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Daintree Rainforest

Outstanding examples representing the major stages of the earth’s evolutionary history

The rainforests of the Daintree contain outstanding examples of flora and fauna representing eight major stages in the earth’s evolutionary history. These include the Age of the Pteridophytes, the Age of the Conifers and Cycads, the Age of the Angiosperms, the final break-up of Gondwana, biological evolution and radiation during thirty-five million years of isolation, the origin and radiation of the songbirds, the mixing of the continental biota of the Australian and Asian plates and the extreme effects of the Pleistocene glacial periods on tropical rainforest vegetation.

The most important living record of the evolutionary history of the marsupials, songbirds and terrestrial vegetation, from the very first land plants to the higher angiosperms, is contained within the area.

The Age of the Pteridophytes

One of the most significant evolutionary events in the history of the world was the adaptation of plants to life on land. The first land plants were the fungi and algae of the Ordovician Period, some 500 million years ago. Spore-producing plants including clubmosses and ferns reached their greatest diversity in a period referred to as the Age of the Pteridophytes, beginning in the Silurian Period some four hundred and thirty five million years ago and extending through to the Devonian and Carboniferous Periods, which lasted until approximately 280 million years ago.

Within the rainforests of the Daintree, outstanding examples of primitive relict flora represent this period. The most primitive plants found within the Daintree include Huperzia (Tassel ferns – formerly Lycopodium), Selaginella, Lycopodiella, Psilotum (Ribbon ferns), Marattia and Angiopteris (King fern).

The Age of the Conifers and Cycads

Terrestrial vegetation underwent a significant evolutionary breakthrough with the origin of the seed. Towards the end of the Carboniferous Period, the dominance of the ferns and clubmosses came to an end with Australia’s movement as a part of Gondwana to the colder and drier climate nearer to the South Pole.

Plants evolved with tough and hardier leaves and new reproductive strategies utilising stationary female cones and pollen as mobile, semi-protected male seeds. These adaptations allowed the colonisation of terrestrial habitats that were previously inhospitable to spore-producing plants. The lower end of the Carboniferous Period brought diversification of vascular plants.

Gymnosperms dominated the Permian Period and small palm-like plants called Bennettitaleans, developed alongside. The climate of the Jurassic Period was substantially warmer and saw the proliferation of cycads and conifers and the extinction of the Bennettitaleans. The cone-bearing cycads and Southern Conifers have changed very little from Jurassic ancestors that flourished between one hundred and ninety-five and one hundred and thirty-five million years ago.

The upland assemblage of the Daintree contains the Kauri pine (Agathis robusta), the Brown Pine (Podocarpus grayae) and Hope’s Cycad (Lepidozamia hopei). These species represent the closest modern counterparts to those found in the Jurassic fossil forests revealed in the Talbragar Fish Beds near Gulgong in New South Wales.

The Age of the Angiosperms

Five major elements in the evolutionary history of the flowering plants are contained within the Daintree rainforests. The Mesozoic Era, beginning with the Triassic period, two hundred and twenty-five million years ago, and containing the Jurassic and Cretaceous Periods brought dramatic evolutionary change for the flora of the world. The origin of the flowering plants remains unknown due to the absence of any fossil record linking flowering plants to more primitive ancestral stock, though this does not diminish their spectacular success.

At around about the time of the separation of Gondwana into its east and west portions, some one hundred and twenty million years ago, angiosperms were established and began diversifying in two essentially separate streams. A significant part of the southern stream became isolated when Australia finally broke away from Antarctica, drifting northwards towards the equator over the following fifty million years.

The Daintree rainforests contain the richest assemblage and highest concentrations of ancient flowering plant families on earth. The most ancient orders of living flowering plants are the Magnoliales and Laurels. Of the world’s nineteen known families, twelve are found in the rainforests of the Daintree compared with seven in the whole of the Amazon basin. Two primitive flowering plant families found in the Daintree, Austrobaileyaceae and Idiospermaceae are monospecific.

The Final Break-up of Gondwana

Several groups of fauna found in the Daintree rainforests are regarded as likely relicts of Gondwana at the time of the final break-up.

