Outstanding examples representing significant ongoing geological processes, biological evolution and man's interaction with his natural environment.

The Gondwana Rainforests of Australia provides outstanding examples of ongoing geological processes associated with Tertiary volcanic activity, and of biological evolution. The World Heritage values include:

  • the caldera of the Tweed Shield;
  • centres of endemism where ongoing evolution is taking place;
  • flora and fauna of low dispersal capability that occur in more than one isolated pocket of the Gondwana Rainforests of Australia;
  • plant taxa that show evidence of relatively recent evolution;
  • animal taxa that show evidence of relatively recent evolution;
    the diversity of plant and animal species.
The Tweed Shield Volcano

The Tweed Volcano with its well-developed radial drainage is easily recognizable as a shield volcano, despite its age (20.5–23.5 million years); it is one of the best preserved for its age in the world. Erosion has left a core, Mt Warning, isolated from a horseshoe-shaped arc of precipitous cliffs — the Mt Warning or Tweed Caldera. This erosion caldera, 35 km across, is one of the major examples of this landform in the world, notable for its size and central mountain mass.

Vestigial surfaces of the volcano’s original dome remain only as sharp ridges, ranges and small plateaus continually reduced and lowered by ongoing erosion. In Queensland, these relicts are Lamington, Beechmont and Springbrook Plateaus. Flanking these high points are series of amphitheatre or cirque shaped valley heads, exposed older plateaus, benches, vertical cliffs, waterfalls and deep gorges carved out by erosion.

This volcanism in the Tertiary, through nutrient enrichment, played a critical role in the survival and ongoing evolution of rainforest as climatic conditions and soil nutrient status generally deteriorated on the Australian continent from the Late Tertiary to the present. The rainforests on the lava flows once covered close to a million hectares, and rose to two kilometres. Today’s relicts still represent the most extensive remnants of subtropical rainforests in Australia.  This centre and the Wet Tropics represent two of the most significant refugia in the world for surviving old lineages of the plant and animal kingdom. 

A centre of endemism

Whereas few species are endemic to Springbrook itself, many are endemic to the broader area of remnants of the Tweed Shield volcano. There are discussed on the ‘Endemics’ page.

Fauna showing evidence of recent evolution

Frogs in the genus
Kyarranus/Philoria (We use Kyarranus in this discussion.)

Five species within this genus inhabit the Gondwana Rainforests of Australia World Heritage Area. They are found in high rainfall rainforest at high altitudes (above 600 metres). They occur in separate localities and are considered to have arisen from evolution following fragmentation of an ancestral population that occurred more widely (allopatric speciation). The distributions of the species are shown below.

K. kundagungan - Mistake Mountain, Main Range, extending across the border to Beaury State Forest
K. loveridgei - McPherson Range (including Springbrook), Eastern Border Ranges, Nightcap Range
K. pughi - Gibraltar Range, Washpool
K. richmondensis - Richmond Range
K. sphagnicolus - New England NP, Dorrigo NP, Werrikimbe NP


Kyarranus loveridgei, Springbrook

Frogs in the genus Pseudophryne

Research has indicated that evolution of the three species of Pseudophryne (Brooding Frog) that are recorded from the Gondwana Rainforests World Heritage Area occurred in the Pliocene (around 5 to 2 million years ago). As is the case for Kyarranus, this is an example of allopatric speciation occurring following fragmentation of a more widely occurring ancestral population.

The Red-backed Brooding Frog, Pseudophryne coriacea, occurs at Springbrook.


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Photo: LiquidGhoul; Wikimedia Commons