Australian digging mammals have played an important role in transforming the country's ancient, infertile soils.

Many mycorrhizal fungi produce subterranean fruiting bodies—or ‘truffles’—which are highly sought after by many marsupial species that specialise in locating and digging them out. In turn, the mammals disperse spores of the fungi across the landscape [3, 4]. 

Despite once being described as common, digging mammal species have been lost from the Australian landscape over the last 200 years. Around half of digging mammal species are now extinct or under conservation threat, and the majority of extant species have undergone marked range contractions [5] and are therefore ‘functionally extinct’ in that they are no longer sufficiently abundant or widespread to maintain their important digging roles.  

Australian ecosystems have therefore undergone a massive loss of ecosystem processes relatively recently. Effects of these losses—such as reduced plant recruitment and growth, flowering, seed set—are likely still to be felt. 

Quenda (Isoodon fusciventer) are one of the only digging mammal species that have remained reasonably abundant across southwest Western Australia [6]. Recognising where populations exist and continuing to quantify and understand their vital role in ecosystem health will help us work towards conservation of our precious urban bushland.  

Although they have an omnivorous diet, showing a high reliance on invertebrate prey, bandicoots such as the quenda eat a considerable banquet of fungi. We used DNA barcoding to determine what food items were present in 60 scats collected across a range of urban reserves. Our analysis revealed over 800 different fungi across our samples, each with its own unique barcode. Each scat sample contained an average of 46 different fungi (range 8–120) [7].  

We had thought that we would be able to identify which fungi species quenda prefer, but it turns out that our study shows us just how few of our fungi have been genetically identified previously. We could only assign 20% of the fungi to known species. For the rest, we know their DNA barcodes, but we have no library to match them to.  

Southwest Western Australia has a huge diversity of mycorrhizal fungi, which is probably greater than any other part of the globe. Much of this diversity lies beneath our feet, and most of us would therefore be unaware of this biodiversity treasure.  

Project partners and collaborators 

Janine Kuehs

Leonie Valentine 

Anna Hopkins 

Bonnie Beal Richardson 

City of Mandurah 

Shire of Mundaring

What you can do 

Quenda have persisted in and around cities across southwest Western Australia. They appear to be resilient little critters, but we can help them too: 

Quenda visit many people’s backyards [10]. Quenda diggings across our lawns are valuable aeration of the soil, increasing water infiltration [2, 6]. As an added bonus, the animals are probably digging out beetle grubs that would otherwise damage the roots of lawn.  

Quenda prefer gardens with more vegetation in them [10]. We can therefore improve the habitat quality of our backyards as well as urban reserves to maintain and potentially increase quenda populations. Planting with dense bushes – such as Acacia lasiocarpa or Calothamnus quadrifidus, which provide protection from predators – would help improve habitat for quenda and other native wildlife. 

Design principles to provide habitat opportunities for bandicoots, and potentially also other wildlife, in residential gardens [10]. 

 

Funding

City of Mandurah 

Australian Research Council 

Western Australian State Government; Centre of Excellence for Climate Change, Woodland and Forest Health 

Project duration 

2016 -  Ongoing

Read more about this work 

1. Valentine, L.E., et al., Bioturbation by bandicoots facilitates seedling growth by altering soil properties. Functional Ecology, 2018. 32: p. 2138-2148. 

2. Valentine, L.E., et al., Scratching beneath the surface: Bandicoot bioturbation contributes to ecosystem processes. Austral Ecology, 2017. 42: p. 265-276. 

3. Tay, N.E., et al., The tripartite relationship between a bioturbator, mycorrhizal fungi, and a key Mediterranean forest tree. Austral Ecology, 2018. 43: p. 742-751. 

4. Dundas, S.D., et al., Digging mammals contribute to rhizosphere fungal community composition and seedling growth. Biodiversity and Conservation, 2018. 27(12): p. 3071-3086. 

5. Fleming, P.A., et al., Is the loss of Australian digging mammals contributing to a deterioration in ecosystem function? Mammal Review, 2014. 44: p. 94-108. 

6. Kristancic, A.R., et al., Quenda; nature’s gardeners, in 2017 Research Findings in the School of Veterinary and Life Sciences, M. University, Editor. 2017. 

7. Hopkins, A.J.M., et al., Urban remnant size alters fungal functional groups dispersed by a digging mammal. Biodiversity and Conservation, 2021. 30: p. 3983-4003. 

8. Howard, K.H., et al., Community Quenda Survey 2012. 2014, WWF-Australia and the Department of Parks and Wildlife, Western Australia: WWF Australia, Perth, WA. 

9. Bryant, G.L., et al., Habitat islands in a sea of urbanisation. Urban Forestry and Urban Greening, 2017. 28: p. 131-137. 

10. Kristancic, A.R., et al., Accepted 29/04/2022 Biodiversity conservation in urban gardens – pets and garden design influence activity of a vulnerable digging mammal. Landscape and Urban Planning, 2022. In press. 

11. Swinburn, M.L., et al., The importance of grasstrees (Xanthorrhoea preissii) as habitat for mardo (Antechinus flavipes leucogaster) during post-fire recovery. Wildlife Research, 2007. 34: p. 640-651.