Culling will not control the contagious deadly cancer threatening the Tasmanian devil, according to new research.
The research, published in the Journal of Applied Ecology, modelled the effects of removing infected animals on the prevalence of the disease in small populations. Its findings agreed with trials on wild Tasmanian devils, which showed that selectively culling diseased individuals does not halt the spread of the deadly cancer.
All trial culling of this species has now been stopped.
First seen in 1996, the contagious cancer, known as ‘Devil Facial Tumour Disease’ (DFTD), has had a catastrophic impact on the Tasmanian devil population. Untreatable and highly infectious, it is spread through bites, and causes tumours around the mouth which interfere with feeding and eventually lead to death.
In some areas, the disease has wiped out up to 90% of the Tasmanian devil population.
Also threatened by persecution, road fatalities and competition with the introduced red fox (Vulpes vulpes), the Tasmanian devil is listed as Endangered by the IUCN. Without drastic conservation measures, this iconic marsupial is predicted to become extinct in the wild within the next 25 years.
Culling has been used as a method of controlling infectious disease in a range of other species, including deer, badgers, wolves and cattle. Although it has proved successful in controlling livestock diseases, the culling of wild animals is controversial, and in some cases has even been shown to make the situation worse.
In an effort to stop the spread of DFTD, a trial cull of Tasmanian devils began in 2004. Infected animals from an isolated population in southeast Tasmania were trapped and euthanized two to five times a year, and the researchers developed a computer model to assess the cull’s effects.
They found that 20% of the Tasmanian devil population was never captured, meaning it could be acting as a reservoir for the disease. For culling to be effective at disease control, every animal would need to be trapped and inspected – something which would not be feasible in the field.
Refocusing conservation efforts
With the culling programme costing over $200,000 (£122,000) a year, critics had argued that the money could be better spent on captive breeding programmes for this endangered mammal.
The new research suggests that alternative conservation strategies need to be found. According to Dr Nick Beeton, one of the researchers, “Our research demonstrates that we must be flexible and be prepared to change strategy as new information comes to light.”
Dr Elizabeth Murchison, who studies the devil facial cancer, said, “It’s much better to do a study like this, than spend a lot of money on a huge culling programme and then find that it hasn’t worked.”
She added that by confirming that culling does not work, conservationists can now focus on alternative strategies for saving the Tasmanian devil, such as captive breeding and the development of a vaccine against the deadly cancer.
Read more on this story at BBC News – Cull ‘cannot save’ Tasmanian devil.
Find out more about the conservation of this species at Save the Tasmanian Devil.
Liz Shaw, ARKive Species Text Author