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Ancient Rainforests or Burning Bush?

Heathland in the Stirling Ranges National Park

Heathland in the Stirling Ranges National Park in south-western Australia: is this more typical of Australia’s Cretaceous vegetation than rainforest?

By Ray Carpenter

New fossil evidence is forcing a rethink of whether rainforest or fire-prone shrubland prevailed in Australia during the age of the dinosaurs.

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Picture Australia during the Late Cretaceous about 70 million years ago, and you may imagine yourself dodging a dinosaur in a lush Daintree-like jungle. Perhaps you know the story – Gondwana was covered in rainforest, and the heathlands and eucalypt woodlands came much later when the climate started to dry out and fires became more frequent.

However, recent plant fossil discoveries are challenging the “primeval rainforest” paradigm, revealing the immense anti­quity of heathland vegetation. You can now explore heathlands in Sydney’s Royal National Park or Blue Mountains and on a spectacular wildflower tour in the global biodiversity hotspot of south-western Australia.

As a palaeobotanist, my job is to study plant fossils to find out how our continent came to be clothed in such an interesting and beautiful flora. The fossil record can never be complete, and there are large gaps with few or no useful fossils.

One such Australian "black hole" for mammals and the leaves of flowering plants is from about 100–60 million years ago. This scarcity of fossils is a great shame, because it was during this interval that Australia began its isolation from Antarctica and the rest of Gondwana, and much of the distinctive identity of our biota must have emerged.

You can’t explore road or river cuttings for leaf fossils in the gap of 40 million years, because...

The full text of this article can be purchased from Informit.