Frogs from the Myobatrachidae and Hylidae families are believed to have had Gondwanan origins. Primitive species within these families found in the rainforests of the Daintree include the Northern Barred Frog (Mixophyes schivelli), the Sharp Snouted Torrent Frog (Taudactylus acutirostris), the Blunt Snouted Torrent Frog (Taudactylus rheophilus), Day’s Frog (Nyctimystes dayi) and an abundant representation of species from the tree frog genus Litoria.

The Northern Leaf-tailed Gecko (Phyllurus cornutus) and the Chameleon Gecko (Carphodactylus laevis) inhabit rainforest within the Daintree and have been used as evidence of Gondwanan origin.

The Southern Cassowary (Casuarius casuarius), the Orange-footed Scrub-fowl (Megapodius reinwardt) and the Brush Turkey (Alectura lathami) are also accepted as having Gondwanan origins.

Biological evolution and radiation during thirty-five million years of isolated rafting of the Australian continental plate

Sclerophyll flora and marsupial fauna that now dominate the Australian landscape have evolved from the exceptionally high concentration of remnant ancestral stock contained within the Daintree rainforest.

The most primitive of the Australian marsupials, the carnivorous Dasyuroids are represented within the rainforests of the Daintree. The Musky Rat-kangaroo (Hypsiprymnodon moschatus) is the most primitive of the kangaroos. It is the only living member to have retained the mobile first toe on its hind feet, which is otherwise characteristic of possums.

The origin and radiation of the songbirds

There are compelling arguments suggesting that the world’s songbirds may have evolved from Australian ancestral stock. Likewise, Australia’s songbirds seem to have evolved from ancestral stock that remain tropical rainforest inhabitants.

Many of the rainforest birds of the Daintree hold vital clues to the origin, evolution and radiation of songbirds within Australia and the world. The relatively recent geophysical development of the New Guinea landscape precludes the possibility of providing an evolutionary stage for its own diverse bird-life. The northern rainforests of Australia provided the more likely circumstances with a land bridge to New Guinea allowing the coincidental habitation of Cassowaries, Kingfishers and Chowchillas.

The Mixing of the Continental Biota of the Australian and Asian plates after eighty million years of separation

The Australian and Asian continental plates are believed to have collided about fifteen million years ago, in the vicinity of what is now the Timor region. This collision was a unique event in that it mixed two evolutionary streams of flora and fauna of likely common origin, which had been essentially separated for at least eighty million years. Other continental collisions allowing a mixing of biota have occurred but none with such a period of separation prior to collision.

Plant genera within the Daintree rainforest believed to have entered Australia following the collision between the Australian and Asian continental plates include Alangeria, Calophyllum, Canthium, Garcinia, Leea and Trema.

Of Australia’s sixteen species of Microhylid frog, twelve occur in the wet tropics and the Daintreee rainforest is habitat for at least four including the Robust Frog (Sphenophryne robusta), the Rain Whistling Frog (Sphenophryne pluvialis), Fry’s Whistling Frog (Sphenophryne fryi) and the Elegant Frog (Cophixalus concinnus).

Non-migratory rainforest birds inhabiting the Daintree that are believed to have arrived following the collision with the Asian Plate, include the Yellow-bellied Sunbird (Nectarinia jugularis), the Mistletoe Bird (Dicaecum hirundinaceum) and the Metallic Starling (Aplonis metallica).

The placental mammals of the rainforests of the Daintree, including the bats and rats, are believed to have entered Australia via the connections with the Asian Plate. The Bush Rat (Rattus fuscipes), Cape York Rat (Rattus leucopus), Spectacled Flying Fox (Pteropus conspicillatus), Tube-nosed Bat (Nyctimene robinsoni), Northern Blossom Bat (Macroglossus minimus), Queensland Blossom Bat (Syconycteris australis), Golden-tipped Bat (Phoniscus papuensis) are prominent examples.

The Water Rat (Hydromys chrysogaster), White-tailed Rat (Uromys caudimaculatus), Thornton Peak Melomys (Uromys hadrourus), Fawn-footed Melomys (Melomys cirvinipes) and Prehensile-tailed Rat (Pogonomys mollipilosus) are thought to have arrived in Australia via a second wave of rodent entry across the land bridge joining New Guinea, to form a part of the ‘Old Endemics’.

