Australian Wildlife Conservancy (AWC) ecologists, Wunggurr Rangers and Ngarinyin Traditional Owners have made an exciting discovery in remote northwest Kimberley – the persistence of two threatened mammal species on Wilinggin Country, a spectacular 1.7 million hectare critical refuge for some of northern Australia’s rarest species.
During recent biodiversity surveys conducted as part of a collaborative partnership between AWC and Wilinggin Aboriginal Corporation (WAC) commenced in 2019, the team detected an endangered Black-footed Tree-rat (Mesembriomys gouldii gouldii) and two vulnerable Kimberley Brush-tailed Phascogales (Phascogale tapoatafa kimberleyensis).
Captured on camera traps set over December and January, the detection of the nationally endangered Black-footed Tree-rat is only the second record of its existence in the region in more than 30 years, while the discovery of the Kimberley Brush-tailed Phascogale significantly extends the known range of this threatened species. These findings highlight the importance of the WAC-AWC conservation partnership, both as a vital means for the sharing of knowledge and as a cooperative effort to protect the Kimberley’s extraordinary biodiversity.
AWC Ecologist, Dr Karen Young, said the discovery was incredibly significant: both the Black-footed Tree-rat and the Kimberley Brush-tailed Phascogale were recently ranked in the top 10 Australian mammals at highest risk of extinction in the next 20 years. Their presence on Wilinggin Country highlights the international significance of this region for conservation.
“While having an initial flick through the camera trap images, up came this photo that made me stop. It was a ‘hang on…can it be…Black-footed Tree-rat…is it really?’ moment. Then we saw it again on images from a different camera on a different day,” Dr Young said.
“Records of the Black-footed Tree-rat in the Kimberley region didn’t occur after 1987 until it was captured again in 2017. Through this partnership we’ve detected it in another location on Wilinggin Country on our first joint field-trip.
“This is really exciting because Wilinggin Country has the only current-time records of the endangered Black-footed Tree-rat in the Kimberley region. This shows just how important Wilinggin Country is for rare species.
“It gives us hope they might be in even more locations.”
The Black-footed Tree-rat has declined markedly in Western Australia, and in the Northern Territory, mainly due to the interaction of key threats like feral cats, wildfires and feral herbivores. With its long black and white tail, and distinctive black feet, the endangered Black-footed Tree-rat is one of the largest tree-dwelling rodents in Australia, weighing up to 800 grams – it has been called ‘the Australian equivalent of a squirrel’. It has a striking appearance, with long, shaggy medium-grey to black fur on top, a pale underside, and large black ears.
Although they live in tree hollows, Black-footed Tree-rats are predominantly ground foragers, living on a diet of mostly seeds, fruits and some invertebrates and grasses. Wildfires not only destroy their shelter, it burns the ground cover and leaves the animals vulnerable to predation by feral cats.
This new record is the first documented record of the Kimberley Brush-tailed Phascogale in Wilinggin Country in recent times. The species is listed nationally as vulnerable. Since 1985, it has only been recorded at three locations, including by AWC ecologists at Yampi Sound Training Area.
“Finding Kimberley Brush-tailed Phascogale on Wilinggin Country starts to fill in some major gaps in their known current distribution and gives us new locations to monitor,” Dr Young said.
“Kimberley Brushtail Phascogales are considered to be limited in the area they occupy and possibly quite fragmented in their distribution. Despite survey efforts by different agencies, groups and land holders, records have been scarce, so we don’t really know much about this species in the Kimberley.”
Also threatened by feral cats and wildfire, the Kimberley Brush-tailed Phascogale is a small, tree-dwelling carnivorous marsupial that is uniformly grizzled grey above, and cream to white underbelly and large ears. It has a conspicuous black, brush-like tail. Like most of their relatives, males of the species die off soon after mating.
This biodiversity survey by WAC Wunggurr Rangers and AWC ecologists was the first to focus on the area known as the ‘Pantijan block’, situated between Walcott Inlet and Prince Regent River.
In extreme heat and humidity, the team deployed 86 cameras across 17 sites in early December, returning to collect them at the end of January. The total survey effort amounted to a staggering 4,644 trap nights. AWC ecologists and WAC Rangers are now working together to conduct an extensive program of camera trap surveys to build an inventory of the species present across the partnership area.
WAC Biodiversity Project Officer Luke Russ said many of the animals spotted in the survey were once common and widespread along northern Australia.
“It’s reassuring knowing they are still living in Wilinggin land,” Mr Russ said.
‘Working with AWC’s ecologists and taking advantage of a helicopter to undertake a round of camera trapping was a great opportunity for myself and the Traditional Owners of the surveyed areas to get out to a remote area and assess the health of the critters we had heard the old people speak of.
“We look forward to working with our partners at AWC to survey more secluded regions and to ensure the continued prosperity of the unique creatures of this region, and empowering the coming generations to dedicate themselves to this vital goal.”
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