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

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.

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

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.

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.

“There is no evidence that lethal control has accelerated hybridisation or had any impact on the genetic structure of the population over the last 11 years.”

Dr Kennedy said the continued low hybridisation in this study area was likely to be influenced by the opportunities for domestic dogs and dingoes to interact. Areas of human habitat tend to be hotspots of hybridisation and the southern rangelands are characterised by low human densities.

“It would be disingenuous to assume these results apply in other regions of Australia. 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 the notion of dingoes, wild dogs and their hybrids not immigrating to other areas if management programs were ceased was unrealistic.

Dr Benjamin Allen, a member of the International Union for Conservation of Nature’s Dingo Working Group, told the symposium the group’s priority issues included gathering information on the evolutionarily significant dingo populations, especially identifying dingo populations with limited domestic dog hybridisation.

The Dingo Working Group is also gathering information on the effects of dingo management on dispersal and hybridisation, and the non-numerical effects of dingo management on populations of dingoes and other fauna. 

Dr Allen said the group was actively engaging with stakeholders and policy makers concerning dingo conservation and management policy.