Australia: The Land Where Time Began

A biography of the Australian continent 

Spinifex Grasslands - the Fauna

This vegetation type supports an unusual fauna, being dominated by termites, ants and lizards. In fact it has the highest number of lizard species of any place in the world, especially among geckos, dragons and some skinks. These grasslands occur on infertile soils with a large biomass and little grazing, so dead plant material becomes available for other herbivores. In this case, the termites, that can utilise such a low nitrogen food because of their gut bacteria.

In these grasslands, ants and termites are the dominant insects. Both being social insects, their colonies act as a buffer for both the extremes of temperature and of the cycles of better times and the bad times. Because they have a secure base they can forage more widely than other insects, that are more like ephemeral plants, being present mostly in the better times. The birds tend to be nomadic and opportunistic.

Among the mammals, the red kangaroo is rare in the sandplains and dunefields. 3 known species of small marsupials live in the spinifex clumps. These are known as Ningaui to the Aboriginal People. There were several other small marsupials in this habitat, but since the replacement of the patch burning by the Aboriginal People by the more intense wildfires after the wetter years, they are either rare or extinct. Feral animals - rabbits, cats and foxes - accounting for many of them.

Hare wallabies (Lagorchestes hirsutus) and bilbies (Macrotis lagotis) have declined markedly. They used to be common in thick spinifex around the margins of burnt patches where they could feed on the sprouting vegetation while it was still soft and easily digestible. With the change in fire regime life got harder for them. They also had competition from rabbits and predation from feral cats to contend with.

Sources & Further reading

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