Peter Unmack




Helen Larson, Curator of Fishes, Museum and Art Gallery of the Northern Territory, Australia

Major Habitat Type

Xeric freshwaters and endorheic (closed) basins

Drainages flowing into

All drainages are endoheric (landlocked), and do not reach the ocean.

Main rivers to other water bodies

This vast area has virtually no permanent, fish-inhabited water.  While a number of creeks and lakes exist, they are dry most of the time.



This ecoregion encompasses the Great Sandy, Gibson, Tanami, and Great Victoria deserts.  It extends south to the coast along the Southern Ocean.


There is a large plateau in the middle of the ecoregion (500-600 m elevation).  The elevation drops with proximity to coasts on either side.

Freshwater habitats

This vast ecoregion covers 2,363,000 square kilometers, or 30% of Australia.  It consists of isolated, saline lakes and creeks that are mostly dry, except for during brief periods of sporadic rainfall.  Little permanent water has been found, and the region\'s fish exploration is severely lacking.

Terrestrial habitats

There is sparse vegetation in the deserts of this ecoregion.  In the Great Sandy Desert, high, red sand dunes extend in parallel rows for hundreds of miles. The region consists of desert sandridges and sandplains with tree steppe, shrubs, and open hummock grassland (World Wildlife Fund 2001a).

Ecological phenomena

Salt lakes that intermittently fill with water support nationally and internationally significant breeding habitat for waterbirds, although many of these lakes have not been assessed (Duguid et al. 2005).

Justification for delineation

This ecoregion is composed of six paleodrainage catchments (here referred to as the Palaeo-Victoria, Palaeo-Sturt, Palaeo-Internal, Palaeo-Oakover, Palaeo-south-western, and the Palaeo-southern), which were formerly connected to neighbouring drainages but have been isolated for quite some time (Van de Graaf et al. 1997;Unmack 2001).

Level of taxonomic exploration

Taxonomic exploration is good in the few areas that have actually been surveyed. Given that few areas have been surveyed outside of the Northern Territory, it is particularly difficult to assess (Duguid et al. 2005). 


  • Duguid, A.,Barnetson, J.,Clifford, B.,Pavey, C.,Albrecht, D.,Risler, J.;McNellie, M. (2005). "Wetlands in the arid Northern Territory. A report to the Australian Government Department of the Environment and Heritage on the inventory and significance of wetlands in the arid NT" Alice Springs: Northern Territory Government Department of Natural Resources, Environment and the Arts.
  • Cooper, S. J. B., Hinze, S., Leys, R., et al. (2002). "Islands under the desert: molecular systematics and evolutionary origins of stygobitic water beetles (Coleoptera: Dytiscidae) from central Western Australia" Invertebrate Systematics 16 pp. 589–598.
  • Humphreys, W. F. (1999). "Relict stygofaunas living in sea salt, karst and calcrete habitats in arid northwestern Australia contain many ancient lineages" W. Ponder and D. Lunney (Ed.) Other 99%. The Conservation and Biodiversity of Invertebrates ( pp. 219–227 ) Mosman, New South Wales: Royal Zoological Society of New South Wales.
  • Humphreys, W. F. (2001). "Groundwater calcrete aquifers in the Australian arid zone: the context to an unfolding plethora of stygal biodiversity" Records of the Western Australian Museum Supplement 64 pp. 63-83.
  • Leys, R., Watts, C. H. S., Cooper, S. J. B., et al. (2003). "Evolution of subterranean diving beetles (Coleoptera: Dytiscidae: Hydroporini, Bidessini) in the arid zone of Australia" Evolution 57 pp. 2819–2834.
  • Unmack, P. J. (2001). "Biogeography of Australian freshwater fishes" Journal of Biogeography 28 (9) pp. 1053-1089.
  • World Wildlife, F. (2001). "Kimberly Tropical Savanna (AA0706)" (2005;
  • World Wildlife, F. (2001). "Great Sandy-Tanami desert (AA1304)" 2005 (2005;
  • World Wildlife, F. (2001). "Great Victoria desert (AA1305)" 2005 (2005;
  • Van de Graaf, W. J. E., Crowe, R.W.A., Bunting, J.A., Jackson, P. and Jackson, M.J (1997). "Relict Early Cainozoic drainages in arid Western Australia" Zeitschrift fur Geomorphologie 21 pp. 379-400.