The Wet Tropics and Gondwana: irreplaceable lands

The Wet Tropics stretches for 450km along the coast of Far North Queensland and covers 894,420 hectares. The dominant vegetation is tropical rainforest but tea tree, eucalypt and mangrove forests are also present. The tropical rainforests of the Wet Tropics are the oldest continuously surviving rainforest on Earth and are more 100 million years old.

Australia was once part of the southern super-continent known as ‘Gondwana’ including landmasses now known as Africa, South America, Antarctica and India. The break-up of Gondwana had a profound effect on global climates and the evolution of all subsequent life forms.

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Photo: WTMA

At the time of Australia’s European settlement, only about one per cent of Australia was still covered by this Gondwanan rainforest. Since then at least three-quarters of that rainforest has been cleared.

Australia’s unique marsupials first evolved in these rainforests, and their closest living relatives still live in the Wet Tropics. The Wet Tropics rainforests represent one of the most comprehensive and diverse living records of the major stages in the evolution of land plants, and contain the highest known concentrations of primitive and archaic rainforest flora.

During ice ages millions of years ago, global falls in sea levels led to a land bridge between the Australian mainland and New Guinea to the north, allowing land-based animals to move between the two land masses. Evolutionary biologists believe this is how Cassowaries colonised New Guinea from Australia.

Australia’s rainforests today

Australian rainforests are currently restricted to a series of discontinuous pockets extending for more than 6,000 km across northern Australia and along the east coast to Tasmania. The largest area of remaining rainforests in Australia is located in the Wet Tropics region of Queensland with relicts dating back to the days of Gondwana. The Wet Tropics of Queensland are of the most significant evolutionary diversity and survival of plants and animals.

The Wet Tropics World Heritage Area is the second ‘most irreplaceable’ natural World Heritage Area on earth and the sixth most irreplaceable protected area, according to a team of international scientists (Science, November 2013).  Seventy-eight sites (across 34 countries) were identified as exceptionally irreplaceable.

There are more than 2,840 recorded species of vascular plants representing 1,164 genera; 75 of these endemic to Australia and 43 restricted to Queensland’s Wet Tropics. Endemic plant species found in this region include orchids, ferns, proteaceae and cycads. It is also rich in fauna species, most of which occur in the lowlands such as Boyd’s forest dragon (Gonocephaulus boydii), Victoria’s Riflebird (Ptiloris victoriae), Musky rat-kangaroo (Hypsiprymnodon moschatus) and of course, the Southern Cassowary (Casuarius casuarius johnsonii), one of the world’s few surviving giant flightless birds and megapodes (mound-builders).

How the Wet Tropics of Queensland World Heritage Area ranks:

  1. Second most irreplaceable natural World Heritage Area
  2. Sixth most irreplaceable ‘protected’ area on the basis of ALL species (bird, amphibian and mammal species)
  3. Eighth most irreplaceable ‘protected area’ on the basis of overall threatened bird, amphibian and mammal species

The Wet Tropics of Queensland fulfils all four criteria to be considered for the World Heritage List:

  1. Outstanding examples representing the major stages of the earth’s evolutionary history.
  2. Outstanding examples representing significant on-going ecological and biological processes in the evolution and development of terrestrial eco-systems and communities of plants.
  3. Superlative natural phenomena or areas of exceptional natural beauty and aesthetic importance.
  4. The most important and significant habitats for in-situ conservation of biological diversity, including those containing threatened species of plants and animals of outstanding universal value from the point of view of science and conservation.