Emerald Swamp, Three Hummock Island (Credit: Simon Haberle)
CAMBRIDGE, United Kingdom — In a groundbreaking discovery that reshapes our understanding of early human migration, researchers have found evidence that the first Aboriginal peoples arrived in Tasmania (Lutruwita) about 41,600 years ago – roughly 2,000 years earlier than previously thought. Their secret weapon for conquering this new territory? Fire.
The study, published in Science Advances, reveals how these early settlers used controlled burning to transform dense forests into more navigable and habitable landscapes. This marked one of humanity’s earliest and most distant migrations from Africa into the Southern Hemisphere.
By analyzing ancient sediments from two island sites in the Bass Strait – the body of water that now separates Tasmania from mainland Australia – researchers uncovered a clear signature of human arrival: a dramatic increase in charcoal deposits indicating widespread burning, followed by significant changes in vegetation patterns.
During this period, Tasmania wasn’t an island but was connected to mainland Australia by a land bridge that appeared during an ice age when sea levels were lower. This bridge, known as the Bassian Land Bridge, provided a crucial pathway for early Aboriginal peoples to move southward into new territory.
The research team examined sediment cores from two strategic locations: Emerald Swamp on Three Hummock Island in the western Bass Strait, and laymina paywuta (meaning “lagoon from a long time ago” in Palawa language) on Clarke Island in the eastern Bass Strait. These sites provided a unique window into the environmental history of the region, preserving evidence of both climate changes and human activities over tens of thousands of years.
“Australia is home to the world’s oldest Indigenous culture, which has endured for over 50,000 years,” explains Dr. Matthew Adeleye from Cambridge’s Department of Geography, the study’s lead author, in a media release. “Earlier studies have shown that Aboriginal communities on the Australian mainland used fire to shape their habitats, but we haven’t had similarly detailed environmental records for Tasmania.”
The findings paint a vivid picture of how these early settlers adapted to and modified their new environment. When they arrived, the eastern part of the land bridge was relatively wet, supporting dense forests. The western region was drier and more open. The newcomers used fire strategically, burning the forests more intensively in the wet eastern areas to create openings for movement and hunting while using lighter burns in the already-open western areas to maintain the existing landscape.
This differential approach to landscape management shows sophisticated environmental knowledge. In the eastern region, the researchers found evidence of major vegetation changes following human arrival, with fire-sensitive plants like Callitris (native cypress) declining and fire-adapted species like Eucalyptus becoming more dominant. The western region showed more subtle changes, suggesting a lighter touch was needed where the landscape was already more open and dry.
These findings challenge previous assumptions about early human capabilities and their impact on the environment. They suggest that these ancient peoples weren’t just passive inhabitants but skilled environmental managers who used fire as a sophisticated tool to reshape their environment, creating landscapes that better suited their needs for hunting, gathering, and movement.
The study also provides crucial insights into how early humans adapted to and survived in new environments during their expansion across the globe, suggesting that the strategic use of fire may have been a key technology that enabled successful human migration into new territories.
Paper Summary
Methodology
The researchers extracted long columns of sediment (cores) from two wetland sites, which preserved layers of material dating back over 50,000 years. These cores were analyzed for three key elements: pollen grains (to determine what plants were growing), charcoal particles (to track fire history), and organic material that could be radiocarbon-dated. By examining these elements layer by layer, they could reconstruct how the environment changed over time, much like reading the pages of a history book from bottom to top.
Key Results
The most significant finding was a sharp increase in charcoal deposits starting around 41,600 years ago, followed by changes in the types of plants growing in the area. In the eastern site, fire-sensitive plants declined while fire-resistant species increased. The western site showed similar but more subtle changes, suggesting different intensities of landscape management in different areas.
Study Limitations
The study relies on indirect evidence of human presence through environmental changes, rather than direct archaeological evidence like tools or remains. The researchers also had to work with just two main sites, though these were carefully chosen to represent different environmental conditions. Dating of very old organic material can also have some uncertainty, though multiple dates were used to build reliable chronologies.
Discussion & Takeaways
This research suggests that early humans were more sophisticated in their environmental management than previously thought, using fire differently in different landscapes to achieve desired outcomes. It also pushes back the date of human arrival in Tasmania by about 2,000 years and provides insights into how early humans might have used similar strategies to colonize other parts of the world.
Funding & Disclosures
The research was supported by the Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage and received in-country support from the Tasmanian Aboriginal Centre. The researchers declared no competing interests. The study was conducted with permission from Aboriginal communities and various Tasmanian government agencies.
