Aboriginal environmental impact

Introduction – Aboriginal Environmental Impact

Aboriginal impact on the land can be assessed by examining the key criteria of sustainability which include population size and the technology used for the resource extraction needed for the consumption of resources that support life and culture. These factors relate strongly to forms of social organization and the environmental consequences of its economy, beliefs and attitudes toward the land. We cannot approach this without thinking about great historical themes: nature and culture, hunter-gatherers, human migration, human resources, the Neolithic Agricultural Revolution, the Industrial Revolution, Old World and New World, technology and economics. Aboriginal culture was, to all intents and purposes, isolated from the rest of the world for about 65,000 years.

The wave of modern humans that has occupied the world migrated out of Africa in about 80,000-75,000 BCE, those who populated Australia crossing to the Arabian Peninsula, then along the coast of India and the Malayan archipelago to set foot in Australia in 65,000 ± 10,000 BCE, the most likely point of entry being the north-west through Flores and Timor but also possibly via a more northern route through Sulawesi.

Genetic evidence suggests that the founding population of First Australians included several hundred women and that, after the initial occupation, only small groups subsequently entered the continent making little genetic impact. Aided by low sea levels and ancient land bridges people on this migration route split into two, one lineage settling in present-day Papua New Guinea and the other Australia, although at the time when this occurred these countries were part of the single land mass known as Sahul. This split is presumed to have been quite ancient as Australian Aboriginals are more closely related to southern Indians than to New Guineans. Physical differences observed in Aboriginals on continental Australia were once taken as evidence for multiple migrations but are now considered the result of adaptations that occurred during the period of Australian occupation. The pattern of migration within Australia is uncertain but fairly uniform (saturated), the centre being occupied at least 30-40,000 BCE when rainfall and lakes were present and Tasmania by 35,000 BCE. Estimates for the time taken for Aboriginals to walk from Africa to Australia indicate an average rate of 1-4 km a year. If this rate was maintained within Australia then the entire continent would have been occupied in 1,000-4,000 years.

Aboriginal society encompassed, on the one hand, many nations and cultures differing in both time and space but, on the other, a commonly structured belief system and a technology with (except for the use of fire and possible influence on the megafauna) that had negligible environmental impact when compared with that of western culture. Aboriginal language groups (nations) occupied regions (countries) with known boundaries so that, in principle, the entire continent was under human management. The Dreaming provided not only a set of laws regulating social relations, land occupation, and land management it also explained the deep sacred and spiritual significance of the Aboriginal relationship to the land, their origins and ancestors, and the natural world.

Aboriginal legacy

Every cultural landscape is the consequence of the technology, values, perceptions, assumptions and aspirations of the people who occupied the land: from these sources communities give the landscape meaning on their own particular terms. Above all the Aboriginal was a part of nature, the Dreaming placing them within the land, sea and heavens produced by their Creator-ancestors while the European was a product of the agricultural Neolithic Revolution that had created a marked distinction between nature and culture, wild and cultivated.

This suite of articles about First Australians has outlined Aboriginal culture and the way its spiritual beliefs influenced land care and its environmental impact, how the c. 65,000 year Aboriginal occupation of the continent has influenced Australia’s landscape, vegetation patterns and species ranges. The articles also anticipate the arrival of a totally different European culture with its own belief system and attitude to the land.

What can we learn from both cultures about the environmental, social and economic circumstances that can assist us in developing an attitude to nature and land management strategies that will help us create a more sustainable future?

This final Commentary article summarizes the environmental, social and economic circumstances of Aboriginal culture and its relationship to later European settlement.

Our ignorance of the history of indigenous peoples is a tragedy of modern times. What we know of Aboriginal society today comes largely from the voices of settler-colonists, not the people themselves. This is ethnography that is poorly remembered and recorded and only now, much too late, being painstakingly pieced together.

