Eradication Program, a few dozen scat collected by the Program and tested for fox DNA at the University of Canberra under the direction of Sarre “were determined to be DNA positive for fox.”

In his 2012 paper, Sarre and his colleagues wrote:

We demonstrate that this destructive species is widespread in northern and eastern Tasmania but has not yet reached the limits of its range.

Fox data called into question

But Simon Fearn, who authored the 2011 internal report as well as a report in 2009 on the Fox Eradication Program, has questioned the reliability of the fecal evidence, noting it may contain some false positives. He concluded in the 2011 report that:

… the Program has no compelling evidence that foxes have ever become established and formed a breeding population on Tasmanian soil.

Fearn revealed that some of the samples contained poop from birds, reptiles or other mammals, and that there were “several documented examples of poor or careless handling of scats in the field which could have resulted in DNA contamination.” Fearn also noted that “hoaxing” may have compromised some of the evidence:

… sufficient evidence exists to suspect that some hoaxing has occurred via mainland fox scats being placed in the landscape.

Clive Marks, director at Nocturnal Wildlife Research in Melbourne, who has been conducting an independent review of the evidence with nine colleagues, has also questioned its reliability. In 2014, Marks and colleagues published a letter to the editor in Forensic Science International: Genetics, explaining that one of the three molecular tests that Sarre used to detect foxes was inadequate “because of the high likelihood of false positives.”

Another issue, according to Marks, is that Sarre has never made his data openly accessible, despite numerous requests. In 2014, Marks sent a letter to the vice-chancellor and president of the University of Canberra, where Sarre is based, expressing his concerns with Sarre’s research and requesting that Sarre be required to share his data to allow other researchers to perform an “independent review.” Marks told us:

Science can’t function without critical review. If data are firewalled from the rest of the scientific community by legal agreement then journals shouldn’t publish papers claiming reaching conclusions that no one can test…

Last year, Marks also wrote to the Journal of Applied Ecology expressing his concerns.

We reached out to Sarre, the Department of Primary Industries, Parks, Water and Environment (DPIPWE) and the University of Canberra for further insights on the research and the investigation. The managing editor of the Journal of Applied Ecology told us that the investigation by the DPIPWE in Tasmania is ongoing and when it has concluded:

… we will assess whether this has any impact on the results and conclusions presented in the paper. The Expression of Concern will be updated as soon as we have determined the appropriate course of action for the paper.

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5 thoughts on “Are there foxes in Tasmania? Follow the poop”

  1. As a former hunter of foxes, I’m confused by the use of poop as evidence. If foxes are “widespread,” as the author of the disputed report claims, why not shoot and count bodies of the dispatched foxes? BTW, I agree with Marks that “journals shouldn’t publish papers claiming reaching conclusions that no one can test…” Journals that do become a major part of the problem by becoming an outlet for dishonest authors.

  2. There are most definitely foxes in Tasmania. Check out the waterfront, where they can sometimes be seen involved in sunning rituals.

    1. Quick PO’B which waterfront I want to go and bag one and claim the $5,000.00 reward. However I won’t spend it until I get it because in sixteen years not one fox has been shot, trapped. poisoned or even photographed in Tasmania…..are you sure you are not confusing the Victorian waterfronts ?

  3. Having lived on a farm in countries where foxes exist I can say with some certainty that if a fox den is established and the vixen has a litter, then you know about it very quickly and not from treading in their poop. Foxes may be cautions when moving, but they are not invisible. They also leave a trail of destruction amongst farms animals, particularly farmyard birds, and rabbits. Fox dens are also easy to find if you use a dog and they leave spoor that is easy to identify. If all the evidence you have is some poop, then you haven’t got foxes. The research into what is going on in Tasmania is unconvincing, and that is being exceptionally kind. The data needs to be made public and to be frank, using a government agency whose funding depends on there being foxes makes public release of the raw data essential.

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