Ecological history of Australia




·        Australia has some of the most ancient rainforests on Earth

·        22nd Dec 1993 Native Title: brings to a close a period of history when we possessed a purely European view of land.

·        Today one-quarter of all living Australians grew up in other lands.

·        Nature has not endowed Australia with a good fossil record



·        120 million years ago southern Victoria was very much cooler with a mean temperature of 10 degrees Celsius.  Southern Victoria at this time had to endure between six weeks of total darkness each year.  The plants were dominated by ancient types such as conifers, ferns, cycads, mosses and  lichens with only a few flowering plants.  Scientists have discovered the world’s oldest flower in the rocks – a diminutive magnolia like bloom perfectly preserved between two layers of clay.  Grevilleas and waratahs evolved after this time. Most of the dinosaurs of Victoria were curiously small – the most common chicken to dog sized bird-hopping dinosaurs that ran on their hindlimbs and ate plants.  The very largest Victorian dinosaur was Allosaurus at about 2 metres high.  In addition to the dinosaurs: pterosaurs (flying reptiles) lungfish, turtles and crocodiles have also been found.  Enormous amphibians known as labryrinthodonts were found in rocks in Victoria too which was a huge surprise for they had become extinct elsewhere in the world some 80 million years earlier.  Also found preserved were cockroaches, cicadas, fleas, water beetles and horseshoe-crabs (now extinct in Australia)

·        Between 86 and 82 million years ago a large sliver of land detached itself from eastern Australia – now largely submerged beneath the sea it included New Zealand, New Calendonia, Lord Howe and Norfolk Islands.

·        New Caledonia:  James Cook in Sept 1774 was the first European to see the strange island and name it New Caledonia.  He noted the great similarity of it to Australia.  There are 3000 species of plants there – New Zealand has only 1460 species.  New Caledonia has some of the most wildly beautiful and primitive plant species to be found on Earth.  Humans arrived about 3500 years ago


·        Gondwana: Antarctic, New Guinea and parts of Indonesia : 80 million years ago – one land mass.  Gondwana straddled the South pole.  Plants  still inhabit the fragment that was once Gondwana ;  proteas, waratahs and Macadamia.  It was then that Tasmantis broke adrift raising Australia’s Great Dividing Range

·        Australasia = Australia, New Zealand, New Caledonia and New Guinea

·        Australia in one the world’s most ancient landmasses with rocks 4,000 million years old found in Western Australia by a North American palaeontologist.  This is magnificent as the earth itself is only 4 600 years old.  Life on this earth has existed for about five-sixths of the planets history.

·        Dinosaurs ruled the planet until 65 million years ago when the asteroid hit Mexico.  Birds and  mammals and many familiar plants were already in existence.  At Cape Paterson an anklebone of an Allosaurus was found.  Hamilton in Western Victoria is the site of Australia’s most important fossil localities.  It gives a glimpse of the Victorian rainforest 4.5 million years ago complete with tree kangaroos, tiny diprotodons and forest wallabies

·        New Guinea was named after Guinea in Africa – both places are home to a dark skinned, crinkle-haired people.

·        Aborigines arrived in Australia from South-East Asia at least 40,000 and more probably 60,000 years ago.  They travelled on the most basic of watercraft.

·        Maoris arrived in New Zealand from Polynesia between 1000 and 800 years ago

·        At present the North Pole has a positive terminal, but over the past 76 million years the Earth’s magnetic field has reversed 71 times.  No- one knows why but at present the magnetic field is weakening each decade

·        Australia is moving north at the rate of approximately 6 cm per year.

·        We can imagine the earth as being like an enormous pot of boiling pea soup.  The continents are the thin scum on the top

·        For over 40 million years Australia has been physically isolated from the rest of the world’s landmasses and in that time the world has chilled considerably.

·        25 million years ago the Australian plate came into contact with the Asian plate causing buckling and the result was the formation of New Guinea with peaks reaching 4000 metres high.  Erosion from these peaks has produced wondrous soils.  The highland valley of Papua New Guinea

·         support some 1614 people per square kilometre which is the highest rural density supported anywhere on Earth.

·        10 – 5 million years ago much of Victoria’s Western district was under the sea – the majestic Grampian mountain range was an island


Papua New Guinea

·        210 species of mammals only 35 less than Australia

·        840 bird species – Australia has 750

·        300 reptile and 220 frog species against Australia’s 750 reptiles and 250 frog species.



Mammals of Australia

·        Marsupials evolved from a South American ancestor some 60 million years ago.

·        Platypus – 20 million year old fossil found in Northern Australia

·        In Queensland 55 million years ago in “Joh Country” remains of crocodiles and large soft-bellied turtles

·        Today half of the Australian mammal fauna is composed of rats and bats

·        23 native mammal species have become extinct in Australia since the arrival of the Europeans.  Tragically, many of these extinction’s have occurred in the last 30 to 40 years when environmental awareness might have helped to save them.  These historic extinction’s of Australian mammals are the worst that the world has experienced in the last 500 years. Many extinction’s happened as late as the 1960’s following the departure of Aboriginal people from their tribal lands.  They suggest that Aboriginal firestick farming was an important factor in maintaining suitable conditions for the middle-sized mammal species.  A further factor would be feral cats, foxes, dingoes etc.


Fauna of Australia

·        Australia supports at least 25 000 species of plants



·        Most of the rivers of the east coast have maintained their positions for tens of millions of years

·        Some rivers have cut as little as a few tens of metres deeper into their beds in over 30 million years.


Why are Australia’s soils so poor?

