Would the Woolly Mammoth or the Tasmanian Tiger be happy in the 21st Century?
Bringing extinct animals back from the dead: can we, could we, and should we?
Would the Woolly Mammoth or the Tasmanian Tiger be happy in the 21st Century?
Bringing extinct animals back from the dead: can we, could we, and should we?
By Tim Doherty (Deakin University), Chris Dickman (University of Sydney), Dale Nimmo (Charles Sturt University), Euan Ritchie (Deakin University) and Thomas Newsome (University of Sydney).
The dingo is Australia’s largest land-based predator, occurring across most of the mainland and on many nearshore islands.
Our new research, published in the journal Mammal Review, reveals the breadth and diversity of dingo diets across the continent.
We compiled and analysed 73 sets of data, containing details of more than 32,000 dingo droppings or stomach contents, to document the range of different species that dingoes eat, and how their diets vary between different environments.
We found that dingoes eat at least 229 vertebrate species. This includes 62 small mammals (less than 500 grams in mass), 79 medium-sized and larger mammals, 10 species of hoofed mammals, 50 birds and 26 reptiles. Dingoes also eat insects, crustaceans, centipedes, fish and frogs.
The true number of species is likely to be much higher because dingo diets have been poorly studied in many parts of Australia, such as Cape York Peninsula.
Large (at least 7 kg) and medium-sized (0.5 to 6.9 kg) mammals were the most common components of dingo diets, followed by small mammals, rabbits, arthropods, reptiles, birds and hoofed animals.
A range of introduced pest species also feature in dingo diets, including deer, goats, rabbits, hares, black rats, house mice, foxes and cats. In recent decades, the occurrence of sambar deer in dingo diets has increased as this invasive species has expanded its range.
Dingoes also eat sheep and cattle, although dietary samples are unable to distinguish between predation and scavenging, and hence tell us little about dingo impacts on livestock production. Dietary samples also do not reveal instances of dingoes killing livestock without eating them.
We found that what dingoes eat depends on where they live. For instance, in arid central Australia, birds, reptiles, rabbits, small mammals and insects form major parts of dingo diets. In contrast, these food groups are less important in temperate and subtropical eastern Australia, where medium-sized and large mammals such as kangaroos, bandicoots and possums are more important.
The higher occurrence of medium-sized mammals in dingo diets in eastern Australia may be due to the lower extinction rates of native mammals there. In contrast, central Australia is a global mammal extinction hotspot, which probably accounts for the low occurrence of medium-sized mammals in dingo diets in arid and semi-arid areas.
Nonetheless, one medium-sized mammal was a major food item for dingoes in arid areas: the European rabbit. In some areas, more than 50% of dingo droppings or stomachs contained the remains of this invasive species. It is possible that native medium-sized mammals previously constituted a major part of dingo diets in arid Australia, but have since been replaced by rabbits.
Local prey availability plays a major role in determining what dingoes eat. For instance, in the Tanami Desert, reptiles were most common in dingo diets during warmer months when they are most active. However, very few studies have collected data on prey availability, partly because of the sheer number of different animals that dingoes eat.
This tally is higher than the number of threatened species in feral cat diets (based on a previous study that used similar methods), even though cats eat almost twice as many different species overall as dingoes (400 and 229, respectively).
Today’s threatened native species co-existed with dingoes for a long time before European colonisation, which means they were able to withstand dingo predation without going extinct.
But now a combination of small population sizes of some threatened species and exacerbating factors such as habitat loss, foxes and cats means some threatened species could be vulnerable to even low levels of dingo predation. Predation by dingoes should therefore be a key consideration when attempting to conserve or restore threatened species.
Dietary studies are one way we can understand how dingoes interact with other species. Our study also highlights that we still have much to learn about our native top predator. In many parts of Australia, the favourite foods of dingoes are still a mystery.
The authors acknowledge the contribution of Naomi Davis, Dave Forsyth, Mike Letnic, Russell Palmer, Joe Benshemesh, Glenn Edwards, Jenny Lawrence, Lindy Lumsden, Charlie Pascoe, Andy Sharp, Danielle Stokeld, Cecilia Myers, Georgeanna Story, Paul Story, Barbara Triggs, Mark Venosta and Mike Wysong to this research.
By Lily van Eeden (University of Sydney), Adrian Treves (University of Wisconsin-Madison), and Euan Ritchie (Deakin University).
