Australian
Screen

Teacher’s notes

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This clip shows the dry centre of Australia. The early aerial scenes show sandy riverbeds where the water flows deep beneath the surface. The following scenes indicate the age of Australia’s centre, with huge outcrops of hard rock surrounded by eroded rock fields – the gibber desert. Later scenes include a shingleback lizard camouflaged as a rock in a gibber deposit, and a gibber bird hunting insects, its only food source. Desert sounds as well as xylophone and wind-instrument music accompany the commentary.

Educational value points

• The gibber desert shown in the clip is a significant inland Australian landform consisting of flat or undulating clay plains densely covered by highly polished stones and pebbles known as gibber, the result of past erosion. The pebbles that accumulate on the surface are often oxidised and dark red or black in colour. Gibber usually appears to be devoid of vegetation but in wetter years it sometimes has an ephemeral cover of grasses.

• As described in the clip, the hidden network of underground rivers meandering through gibber plains 'supports a rich mosaic of life’, usually dominated by low open woodland. Acacias are the mainstay of this woodland and include the prickly 'dead finish’ (Acacia carneorum), gidgee (Acacia cambagei) and mulga (Acacia aneura). Mulga seedlings only 10 cm high have been found to have taproots reaching 3 m deep into the sandy alluvium of these watercourses.

• Gibber plains are occasionally interspersed with mesas, or columns of resistant rock, as illustrated here, often capped with silcrete, a crust formed when silica is dissolved and resolidifies as cement. While the mesas are generally very stable, the slopes around them can be deeply eroded by water rushing at high speeds down the sides of the mesas.

• The shingleback lizard (Tiliqua rugosa) seen in the clip is well adapted to the harsh climate of the gibber region. Its thick skin, covered with scales, keeps water loss to a minimum. Its short rounded tail, looking just like its head to confuse predators, operates as a fat-storing organ. After a good season, it can go for many months without food if necessary. The lizard’s scientific classification is Phylum: Chordata, Class: Reptilia, Order: Squamata, Family: Scincidae.

• Previously known as the gibber bird, the gibber or desert chat (Ashbyia lovensis) is a terrestrial bird of the gibber desert and short-grass plains of south-eastern central Australia. It is seen here hunting insects and in its characteristic pose – standing upright on rocks. Its scientific classification is Phylum: Chordata, Class: Aves, Order: Passeriformes, Family: Meliphagidae.

• The music in this clip is particularly atmospheric and was produced by music director Kevin Hocking (1932–) working with the Melbourne Symphony Orchestra. Hocking’s score for Nature of Australia won the French television award for best documentary score of the year.