A NEW paper by Mike Letnic from the University of Sydney adds more weight to the argument that the best way to save Australia’s small native rodents, in particular the dusky hopping mouse, is to protect the dingo because it also preys on foxes and foxes are more damaging to the small cute and furies than the dingo.
Landholder Jim Inglis reckons the scrub tick does a better job than the dingo at controlling foxes in higher rainfall regions – foxes that kill the pademelons on his property.
The European fox, Vulpes vulpes, was introduced into Australia in the early 1870s for recreational hunting purposes. Along with the domestic cat, Felis catus, the species has been implicated in the extinction or range reduction of many Australian native marsupials and rodents.
The dingo, Canis lupus dingo, is a descendant of the wolf and thought to have been in Australia for a bit longer than either the fox or cat – about 4,000 years longer.
Dingoes will eat foxes and cats, but they also eat lambs and other livestock. Baiting programs have traditionally been more effective against dingoes than, for example, foxes to the extent that there is now an Australian Dingo Conservation Association – concerned the species could be driven to extinction.
An increasing number of ecologists are claiming that one way of saving small native marsupials and rodents is to actually protect dingoes, because they suppress numbers of foxes.
Mike Letnic from the School of Biological Science at the University of Sydney is one of the latest to publish findings along these lines. His latest research, just published in the journal ‘Animal Conservation’, claims that maintaining or restoring dingo populations may be a useful strategy to mitigate the predatory impacts of foxes on small and medium sized mammals in arid environments.
Dr Letnic qualifies his findings though, acknowledging, that the mass extinction of mammals from the Australian deserts has occurred in the last 100 years, despite the presence of dingoes, makes it clear that dingoes are not a ‘silver bullet’ for biodiversity conservation.”
A regular reader of this weblog and landholder, Jim Inglis, sent me the picture of the headless Red Necked Pademelon, Thylogale thetis, killed on his lawn on May 1, 2009, by a fox. He has also written that foxes are thriving alongside dingoes at his place which has a higher rainfall than the Strzelecki Desert where Dr Letnic carried out his research.
According to Mr Inglis,
“Dingoes are bad news for the natives that are their natural prey but could possibly help the preservation of these smaller animals that were more the focus of foxes and cats.
“As Dr. Lentic says, they certainly aren’t any silver bullet. Though they possibly restrict cats and foxes in open desert country, these two species “play them off a brake” in rough scrub and forest country.
“What controls cats and foxes in coastal mountain bushland more than dingoes is the scrub tick which luckily no one has yet developed a way to eradicate though I believe they are still foolishly trying.
“If people get a scrub tick they should extract it gently and put it back where they got it.”
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Links and Notes
http://www.wiley.com/bw/journal.asp?ref=1367-9430&site=1
http://www.dogslife.com.au/dogs_life_articles?cid=9454&pid=146591
http://www.ecosmagazine.com/nid/10/issue/4862.htm
http://www.cosmosmagazine.com/node/850
Not Available online:
Does a top-predator provide an endangered rodent with refuge froman invasive mesopredator?
M. Letnic, M. S. Crowther & F. Koch, Animal Conservation (2009) 1-11.
Abstract
In arid environments, ecological refuges are often conceptualised as places where animal species can persist through drought owing to the localised persistence of moisture and nutrients. The mesopredator release hypothesis (MRH) predicts that reduced abundance of top-order predators results in an increase in the abundance of smaller predators (mesopredators) and consequently has detrimental impacts on the prey of the smaller predators. Thus according to the MRH, the existence of larger predators may provide prey with refuge from predation. In this study, we investigated how the abundance of an endangered rodent Notomys fuscus is affected by Australia’s largest predator, the dingo Canis lupus dingo, introduced mesopredators, introduced herbivores, kangaroos and rainfall. Our surveys showed that N. fuscus was more abundant where dingoes occurred. Generalised linear modelling showed that N. fuscus abundance was associated positively with dingo activity and long-term annual rainfall and negatively with red fox Vulpes vulpes activity. Our results were consistent with the hypothesis that areas with higher rainfall and dingoes provide N. fuscus with refuge from drought and predation by invasive red foxes, respectively. Top-order predators, such as dingoes, could have an important functional role in broad-scale biodiversity conservation programmes by reducing the impacts of mesopredators.
