Studying bettongs & bandicoots

In the Midlands of Tasmania there are five bettongs named Egbert, Percy, Dot, Cyril and Maud. They’re not pets, but they wear collars. They’re not criminals, but Riana Gardiner tracks their every move.

Riana is a PhD candidate from the University of Tasmania. She’s one of five students investigating how native animals feed, move and avoid predators in the Midlands, a fragmented landscape. Riana has chosen to focus on Eastern Bettongs.

Truffle-eating ecosystem engineers

Eastern Bettongs are native marsupial mammals, about the size of a rabbit. They’re also known as rat kangaroos – they move about with a low, springy hop. They live in woodlands, nest in bracken fern and move into more open areas to feed on truffles. Bettongs are important ‘ecosystem engineers’: their digging plays a key role in turning over topsoil in woodlands, and in maintaining plant and fungi species.

They’re also considered ‘critical weight range’ mammals – they’re the perfect prey size for cats, dogs and foxes.

Because of fox predation and large-scale land clearing, they’re now extinct on mainland Australia.

The Midlands is one of the few strongholds for bettongs in Tasmania. But even here, their numbers are in decline, due, in part, to habitat fragmentation – the large, exposed paddocks between woodland patches make bettongs more vulnerable to predation and cars.

But we don’t know a lot about bettongs in the Midlands. How far do they travel? What part of their habitat do they use? Do they stick to woodlands or do they use paddocks and cultivated land? And how close together do woodland patches need to be, to allow movement between populations?

Riana’s research

So Riana’s job is to dig up information on these burrowing truffle-eaters. Like Rowena, she fits the bettongs (Egbert, Percy and friends) with lightweight GPS collars. She can then track, on a map, where they move and what part of the habitat they’re using. She takes the collars off after a month.

First though, Riana must catch these nocturnal mammals. In the late afternoon she baits the traps with a delicious mix of peanut butter, rolled oats, vanilla essence and peanut oil (as Riana says, “It’s very hard to not eat it!”).

In the middle of the night she returns to check the traps. If she catches a bettong she fits it with a collar, to track its movements.

So far, Riana has tracked 17 bettongs. While she hasn’t finished her field work, she’s noticed that bettongs stick close to vegetation and are not often found in open landscapes. At the end of her PhD, Riana will be able to tell groups like Greening Australia and Bush Heritage what bettongs consider ‘good habitat’.

Eastern Barred Bandicoots: a cautionary tale

Riana is two years through her PhD, but her research has already provided a cautionary tale. She initially planned to study both the Eastern Bettong and the endangered Eastern Barred Bandicoots. Both are of conservation interest as they are extinct in the wild on the mainland. However, Riana has only detected one bandicoot on a camera trap, and is continuously told that they haven’t been seen in more than 8 years. So she posted flyers around the Midlands that read ‘Have you seen this animal? We want to hear from you.’ “They were like wanted posters,” she says.

We hope that this collaboration between the University of Tasmania, Greening Australia, Bush Heritage, the Tasmanian Land Conservancy and the state Government will reverse these worrying trends. We’re working with committed landholders to restore habitats to support native animals. We hope that our restoration projects will ensure bettongs like Egbert, Cyril and Maud will be hopping around the Midlands for many years to come. 

- Kate Cranney, Science Communicator Intern.