The landscapes of the Tanami Desert are mainly featureless sand plains with small areas of moderate sand dunes or low ridges and stony rises. Much of the Tanami Desert is covered with spinifex grassland with acacia shrubland and widespread bloodwood eucalypts. Mulga is found on the occasional patches of red earth. The Tanami also contains low-lying swampy plains with samphire on buried drainage systems and ephemeral wetlands such as Lake Ruth and Sanctuary Swamp.
Over 14 million hectares of the Tanami Desert are held within the National Reserve system: four million hectares within the Northern Tanami Indigenous Protected Area (IPA) and more than 10 million hectares within the Southern Tanami IPA, Australia’s largest Indigenous protected area.
The Tanami Desert covers 310,000 square kilometres, most of which lies in the Northern Territory. The western section of the Tanami lies in Western Australia between the Great Sandy Desert and the Kimberley.
The Tanami bioregion has a semi-arid climate influenced by the monsoon, so that most rain falls within the summer months. The median annual rainfall (1890–2005) averaged across the bioregion is 298 mm.
Warlpiri lands. Yuendumu and Lajamanu.
Flora and fauna
The sandplains of the Tanami support hummock grasslands of soft spinifex (T. pungens) with a mixed and sparse overstorey of desert bloodwoods (Corymbiaspp.), corkwood (Hakea lorea), acacias and grevilleas. The uplands support acacia scrubland and soft spinifex. Drainage lines in the north support ribbon grass (Crysopogonspp.) and Flinders grass (Iseilemaspp.) short-grasslands, often as savannas with river gum. Wetlands areas in the southern Tanami may be fringed by coolibah (Eucalyptus coolabah), bluebush or desert honey myrtle (Melaleuca glomerata).
The Tanami Desert is considered a stronghold for many rare or declining animal species within the Northern Territory, such as greater bilby, brush-tailed mulgara, Australian bustard and great desert skink. Three plant species are endemic to the Tanami bioregion.
The Tanami bioregion supports one threatened plant species (dwarf desert spike-rush Eleocharis papillosa) and 25 threatened or vulnerable animal species, including:
- Greater bilby (Macrotis lagotis)
- Brush-tailed mulgara (Dasycercus blythii)
- Kakarratul/northern marsupial mole (Notoryctes caurinus)
- Warrana/Great Desert Skink (Liophilis kintorei)
- Princess parrot (Polytelis alexandrae)
- Masked owl (Tyto novaehollandiae)
- Australian bustard (Aredeotis australis)
- Red goshawk (Erythrotriorchis radiatus)
- Grey falcon (Falco hypoleucos)
- Gouldian finch (Erythrura gouldiae)
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. Feral camels, horses and donkeys are a management issue in the southeast of the bioregion and are increasing in number in the WA section of the bioregion.
Invasive species particularly 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.
Parkinsonia (Parkinsonia aculeata) is establishing around watering points on pastoral leases on the edge of the bioregion. If not controlled, it can form dense, impenetrable thickets.
Vegetation clearing for mining and exploration is a potential threat to ecosystems in the south-west of the Tanami Desert.