Minimum founding populations for the first peopling of Sahul

• DOI: 10.1038/s41559-019-0902-6
• Publication Date: 2019-06-17T16:03:38Z
• Authors: Corey J. A. Bradshaw; Sean Ulm; Alan N. Williams; Michael I. Bird; Richard G. Roberts; Zenobia Jacobs; Fiona Laviano; Laura S. Weyrich; Tobias Friedrich; Kasih Norman; Frédérik Saltré
• Keywords: 0301 basic medicine; 03 medical and health sciences; Archaeology; Humans; 930; 15. Life on land; Demography

The timing, context and nature of the first people to enter Sahul is still poorly understood owing to a fragmented archaeological record. However, quantifying the plausible demographic context of this founding population is essential to determine how and why the initial peopling of Sahul occurred. We developed a stochastic, age-structured model using demographic rates from hunter-gatherer societies, and relative carrying capacity hindcasted with LOVECLIM's net primary productivity for northern Sahul. We projected these populations to determine the resilience and minimum sizes required to avoid extinction. A census founding population of between 1,300 and 1,550 individuals was necessary to maintain a quasi-extinction threshold of ≲0.1. This minimum founding population could have arrived at a single point in time, or through multiple voyages of ≥130 people over ~700-900 years. This result shows that substantial population amalgamation in Sunda and Wallacea in Marine Isotope Stages 3-4 provided the conditions for the successful, large-scale and probably planned peopling of Sahul.