Great Victoria Desert
A vast, sparsely populated region covered by dunefields and gibber plains, the Great Victoria Desert receives little rain and experiences extreme temperatures. A highly desert-adapted fauna lives here and the area is known for its lizard diversity. Climate and isolation render pastoralism and agriculture inviable, so the region has suffered few direct effects of European settlement. The presence of a weapons testing range and nuclear weapons test sites has further isolated the region and means that this is one of the least populated areas of Australia.
Location and General Description
The vast Great Victoria Desert extends from the Eastern Goldfields area in Western Australia across the southern parts of central Australia to the Stuart and Gawler Ranges in South Australia. The climate is arid, with mean annual rainfall ranging from below 150 millimeters (mm) to over 250 mm. Rainfall is aseasonal, but shows great variability between years. Summers are very hot, with mean maxima during summer between 32 °C and 35 °C. Diurnal ranges are also large, and overnight minima commonly fall below 0 °C during winter. Much of the region is occupied by sand dunes, with areas of calcrete and silcrete. Dunes cover low-elevation areas, interspersed among low ranges, dissected tablelands, and plains.
Much of the Great Victoria Desert is vegetated by open woodlands, typically eucalypts (Eucalyptus gongylocarpa, E. pyriformis, and E. socialis) with a hummock grass understory (Triodia spp., largely T. basedownii), mulga (Acacia aneura) with other grasses (Aristida spp. and Plectrachne spp.), or belah (Casuarina cristata) with shrubs (Maireana sedifolia, Dodenaea attenuata). The ‘Giles Corridor’ is a narrow strip of Acacia vegetation and the only continuous shrubland to completely traverse the Great Victoria Desert. This corridor links the Pilbara region in Western Australia to the Central Ranges by going though the Lake Carnegie region in the Great Victoria Desert and the southern part of the Gibson Desert.
Gibber plains also occur in this ecoregion, consisting of areas in which the soil is covered by a closely-spaced layer of pebbles, and glazed with a thin wind-polished layer of iron oxides. Gibber plains are normally almost devoid of vegetation, but following rains may be densely covered with ephemeral species, especially Fabaceae, Compositae, and Amaranthaceae.
One of the strategies that allows animals to persist in such extreme environments is to be highly mobile and follow favorable conditions across great distances. Consequently endemism is low, especially among birds and larger mammals. Nevertheless, the endangered chestnut-breasted whiteface (Aphelocephala pectoralis) has a relatively restricted range, spanning the eastern parts of this region and the western parts of the adjoining Tirari-Sturt stony desert region. The vulnerable malleefowl (Leipoa ocellata) occurs within the Unnamed Conservation, and, although not reported from the region in recent decades, it is conceivable that the enigmatic and critically endangered night parrot (Geopsittacus occidentalis) is still present.
The Great Victoria Desert also has an exceptionally high diversity of reptiles, including the vulnerable great desert skink (Egernia kintorei) which had been considered extinct in South Australia until its rediscovery by Aboriginal landholders in 1998. More than 100 species of reptile have been recorded, with Gekkonidae (e.g. Diplodactylus), Agamidae (e.g. Ctenophorus), Scincidae (e.g. Ctenotus, Egernia, Lerista and Morethia), and Elapidae (e.g. Simoselaps and Suta) being particularly diverse. Extensive lizard radiations and speciation occurred all over the arid interior of Australia, largely in response to climatic changes in the late Pleistocene and the associated shifting and isolation of vegetation pockets. An example of this isolation can be seen in the Great Victoria Desert, where a population of Ctentus brooksi is isolated from populations in the Simpson Desert by a narrow strip of scrub vegetation in south-central Northern Territory. Although the barrier is only several thousand years old, distinct subspecies have evolved, with C. b. brooksi found in the Great Victoria Desert. Diversification in habitat results in high lizard density: in a portion of the Great Victoria Desert in Western Australia up to nine different species of geckos may overlap, with species utilizing a wide variety of food and habitats (sand seas, sandridges, rocky breakaways, and salt lakes).
Several threatened mammals, the endangered sandhill dunnart (Sminthopsis psammophila), the endangered marsupial mole (Notoryctes typhlops), and the vulnerable mulgara (Dasycercus cristicauda) still occur within the region. Australia has experienced nearly half of the world’s mammal extinctions within the past 200 years, with most of the extinctions concentrated in drier interior regions of the continent. These extinctions include a number of species which once utilized the Great Victoria Desert: the pig-footed bandicoot (Chaeropus ecaudatus), short-tailed hopping mouse (Notomys amplus), long-tailed hopping mouse (N. longicaudatus), and lesser stick-nest rat (Leporillus apicalis). The greater stick-nest rat (L. conditor) has been extirpated from the region and survives only on offshore islands. There are no known extinction among the flora, and just one endangered species, the recently described Stemodia haegii.
Although the low level of threatened species may be an artifact of low collecting efforts, it is also indicative of the relatively low levels of disturbance since European settlement, which is also evidenced by the low incidence of alien species. The plant associations identified by Davies as being inadequately conserved in the South Australian part of the region are now effectively conserved in the Pitjantjatjara Lands.
Located north of the dog fence, Australia’s largest mammalian predator, the dingo (Canis lupus dingo), occurs throughout the region. The other notable predators found here are the perentie (Varanus giganteus) and Gould’s goanna (Varanus gouldii) which can both exceed 1.6 meters (m) in length. Feral foxes (Vulpes vulpes) and cats (Felis catus) also occur, and have been implicated in the decline of a number of vertebrate species.
