Modelling the Dispersal of the First Americans through and Inhospitable Ice-free Corridor

概要

論文の詳細を見る
An ice-free corridor is believed to have existed during the late Pleistocene, but it is suspected that ecological conditions may have been severe. Hence, it is controversial whether the route could have been used by the first Americans in their southward expansion from Beringia to the interior of North America. Two demographic models, both assuming negative population growth in the corridor, are examined to evaluate the possibility of a successful crossing. First, a deterministic reaction-diffusion model shows that the condition permitting traversal could have been met, provided the diffusion coefficient (one-half the variance of random migratory activity) was not too large. Based on the mitochondrial DNA sequence divergence data of Vigilant et al. (1989), I obtain an estimate of the diffusion coefficient applicable to prehistoric hunter-gatherers, which is smaller than available estimates for recent humans. Second, the average waiting time between two successful crossings is derived from a probabilistic branching chain model with migration. Although there is much uncertainty regarding the appropriate values of the parameters, the average waiting time appears to be too long. Taken together, the theoretical analyses of this paper suggest that the ice-free corridor probably could not have served as the principal dispersal route.
学術雑誌目次速報データベース由来の論文