Native American shell ring villages may have been occupied then
abandoned because of climate change
Analysis of mollusk shells reveals environmental changes in U.S. coastal communities around 4,000 years ago

Date:
March 2, 2022
Source:
PLOS
Summary:
Mollusk shells at 4,000-year-old Native American shell ring villages
indicate that environmental change may have driven the formation and
abandonment of these coastal communities, according to a new study.



FULL STORY ========================================================================== Mollusk shells at 4,000-year-old Native American shell ring villages
indicate that environmental change may have driven the formation and abandonment of these coastal communities, according to a study by Carey
Garland and Victor Thompson in the open-access journal PLOS ONE on March
2, 2022.


========================================================================== Shell ring villages were coastal communities built around fishing, as
indicated by their sitting next to shellfish estuaries, and their large
mounds of mollusk shells which remain to this day. Shell rings formed some
of the earliest human village settlements along the U.S. South Atlantic
coast but were abandoned at the end of the Late Archaic around 4,000
years ago. While scholars have proposed socio-ecological explanations,
there has been limited examination of the physical evidence for these.

Garland, Thompson and colleagues analyzed the biochemistry and
paleobiology of mollusk shells found at three abandoned shell rings
on Sapelo Island in Georgia, U.S. For example, they measured the size
of oyster shells as an indicator of the health of the environment and
compared oxygen isotope values to determine salinity conditions. They integrated their findings with chronological data -- such as tree
ring analyses -- using a Bayesian chronological model, to determine environmental fluctuations over time.

The researchers found that the three Sapelo shell rings, known as Ring
I, Ring II and Ring III, were occupied in the Late Archaic for varying, sometimes overlapping, periods. Ring II appeared to be the oldest and longest-lasting, founded around 4290 years ago and being occupied until
3950 years ago, with Ring I lasting around 150 years in the middle of
this period. Ring III was the newest and outlasted the others, before abandonment around 3845 years ago.

While Rings I and II featured large oyster shells, those at Ring III
were significantly smaller, indicating a decrease in oyster shell size
over time.

Smaller oysters tend to be less healthy or younger, so this may indicate
a depletion in oyster stocks and/or oyster health. Oxygen isotopes also indicated significantly lower salinity conditions by the time of Ring
III as compared to Rings I and II.

The analysis suggests that the inhabitants of the shell ring villages experienced environmental fluctuations, especially around the occupation
of Ring III. Coastal settlement may have initially been an adaptation
to climate change as a way to effectively manage fisheries -- which are
highly sensitive to such changes. However, by the time of occupation of
Ring III, fishing may have become unsustainable, leading to dispersals
to other settlements and other forms of subsistence.

The authors believe that their work provides "comprehensive
evidence for correlations between large-scale environmental change
and societal transformations on the Georgia coast during the Late
Archaic period." The authors add: "The emergence of village life
and adaptation to coastal environments are significant transitions in
human history that have occurred at various times and places across
the globe. Our research shows that Indigenous peoples who established
North America's first coastal shell ring villages some 4200 years
ago were resilient and, through cooperation and collective action,
were able to adapt to environmental instability and resource shortfalls." ========================================================================== Story Source: Materials provided by PLOS. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Carey J. Garland, Victor D. Thompson, Matthew C. Sanger, Karen
Y. Smith,
Fred T. Andrus, Nathan R. Lawres, Katharine G. Napora, Carol E.

Colaninno, J. Matthew Compton, Sharyn Jones, Carla S. Hadden,
Alexander Cherkinsky, Thomas Maddox, Yi-Ting Deng, Isabelle
H. Lulewicz, Lindsey Parsons. A multi-proxy assessment of the
impact of environmental instability on Late Holocene (4500-3800 BP)
Native American villages of the Georgia coast. PLOS ONE, 2022; 17
(3): e0258979 DOI: 10.1371/ journal.pone.0258979 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220302150404.htm

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