Disease threat to native mammals of Top End

native mammal
Disease threatens native mammal populations in the north of Australia.

A disease investigation into the cause of the alarming decline in small native mammals of the Top End has shed light on the challenge facing Australia in saving our unique wildlife.

Research Fellow, Dr Andrea Reiss from Murdoch University will present the research report ‘investigation of potential disease associated with Northern Territory mammal declines’ at the International Conference of the Wildlife Disease Association, being held in Queensland from July 26 to 30.

Dr Reiss said while disease posed a future threat to these small native mammal species, the research to date showed no evidence that the declines which have occurred over the past 20 years were primarily caused by disease.

“Our examination of disease was only conducted over 18 months and the jury is still out, but the cause of the declines is likely to be a complex interplay of factors including changed fire regimes and introduced predators such as feral cats, as well as disease. Worryingly, the declines are happening even in protected habitats, such as national parks,” she said.

The project, undertaken by the Conservation Medicine Program, Murdoch University, in collaboration with the Northern Territory Department of Land Resource Management, was funded by the Northern Australia Hub of the Australian Government’s National Environmental Research Program and the Northern Territory Department of Land Resource Management. It involved examining and sampling almost 300 animals from five main sites across the Northern Territory: Bathurst Island, Cobourg Peninsula, Kakadu National Park, Groote Eylandt and Darwin.

The brushtail possum, northern brown bandicoot, northern quoll and brush-tailed rabbit rat were the focus of research, along with introduced black rats and feral cats, as potential disease carriers.

Although most of the animals examined were found to be in good condition, the researchers found evidence of parasites, viruses and bacteria, including several never before reported within those species in the Northern Territory.

“We believe some of those diseases could pose a further threat to these animals. Populations are vulnerable to disease because they are small and isolated, may have poor genetic variability, and because the disease threat comes on top of others such as vegetation changes and introduced predators,” she said.

Dr Reiss explained that disease is increasingly recognised as a driver of wildlife population declines and extinctions, with Australian examples such as Tasmanian devil facial tumour disease and chytrid fungus in frogs, while overseas, white nose syndrome has devastated bat populations.

“There is much still to learn about Australia’s wildlife, including a huge gap in baseline information about health and disease,” Dr Reiss said.

“We need that knowledge in order to give our conservation efforts the best chance of success,” she said.

“Habitat preservation is vital, but on its own it is not enough to protect our unique native animals,” she added.



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