Some of the first human beings to arrive in Tasmania, over 41,000 years ago, used fire to shape and manage the landscape, about 2,000 years earlier than previously thought.
A team of researchers from the UK and Australia analysed charcoal and pollen contained in ancient mud to determine how Aboriginal Tasmanians shaped their surroundings. This is the earliest record of humans using fire to shape the Tasmanian environment.
Early human migrations from Africa to the southern part of the globe were well underway during the early part of the last ice age -- humans reached northern Australia by around 65,000 years ago. When the first Palawa/Pakana (Tasmanian Indigenous) communities eventually reached Tasmania (known to the Palawa people as Lutruwita), it was the furthest south humans had ever settled.
These early Aboriginal communities used fire to penetrate and modify dense, wet forest for their own use -- as indicated by a sudden increase in charcoal accumulated in ancient mud 41,600 years ago.
The researchers say their results, reported in the journal Science Advances, could not only help us understand how humans have been shaping the Earth's environment for tens of thousands of years, but also help understand the long-term Aboriginal-landscape connection, which is vital for landscape management in Australia today.
Tasmania currently lies about 240 kilometres off the southeast Australian coast, separated from the Australian mainland by the Bass Strait. During the last ice age however, Australia and Tasmania were connected by a huge land bridge, which allowed people to reach Tasmania on foot. The land bridge remained until about 8,000 years ago, after the end of the last ice age, when rising sea levels eventually cut Tasmania off from the Australian mainland.
"Australia is home to the world's oldest Indigenous culture, which has endured for over 50,000 years," said Dr Matthew Adeleye from Cambridge's Department of Geography, the study's lead author. "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 researchers studied ancient mud taken from islands in the Bass Strait, which is part of Tasmania today, but would have been part of the land bridge connecting Australia and Tasmania during the last ice age. Due to low sea levels at the time, Palawa/Pakana communities were able to migrate from the Australian mainland.
Analysis of the ancient mud showed a sudden increase in charcoal around 41,600 years ago, followed by a major change in vegetation about 40,000 years ago, as indicated by different types of pollen in the mud.
"This suggests these early inhabitants were clearing forests by burning them, in order to create open spaces for subsistence and perhaps cultural activities," said Adeleye. "Fire is an important tool, and it would have been used to promote the type of vegetation or landscape that was important to them."
The researchers say that humans likely learned to use fire to clear and manage forests during their migration across the glacial landscape of Sahul -- a palaeocontinent that encompassed modern-day Australia, Tasmania, New Guinea and eastern Indonesia -- as part of the extensive migration out of Africa.
"As natural habitats adapted to these controlled burnings, we see the expansion of fire-adapted species such as Eucalyptus, primarily on the wetter, eastern side of the Bass Strait islands," said Adeleye.
Burning practices are still practiced today by Aboriginal communities in Australia, including for landscape management and cultural activities. However, using this type of burning, known as cultural burning, for managing severe wildfires in Australia remains contentious. The researchers say understanding this ancient land management practice could help define and restore pre-colonial landscapes.
"These early Tasmanian communities were the island's first land managers," said Adeleye. "If we're going to protect Tasmanian and Australian landscapes for future generations, it's important that we listen to and learn from Indigenous communities who are calling for a greater role in helping to manage Australian landscapes into the future."
The research was supported in part by the Australian Research Council.