Central Ranges xeric scrub
The Central Ranges xeric scrub is an ecoregion in central Australia consisting of approximately 108,800 square miles in extent. This ecoregion is categorised as within the Deserts & Xeric Shrublands biome.
Due to the time of formation of surficial rocks of much of the ecoregion's surface, dating to 400 to 300 million years before present, the Finke, Hale and Todd Rivers each can have their present courses dated to claim a catchment that is one of the oldest well defined drainage basins on Earth.
Location and general description
Situated in the Central Ranges of Australia, this ecoregion is chiefly set in the southern portion of the Northern Territory, with partial intrusion into Western Australia and South Australia. Soils in the ecoregion are poorly developed.
The ecoregion is underlain by one of the oldest exposed rock layers on Earth, since mountain uplift was not a prominent feature of this region, and rivers such as the Finke have a course set by meanders dating to hundreds of millions of years before present.
The dominant plant associations consist of thick, tough spinifex grassland with interspersed wooded areas of myall and desert oak (Acacia coriacea). The entire ecoregion, and especially the MacDonnell Ranges, present habitat for numerous specialized endemic plant taxa, including the cabbage palms of Palm Valley within Finke Gorge National Park.
There are 376 recorded vertebrate species within the Central Ranges xeric shrublands. While endemism is low in this ecoregion, endemic species are represented by the mountain dtella (Gehyra montium), the seven-striped ctenotus (Ctenotus septenarius), Nephurus amyae, and Lerista speciosa, reptiles found only in the Central Ranges xeric shrublands. There is one special status non-endemic reptile: the Endangered woma (Aspidites ramsayi).
Special status avian species within the ecoregion are: the Near Threatened Alexandra's parrot (Polytelis alexandrae}, the Near Threatened Australian bustard (Ardeotis australis), the Near Threatened black-tailed godwit (Limosa limosa), the Near Threatened bush thick-knee (Burhinus grallarius), the Vulnerable great knot (Calidris tenuirostris), the Near Threatened grey falcon (Falco hypoleucos), the Near Threatened letter-winged kite (Elanus scriptus) and the Endangered plains wanderer (Pedionomus torquata).
Threatened mammals in the Central Ranges xeric shrublands are represented by the Vulnerable greater bilby (Macrotis lagotis), the Near Threatened black-footed rock wallaby (Petrogale lateralis), the Critically Endangered central rock rat (Zyzomys pedunculatus) and the Vulnerable plains mouse (Pseudomys australis).
The conservation status assigned to the Central Ranges xeric scrublands is Vulnerable. This ecoregion has been classifed with a G200 designation, meaning it is regarded as a priority area for conservation in a worldwide context. The Finke Gorge National Park is a protected area of the ecoregion.
Source: Protected Planet
Types and severity of threats
Chief threats to the Central Ranges xeric scrublands ecoregion are overgrazing by livestock, particularly cattle; however, human introduced equines and alien species rabbits are also threats due to herbivory and trampling.
Justification of ecoregion delineation
The Central Ranges Xeric Shrub ecoregion contains four IBRAs (Interim Biogeographic Regionalisation for Australia): Burt Plain, MacDonnell Ranges, Finke, and Central Ranges (Thackway and Cresswell 1995). Vegetation includes mulga scrubland, grassland, and open woodland on sand ridges and sand plains with highlands that include the Central Australian Mountain Ranges Centre of Plant Diversity (Latz and Pitts 1995).
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