The extreme effects of the Pleistocene Glacial Periods on Tropical Rainforest Vegetation

Australian rainforests contracted severely during the Pleistocene glacial periods causing extinctions, speciations and profound changes to the distribution of flora and fauna. The rainforests of the Daintree contain outstanding examples of ancient lineage that survived these otherwise devastating impacts. They include the Kauri Pine (Agathis robusta) and (Gymnostoma australianum).

Outstanding examples representing significant ongoing geological processes, biological evolution and man’s interaction with the natural environment

The long-isolated ancient floras of New Caledonia, Madagascar and the Australian Wet Tropics have exceptionally high levels of endemism. These centres of endemism are diverse pools of unique genetic material retaining elements over the widest evolutionary time span and containing potential significance for future radiation in a world of changing global climates and ongoing continental drift.

The Australian Wet Tropics centre of endemism is unique as a part of an ancient continental, as opposed to island, landscape uplifted more than 100 million years ago and tectonically stable for the greater part of the period of angiosperm evolution. Northern Australia has been postulated as a major centre of evolution of rainforest flora.

The Daintree is the jewel in Australia’s tropical rainforest crown. Its rich array of rare and endemic flora demonstrates the origin, evolution and dispersal of flowering plants (angiosperms). Many of the endemic species and genera are narrowly restricted within the area that is north of the Daintree River. The variations in elevation above sea level and changes in topography and soil types contribute to the conservation of diversity and complexity of the rainforest and associated communities present.

Superlative natural phenomena, formations or features or areas of exceptional natural beauty

The grandeur and beauty of the fan palm forests of the Daintree Coast are breathtaking in their magnificence. Sparkling rainforest creeks and constantly varying reflections of light through the leaves lighten and enhance the brilliance of the multi-green vegetation.

In the upper reaches of the Daintree rainforest, intricate networks of tributary feeder creeks join to establish larger supplies that are characterised by a succession of awe-inspiring waterfalls. Monumental forces of erosion have gouged deeply incised passage through the granite labyrinth of the Thornton Range. White-water aggression contrasts brilliantly with a primordial backdrop mosaic of green and grey in a multitude of shades and textures.

The structural integrity of the entire landscape is built around an anchorage of densely packed trees of varying diameter; mostly with exaggerated buttress roots. Contiguous crowns are knitted into an interconnected whole by comprehensive networks of vine.

The ecological complexity of the entire landscape resounds of multiplicity. Every surface is festooned with botanical celebrity. Every conceivable niche reveals a corresponding occupancy and every intonation exposes depths of territorial diversity.

Darkened to a mere fraction of its external intensity, a primitive world perseveres beneath a triple-tiered silhouette of interconnected giants. On those relatively infrequent occasions when cloud disperses, sunlight is broken into kaleidoscopic fragments by intricate layers of interwoven foliage.

Upon closer inspection and the kind of familiarity and refinement in knowledge that comes with years of observation and interrelationship, entirely unexpected peculiarities break the intransigence of the millennia.

Exceptional coastal scenery with white sandy beaches and rainforest-clad mountains plunging dramatically towards the fringing reef and in close proximity to the shore, provide vistas of outstanding natural beauty.

In the heavy wet season, the high rainfall and rugged topography contribute to cascading waterfalls and a lushness that heralds the prime growing time – the most alive time of the year.

The most important and significant natural habitats where threatened species of plants and animals of outstanding universal value from the point of view of science and conservation still survive

The Daintree provides habitat for a number of threatened and endangered species, with high concentrations of monotypic genera reflecting the refugial nature of the rainforests. Included in the list are many rare and very restricted species belonging to the primitive angiosperm families such as Idiospermum australiense, (Idiospermaceae), Haplostichanthus (Annonaceae), Tetrasynandra (Monimiaceae) and Endiandra (Lauraceae).

Among the fauna, there are several species with highly restricted distributions. The endangered Southern Cassowary (Casuarius casuarius) inhabits the rainforests of the Daintree. The Musky Rat-kangaroo (Hypsiprymnodon moschatus), a species of considerable evolutionary significance and restricted to the rainforests of the Wet Tropics, is well-represented throughout the Daintreee lowland rainforests.