The Pedirka Desert is a small desert 100 km north-west of Oodnadatta. It consists of a gently undulating plain with parallel dunes of ‘fiery’ red sands surrounded by stony tablelands. The dunes carry spinifex and acacia shrubland, with mulga shrublands elsewhere. The desert lies on the western margins of Witjara National Park.
The Pedirka Desert covers 1250 square kilometres of land in the southern part of the Finke bioregion, which straddles the Northern Territory/South Australian border.
The climate of the Finke bioregion is arid and hot, with very low rainfall and high evaporation. The median annual rainfall (1890–2005) averaged across the bioregion is 152 mm.
Flora and fauna
The plains of the Perdika Desert support a low open woodland of hakeas, grevilleas, mulga (Acacia aneura) and turpentine mulga (A. brachystachya). The sand dunes support a tall shrubland of hakeas and grevilleas and umbrella bush (Acacia ligulata) over a grassy understorey of Aristidaspp.
Little information exists on the threatened species recorded within the Pedirka Desert. Threatened and vulnerable species may include:
- Princess parrot (Polytelis alexandrae)
- Grey falcon (Falco hypoleucos)
- Australian bustard (Aredeotis australis)
- Plains wanderer (Pedionomus torquatus)
- Plains rat (Pseudomys australis)
- Itjaritjara/southern marsupial mole (Notoryctes typhlops)
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.
Invasive species in particular 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 wildfiresdriven by climate changehave the potential to devastate the biodiversity of arid ecosystems. Buffel grass invasion evident in the broader Finke bioregion.