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
Chris Johnson thinks that reintroducing healthy Devils–from captive breeding programs–to the mainland could also be helpful in keeping fox (and cat) numbers in check. Prior to facial tumor disease, Devils appear to have done that job in Tasmania. Here’s a link to his article. http://tinyurl.com/d4r5om
Eventually, the government may even consider allowing people to keep Devils as pets, if that’s not too heretical.
Hmm. Too bad. Foxes are quite beautiful, but I suppose you’ve gotta do what you’ve gotta do.
when I lived up on the mountain adjacent to World Heritage National Park there were Pademelons and Dingoes but NO foxes or cats.
Australia is the only country that has had a dog as it’s No 1 predator. The aboriginals were a dingo community – the tribal head’s dingo was the top dingo and the tribal head’s wife’s dingo bitch was the top bitch.
BTW when exactly did the cat arrive in Australia – I understood it first arrived on the western coastline from shipwrecks well before the white man got here.
Dingos, like any other predator, go for the easiest available feed. The Dog Fence, from Fowlers BAy SA, winding across to NSW & into Qld, was built to separate dingos from the Australian sheep flock.
Sheep, which conveniently herd, are a far easier meal than foxes or cats. Also, some Australian natives, in particular the Southern Hairy Nosed Wombat, have thrived inside the protection of the dog fence, in comparison to populations outside the fence. A benefit here is a cost there. There are no easy answers.
30 years ago the Qld govt went to considerable expense to resume 99% of Fraser Is. as a national park knowing that its broad surrounding straits would make it capable of providing refuge for many of our endangered ground dwellers.
So after 30 years what has this beautiful refuge become?
A bloody dingo nursery, that’s what!
I have seen so called lists of wildlife for Fraser Is which are quite long and include macropods etc which are not at all evident.
If these natives can’t fly or climb trees they’re pretty much non existent on the island, it seems to me.
On enquiring how these lists were made a ranger told me that it was most likely from the assorted bones in dingo faeces.
I was also told that many animals on this list were of crepuscular habit and were not very visible.
Well the wraith of odin is also of crepuscular habit and like most of the animals on this list, it no longer leaves tracks or scats either.
Jen,
People don’t realise that dingoes did not exist in much of the open desert country in the centre before the coming of the white man.
Eg, all of the rich channel country around Birdsville, Innaminka etc was first grazed as sheep country with not a dingo in sight until some time during the 1st half of the 20th century.
This may be part of the reason for some small native animal preservation in these areas. Particularly the Bilby.
The old fences were 6 wire sheep fences and Cordillo Downs which occupies all the NE corner of SA had a fully operational wool scour and all the surrounding properties got their wool scoured there and freighted to the rail-head at Marree by Afghan camel train down the Maree [Birdsville, depending which side of the border you lived] track.
When the dogs moved in [to feast on the easy pickings] the areas were too large and difficult to dog-net so everyone went to cattle.
There were so many dog/dingo mongrels out there that any time you killed and butchered a beast [on the ground, in their hide, as quick as you could], you would have up to a thousand dogs around you baying for blood.
That’s how I’ve got eyes in the back of my head.
Interesting theory but it appears to only function in complete isolation from domestic farming and without reference to the climate cycle. If there is an abundant supply of lambs, kids and calves then the chances of Dingos having any impact on fox numbers are minimal. And any research on the impact of foxes on smaller marsupials should be tempered by reference to the current state of rabbit control measures. Reduce the rabbit population with a new bio-control measure and pity help the woodland natives as hungry foxes seek alternate food supplies.
Similarly, most marsupials are better able to produce multiple off-spring to take advantage of a good season than foxes. They reach puberty earlier and generally have shorter gestation periods. But when a dry season takes hold it is not uncommon to see 80% declines in population within a few months. And this range of natural variation is a very tricky context to be drawing conclusions about the impact of predators. As the research by Lindenmeyer, Lamb, Wormington and many others on tree hollow using species has shown, if there is no seasonal variable in the equation then the whole science is pure crap.
Interestingly, examination of the stomach contents of central Australian feral cats has revealed that the majority of their food supply was provided by an artificial abundance of common rats and mice, not the endangered marsupials. And if the rats and mice are primarily feeding off human habitat modifications like crop seeds etc, which are in excess of native food supplies, then the feral cats are of minimal concern for the marsupials.
This again highlights the importance of building a complete picture of the pre-settlement range of variation in native animal density, as the only valid basis for determining ‘duty of care’ benchmarks in wildlife management. A plague of dingos, based on half baked theory would be gross negligence.
