The sea level was much lower 70,000 years ago, resulting in Australia, New Guinea, and Tasmania being connected as one landmass called Sahul. Approximately 65,000 years ago, the first humans arrived in Sahul, which was previously uninhabited by any hominin species. However, due to the incomplete archaeological record, researchers still have limited knowledge about the routes and speed of human migration in the region.
In a recent study published in Nature Communications, a team of researchers reconstructed the landscape evolution during this time period to gain a better understanding of the migration strategies and living locations of the first peoples in what is now Australia.
The researchers utilized a landscape evolution model that detailed the climatic changes from 75,000 to 35,000 years ago. This model provided a more realistic depiction of the terrains and environments inhabited by the early hunter-gatherer communities as they traversed Sahul.
In addition to the changing landscape, the researchers ran thousands of simulations to explore various migration routes. They considered two entry points into Sahul: a northern route through West Papua and a southern route from the Timor Sea shelf.
The simulations predicted migration routes passing through 34 out of 40 archaeological sites older than 35,000 years. Based on these simulations, the researchers calculated migration speeds ranging from 0.36 to 1.15 kilometers per year, similar to previous estimates. The simulations also indicated a high likelihood of human occupation at many iconic Australian archaeological sites.
The predicted migration routes showed that human settlers dispersed across the continental interior along rivers on both sides of Lake Carpentaria. They primarily foraged along the way, following water streams, and also traveled along receding coastlines as sea levels rose again.
The researchers did not identify well-defined migration routes but observed a “radiating wave” of migrations. However, their model suggested a high likelihood of human presence near proposed Indigenous movement pathways, known as super-highways.
One interesting outcome of the study is the potential to identify areas of archaeological significance in a cost-effective manner. By mapping the probability of human presence in Sahul, the researchers could potentially pinpoint areas where archaeological finds may be located. Although the approach cannot determine the preservation of specific sites, it can estimate if artifacts have moved or been buried over time.
This study is the first to demonstrate the impact of landscape changes on the initial migration in Sahul, offering a new perspective on its archaeology. Applying a similar approach in other regions could enhance our understanding of humanity’s journey out of Africa.
