Bayesian-modeled colonization estimates demonstrate episodic dispersals into the Caribbean that support the southward route hypothesis.

The arrival of modern humans into previously unoccupied island ecosystems is closely linked to widespread extinction, and a key reason cited for Pleistocene megafauna extinction is anthropogenic overhunting. A common assumption based on late Holocene records is that humans always negatively impact insular biotas, which requires an extrapolation of recent human behavior and technology into the archaeological past. Hominins have been on islands since at least the early Pleistocene and Homo sapiens for at least 50 thousand y (ka). Over such lengthy intervals it is scarcely surprising that significant evolutionary, behavioral, and cultural changes occurred. However, the deep-time link between human arrival and island extinctions has never been explored globally. Here, we examine archaeological and paleontological records of all Pleistocene islands with a documented hominin presence to examine whether humans have always been destructive agents. We show that extinctions at a global level cannot be associated with Pleistocene hominin arrival based on current data and are difficult to disentangle from records of environmental change. It is not until the Holocene that large-scale changes in technology, dispersal, demography, and human behavior visibly affect island ecosystems. The extinction acceleration we are currently experiencing is thus not inherent but rather part of a more recent cultural complex. Significance We provide global assessment of the possible link between Pleistocene hominin arrival and island extinction. The existing records on islands around the world do not support a significant and detrimental impact on island biotas following island colonization prior to the Holocene. This suggests that models using island extinctions as evidence in support of anthropogenic megafaunal overhunting, or as extensions of continental-level extinctions, need to be reconsidered.

Across the world's seas and oceans, archaeological research focused on islands has generally privileged those that are larger in size. Explanations for this phenomenon range from the (mis)perception by scholars that prehistoric peoples were more attracted to the presumed greater number and diversity of resources typically available on larger islands, to the ephemeral aspect of archaeological evidence on smaller land areas. These are coupled with logistical and infrastructure issues that often limit access to labor, equipment, and transportation to conduct field activities (e.g., remote atolls in the Pacific). A growing body of research demonstrates, however, that ancient peoples regularly and readily occupied and/or accessed many smaller islands for both terrestrial and marine resources. In some cases, within an archipelago, evidence shows an earlier occupation on smaller islands versus larger ones, or an attraction to the former given unique or seasonal resource availability and/or defensive capabilities. We describe cases from several areas of the world that highlight the importance of relatively small islands (∼1–500 km²) for understanding human adaptations in what many have considered to be among the most marginal of environments.

In the first issue of the Journal of Island & Coastal Archaeology published 10 years ago, Erlandson and Fitzpatrick (2006) outlined eight topics which demonstrated why island and coastal archaeology were relevant to understanding a host of issues related to human cultural and biological evolution across time and space. Here, we evaluate recent trends and developments in island and coastal archaeology and discuss how research over the last decade has changed and continued to illuminate the antiquity of maritime adaptations, human dispersals, historical ecology, and many other issues on a global scale. With rising seas and marine erosion threatening island and coastal archaeological sites around the world, archaeologists face urgent challenges in the coming decades as we continue to promote research and conservation of the global island and coastal archaeological record.