Environment

The scale of landscape modification that occurred as a result of Aboriginal land care is a matter of much academic debate but there is increasing evidence suggesting that when Europeans arrived in New Holland they were greeted by a landscape that had been considerably modified from its natural state. However, it was the biotic landscape that had been changed: in contrast to the major urban cultures the English knew of elsewhere in Europe, South America, North America and Asia this was a nomadic culture without the civic adornment of carefully engineered stone monuments, stone buildings, roads or bridges. There were no transport systems or beasts of burden and no wheel: people moved about in the way that they had moved from Africa to Australia, by walking. The most complex transport system consisted of simple water craft, although the entire continent was connected by walking tracks. There were very few physical indications of a human presence that had begun well before the occupation of Europe by modern man and tens of thousands of years before the occupation of North America. Obvious indications of their presence were very few, some archaeological artefacts, stone tools (microliths), pockets of rock art, a few stone bases to temporary dwellings, and several minor rocky reconfigurations like the weirs used to trap fish. There was no use of metals, no written language, and minimal plant cultivation: it was a Stone Age culture that had not experienced an urban or agrarian revolution and Europeans were usually only aware of Aboriginal presence through their temporary camps and the shell middens that remained from millennia of feasting by lakes and the sea – but mostly through the smoke produced by their fires.

Evidence of how Aboriginal land management techniques changed over time, and the scale of their environmental impact, is gleaned mostly from archaeological investigation together with biological and ecological research. Some evidence has also been obtained from the numerous descriptions and observations that are recorded in the journals, reports and letters of the early coastal navigators, settlers, explorers, and botanists, along with artists’ illustrations of the land and its vegetation as depicted in the period of coastal navigation and early British settlement. There are still diverging views on Aboriginal environmental impact some maintaining that this was negligeable^[21] while others like Tim Flannery have argued that they hunted the megafauna to extinction.

With attention focused on plants at least five ways in which Aboriginals have modified Australia’s vegetation can be listed; and all are still understood:

• • • use of wild plants for food and material culture
    • transport of plant propagules along Dreaming trails
    • effects of hunting and foraging on trophic relationships in the food chain
    • the use of fire

It was through the use of fire that First Australians left their most enduring impact on the landscape, but we can outline in more detail some particular ways in which vegetational and ecological change could have occurred by the use of plants for food and material culture, as listed by Philip Clarke in his Aboriginal People and their Plants:^[9]

• • • Removing the edible crowns of Cabbage Palm (Livistona spp.)
    • Collecting plant fruits, notably that of the parasitic mistletoes and native apples Solanumspp.
    • Digging out yams, native truffles, and a wide range of corms, bulbs and tubers, especially those of sedges and bulrushes. Digging and replanting of yams in particular could give the appearance of worked fields
    • Building shelters, ochre quarries and fish traps
    • Eating grubs, especially root grubs. Explorer Basedow noted the ravages of root grubs when gathering ceased
    • Middens of ash, bone and shell are found at ancient coastal, river and creek camping sites, built up over many generations and sometimes the sites of fruit trees that have probably grown from the seed of ancient feasts
    • Tracks to sources of food and water, to mountain passes and sacred landscape features were maintained by fire

Burning

We will probably never know the full impact of Aboriginal burning and firestick farming. On the one hand we have the view of people like historian Bill Gammage contending that fire had been pervasive across the continent for many thousands of years, used by Aboriginals as a highly sophisticated and finely honed system of land management. That “Most Australia was burnt about every 1-5 years depending on local conditions and purposes ^[7]

However, different factors are at play in different regions and as different fire regimes may be applied according to local conditions, so caution is needed in making generalisations about fire regimes of the past. Ecologically there seems a strong interdependence of fire, kangaroos, humans and grassland.

Many species are clearly adapted to fire and their numbers may have been increased by Aboriginal burning???. Possibly altered the balance of species through their hunting. Probably carried seeds, fruits and nuts around the country, digging and foraging being a form of cultivation. The winter clothing of Europeans was partly a product of pastures created by generations of Aboriginals.Blainey 83.