Yes Ian, marsupial capacity for rapid reproduction is their greatest asset.
I get big red fox irruptions which give the natives Larry Dooley but once the fox plague subsides I am amazed to see these small wallabies reappear.
The foxes can’t kill the bigger wallabies but they chase them until they cast their young and some of these bigger wallabies [whiptails, swamp, red necked etc] are struggling to survive through not raising any young.
Wallabies can live where dogs can’t go [cliff faces etc] but not where foxes can’t go.
“An increasing number of ecologists are claiming that one way of saving small native marsupials and rodents is to actually protect dingoes, because they suppress numbers of foxes.”
In my experience this is wishfull thinking. The MO of predators especially where the pickings are easy is, “why rock the boat?”
If they ever fight, one on one, no one wins and both can get hurt. They simply respect each other.
Where the dog is clearly at an advantage in open treeless desert and in bigger packs then that rule may not apply but in most of the country it does. In the case of Fraser Is., dingoes are so out of balance that they are in complete control.
As a matter of interest, on other similar coastal sand islands where there exists the normal cross section of people, industry, farming, tourism etc that used to exist on Fraser, dingoes remain very much in the minority and not near as much a problem and the native wildlife is hugely more diversified.
Does this indicate that the real problem is Natonal Parks and their questionable policies?
Spot on, Spangles. National Parks ARE the problem. Whenever the greens get control of something they are guaranteed to turn it to crap.
And in relation to Fraser Island dingoes, the parkies have already been observed releasing pure breds back into mainland forests. For many decades pure breds were only found on Fraser but can now be found as far as northern NSW. They claimed to be culling them when the public was outraged about the human fatalities but all they did was trap and transport, just as they do with crocs.
It is likely that this “research” has been produced as justification for a policy that they have already set in place.
When did feral cats reach Australia? This is not known exactly, but the idea that they came ashore from wrecked Dutch ships in the 17th century is very likely. I understand that most Aboriginal languages, even for those tribal groups well into the central deserts, had a name for the cat in their own language well before the first Europeans started collecting Aboriginal animal and plant names, and certainly before explorers or pastoralists started taking pet cats into inland areas. Coal-roasted cat was considered a delicacy by Aboriginals, but they were unable (or unwilling) to hunt it to extinction. This is a pity as it now appears that feral cats are a bigger threat to small native animals than feral foxes, the latter being controllable by fencing and 1080 baiting.
Yorkie, yes it does seem that wild feral cats are pretty bait-proof and are well established in the drier areas, however where the paralysis tick [Ixodes holocyclus] lives you don’t seem to find them.
The domestic feral cat however, is still a problem here. Like the family moggie that is put out at night to get its fill of wildlife [including ticks] and then comes home in the morning to get “Frontlined” so it can do it all again the next night.
In my neck of the woods where the scrub tick is plentiful I have yet to find a genuine colony of wild feral cats like you see, say, west of the main range. Not even a loner. The ones I trap in cages are invariably domestic ferals complete with bells, whistles, names and addresses.
After a second visit I have been disposed to taking them for swimming lessons without advising the owner.
If only a dry-country version of the scrub tick could be developed. And one for careless cat owners.
Is there a powerful owl nest in your neck of the woods, Spangles? If there is then don’t bother with drowning the moggies, just give them a small dose of panadol and leave them near the Ninox nest. Its quick and you might get to see the moggies being slowly dismembered for the chicks. It is nature at work, no corpse, no crime.
There may not be any silver bullets, but there are some more conventionally constructed ones that perform superbly on foxes and cats.
My personal favourite is the .224″ Hornady 60gn. hollow point, driven at over 3400 ft/sec. from a 26″ barrel chamberd for the .22/250 Ackley Improved cartridge. (Older readers will understand that this outclasses the classic .220 Swift of yore.)
The use of this technology is is known hereabouts as “applied ecology”.
That’s a handy idea Ian, but it’s also another story. The local owls, of which there were plenty, including the powerful owl, have been reducing in number mainly, I think, from eating poisoned rats and mice.
A combination of good seasons plus increased human population has led to rodent increases, has led to poisoning, has led to transfers of poison to owls, raptors etc.
Poisoning of rodents should only be done indoors with non transferable poisons or just use traps.
For big numbers of rodents use 44 gallon drums half full of water, a wire across the open top and cotton reels either side of the bait in the middle of this wire. And I’m sure there are better ideas.