Great Victoria Desert (Environmental Region 7.5)
This region consists of two environmental associations. It comprises essentially the field of regular parallel dunes of the Great Victoria Desert and tracts of salt lakes. The dunefield mantles an erosional plain, and low outcrops of granite or volcanics from inselbergs or tors within the dunefield. The dunes consist largely of red sand derived from the Western Australian Shield, with a gradual colour change southward to where white sands derived from the cost predominate. Tall shrubland dominated by several species of mallee but accompanied by other species, e.g. teatree, black oak and false sandalwood, covers dunes and interdune lows. From the high dunecrests foreground or middleground panoramic views occur. However because of the mallee, views are usually restricted. The variation in vegetation composition between dunes and swales is a notable feature. The climate is mild to hot in summer and cool to cold in winter with vary low and unreliable rainfall and high evaporation throughout the year. Mean annual rainfall decreases from 350 mm in the south to 150 mm in the north, while mean annual evaporation increases from 2400 mm to 3200 mm over the same area. Mean monthly evaporation reaches 400 mm in January and exceeds the 90th percentile of monthly rainfall throughout the year. Temperatures show high diurnal and seasonal variation.