Media release

From: Edith Cowan University

ECU study could help conserve the world’s rarest marsupial

New research from Edith Cowan University (ECU) could help to protect the world’s rarest marsupial.

The critically endangered Gilbert’s potoroo, which is native to Western Australia, has less than 150 individuals remaining in the wild.

Researchers from ECU along with the Department of Biodiversity, Conservation and Attractions (DBCA) have been working together to better understand their diet, in a bid to ensure their population.

“We are looking to recover the species through translocations, which is moving organisms from one location to another to create an insurance population in case anything was to happen in their existing populations,” School of Science PhD student Rebecca Quah explains.

“In doing that, one of the challenges was trying to determine what they are eating and where those resources can be found. Mycophagus – or fungi-eating mammal diets are quite hard to study because a lot of fungi remain undescribed.”

Non-invasive diet analysis

Ms Quah said environmental DNA (eDNA) metabarcoding techniques were applied to scat (faeces) samples, a technique that is increasingly being used for dietary studies in wildlife.

“Traditionally, researchers would go through undigested material in scats to study animal diets, but trying to identify fungal spores remained a challenge,” Ms Quah said.

“This research used a molecular technique, known as eDNA metabarcoding to decipher what animals are eating. It’s a non-invasive way of studying diet and all you need are fresh scats from the environment.”

This research focused on whether the diets of more common fungi-eating mammals overlapped with the Gilbert’s potoroo, on the basis that these mammals historically co-existed.

“We examined quokka, quenda and bush rat scats and found that there was some overlap in the diet of the four mammals, and that habitat use between the quokka and potoroo were also really similar,” Ms Quah said.

“Based on our results, we recommend focusing on areas where all three species persist together as an indicator of suitable food, or habitat, for future potoroo translocation sites.”

A rediscovered species

Once thought to be extinct, several methods to boost numbers of Gilbert’s potoroos have been attempted since they were rediscovered in 1994.

“Soon after their rediscovery, breeding them in captivity was tried, but that didn’t work out, particularly because of how picky they are with their food resources,” she said.

“This is why wild-to-wild translocations are so important. In 2015, a bushfire destroyed 90 per cent of core potoroo habitat in Two Peoples Bay, which is home to the only natural population of Gilbert’s potoroo. Fortunately, insurance populations had been established on Bald Island and in a fenced enclosure at Waychinicup National Park by DBCA.

DBCA Research Associate Dr Tony Friend said with the critically endangered population scattered across four sites, two of which are islands off the Western Australian coast, researchers are hoping to find another mainland site for a translocation.

“The search for new translocation sites is an important next step in the recovery of Gilbert’s potoroo from near extinction. This publication shows that examining the fungal diet of mammals that occur with the potoroo can help in deciding where to establish new populations,” Dr Friend said.

Ecosystem engineers

The broader topic of Ms Quah’s PhD is looking at the conservation and translocations of fungi-eating mammals.

“Fungi-eating mammals are ecosystem engineers – they dig for fungi which helps in soil turnover, and they act as vectors for fungal spore dispersal.

“Fungi have several ecological functions, including having mutually beneficial relationships with plants, so mycophagous mammals are really important in maintaining healthy ecosystems.

“Unfortunately, many of Australia’s mammals are threatened because of predation from introduced cats and foxes. That is why it is vital that we do everything we can to help protect our native wildlife, and translocations are one important way to accomplish that goal.”