·        Without geological activity (volcanoes) or glaciers, soil cannot be renewed.  As a result Australia has by far the poorest soil of any continent.

·        Eroded volcanoes produce some of the only fertile soil in Australia.  Wherever this occurs it supports intensive agriculture or prime grazing land.  The basalt plain of Victoria’s Western District is the largest of these area.


Arrival of humans

·        Until around a million years ago, the entire panorama of hominid evolution had been played out on the wide plains and rift valleys of Africa.  It was our immediate ancestor, ‘Homo erectus’, that became the first member of our family to leave the ancestral African home

·        ‘Homo sapiens’ began to spread across the landscape

·        All living people spread out of Africa, possibly some 130 000 years ago.

·        50 000 years ago our ancestors had progressed even further as hunters.  South African cave deposits show the remains of prey such as pigs and buffalo, rhino and elephant.

·        By 40 000 years ago people living in northern Africa were making stone points with tangs to which a handle was attached.  Traps were being made using nets and spears


Aborigines – where did they come from?

·        There are no people presently resembling Aborigines and New Guineas in South-East Asia.  One has to go as far afield as the Phillippines, peninsular Malaysia and the Andaman Island to find a few tiny groups of pygmy negrito people who look anything like Australian Aborigines.  Researchers have therefore long assumed that the ancestors of the Australian Aborigines were displaced from their South-East Asian home by invading Mongoloid peoples.

·        1970 – Lake Mungo in Western New South Wales – remains of cremated woman found in a sand dune dated around 38 000 years ago

·        1974 – uncremated fully articulated skeleton of a adult man was discovered.  Pink ochre powder had been sprinkled over the upper part of his body – 32 000 years old.

·        Western Australia revealed human presence from 30 000 years ago

·        Tasmania show caves in the south-western part of the island at 35 000 years.  7000 years ago evidence of bone tools and needles used for sewing skin cloaks.  5000 Aborigines lived in scattered small groups over the Island.  By 1830 only 300 Aborigines survived.  By 1847 all but 47 had died.  The remainder were send to Flinders Island.  Truganini was the last Aborigine in Tasmania dying in 1876.  She brought to an end a disastrous close to a chapter of murder and cruelty.  No European was ever tried for the murder of a Tasmanian Aborigine

·        Disease was a more important factor: measles, flu, smallpox, gonorrhoea, syphilis etc.

·        Tasmanian Aborigines in 1802 lived in often bitterly cold climates but they lacked clothing and the ability to make fire – they did not eat

·         fish.  They had no hafted implements such as axes, no boomerangs or spearthrowers, no dingoes and no stone tools

·        5000 years ago the manufacture of stone axes with fine edges became very popular throughout Australia

·        Arnhem Land art galleries show paintings over 3000 years old holding boomerangs



·        Poor land means poor seas too.  The low productivity of Australia seas means that with a mere 17 million people, it imports $500 million worth of seafood each year

·        Our oceans are mirror images of our land – they are biological deserts of great fragility.


Ice age

·        Reached its peak 25 000 to 15 000 years ago.

·        Sea levels fell as much as 160 metres.

·        Large landmasses suddenly appeared in the world’s oceans

·        Australia was particularly dramatically affected for the continent became cold and extremely arid.

·        The centre was turned into a vast dustbowl of swirling sand dunes where vegetation could not survive.

·        Trees vanished from most of the land.


Melting of the ice age

·        Suddenly 15 000 years ago the ice-caps melted rapidly

·        By 9 000 years ago the world resembled the one we know today

·        Papua New Guineans would have been in contact with Aboriginal people until 10000 years ago.



·        31st August William Dampier, Captain of the Roebuck met with a party of 10 Aborigines while searching for fresh water.  One Aborigine was shot



·        Before European contact Australia was home to 300000 – 600000 people who spoke 250 languages

·        Trade took place with stone axes quarried at Mount Isa and later found in the Gulf of Carpentaria and pearl shell from the Kimberley was traded down in southern Australia

·        By 1788 Aboriginals had developed a large number of sophisticated practices for conserving animal resources.  ‘Story places’ were off limits to hunters and acted as reservoirs for such mammals as tree kangaroos

·        The traditional European view of Aboriginal cultures has been that life stood still for the Aborigines since they had arrived in Australia.  They arrived in the stone age and were still in it by the time Cook arrived.  No agriculture, widespread nomadism (this was a response of adaption to the erratic availability of resources), simple dwellings and limited material possessions.  This is a superficial and naïve view.  A lack of agriculture ahs long been cited as evidence of the ‘backwardness’ and ‘laziness’ of Aborigines. Many of the features of Aboriginal lifestyles that we continue to view a primitive are highly specialized responses to Australian conditions.

·        First fleet of convicts arrived 26th January 1788

·        It was indeed the British legal concept of ‘terra nullius’.  It gave the British the right to occupy ‘unused’ land.

·        Between  1788 and 1890 the Aboriginal population of Australia was reduced to 50 000.

·        In Victoria there were only 1907 Aboriginal people left by 1863.  By 1967 there were 3 people of pure Australoid descent



·        Often involved hundreds of participants drawn from several tribal groups.  They could only take place in exceptional circumstances for enough food to be present in one place to feed hundreds of people for weeks




Land degradation

·        Already after less than 200 years of use, 70% of the 22 million of arable land is degraded and in need of soil restoration.



·        Today mining earns Australia some 29 billion dollars while agriculture earns only 16 billion dollars



·        22nd December, Prime Minister Keating recognised the legality of native title in Australia.  With it ‘terra nulius’ was abolished from the law books and gave recognition that Aboriginal tribal law has a place in Australian society.