A Multi-proxy assessment of the impact of climate change on Late Holocene (ca 4500-3800 BP) Native American villages of the Georgia coast

Circular shell rings along the Atlantic Coast of southeastern North America are the remnants of some of the earliest villages that emerged during the Late Archaic Period (5000 – 3000 BP). Many of these villages, however, were abandoned during the Terminal Late Archaic Period (ca 3800 – 3000 BP). Here, we combine Bayesian chronological modeling with multiple environmental proxies to understand the nature and timing of environmental change associated with the emergence and abandonment of shell ring villages on Sapleo 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 ( Crassostrea virginica ) that people harvested from less saline estuaries compared to earlier occupations. These data, when integrated with recent tree ring analyses, show a clear pattern of environmental instability throughout the period in which the rings were occupied. We argue that as the climate became unstable around 4300 BP, aggregation at shell ring 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. 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 correlations between large-scale environmental change and societal transformations on the Georgia coast during the Late Archaic period.

Barrier islands of the central Georgia coast: Formation, function, and future

ABSTRACT Georgia’s coastline is composed of a series of short, wide, mixed-energy (tide-dominated) barrier islands, each backed by extensive marsh, topped with mobile dunes, and flanked by deep inlets. Many of the islands, particularly those along the southern Georgia coast, consist of Pleistocene cores surrounded by mobile deposits that attached during the Holocene sea-level transgression. Positioned within the head of the funnel-shaped South Atlantic Bight, tidal ranges here commonly reach ~2–3 m. As a result, inlets are numerous and the back-barrier environment hosts nearly 400,000 acres of salt marsh. Today, many of the barriers are transgressive, and hard structures such as revetments and groins are becoming increasingly more common to stabilize shorelines along the four developed islands. This field guide presents evidence of island formation, modern ecologic function, and likely future changes for three island groups: (1) Blackbeard, Cabretta, and Sapelo Islands; (2) Sea Island and St. Simons Island; and (3) Jekyll Island. The field trip provides evidence of the Pleistocene-age island cores, the natural southward migration of the mobile Holocene-age sandy shorelines, and the impacts of storm erosion and hard structures built to combat that erosion. This field guide serves as the static, print companion to an online virtual field trip (https://storymaps.arcgis.com/stories/0aa3fd921cc4458da0a19a928e5fa87c).

Risk Perceptions and Flood Insurance: Insights from Homeowners on the Georgia Coast

Scholars highlight a wide array of factors that can influence individual decision-making under risk. Utilizing survey data, we explore many potential factors that affect risk perception and protective behaviors. Our focus is on coastal Georgia, which has lower historical risk relative to the rest of the Southeast U.S., and which many people perceive as relatively safe, but was recently adversely affected by two major storms. The results indicate a majority of coastal residents expect coastal storms and other hazards to be worse in the future. The regression results suggest perceived damages, risk tolerance, wealth exposure, and flood zone are robust determinants of flood insurance purchase. Other factors, like flood zone awareness and attitudes towards community risk management initiatives—like shoreline armoring, beach replenishment, and coastal retreat—are also indicated to have a high correlation with flood insurance purchase.

Pathologic findings and causes of death in bottlenose dolphins Tursiops truncatus stranded along the Georgia coast, USA (2007-2013)

Between 2007 and 2013, before the 2013 cetacean morbillivirus outbreak, 26 fresh bottlenose dolphin carcasses were necropsied on the coast of Georgia, USA. Here, we present the pathological and microbiological findings associated with their most likely causes of death. The primary cause of death was determined in 25 individuals and included systemic bacterial infection (n = 7), verminous and bacterial bronchopneumonia (n = 5), drowning/entanglement (n = 5), disseminated histoplasmosis (n = 1), intestinal intussusception (n = 1), vegetative endocarditis (n = 1), meningitis (n = 1), necrotizing dermatitis (n = 1), disseminated angiomatosis (n = 1), emaciation (n = 1) and stingray spine trauma (n = 1). Histiocytic and eosinophilic bronchopneumonia associated with Halocerchus sp. infection was observed in 69% of the animals (18/26) and eosinophilic gastritis due to Anisakidae nematodes was found in 36% of the examined stomachs (8/22). Moderate to severe eosinophilic pancreatitis with fibrosis was observed in 4 animals infected with Brachycladiidae trematodes. Proliferative and ulcerative lymphoplasmacytic dermatitis was found in 5 animals and was considered to contribute to deteriorated health status in 2 calves. Pulmonary and lymph node angiomatosis were observed in 15 and 10 animals, respectively. In at least 2 animals, the concentration of polychlorinated biphenyls (PCBs) in the blubber exceeded 1500 µg g-1 of lipid. Bottlenose dolphins stranded on the Georgia coast have a wide range of inflammatory lesions associated with a variety of helminth, bacterial, and fungal pathogens. Some resident animals have also been exposed to high levels of PCB contamination, which could reduce host immunocompetence. Higher exposure to these or other pathogens could result in further decline in the health of resident and migrant dolphin populations in this region.

EXPLORING THE GUALE VILLAGE AND SPANISH MISSION OCCUPATIONS AT THE SAPELO SHELL RING COMPLEX THROUGH BAYESIAN ANALYSIS

ABSTRACT Bayesian analysis of radiocarbon (14C) dates in North American archaeology is increasing, especially among archaeologists working in deeper time. However, historical archaeologists have been slow to embrace these new techniques, and there have been only a few examples of the incorporation of calendar dates as informative priors in Bayesian models in such work in the United States. To illustrate the value of Bayesian approaches to sites with both substantial earlier Native American occupations as well as a historic era European presence, we present the results of our Bayesian analysis of 14C dates from the earlier Guale village and the Mission period contexts from the Sapelo Shell Ring Complex (9MC23) in southern Georgia. Jefferies and Moore have explored the Spanish Mission period deposits at this site to better understand the Native American interactions with the Spanish during the 16th and 17th centuries along the Georgia Coast. Given the results of our Bayesian modeling, we can say with some degree of confidence that the deposits thus far excavated and sampled contain important information dating to the 17th-century mission on Sapelo Island. In addition, our modeling of new dates suggests the range of the pre-Mission era Guale village. Based on these new dates, we can now say with some degree of certainty which of the deposits sampled likely contain information that dates to one of the critical periods of Mission period research, the AD 1660–1684 period that ushered in the close of mission efforts on the Georgia Coast.

Human-Environmental Dynamics of the Georgia Coast

This chapter synthesizes and evaluates settlement and subsistence patterns in relation to landscape change for Native American occupations of the Georgia coast in the southeast USA. Dynamic coastal processes of the region have altered the topography and distribution of resources, including those important to humans. These processes were neither uniform in space nor time, with variations leading to the creation of micro-habitats. We assess these habitats, individually and as part of a complex whole, to better elucidate the nature of human–environmental interactions and socio-ecological systems. Understanding this complex relationship helps reveal social trajectories and environmental impacts on the ecosystem of coastal groups. This research, based on historical ecology, is used as a departure point to discuss the future of humans along changing coastlines. We argue that past peoples dealt with similar coastally-related issues as today, such as sea level fluctuations or changes to once productive resources. The knowledge archeologists have gained concerning past human–environmental interactions must be conveyed to the public, including policy-makers, to transform society for the better.