Farmers have struggled for millennia to protect their livestock from wolves, lions, bears, and other large carnivores. It’s expensive and time-consuming for farmers, governments and related agencies. Many current approaches have led to dramatic reductions or the complete loss of some apex predators from many regions of the globe.
Despite these substantial costs and their long history, we have remarkably little understanding of what methods best reduce livestock attacks.
A recent synthesis study, led by Lily van Eeden, Ann Eklund, Jennie Miller, and Adrian Treves with a total of 21 authors from 10 countries, found that there’s a worldwide dearth of rigorous experimental studies testing the effectiveness of interventions to protect livestock from carnivores.
Where studies do exist, results were mixed. Some management interventions did reduce livestock losses, some made little to no difference, and some resulted in increased livestock losses. This means that for some methods, farmers would be better off doing nothing at all than using them.
The scant evidence is cause for concern. Aside from financial waste, preventable livestock attacks cause economic, emotional, and social costs for farmers. And both livestock and carnivores may be left maimed and suffering by human failures to separate the two sets of animals.
Too often, studies and management programs measure success based on money spent or saved, numbers of community members who contributed, or carnivores killed. None of these factors necessarily mean livestock loss is prevented or reduced.
In fact, livestock owners, policy makers, and scientists should work together to build an evidence base and discover what works best to reduce attacks on livestock under different conditions.
Where we found rigorous studies quantifying livestock loss, three methods were consistently effective: livestock guardian dogs, some kinds of fencing, and a deterrent called “fladry” (a Polish word for strips of cloth or plastic flagging hung at regular intervals along a rope or fence line).
Livestock guardian dog breeds, such as Maremma and Komondor, are typically much larger than herding dogs. They are raised with and trained to consider themselves part of a livestock herd and so protect their herd from threats.
While dogs are most common, they’re not the only guardian animals: llamas, alpacas, and donkeys are also used to protect livestock from smaller predators like coyotes and foxes, but more research is needed to determine how effective they are.
Fencing can be simple post-and-wire, an electric fence, or corrals, kraals or bomas (circular enclosures used in some parts of Africa) constructed from stones or wood.
Livestock can be kept within fenced areas all the time, or only at night when they are most vulnerable to carnivores (who often hunt at night, dawn, or dusk).
Our study didn’t find sufficient evidence to show that all kinds of fencing work, but there was enough that they should be considered generally effective and adapted to local conditions.
“Fladry” is a Polish word for strips of cloth or plastic flagging hung at regular intervals along a rope or fence line. Fladry is usually red, which is considered the most effective colour for scaring away carnivores. This method has been proven effective at deterring predators like grey wolves and coyotes from entering pastures.
Interestingly, all three of the methods we found to be generally effective do not involve killing carnivores.
This is good news for carnivore conservation, because it means that management can simultaneously protect livestock and carnivores. Large carnivores can play crucial roles in ecosystem regulation, so removing them can cause cascading consequences for landscapes and biodiversity.
Given the damage that ineffective management can cause to farming communities, animal welfare, and ecosystems, we hope our research serves as a catalyst for policy-makers and practitioners to think critically about the methods they use and why.
Too often, we continue to use a particular method due to habit and history, but that doesn’t mean it’s the best way to protect assets.
Governments that continue to fund and encourage ineffective management are not giving farming communities the best chance of success.
A new study published in the peer-reviewed journal PLOS Biology reveals certain nonlethal methods are effective for managing predators in agricultural landscapes. Twenty-one authors from 10 nations reviewed 114 peer-reviewed scientific studies measuring the effectiveness of lethal and non-lethal methods for reducing carnivore predation on livestock. Livestock guardian dogs, livestock enclosures and fladry all were scientifically shown to be effective conflict deterrents.
Australia is failing to meet international obligations to protect our unique wildlife, experts say.
Recounting a list of Australian animals on the brink of extinction comes all too easily to Euan Ritchie, an Associate Professor in Wildlife Ecology and Conservation at Deakin University.
“Obvious examples include the orange-bellied parrot, which only has a few individuals left in the wild,” he says, referring to the multi-coloured grass parrot with a total population of less than 50 that migrates between Tasmania and mainland Australia…
By Bradley Smith (CQUniversity Australia), Euan Ritchie (Deakin University) and Lily van Eeden, (University of Sydney).
Australia’s Commonwealth Coat of Arms depicts two iconic native animals – the kangaroo and the emu. Both are unquestionably fair dinkum Aussies, unique to this continent and having lived here for a very long time. A “very long time”, according to Australian legislation (the EPBC Act 1999), is any species having been present since before the year 1400.
