Temporal trends in the colonisation of the Pacific: Palaeodemographic insights

The colonisation of eastern parts of the Pacific Islands was the last phase in the preindustrial expansion of the human species. Given the scale and challenges of the endeavour it is unsurprising that scholars have long been interested in understanding the conditions that drove and supported the exploration and settlement of this vast region. There has been speculation as to the influence of demographic factors, either as drivers or in some way regulating the rate and success of human expansion, but testing this has proven challenging. This study evaluates two hypotheses of population dynamics: the adaptation/resilience hypothesis, which proposes that populations respond to localised environmental conditions and changes in subsistence strategy, technology, differences in pathogen loads, and other events that occur at different times in different places; and the temporal hypothesis, which proposes that populations respond to major events such as climate change that occur in a region at an absolute point in, or over an absolute period of, time (noting that the two hypotheses are not mutually exclusive). Applying new methods for estimating the rate of natural population increase from human skeletal remains, this study utilised 23 samples to evaluate trends in population increase following the human expansion into the region. The results indicate a trend in population growth following colonisation, with initially high population growth, followed by a significant decrease and subsequently an increase in growth rates. The lack of a temporal trend may represent a high degree of heterogeneity in the impacts of climate change on individual archipelagos and islands.