The Tirari Desert, along with the Strzelecki and Sturt Stony deserts, forms the complex of desert country in north-eastern South Australia. The Tirari is part of the Simpson–Strzelecki Dunefields (SSD) bioregion.
Cooper Creek flows through the Tirari Desert, allowing a corridor of coolibah shrubland to flourish. The desert also contains salt lakes and sand dunes, which run from north to south. The dunes are covered with canegrass and sparse acacia shrubland.
The Tirari Desert forms the eastern edge of Lake Eyre and is partly located within the Kati Thanda – Lake Eyre National Park.
The 15,000 square kilometres of the Tirari desert lies fully within South Australia. The Simpson Desert lies to its north and the Sturt Stony and Strzelecki deserts lie to its east.
The SSD bioregion has an arid, subtropical climate and includes the driest area of Australia. Rainfall is unreliable but usually occurs in summer storms. The median annual rainfall (1890–2005) averaged across the entire bioregion is 125 mm.
Flora and fauna
The vegetation of the Tirari Desert is similar to that of the Simpson and Strzelecki deserts: sandhill canegrass (Zygochloa paradoxa) and sandhill wattle (Acacia ligulata) cover the dune crests and mobile slopes, while hard spinifex (Triodia basedowii) grows on stable slopes and the sandy corridors between dunes.
Dune flanks often support a sparse, tall shrubland of acacia, eremophila and grevillea. Saltbush (Atriplexspp.) and bluebush (Maireanaspp.) are also found on swales and interdune flats. Narrow river red gum (Eucalyptus camadulensis) and coolibah (E. coolabah) woodlands are found around permanent waterholes along Cooper Creek.
Threatened and vulnerable species recorded in the Tirari Desert include:
- Ampurta/Crest-tailed mulgara (Dasycercus cristicauda)
- Wilkiniti/dusky hopping mouse (Notomys fuscus)
- Fawn hopping-mouse (Notomys cervinus)
- Grey falcon (Falco hypoleucos)
- Woma python (Aspidites ramsayi)
Introduced predators such as red foxes and feral cats have been a primary cause of the extinction of small- to medium-sized mammals across Australia’s arid inland. Along with wild dogs, they continue to pose significant threats to mammals, reptiles and ground-dwelling birds across all of Australia’s desert ecosystems.
Introduced herbivores such as camels, donkeys, horses and rabbits cause significant damage to desert ecosystems through overgrazing, particularly around water sources where they tend to congregate in dry times. Camels foul waterholes and have significant impacts upon fragile salt lake and freshwater ecosystems.
Of all the invasive species, buffel grass (Cenchrus ciliaris) poses the greatest threat to Australia’s desert ecosystems as it can quickly come to dominate the ground layer of vegetation. It burns hotter and more quickly than the native grasses it replaces. Buffel grass invasion in combination with larger and more intense wildfires driven by climate change have the potential to devastate the biodiversity of arid ecosystems.
Extraction and diversion of water from inland river systems reduces the water these areas receive and store, leading to the reduced health of waterholes, riverine and floodplain vegetation and the habitat they provide for fauna.