Circular shell rings along the South Atlantic Coast of North America are the remnants of some of the earliest villages that emerged during the Late Archaic (5000-3000 BP). Many of these villages, however, were abandoned during the Terminal Late Archaic (ca 3800-3000 BP). We combine Bayesian chronological modeling with mollusk shell geochemistry and oyster paleobiology to understand the nature and timing of environmental change associated with the emergence and abandonment of circular shell ring villages on Sapelo Island, Georgia. Our Bayesian models indicate that Native Americans occupied the three Sapelo shell rings at varying times with some generational overlap. By the end of the complex's occupation, only Ring III was occupied before abandonment ca. 3845 BP. Ring III also consists of statistically smaller oysters harvested from less saline estuaries compared to earlier occupations. Integrating shell biochemical and paleobiological data with recent tree ring analyses shows a clear pattern of environmental fluctuations throughout the period in which the rings were occupied. We argue that as the environment became unstable around 4300 BP, aggregation at villages provided a way to effectively manage fisheries that are highly sensitive to environmental change. However, with the eventual collapse of oyster fisheries and subsequent rebound in environmental conditions ca. post-3800 BP, people dispersed from shell rings, and shifted to non-marine subsistence economies and other types of settlements. This study provides the most comprehensive evidence for correlations between large-scale environmental change and societal transformations on the Georgia coast during the Late Archaic period.

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Published in PLOS ONE, v. 17, issue 3, e0258979.

© 2022 Garland et al.

This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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This research was supported, in part, in association with the Georgia Coastal Ecosystems LTER project, National Science Foundation (https://beta.nsf.gov/funding) grants awarded to VDT, MCS, and KYS (NSF Grants OCE-0620959, OCE-123714, 1748276).

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All data needed to evaluate the conclusions are presented in the paper, and all raw isotope data are available at https://doi.org/10.6073/pasta/4a7b654d265cca39fabaac3f4aeb55b2.

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S1 Text. https://doi.org/10.1371/journal.pone.0258979.s004

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