Information about Dune Systems of Outback Australia

The Australian Arid Zone contains the most spectacular and largest longitudinal dune systems in the world. The first dune systems were created during arid and windy glacials around 900,000 years ago in the Lake Amadeus region in Central Australia. Because these cycles of glacial and interglacial were repeated, it is very difficult to determine the exact age of sand dune deserts. Thermo luminescence has been used to determine the age of sand dune particles. Core samples in the Simpson Desert taken by the University of Wollongong suggest it is only around 20,000 years old. Present theory suggests most of the current dune systems in Australia were formed by a dominating sub tropical anti cyclonic air system which has prevailed over the Australian continent for the past 20 to 30,000 years, continually picking up dust and sand from depot centres and depositing it as vast longitudinal dunes, some over 100kms in length.. This geological process is akin to a living-breathing organism. Lake Eyre becomes the heart. The great rivers flood, carrying silt down into this vast holding pan, where it is picked up and carried by the wind into the Simpson Desert. Likewise, the MacDonnell Ranges, once the size of the Rockies have eroded down to form the sands of the Red Centre.

The vegetation varies from desert to desert, however there are some commonalities. There are several vegetation groups and micro ecologies within sand dune systems. The longitudinal dunes support an entirely different vegetation to that of the interdunal corridors or swales. The most common plant groups in the Simpson, Tirari, Strzelecki and Great Victoria dune fields are Chenopodiaceae (saltbushes), Compositae (daisies and composites) and Graminae (grasses).The tops of the ridges are demobilised by binding plants such as sandhill canegrass Zygochloa paradox. This extraordinary plant is a perennial grass that sprouts from the root, generally during warm summer periods of rainfall. The new growth dies off quickly, however it continues to play a binding role. Observed patches of “dead” canegrass have continued to bind sand hills in Western New South Wales for over 20 years. Canegrass is both ubiquitous and beautiful. As the heat goes from the day, and the burning light of the sun disappears behind Simpson Desert dune crests, the eastern faces of the dunes in shadow are stunning, the driftwood blue of the clumps of canegrass contrasting with the reds and oranges of the desert sands.Triodia (Spinifex) is the other dominant grass in the dunefields of Australia. It tends to grow in the swales and on the dune faces, but not on the ridges. It is also not seen in saline or clay based soil areas. This is dealt with in detail in the section on Spinifex. These two plants are what botanist on the Madigan Expedition - Robert Crocker was to describe as, "Present throughout with remarkable homogeneity."In the Simpson, Tirari and Strzelecki deserts, acacia bushes and trees are prevalent on the dune faces and in the swales, however they rarely appear on the crests, aside from the sandhill wattle Acacia dictyophleba. The umbrella bush Acacia ligulata is very common on the dune slopes and in the swales. By digging around this plant and identifying it's swollen roots, one can find fat witchetty grubs, once an important Aboriginal food source. Another common acacia bush is the Elegant Wattle Acacia victoriae, with it's gnarled bark, singularly unattractive foliage and absolutely stunning and showy creamy blossoms. As well as this is Dead Finish Acacia tetragonophylla the last plant to survive in the drought. On the eastern and northern sides of the Simpson Desert are the beautiful Gidgee Acacia georginae. Whilst the foliage of this plant is generally poisonous, travelling through gidgee swales is like gliding through ancient olive groves, the plants en masse contrast with the red sand with a stunning aqua colour.




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The scent given off by their volatile oil when wet or humid is considered by some to smell like cat's piss. I call it eau d' gidgee, and it must be an acquired taste, because the longer I spend in the desert the more it appeals to me. There is also the ubiquitous Mulga Acacia aneura, predominately in it's sandhill form, which is dealt with in detail on the Mulga Shrublands page. Myrtaceae (eucalypts) are not seen in the Simpson except along river lines and floodplains on the deserts edge. Hakea and Grevillea are also represented in all the Australian deserts. Grevilleas have stunning flowers that drip with pollen, often providing food sources for Aboriginal people. One of the most sensual and exotic cullinary experiences is to wrap your lips around the blossom of a golden Honey Grevillea Grevillea eriostachya. In the dunefields of the Great Victoria Desert you will see the large eucalypt Marble Gum Eucalyptus gongylocarpa growing in sandy soils, even on the dune crests. The marble gum grows up to 20 meters high. Tall trees in dunefields are perhaps the most striking differences between the western and northern dunefields and their southern and eastern cousins. There are also many different types of Mallee, such as the Ooldea Mallee Eucalptus youngiana and the Kingsmill Mallee Eucalyptus kingsmillii with their strikingly beautiful large flowers.There are also open woodland communitys of Black Oak Casuarina pauper, and the native pine Callitris verrucosa. In the Great Sandy and Little Sandy Deserts of the northwest, spinifex is the most common plant. There are also a number of eucalypts represented, notably the snappy gums Eucalyptus brevifloai and E.leucopholia, and the bloodwoods corymbia sp. There is the striking Desert Walnut Owenia reticulata and several native figs. Senna is well represented as well as a myriad of small flowering plants. One plant which often outcompetes spinifex in the northern and western deserts is Desert thryptomene thryptomene maisonneuvii with its beautiful white and pink flowers. It smells of sweet plasticine.
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Crotalaria Cunninghamii - the rattle pod or parrot bush. Aboriginal people would shred the sinewy stems and make sandals to protect their feet from heat.

the Nappanerica Dune -"Big Red" with a flooded swale in the foreground.


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