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Forest Habitats

Rainforest

Rainforest contains our richest terrestrial habitat. Just two million hectares remain of perhaps eight million which existed when Cook took possession of Australia in 1770. All of the mainland rainforest would fit into a 70.6 km diameter piece of land. Tasmania is better off, with a 38.1 km diameter circle. From the Kimberley around the north coast, down the east coast to Tasmania is where you find these ancient forests. Professor Michael Archer has said of them "the single most important biological resource we hold in trust for Australia's future".

Tall open forests
The tall open forests dominated by eucalypts are not much more common. They cover less than five per cent of the continent. But there were times when much of Australia was covered by forest. As they retreated due to the increasing "ten million year drought", their wildlife occupants from a myriad of invertebrates, fish, reptiles, amphibians, birds and mammals became more and more squeezed by their shrinking forest habitats. Many animals adapted to the opening of the forests and became woodland and savanna dwellers. Today, the forests still retain an incredible diversity of species.

What is the nature of their habitat?
Rainforests are multi-storeyed habitats complete with a richness of furniture. The penthouses are the giant figs and other emergents. These are the sunny sites above the massive forest canopy. Soft fruits and part digested seed rain from flocks of feeding pigeons. Screaming lorikeets seek out flowers of eucalypts, black beans and booyongs. King parrots rip open bunya cones and on Fraser Island, the cones of towering kauri pines; on Cape York palm cockatoos strip palm nuts. The dense canopy contains many flowering and soft fruiting species as well as carrying an incredible load of epiphytes. This is a humid environment which supports a rich fauna.

What lives in the rainforests?
Some 40 species of rainforest mammals move through layers in the forest, and 14 of these are rainforest specialists which live only in this habitat. These include five species of possums, two species of tree kangaroos, five species of rodents, including the Djidjiparra (prehensile tailed rat), and two species of Antechinus. All utilise the structure of trees as furniture. 18 species are forest generalists and these include seven species of possums including a glider, one species of wallaby, four rodent species, two species of bandicoots, three species of Antechinus, and one species of quoll. About the rainforest margins occur four wallaby species which obtain most of their food from surrounding grass patches. Two generalists, the echidna and dingo also occur. The platypus and Rakali (water rat) penetrate the rainforest habitat by way of creek systems.

In this remarkable list are ground and root grubbers, tree climbers, fungi chewers, canopy chewers, nectar and flower eaters, fruit collectors, omnivores and carnivores. The warm, damp earth of the floor is alive with fungi, bacteria, algae, worms and insects waiting to break down any carcass which may fall. Of course all of these species are not found together in one place. The size of the populations and number of species is determined by the structure of particular forests and their carrying capacity. These are only the mammals, without the fruit bats and insectivorous bats. There is an equivalent range of frogs and birds. Despite the variety of pythons, dragons, geckoes and skinks, reptiles however have their "heaven" in the sunlight of the arid zone.

What lives in the tall open forests?
Tall open forests dominated by eucalypts, brush boxes and turpentines , are warmer, drier sunnier places. The tall trees are rich in nesting hollows for gliders and the sunlight reaching the floor allows for a vigorous understorey. This is ideal habitat for reptiles, kangaroos and wallabies. Here too is more habitat diversity for birds, ranging from the large lyrebird and emu to our smallest thornbills sand mistletoe birds. Many insects and other invertebrates which rely on the sun's warmth to get them going favour the open forests over the damp darkness of the rainforests. Even so, rainforests are very rich in their specialised invertebrates which are often associated with an individual plant species.