But in Western Australia, under the state’s Biodiversity Conservation Act 2016, no native animal is guaranteed protection. The Act includes a caveat whereby the relevant minister may determine that a native species is in fact, not.
This week, WA’s environment minister Stephen Dawson did just that, declaring that from January 1, 2019, the dingo, Australia’s native canine, will no longer be classified as native fauna.
The dingo does meet the federal government’s criterion, having lived in Australia as a wild canid for an estimated 5,000 years. But under the planned changes in WA, the dingo will lose its current listing as “unprotected fauna”, and will from next year be considered indistinguishable from either the common domestic dog or feral dogs.
According to the biological species concept, a species is a group that has the ability to interbreed and produce viable, fertile offspring. Dingoes, dogs and other canids do interbreed (or “hybridise”), and indeed this is one of the key reasons why the pure dingo is listed as vulnerable by the International Union for the Conservation of Nature.
But this ability to hybridise is also one of the main justifications cited by the WA government in its decision to revoke the dingo’s citizenship (the fact sheet has since been removed from the website, but can be accessed here). The rationale is that if dingoes and dogs are technically the same species, why should dingoes get special treatment?
However, the biological species concept is problematic when applied to canids. If you lump dingoes and dogs together because they readily interbreed, then logically we must do the same for wolves, coyotes, jackals or other canids that can also interbreed (and have done for millenia).
It’s hard to imagine anyone seriously suggesting that a grey wolf and a pug are the same species. This suggests that this criterion alone is insufficient to solve the conundrum. Indeed, there are at least 32 different species concepts, clearly illustrating the difficulty of defining a single rule by which all organisms should abide.
Despite this, a recent paper that argues the biological species concept should be applied to dingoes, was cited as supporting evidence by the WA government. Adopting this narrow interpretation of taxonomy is perhaps somewhat premature. It ignores other investigations that provide evidence to the contrary. Given the contention around defining species, it seems unwise to determine the species status of dingoes independently of other, more comprehensive evidence and argument.
All canids share similarities, but their differences are also many and marked. The dingo can be distinguished from other dogs in various ways: their appearance, anatomy, behaviour, their role in ecosystems, and their genetics (their evolutionary history and degree of relatedness to other species). Dingoes seem to be largely devoid of many of the signs of domestication.
It is therefore reasonable for the dingo to be considered separately from wolves and domestic dogs, while also acknowledging that they all occupy the same broad species classification, Canis lupus.
Having lived in Australia as free-living, wild populations for around 5,000 years almost exclusively under the forces of natural selection, and separately from any other dog lineage until European arrival, there is no notion of the dingo as a domestic animal gone feral. To classify dingoes as nothing more than “feral domestic dogs” expunges their unique, long and quintessentially wild history. Dingoes are not ecologically interchangeable with any other type of dog, either wild or domesticated.
Labelling the dingo as a feral domestic dog changes their legal status and removes any current obligations for developing appropriate management plans. This demotion of status could lead to intensified lethal control. Indeed, control may even be legally mandated.
In the absence of thylacines, mainland Tasmanian devils, and other apex predators, the ecological role that the dingo plays in the Australian landscape is vital. Dingoes help to control kangaroo and feral goat populations, and in some cases foxes and cats as well.
Given WA’s remoteness, it remains one of the few bastions of pure dingoes, and as such it presents an opportunity to seek ways to protect them rather than pave the way for their removal. The WA government’s decision also sets a dangerous precedent for the management of dingoes, and indeed other contentious native wildlife, elsewhere in Australia.
How we choose to classify plants and animals might sound like dry science. But it has genuine implications for policy, management and conservation. Our scientific naming systems are vital for helping to organise and understand the rich biological diversity with which we share the planet, but it is important to remember that these systems are informed not just by biology but also by our values.
In this case, economic and political interests appear to have been favoured over wildlife preservation, and given Australia’s unenviable conservation record this is deeply concerning.
Widespread reforms to WA’s Biodiversity Conservation Act, expected next year, will not consider a change to the existing classification of a dingo as a wild dog, not native to Australia.
The iconic animals are considered no different to wild dogs and can be trapped or killed without permission in many places.
Dingoes are currently classed as unprotected native fauna and a declared pest, but the animals will be listed as non-fauna under widespread reform to the Act…