Scientists Use DNA From Droppings to Track the World's Rarest Marsupial, With Fewer Than 150 Left in the Wild

Level 2 - Elementary

Gilbert's potoroo is officially the world's most critically endangered marsupial. It was thought to be extinct for more than 100 years until it was rediscovered in 1994. Fewer than 150 animals survive today, all living in one small area near Albany in Western Australia.

Scientists from Edith Cowan University and the Western Australian government have developed a new method to study these animals without catching them. They collect the potoroo's droppings from the forest floor and extract DNA from them. This is called environmental DNA, or eDNA.

By analysing the eDNA, researchers can identify individual animals, learn about what they eat, and check their genetic health. This is very useful because trapping potoroos to collect samples is stressful for the animals and difficult to do safely in the dense forest.

The scientists hope this technique will help them find new areas where potoroos could safely live. If they can set up a second population in a different location, the species would be much safer if a fire or disease killed the main colony.

critically endangered: facing an extremely high risk of extinction in the wild

rediscovered: found again after being lost or thought to no longer exist

environmental DNA (eDNA): genetic material shed into the environment by organisms, collected from soil, water, or droppings

extract: to remove or take something out of something else

population: a group of animals of the same species living in a particular area

species: a group of living things that share the same characteristics and can breed together

technique: a particular way of doing something, especially in science or art

dense: closely packed together; thick

Level 3 - Intermediate

Researchers from Edith Cowan University, in partnership with the Western Australian Department of Biodiversity, Conservation and Attractions, have published a study showing that environmental DNA extracted from Gilbert's potoroo droppings can serve as a reliable, non-invasive monitoring tool for one of the planet's most critically endangered mammals. The potoroo, Potorous gilbertii, has fewer than 150 surviving individuals, all confined to Two Peoples Bay Nature Reserve near Albany in southwestern Australia.

The technique involves collecting fresh scat from the forest floor and processing it in the laboratory to isolate DNA. By sequencing the genetic material, scientists can distinguish individual animals, analyse their dietary composition -- the potoroo's survival depends heavily on specific underground fungi called hypogeal fungi -- and assess their genetic diversity. Genetic diversity is critical: with such a small population, inbreeding can quickly reduce the immune resilience of the species.

Conventional monitoring of Gilbert's potoroo has relied on live-trapping, which requires setting wire cages in the dense coastal heathland habitat, then handling the animals to take tissue samples. This method is not only labour-intensive but can cause stress that affects reproductive success. The eDNA approach removes those risks and allows more frequent and widespread surveys without disturbing the animals.

The conservation stakes are high. The entire known wild population lives in a single 4,750-hectare reserve, making it extremely vulnerable to a single catastrophic event such as wildfire or disease. Scientists say the eDNA data are now essential for identifying nearby sites -- carefully chosen for the right fungi and vegetation -- where a second insurance population could be established to safeguard the species' long-term survival.

non-invasive: not requiring entry into the body or direct contact with a living animal

scat: animal droppings, especially used in wildlife biology

hypogeal fungi: underground fruiting fungi, also called truffles, which form a critical part of the potoroo's diet

inbreeding: the reproduction of closely related individuals, which reduces genetic diversity and can weaken a population

heathland: an open area of land covered with shrubs and low-growing plants, typical of coastal Australia

reproductive success: the ability of an animal to produce healthy offspring that survive to breed themselves

insurance population: a second group of a species kept in a separate location to safeguard against the loss of the main population

hectare: a unit of land area equal to 10,000 square metres, about the size of two football fields

Level 4 - Advanced

A collaborative study between Edith Cowan University and the Western Australian Department of Biodiversity, Conservation and Attractions, published in 2026, demonstrates that non-invasive environmental DNA profiling of Gilbert's potoroo (Potorous gilbertii) scat yields individual identification, dietary metabarcoding, and genomic diversity metrics of sufficient resolution to underpin evidence-based conservation management for the world's most critically endangered marsupial. With the entire known wild population of fewer than 150 animals concentrated within the 4,750-hectare Two Peoples Bay Nature Reserve, the imperative for a low-disturbance monitoring protocol that can be deployed at high spatial and temporal frequency is acute.

The methodological advance sits within the broader eDNA revolution in wildlife monitoring. Where traditional mark-recapture via live-trapping demands repeated physical handling -- stressful for an animal already operating near the edge of reproductive viability, and logistically demanding in the dense kwongan heathland habitat -- scat eDNA allows genome-level characterisation from a substrate passively deposited across the landscape. Dietary metabarcoding, in particular, addresses a longstanding management gap: the potoroo's near-obligate dependence on hypogeal ascomycete and basidiomycete fungi makes fungal community composition a first-order habitat-suitability criterion, yet the relevant fungi are almost entirely subterranean and invisible to conventional vegetation surveys.

Population genomics data extracted from the scat library have begun to quantify the erosion of heterozygosity in the Two Peoples Bay meta-population -- a known correlate of compromised immune function and reduced adaptive capacity. Effective population size (Ne) estimates derived from runs-of-homozygosity analyses suggest the population is well below the 50/500 rule thresholds, reinforcing the urgency of translocation. The eDNA framework now provides conservationists with a real-time genetic dashboard: changes in individual identity, kinship structure, and allele frequency can be tracked non-invasively across consecutive seasons, enabling proactive detection of inbreeding depression before it becomes demographically apparent.

The translocation imperative -- establishing at least one geographically independent insurance population in suitable habitat -- remains the species' existential hedge. The eDNA dietary data are now being used to rank candidate sites by fungal-guild compatibility, matching the species-specific mycophagous spectrum of Two Peoples Bay individuals against soil eDNA surveys of potential recipient sites. If a second self-sustaining population can be established and monitored at comparable genomic resolution, Gilbert's potoroo would for the first time since its 1994 rediscovery sit on a trajectory of managed resilience rather than catastrophic single-point-of-failure extinction risk.

metabarcoding: a technique using DNA sequencing to identify the species present in an environmental sample such as soil or gut contents

heterozygosity: a measure of genetic diversity within a population; higher values indicate more genetic variation

effective population size (Ne): a measure of the number of individuals in a population that contribute genes to the next generation; smaller than census size

runs-of-homozygosity: stretches of identical DNA inherited from both parents, used to measure inbreeding in a population

mycophagous: feeding on fungi

kwongan: a type of species-rich shrubland found in southwestern Australia, characterised by low-nutrient sandy soils

translocation: the deliberate movement of animals from one location to another to establish or supplement a population

50/500 rule: a conservation guideline stating that a population needs at least 50 individuals to avoid inbreeding depression and 500 to maintain long-term evolutionary potential

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Scientists Use DNA From Droppings to Track the World's Rarest Marsupial, With Fewer Than 150 Left in the Wild

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