Boundaries

This ecoregion is largely defined by the boundaries of the Lake Eyre Basin, although it also includes the Barkly Tableland, the Bulloo-Bancannia Basin, and the Lake Torrens Basin.

Topography

Most of the ecoregion is covered by low elevation desert and sand dunes.  However, parts of the Central and MacDonnell Ranges in the west, as well as the Torrens Ranges in the south, are included in this ecoregion.

Freshwater habitats

This ecoregion encompasses one massive—and formerly interconnected—river system covering over 1,677,000 square kilometers, or 21% of Australia (Wager and Unmack 2000).  Lake Eyre is a large terminal lake that floods intermittently and is located at 15 m below sea level.  In dry years it is dominated by a large salt pan.

Several rivers flow across the desert and reach the lake in years with high water levels.  All rivers and creeks of this ecoregion are ephemeral with short periods of flow following rain and extended periods of no flow.  Braided channels, floodplains, waterholes, salt lakes, and wetlands characterize the freshwater systems of this ecoregion.  The braided watercourses that often extend across large flat floodplains in western Queensland are referred to locally as "Channel Country."  The ecoregion also overlies much of the Great Artesian Basin such that several groups of artesian springs also occur here.

Terrestrial habitats

Grasslands, deserts, and open woodlands are the major vegetation types found in this diverse region.  The Simpson and Tirari-Stuart Deserts cover large parts of the ecoregion.  The Simpson Desert contains dunehills and sandplains covered with sparse shrubland and grasses.  The Stuart Stony Desert has chenopod shrublands, belah and mallee open woodlands, and mulga woodlands and scrubland with extensive gibber plains (Thackway & Cresswell 1995).  In the north Mitchell Grass Downs cover undulating plains of brown and grey clays and form an extensive band of almost treeless grasslands (World Wildlife Fund 2001).

Description of endemic fishes

Two monotypic genera—Neosiluroides and Scaturiginichthys—are endemic, and both have particularly restricted ranges. The Finke River contains two endemic species, a hardyhead (Craterocephalus centralis) and a goby (Chlamydogobius japalpa). Nineteen species out of 33 (58%) in the ecoregion are considered endemic. Eight of those species live in small, highly restricted spring-fed environments.

Ecological phenomena

Due to the extreme aridity of this province, many species appear to have exceptional dispersal qualities in order to be able to recolonize areas following droughts.  Several fishes within Dalhousie Springs have exceptionally high temperature tolerances, with Neosilurus gloveri, (Dalhousie catfish), Craterocephalus dalhousiensis (Dalhousie hardyhead), and Chlamydogobius gloveri (Dalhousie goby) all naturally occurring in minimum temperatures of 40^oC (Glover 1989; Wager & Unmack 2000).  Chlamydogobius eremius (desert goby) can also can live at temperatures as high as 40^oC (Glover 1973) as most species in this genus are able to do.  Several species also have high salinity tolerances; Glover reported Chlamydogobius eremius tolerates up to 60ppt, while Craterocephalus eyresii (Lake Eyre hardyhead) has been recorded up to 110ppt (Glover 1982).  Two species in Edgbaston Springs, Scaturiginichthys vermeilipinnis (redfinned blue-eye) and Chlamydogobius squamigenus (Edgbaston goby) likely experience extreme variations in temperature in summer.  Water temperatures have been recorded to vary over 20^oC in 3-4 hours (Wager & Unmack 2000).

Justification for delineation

The Barkly Tablelands, Lake Eyre, Bulloo-Bancannia, and Lake Torrens basins have high faunal similarity and thus have been combined into the Lake Eyre Basin ecoregion. This entire area is isolated by drainage divides.

Level of taxonomic exploration

Overal taxonomic exploration is good, with aspects of the fauna being relatively well known.  However, a number of taxonomic problems remain in regards to the taxonomic status of Retropinna semoni, the Australian smelt (Wager & Unmack 2000; Hammer et al. 2007), one Mogurnda population (M. Adams pers. comm.), and within Hypseleotris (Thacker et al. 2007).  Populations of Macquaria ambigua (golden perch) are also considered distinct, but remain undescribed (Musyl & Keenan 1992).