Quenda poo critical to saving threatened tuart trees

By Angela Heathcote July 12, 2018
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Successful urban-dwellers they may be, but new research has found that quendas, also known as southern brown bandicoots, are critical to maintaining the health of Australian forests.

SOMETIMES MISTAKEN for big rats, quendas (Isoodon obesulus) – more commonly known as southern brown bandicoots – are successful urban-dwellers, often caught sipping from dog bowls or hiding under houses.

Found across Western Australia, their populations have persisted making them the only digging mammals that have managed to survive rapid overdevelopment of their habitats.

But they weren’t always city-slickers. New research has revealed the critical role they play in the ecosystem of Australian forests, specifically, the symbiotic relationship they have with the critically endangered tuart tree (Eucalyptus gomphocephala).

According to experts from Murdoch University, trees like tuart have suffered from the impacts of changing climate. Many of the forest trees are susceptible to insect infestations and fungal diseases. It’s estimated that over 500 ha of tuart woodland in Perth collapsed between 2010 and 2011.

The tuart trees rely on a type of fungi known as ‘ectomycorrhizal’, which helps the trees grow and survive adverse conditions. And now, by growing tuart seedlings in soil and mixing it with quenda scat, researchers found that the humble bandicoot is the critical link between the tuart trees and the fungi.

“We found that spores of fungi from the quenda poo can successfully germinate and colonise the roots of tuart seedlings after passage through the quenda gut,” Edith Cowan University fungal ecologist Anna Hopkins and Murdoch University quenda expert Natasha Tay told Australian Geographic.

“What this study shows, for the first time, is how quenda are a key linking element between the fungi and the tuart, helping disperse viable fungal spores throughout the landscape in their poo, and are thus critical to maintaining healthy tuart forests.”

Anna added that it’s not just the spreading of fungal spores that makes quendas important – it’s also their digging that mixes soil layers, helping with water infiltration and nutrient cycling.

Unfortunately, while quendas are better adapted to urban life than other animals, they still face a number of threats. “The clearing of habitat for urban expansion is the biggest threat to quendas. Not only do they lose suitable habitat, but it also brings quenda into closer contact with roads and predation by feral or pet animals,” said Natasha.

And a decline in their populations, as this new research shows, will have wider impacts for Australian forests. “I hope that this study will help people to understand just how interconnected our ecosystems are. The ectomycorrhizal fungi, the quenda and the tuart all rely on each other to survive and create healthy forests,” Anna said.