'Drastic reductions' of Australia's northern bettong population reported
Researchers are calling for urgent measures to save the northern bettong from extinction after a five-year study found just two remaining populations of the animal in the wild.
The research, led by WWF Australia working with the Queensland government and scientists from James Cook University, has recommended state and federal governments look to establish insurance populations for the small marsupial known as the “rat kangaroo”.
Northern bettongs are endemic to far north Queensland and their numbers have declined dramatically since European colonisation.
Studies from the 1980s suggested the animal could be found in four areas – Mount Windsor, the Carbine tableland, Lamb range and Coane range.
The project team for the latest population study used trapping and 587 sensor cameras to search for the species in nearly 100,000ha of the wet tropics.
The results, published by WWF on Thursday, only found northern bettongs at Lamb range and Mount Spurgeon in the Carbine tableland, with no trace of the species detected at either Mount Windsor or Coane range.
The project team said this meant the number of distinct populations had halved and that the total land area the animals occupied had fallen by about 70% – from 500 square kilometres to 145 square kilometres – in the past three decades.
They estimate there are at most 2,500 animals left in the wild and that only the population at Lamb range could be considered stable.
“It is clear from the results of this project that northern bettong populations have suffered drastic reductions over the last three decades,” the report states.
It says the decline in the species has been caused by factors including changes in climate, land management practices, predation by feral animals, habitat clearance and changed fire regimes.
The scientists have called on the federal government to upgrade the species threat status from endangered to critically endangered, and for both state and federal governments to consider options for an insurance population.
“This is a pretty alarming decline for the northern bettong,” said Tim Cronin, the senior manager of species conservation at WWF Australia. “If we don’t do something soon, we will lose them.
“Any time you’ve got a species with only one stable population left in the wild, it leaves it really vulnerable to things like a fire event.”
He said while there were risks associated with translocating animals to establish new populations, the research team believed it was necessary to explore it in this case.
It has also called for the existing populations to be properly protected and their habitat restored.
The Senate is examining Australia’s fauna extinction crisis.
Conservationists have called for better resourcing and coordination of threatened species work so that more Australian wildlife does not suffer the same fate as the Bramble Cay melomys, a tiny rodent that went extinct in 2009 after governments failed to act in time to save it.
The northern bettong project team said its study was another example of species decline that was occurring across the country.
Caitlin Weatherstone, a wildlife
ecologist who worked on the project, said if the animal was lost it would have knock-on effects for the surrounding ecosystem.
The project found the marsupial played an important role in its environment because it was one of the main animals that ate truffles and dispersed truffle spores through its habitat.
Its decline could affect truffle biodiversity in these areas “with unknown consequences for plant-fungal interactions and ecosystem health”, the report said.
“If we lose that animal out of the ecosystem we don’t know what’s going to happen,” Weatherstone said. “It will affect forest health but we don’t know by how much at this point.”
A spokesperson for Queensland’s department of environment and science said about 80% of the northern bettong’s habitat was on land managed by the Queensland parks and wildlife service.
As a result of the population study, the department had produced an updated field guide for the management of fire in northern bettong habitat. “With the department’s collaborators, JCU and WWF-Australia, DES will consider the report to determine the best way forward from this point,” the spokesperson said. Comment was sought from the federal environment department.