Scientists tracing ancient Aboriginal fire practices on remote Tasmanian island unearth fresh timelines

A core sample taken from a remote Tasmanian island suggests Aboriginal people were using fire management on the island at least 41,000 years ago, experts have said. The findings by a joint project involving the Tasmanian Aboriginal Centre (TAC) and scientists could provide insight into how people adapted to changing climates.

The wetland on lungtalanana/Clarke Island is revealing information about environmental and fire history
[Credit: Andry Sculthorpe]

The TAC invited fire ecologist David Bowman and Australian National University natural history professor Simon Haberle to lungtalanana/Clark Island in Bass Strait to conduct research after it was ravaged by fire in 2014.

They took a core sample from a lake on the island which contained charcoal and pollen. From that they were able to reconstruct the island's fire history by determining how often vegetation had burnt over thousands of years.

"We found a lake which had superb organic sediments in the base and we assumed that they were just from the last 10,000 years," Professor Bowman said. "We radiocarbon dated the sediments and we discovered, to our amazement, that these sediments actually stretch back to 40,000 years. We found a site which is quite unique in southern Australia and indeed the southern hemisphere."

Fire ecologist David Bowman is working with Andry Sculthorpe from the Tasmanian Aboriginal Centre 
[Credit: ABC News, Rhiannon Shine]

Professor Haberle said the radiocarbon dating suggested fire management had occurred on the island at least 41,000 years ago. He said the core sample showed fire regimes on lungtalanana/Clark Island had changed substantially over that period.

"Part of that change was really due to the landscape management activities of Tasmanian Aboriginal people as they lived on those islands and used fire as a tool to manage the landscape," he said. "What we see is that over most of the period of the record, frequent and low-intensity fires occurred on the island. This can really only happen through regular burning of the vegetation, most likely because of people lighting those fires and managing the landscape."

Fires 'catastrophic after colonisation'

Professor Haberle said when Tasmanian Aboriginal people left the island the fires became more intense.

Map showing Clarke Island [Credit: Google Maps]

"When Europeans arrive there is a change in the fire regime and there are many very strong fires and in many cases catastrophic fires have occurred in the recent past," he said. "Those fires are a result of the kind of changes in the land management strategy."

Professor Bowman said the findings were significant and could provide insight into how people adapted to changing climates.

"Finding a sediment trap with such antiquity is absolutely astonishing with huge interest to interrogate," he said. "Scientists have looked at various sediment traps but nothing really of the quality and the time depth in southern Australia. We are terribly excited about this core."

The TAC has been rekindling traditional burning on its land for the past three years. Heritage project officer Andry Sculthorpe said the results from lungtalanana/Clark Island were important, though not surprising.

Researchers (left to right) Aine Nicholson, ANU professor Simon Haberle and Andry Sculthorpe inspect a core sample 
[Credit: David Bowman]

"When you actually see it in diagrams and through evidence collected about how those people may have been living there, and some of the landscape change, it is really interesting," he said. "It gives a deeper time scale to how things were in the past and how we can relate that to what we could do today. Fire is something that was always used by Aboriginal people to shape the environment and to keep country healthy."

Lessons from ancient culture: academic

Professor Bowman said traditional burning should play a greater role in today's fire mitigation.

"This would be, I think, a really great aspiration for Tasmania - to help a group of people who have had their culture disrupted by colonisation to rekindle their traditions and actually serve their society, our society, by making flammable, dangerous environments much safer," he said.

"This is getting quite urgent now because of the deteriorating climate conditions. We must learn from the past, we must learn from the first Australians. They obviously did something very clever, that they were able to sustainably coexist in a very flammable environment."

The group plans to return to the island before the end of the year to conduct further research, and use the findings to educate and train the next generation.

Author: Rhiannon Shine | Source: ABC News Website [September 12, 2017]