Central Salt Lakes and Plateaux (Environmental Region 7.3)
This region consists of 21 environmental associations. The eastern margin is the Arcoona plateau, a low plateau on sandstone and quartzite with an undulating surface of gibbers over red duplex soils. The Arcoona plateau continues westward into the Woomera plateau which is underlain by the same formation but its surface is a less dissected, undulating upland plain with shallow loamy soils. The Woomera plateau rises sharply from the surrounding clay and sand plains in the south, and in the north and west there is a transition into stony plains. The plateau is characterized by the absence of trees and tall shrubs, except on floodplains, where mulga, dead finish, bullockbush, occasional red gums and other species may be found. The gibber-covered areas are either bare or carry a scattered growth of samphire and bindyi. A low shrubland of saltbush and Ixiolaena daisies is found in the crabholes where gibbers are less dense. The depositional plains to the south and south-west of the plateau are covered with deep calcareous earths characteristically carrying on open myall woodland with a bluebush understory, or red aeolian sand sheets and dunes with open mulga shrubland or low woodland of black oak or native pine. The scenery is generally determined by the expanses of gibber-covered plateaux or salt-encrusted lake beds and hence background panoramic views are common throughout the region. However on the plains near the plateau edges, in dunefields around the smaller lakes and in some more hilly areas, local features such as rocky hills, gypsum deposits, or plateau remnants may be important in the views. The climate is mild to hit in summer and cool to cold in winter with low and unreliable rainfall and high evaporation throughout the year. Mean annual rainfall ranges from less than 150 mm in the north-east to 300 mm in the south-west. Mean monthly evaporation reaches 400 mm in January and exceeds the 90th percentile of monthly rainfall throughout the year. Mean annual evaporation increases from 2500 mm in the south to 3300 mm in the north-east. Temperatures show high diurnal and seasonal variation.
