Truffle-like fungi fruit below the soil surface and cannot release spores into the air, so they depend on animals to dig them up and disperse them. The potoroo finds them by scent, excavates small conical pits with its forefeet and eats the fruiting bodies; fungi can account for the large majority of its diet in some seasons.
Spores pass through the digestive tract intact and are voided in scats, sometimes hundreds of metres from where they were eaten. Where they land, the fungi can form mycorrhizal associations with tree roots, extending the effective absorptive surface of the root system and improving uptake of phosphorus and nitrogen in Australia's characteristically poor soils.
The digging itself also matters. Potoroos and related bettongs turn over substantial quantities of soil each year, which mixes litter into the profile and creates catchments for seed and water. The loss of these small diggers from much of the continent is one of the less visible consequences of fox and cat predation.