Australia: The Land Where Time Began

A biography of the Australian continent 

Land Types of the Arid Zone

Channel Country

The channel country is comprised of flooded alluvial plains, watercourses, and swamp and claypan areas of deep grey cracking clays. The watercourses and channels are fringed by River red gum, coolabah, belalie, and creek wilga. The flood plains and swamps are vegetated with perennial and low annual grasses with bluebush, lignum and a n umber of forbs and sedges. In the Georgina/Diamantina River regions the claypan and swamp areas are dominated by bluebush and lignum, and in some places, old man saltbush and cotton saltbush.

Desert Uplands

In the north-east of the region, desert country is the dominant land type, consisting of flat to gently sloping sandplains with deep sandy red and yellow earths. The area lacks suitable pasture species because of infertile soils and low, variable rainfall, and in many cases browse species are of high importance. The main tree species are silver-leaved ironbark, box and yellowjack/bloodwood. There are also Acacias and other species occur within these communities. Spinifex or a mixture of wiregrass and other grasses form groundcover. In some areas wattles (acacias) can form dense stands.

Dunefields and Sandplains

These types of land occur in the far west and south-west of the region. Sandhills and sandplains are composed of deep-red, yellow and white siliceous and earthy soils. The areas are dominated by spinifex with canegrass in some regions. Spinifex is associated with wattles and eucalypts in wooded areas.

Gidyea

This land type is gently-sloping plains with deep-brown cracking clays and some stone cover, flat outwash areas with deep sandy-texture contrast soils, and ridges and hills with dense stone cover. The dominant tree cover is Gidyea with scattered areas of false sandalwood. The most common cover in thick Gidyea are annual grasses and Sclerolaena species (gidyea burrs).

Mitchell

Mitchell areas are flat to gently undulating plains with deep-brown or grey and sometimes red cracking clay soils with strongly self-mulching surfaces. The downs are often open grasslands but may be lightly wooded with bauhinia, vine tree, whitewood, rosewood, and boree. They also grade into gidyea country. The main ground cover is Mitchell grass with a variety of other grasses and forbs in healthy pastures.

Mulga

Soft mulga country occurs as flat to gently sloping plains with deep-red earths and texture contrast soils. Mulga, poplar box, false sandalwood, and occasionally gidyea, form open woodlands. Dense shrub layers (including Charleville turkey bush) limit pasture production. Ground cover is composed of wiregrass, neverfail, and windmill grasses. Hard mulga lands for plains and low hills with shallow red earths and stony soils. Mulga is dominant, forming open scrub and woodland.

Sources & Further reading

1. Mary E. White, The Greening of Gondwana, the 400 Million Year story of Australian Plants, Reed, 1994
2. Mary E White, After the Greening, The Browning of Australia, Kangaroo Press, 1994
3. Penny Van Oosterzee, The Centre - The Natural history of Australia's Desert Regions, Reed Australia, 1993