If Gammage is correct then the land was managed so well, and they trod on the land so lightly that western science has been unable to detect its presence, an incredibly subtle feat that nowadays grows annually in stature against the admired wonders of so-called civilisation from the pyramids, hanging gardens of Babylon, Roman roads and bridges to the modern megalopolis, space flights and nuclear fission.

Aboriginal influence on vegetation has been estimated through the presence of charcoal dated in sedimentary layers. The current superdominance of Eucalyptus in Australia may be a relatively recent phenomenon, the result of the extraordinary adaptation of the genus to fire.^[8]This was no doubt combined with the impact of Aboriginal burning.

There is a complex relationship between fire, vegetation types, fauna (extinctions and the effect of introduced carnivores and herbivores). Some animals probably multiplied through Aboriginal effect on predators or vegetation etc.

In recent times there has been a closer attention to climate modeling as a result of vegetation change as different vegetation types can influence evaporation and rainfall, alter surface reflectivity which, in turn, leads to changes in the weather and climate. Early studies are trying to assess the effect, on a global scale, of early agriculture involving land clearing and livestock, while in Australia there is the possible influence of Aboriginal burning. An “early anthropogenic hypothesis”, though slightly controversial, suggests that these practices had a definite influence on climate, agriculturalists producing an anomalous reversal in natural declines of atmospheric carbon dioxide 7,000 years ago and methane about 5,000 years ago.

Many of the food plants of the north seem to have remained the same as those of Indonesia, Malaysia and the Philippines rather than Australian natives, possibly hinting to times past

Hunting & megafauna

The extinction of the megafauna becomes significant because of the removal of major herbivores and predators from the food chain. The scale of this impact is uncertain but ecologists are clearly of the view that it might have been sufficient to have had an observable effect on the vegetation.

Perhaps the nearest to a consensus view is that Aboriginal burning produced vegetational change that severely altered the food supply and diet of these animals. Also, their size alone would have made them vulnerable to fire, being unable to sustain speed or find safe cover during the fire. Often slow creatures with large body mass this would make them susceptible to both fire and hunting. Some would have been relatively tame, making obvious game animals while the young, especially, would be prone to human predation which would have had an immediate impact on population numbers, especially in animals with a long gestation period.

The dingo

At the time of European settlement dingoes were in all major habitats, those in the west were larger than those in the east and although the common colour was reddish Brown there were black ones and an alpine variant with thick white fur.^[10] Archaeological evidence shows that the dingo was present in several parts of Australia by 3,000 to 3,500 BP though they are not currently present in Tasmania or Papua-New Guinea. It probably took less than 500 years for them to occupy the entire continent although they only have one breeding cycle a year.^[11] Dogs similar to the dingo are found across SE Asia including the Papua-New Guinea highlands with the possibility of transference across Torres Strait by the islanders who shared technologies with the mainland Aborigines. There is also a close resemblance to pariah dogs and their ancestors in India. Early Timor trade (in a SE Asia trading network known to exist for about 8,000 years probably linked to a marine network in the Indian Ocean) represents another possible point of entry. Aboriginals used them as pets, food, warmth and for hunting.^[12]

When the dingo arrived on the Australian mainland there were two other sizeable carnivores, the Tasmanian Tiger and the Tasmanian Devil and that there is little doubt that the dingo drove the Tiger to extinction (the most recent thylacine remains date to 2,200 BP) although Aboriginals may have also been involved.^[13] As the dingo competed with Aborigines for food like wallabies and kangaroos it is possible that as the Aboriginal population was increasing there was aneed to hunt smaller game.

Dingoes have a varied diet preferring animals of 10-20 kg, often killing more than they need and hunting in packs.^[14] Their impact seems clear as a study published in 1980 indicated that on the east side of the dingo-proof fence running from SA through Qld red kangaroo numbers were 166 times greater and emu numbers 20 times greater than in the ?west.^[13]

First published on the internet – 1 March 2019
. . . minor revision 1 January 2022
4 July 2023 – minor revision

Fire-stick Farming. Aboriginal Martu man burning off spinifex. Great Sandy Desert. Photo Courtesy Mike Smith 1996