Margy Deveraux employs burning techniques in
Marranungu country, Finnis River, NT. Photo: Deborah Rose
The environmental impact of Aboriginal landscape
burning is one of the most complex and contentious issues in
Australian ecology. Dr David Bowman , CRC researcher from
the Parks and Wildlife Commission of the NT, has reviews the
Dr Bowman was invited to write his review by the prominent
journal New Phytologist , as the 86th in their ongoing
series of reviews honouring the great British ecologist Sir Arthur
In his review, Dr Bowman showed how research on the issue of
Aboriginal landscape burning has been uncoordinated and undertaken
by people from different disciplines using different methods.
Although great uncertainty and gaps in knowledge remain, the
available ethnographic evidence leaves little doubt that Aboriginal
burning played a central role in the maintenance of the land
subsequently colonised by Europeans.
Both 19th century European colonists and 20th century
anthropologists have documented the indispensability of fire as a
tool in traditional Aboriginal economies, a tool aptly described as
But it remains unclear as to whether or not Aborigines had a
predictive ecological knowledge of the consequences of their use of
fire, particularly on relatively long-term ecological
Some evidence suggests that Aborigines used fire to achieve
short term outcomes, such as providing favourable habitats for
herbivores or increasing the local abundance of food plants.
However, much more ethnographic research into Aboriginal burning
remains to be carried out to determine just how and why they used
Given the enormous and ongoing cultural changes wrought by
European colonisation, Dr Bowman suggests it is important to
determine how the use of fire now differs between younger and older
generations of Aboriginal people.
Otherwise, we might draw ecological conclusions from present
practices, whereas past practices were those that really affected
our flora and fauna.
Dr Bowman says that a lot of ecological evidence suggests that
Aboriginal burning caused substantial changes in the geographic
range and demographic structure of many vegetation types right
The evidence also suggests that burning was important in
creating habitat mosaics for small mammals in arid
As well, burning created fire breaks, which helped to maintain
some infrequently burnt habitats upon which about 10 per cent of
Australia's terrestrial birds depend.
However, much of this evidence is circumstantial and is based on
changes which were observed following the cessation of Aboriginal
burning after European colonisation.
There have been very few experimental investigations of the
possible ecological impacts of Aboriginal burning.
Use of modelling has helped to corroborate the importance of
Aboriginal fire regimes in maintaining one tree species, Cypress
pine (Callitris intratropica), in the monsoon tropics.
Dr Bowman suggests there may be great potential to use models to
explore the long-term effects of the various fire regimes used by
Aboriginal people prior to European colonisation.
The original impact of humans on the Australian environment is
speculative. Unfortunately, we only have vague and disputed time
frames proposed for the waves of colonisation and shifting
settlement patterns of Aborigines over the last 100,000 years or
Charcoal and pollen evidence from long sedimentary cores is
ambiguous and cannot be used to demonstrate unequivocally the
initial impact of Aboriginal people on the Australian
There are very few studies that specifically link archaeological
and palaeoecological data to determine the impact of Aboriginal
burning. The studies that do so demonstrate localised impacts at
The sparse evidence available does not support at least four
speculative hypotheses currently in vogue, namely that Aboriginal
- Caused the extinction of some Australian megafauna (large
herbivorous and other carnivorous marsupials)
- Was critical in maintaining habitats of small mammals that have
become extinct since European colonisation,
- Initiated widespread and accelerated soil erosion, and
- Forced the evolutionary diversification of the Australian
However, Dr Bowman says that the available evidence does suggest
that there were some evolutionary impacts of Aboriginal
There may have been extinction of some fire sensitive species of
plants as well as extinction of animals dependent upon infrequently
burnt habitats, particularly during periods of climatic stress.
Also, it may have extended the range of fire adapted species,
such as the eucalypts, into environments climatically suitable for
rain forest. Lastly, it may have helped to maintain structurally
open vegetation such as grasslands.
In concluding his review, Dr Bowman suggests that
palaeoecological research (that is research using fossil evidence)
has become too popular in considering the impact of Aboriginal
burning on the Australian landscape.
He suggests it should give way to experimental studies of the
role of the different fire regimes imposed by man in contemporary
ecosystems which have not been destroyed by European
Integrated studies using remote sensing, geographic information
systems, mathematical modeling, experimental manipulation and
autecological studies of key plant and animal groups would advance
the our understanding of the impact of Aboriginal burning.
He feels there is an urgent need to include Aboriginal people in
such research and we need to move beyond the poetic concept of
'fire-stick farming' to coherent scientific analysis.
Dr Bowman feels that his review is timely, because of as the
increasing interest in the role of Aboriginal burning in the
functioning and management of many Australian ecosystems.
Spin-offs from the review were invitations for Dr Bowman to give
lectures on the topic at Harvard, Cambridge and Oxford
Universities. As well, numerous questions have been raised by the
work which have stimulated new research.
For example, Dr Bowman himself has recently collaborated on a
predator-prey model to determine if Aboriginal over-hunting is a
plausible explanation for the extinction of the marsupial
megafauna. The results from this work will be presented later this
year at a conference in Perth devoted to this issue.