Long term study finds lethal control not putting dingo purity at risk

UNSW conservation biologist Dr Kylie Cairns has published findings in a scientific journal that she says shows wild dingo populations have less dog lineage than previously thought, challenging the view that pure dingoes are on the decline due to crossbreeding.

"For decades, there was fear that dingoes were breeding themselves into extinction," Dr Cairns said. "Our findings suggest this isn't the case, and dingoes are largely maintaining their identity, which has implications for their management and conservation."

The research team used a new genome-wide test to analyse the DNA of 391 wild and captive dingoes and conducted detailed ancestry modelling to find wild dingoes had far less dog ancestry than suggested by prior genetic studies.

Dr Cairns said the old method, which relied on a relatively small number of genetic markers and limited reference population, overestimates the amount of dog ancestry in dingo samples - sometimes by over 30 per cent.

In Victoria, where previous reports suggested the pure dingo population was as small as 4 per cent, the study found 87.1pc of animals tested were pure dingoes and 6.5pc were historical dingo backcrosses with more than 93 per cent dingo ancestry.

Similarly, in New South Wales and Queensland, where dingo-dog hybridisation was assumed to be pervasive, most animals were found to be pure dingoes, and only two wild canids had less than 70 per cent dingo ancestry.

Fellow conservation biologist Professor Mike Letnic said existing management decisions had been based on the findings from old DNA testing technology, whereas the latest information could inform alternative dingo management strategies.

His and Dr Cairns' argument builds on the 2021 debate about whether the terminology of wild dog or dingo should be used.

They say using the term 'wild dog' means they are all considered invasive species under biosecurity legislation and subject to eradication measures.

However, a decade-long study has found there is no evidence that lethal control to reduce livestock losses and for conservation of native wildlife in the southern rangelands of Western Australia is putting dingo purity at risk.

Dr Malcolm Kennedy, formerly with the Department of Agriculture and Fisheries and now with the Queensland Department of Environment and Science, outlined his research showing stable dingo population structure and purity over 11 years of lethal management at the Wild Dog Management Symposium at Armidale on March 14-16.

He said the research found that lethal control did not accelerate hybridisation between dingoes and domestic dogs or have any impact on the genetic structure of the population in the study area over 11 years.

This period represented up to six generations of dingo (assuming 18-24 months to breeding).

Dr Kennedy said to manage the impacts of dingoes/wild dogs and their control, an understanding was needed of the effects of control on their populations in the short and long term.

He said some people believed ongoing wild dog control would increase the risk of hybridisation of dingoes with domestic dogs which threatened the genetic integrity of pure dingoes.

"It has been hypothesised that lethal control of dingoes can fracture packs leading to increased dingo-domestic dog hybridisation and in turn, hybridisation may result in changes in predation behaviour," he said.

"There is currently no data to support these hypotheses, but these assertions are accompanied by calls for the reduction of lethal dingo control to preserve dingo genetic purity."

Dr Kennedy and colleagues studied the genetic effects of lethal control on dingoes at the landscape scale in the southern rangelands of Western Australia where there are four genetically distinct dingo populations occupying different geographical areas of the state.

Three of these intersect in the area of the Murchison Regional Vermin Cell, which encompasses 61 pastoral stations on an area of 6.5 million hectares.

Researchers worked with Meekatharra Recognised Biosecurity Group, Carnarvon Recognised Biosecurity Group and Central Wheatbelt Biosecurity Association.

The scientists investigated how dingo population structure and genetic purity had changed, using DNA samples collected in 2009, 2014 and 2020.

They identified barriers and corridors to gene flow and assessed geographic distances between closely related individuals within and around the Murchison Regional Vermin Cell.

"Fencing appears to be an effective management tool as there is some evidence of reduced gene flow in areas where the fences are well maintained," Dr Kennedy said.

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A high proportion of the population (69 per cent) were pure dingoes of greater than 90 per cent dingo ancestry, and 98 per cent of the population were greater than 80 per cent pure dingo ancestry with two per cent being hybrids.

This was in line with results from more than 1000 DNA samples collected in Western Australia by the Department of Primary Industries and Regional Development.

"In the context of ongoing lethal control there was no significant change in any genetic variable (including dingo purity) of the dingoes across 11 years of lethal control," Dr Kennedy said.

"Lethal control has been hypothesised to affect dingo dispersal and genetic integrity of packs but we found kinship was heavily skewed towards related individuals occurring in proximity to one another.

Distances between first order kin (siblings or parent-offspring) were 0-360km, but there was a strong bias to kin within 50km with occasional longer dispersal events.

"It would be disingenuous to assume these results apply in other regions of Australia," Dr Kennedy said. "However, baiting has been occurring in the WA southern rangelands for at least 40 years and the population remains at 98 per cent dingo purity."

This was confirmed by the National Wild Dog Geneflow project, a wide-ranging genetic study undertaken by the NSW Department of Primary Industries Vertebrate Pest Research Unit, Zoological Genetics, NSW Farmers and NSW Local Land Services, which revealed a continual immigration from family groups to other family groups across the eastern seaboard.

National Wild Dog management coordinator Greg Mifsud said he was perplexed by Dr Cairns' research.

"Her data shows there are no first and second crosses, then she says lethal control is increasing hybridisation," he said. "Where she sees the most hybridisation is where there are the most dogs to mate with - Cairns, the Gold Coast, Byron, where dogs provide opportunity."

Mr Mifsud said dingos and wild dogs had to be managed and the paper by Dr Kennedy showed lethal control wasn't harming them.

"Dr Cairns is trying to convince the public that dingoes should be afforded special protection, but we don't do that for kangaroos," he said.

"She says dingoes are super special but we manage animal species of all sorts.

"The nonsense that graziers are about eradication is just that, nonsense."

Dr Cairns said no other native species was treated the same way as dingoes were, being subject to lethal control measures across all landscapes, "including ones where they should be protected".

"Dingoes are a threat to some livestock, but they're not a pest in all contexts," Prof Letnic said. "They play a crucial role as apex predators in maintaining ecosystem function and biodiversity, so there's a real need find a balance in management and ensure there are places in the landscape where we maintain populations."