How DNA from Scat Is Helping Rescue the World’s Rarest Marsupial

The Plight of Gilbert’s Potoroo

Deep in the forests of southwestern Australia, a tiny, rabbit-sized marsupial known as the Gilbert’s potoroo (Potorous gilbertii) clings to survival. With fewer than 150 individuals remaining in the wild, it holds the dubious title of the world’s rarest marsupial. Once thought extinct after no sightings for over a century, the species was rediscovered in 1994 at Two Peoples Bay Nature Reserve. Since then, conservationists have raced to protect the potoroo from its greatest threats: habitat loss, predation by foxes and cats, and increasingly severe bushfires fueled by climate change. But a new, non-invasive tool is providing unexpected hope: DNA from their droppings.

Unlocking Secrets Through Scat DNA

Scientists from Australia’s Department of Biodiversity, Conservation and Attractions have turned to cutting-edge genetic techniques to study the potoroo’s diet without disturbing the animals. By analyzing traces of DNA in the animals’ scat, the team has uncovered critical information about the underground fungi that make up the majority of the potoroo’s diet. These fungi – known as mycorrhizal fungi – form symbiotic relationships with tree roots and are essential for forest health. The potoroos, in turn, act as fungal dispersers, spreading spores through their droppings.

How the Technique Works

The process, called DNA metabarcoding, allows researchers to identify fungi species from tiny fragments of genetic material in scat samples. Unlike traditional methods (e.g., visual inspection of spores under a microscope), DNA analysis is far more precise and can detect fungi that are too small, degraded, or similar-looking to distinguish by eye. The team collected dozens of droppings from known potoroo habitats and sequenced the fungal DNA present.

Results revealed a surprising diversity of fungi, including several species previously unknown to science. More importantly, the data showed that potoroos depend on a specialized subset of fungi that are only found in certain soil types and forest ages. This discovery has profound implications for conservation.

Implications for Habitat Selection and Backup Populations

Because potoroos rely so heavily on specific fungi, any relocation of animals to new sites must ensure the appropriate fungi are present. The scat DNA analysis gives conservationists a roadmap: they can now survey potential habitats by testing soils for the same fungal DNA. This reduces the risk of moving potoroos to areas where they would starve or fail to reproduce.

Establishing Safe Havens

Australia’s bushfire season is becoming more intense each year. In 2019–2020, massive wildfires devastated millions of hectares, including some of the potoroo’s limited range. Establishing backup populations on offshore islands or in well-managed sanctuaries is now a top priority. Using the fungal DNA markers, scientists can identify islands with the right soil fungi, then introduce small groups of potoroos to create insurance populations. The method is already being tested on Bald Island, where a previous translocation is being monitored with the same scat technique.

Beyond One Species: Broader Applications

The success of this approach is inspiring similar work with other threatened species. Many herbivorous mammals – from bilbies to bettongs – also rely on fungi as a key food source. Applying scat DNA analysis to multiple species could help design more effective ecosystem restoration plans. Moreover, the technique is non-invasive, meaning it can be used repeatedly without stressing animals – a major advantage for critically endangered populations.

Conclusion: A Small Scat, A Big Impact

The story of Gilbert’s potoroo is far from over, but the use of DNA from droppings has given conservationists a powerful new tool. By turning what was once considered waste into a library of vital information, scientists are not only learning about the potoroo’s secretive lifestyle but also gaining the knowledge needed to guide their recovery. As wildfires rage and habitats shrink, every piece of genetic evidence helps ensure that the world’s rarest marsupial does not disappear forever.

For those interested in supporting these efforts, consider donating to organizations that fund habitat preservation and fire management in southwestern Australia.