As a consequence of the climate and the geographical isolation of the region, pastoralism and agriculture are not considered viable. Consequently, there has been little land clearance or grazing by domestic stock. A weapons testing range and nuclear weapons test sites are located in this region. Some areas have been disturbed by mineral exploration and mining, but these impacts are low when considered at the regional scale. Furthermore, extensive tracts of land are protected from exploitation. The Unnamed Conservation Park (21,289 square kilometers) on the South Australian – Western Territory border is the largest of South Australia’s conservation areas. A further 103,000 square kilometers is effectively conserved in the adjacent Pitjantjatjara Lands, which were ceded to traditional landowners by the South Australian Parliament in 1981. In Western Australia, some 20 percent (5000 square kilometers) of the Great Victoria Desert Nature Reserve falls within the region.
Types and Severity of Threats
A series of nuclear weapon trials were conducted at Maralinga and Emu by the United Kingdom between 1953 and 1963, as a result of which a number of sites were contaminated with radionuclides. The presence of plutonium-239 is of special concern, due both to its long half-life and the risks posed by inhalation. Although a rehabilitation program was carried out between 1996 and 1999, there remains considerable controversy as to its effectiveness.
There has also been disturbance associated with the Woomera rocket and weapons testing range, primarily through road-building. The increasing popularity of 4-Wheel-Drive vehicles presents the potential threat of disturbance in the vicinity of any tracks in this region, although this is not a problem in the Woomera Range, Maralinga, and the Pitjantjatjara Lands where public access is strictly regulated. The main sources of widespread disturbances come from feral animals, especially rabbits (Oryctolagus cuniculus) which adversely affect native vegetation. House mice (Mus musculus) can be highly abundant after good rains, and may adversely affect smaller native mammals.
Justification of Ecoregion Delineation
The Great Victoria Desert ecoregion comprises the IBRA of the same name. This active sandridge desert is characterized by Eucalyptus gongylocarpa, mulga, and E. youngiana over hummock grassland dominated by Triodia basedownii.
Additional Information on this Ecoregion
- For a terser summary of this entry, see the WWF WildWorld profile of this ecoregion.
- Blakers, M., S.J.J.F. Davies, and P.N. Reilly 1984. The Atlas of Australian birds. Melbourne University Press, Melbourne, Australia. ISBN: 0522842852
- Boomsma, C.D., and N.B. Lewis 1980. The native forest and woodland vegetation of South Australia. Woods and Forests Department, Adelaide, Australia.
- Briggs, J.D., and J.H. Leigh 1996. Rare or threatened Australian plants. CSIRO Publishing, Melbourne, Australia. ISBN: 0643057986
- Brouwer, J., and S. Garnett, editors. 1990. Threatened birds of Australia. Royal Australasian Ornithologists' Union, Moonee Ponds, Victoria, Australia.
- Cogger, H.G. 2000. Reptiles and amphibians of Australia. Reed New Holland, Sydney, Australia. ISBN: 0801427398
- Davies, R.J.P. 1982. The conservation of major plant associations in South Australia. Conservation Council of South Australia, Adelaide, Australia.
- Dept. P.I.E. 1990. Rehabilitation of former nuclear test sites in Australia. Department of Primary Industries and Energy, Canberra, Australia. ISBN: 0644126957
- Greenslade, P., L. Joseph, and R. Barley, editors. 1986. The Great Victoria Desert. Nature Conservation Society of South Australia, Adelaide, Australia.
- Hilton-Taylor, C. 2000. 2000 IUCN red list of threatened species. IUCN Publications Unit, Gland, Switzerland and Cambridge, United Kingdom. ISBN: 2831705657
- Laut, P., P.C. Heyligers, G. Keig, E. Loffler, C. Margules, R.M. Scott, and M.E. Sullivan. 1977a. Environments of South Australia Province 7 Western Pastoral. Commonwealth Scientific and Industrial Research Organization, Canberra, Australia.
- Laut, P., G. Keig, M. Lazarides, E. Loffler, C. Margules, R.M. Scott, and M.E. Sullivan. 1977b. Environments of South Australia Province 8 Northern Arid. Commonwealth Scientific and Industrial Research Organization, Canberra, Australia.
- Newby, K.R. 1984. The biological survey of the Eastern Goldfields of Western Australia Part 2 Widgiemooltha-Zanthus study area II Physical environment. Records of the Western Australian Museum supplement 18: 29-40.
- Pianka, E.R. 1984. Diversity and adaptive radiations of Australian desert lizards. Pages 371-376 in M. Archer, and G. Clayton, editors. Vertebrate zoogeography and evolution in Australasia. Hersperian Press, Perth, Australia.
- Short, J., and A. Smith. 1994. Mammal decline and recovery in Australia. Journal of Mammalogy 75(2): 288 – 297.
- Specht, R.L. 1972. The vegetation of South Australia (2nd Edition). Government Printer, Adelaide, Australia. ISBN: 0724318607
- Strahan, R., editor. 1995. The Mammals of Australia. Reed Books, Sydney, Australia.
- Thackway, R., and I.D. Cresswell, editors. 1995. An Interim Biogeographic Regionalisation for Australia: a framework for establishing the national system of reserves, Version 4.0. Australian Nature Conservation Agency, Canberra.
- Van Oosterzee, P. 1991. The Centre: the natural history of Australia’s desert regions. William Heinemann/Reed Books, Sydney, Australia.
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