Unit 3 Outdoor and Environmental Education Australian Outdoor Environments Before Humans

Continental Drift

40 to 50 million years ago Australia split off from Antarctica Some species of animals and plants have remained common from this earlier break up of the super continent…Pangaea….that became Gondwana and eventually Australia. Some examples include:

Banksia tree on the left is found in Australia, South Africa and India                                                                                                                        Beech Tree above is found in Australia ,New Guinea and South America

Biological Isolation Geological Stability An erratic climate The uniqueness of the Australian environment has been shaped by three main factors: Biological Isolation Geological Stability An erratic climate

Biological Isolation Over the past 40 million years since separation from Gondwanaland the flora and fauna have been able to evolve in isolation

Geological Stability Volcanoes and glaciers have not been active for a very long time. The land mass is made up of very old rock with very poor soils. The soil has been subjected to much wind and erosion. The poor state of the soils has had an influence on the flora and fauna.

An erratic climate There seems to be a swing between climate extremes. Australia moves from long lean droughts (El Nino) to flooding rains (La Nina). This erratic climate has affected the reproductive cycles and survival rates of the flora and fauna.

Fire and Drought Fire has had a significant impact on the Australian landscape it has greatly influenced the type of vegetation that now predominates the continent.

FIRE As Australia became drier tropical forests retreated to gullies and valleys Arid areas spread helped by the higher incidence of naturally occurring bushfires Increased frequency of fire led to many plant and animal adaptations Fire frequency and intensity has increased since European settlement : Why? Work Task One