Complexities of Stable Carbon and Nitrogen Isotope Biogeochemistry in Ancient Freshwater Ecosystems: Implications for the Study of Past Subsistence and Environmental Change

Stable carbon and nitrogen isotope analyses of human and animal tissues have become an important means of studying both anthropogenic and natural food webs in aquatic ecosystems. Within the rapidly expanding field of human and animal paleodietary analyses, archaeologists routinely incorporate isotopic data from fish, birds, and aquatic mammals into their interpretations of ancient freshwater resources use; however, these studies rarely consider the complex and dynamic nature of the carbon and nitrogen cycles that give structure to nutrient regimes and their isotopic compositions in freshwater ecosystems. This review outlines two thematic areas in which this surge in stable isotope applications to the study of ancient human societies could be enhanced by incorporating concepts from limnology, ecology, and biology. First, building on studies conducted in modern ecosystems, this paper outlines key aspects of the stable isotope ecology of freshwater environments, highlighting the importance of considering physical and biological processes associated with ancient biogeochemical cycles when conducting human paleodietary reconstructions. Second, this paper discusses areas where isotopic analyses of archaeological freshwater animal remains could contribute to broader research fields including climate change and cultural eutrophication research, human impacts on long-term food web dynamics and animal behavior, and by providing novel approaches to reconstructing ancient fish management practices

Dorset plant use at the Port au Port site (DdBq-1), Newfoundland: A contribution to Paleoeskimo paleoethnobotany

This paper aims to expand a small but growing field of Paleoeskimo paleoethnobotany in two ways. First a review is provided of several unpublished student studies focusing on Dorset and Groswaterplant-use by way of analysis of macrobotanical remains recovered from archaeological contexts. Second, new paleoethnobotanical analyses of botanical specimens from a Dorset occupation at the Port au Port site (DdBq-1), western Newfoundland, are presented. Contrary to the notion that northern sites often have poor botanical preservation, a large quantity and diversity of seed remains were recovered. It is hoped that this study will encourage further paleoethnobotany work by providing evidence that Paleoeskimo sites often preserve botanical remains and that analyses of these materials can enhance understanding of human-plant interactions of past northern peoples

Archaeological herbivore δ13C and δ34S provide a marker for saltmarsh use and new insights into the process of 15N-enrichment in coastal plants

Saltmarshes are tremendously important culturally and ecologically because they can provide abundant nutrient-rich fodder for grazing livestock, with relatively little resource investment. They also perform critical ecological services, including detoxifying water and stabilizing coastlines. For these reasons, methods for investigating the nature and extent of past saltmarsh use have significant potential to provide new insights into patterns in coastal adaptations among past agricultural societies as well as paleoenvironmental change. Stable nitrogen isotope (δ15N) analyses of animal bone collagen have been used to investigate ancient saltmarsh use based on the idea that plants growing in saline and/or coastal regions can have higher δ15N values. However, interpretation of δ15N evidence for saltmarsh use can be challenging because variation in terrestrial nitrogen sources and cycling can result in similarly elevated in δ15N values in animals that did not feed in saltmarshes. Ecological studies show that stable carbon (δ13C) and sulfur (δ34S) isotope analyses are well suited for investigating saltmarsh use because key species (particularly those in the genus Spartina) that dominate these ecosystems in many areas of the world are C4 plants capable of incorporating sulfuide-derived, 34S-depleted sulfur. We investigate the utility of δ13C, δ34S, and δ15N for tracking saltmarsh use in archaeological herbivores (n = 80) from seventeenth-to-eighteenth-century Acadian settlements in Canada, which were renowned for their agricultural use of saltmarsh ecosystems. Results show extreme variation in δ13C and δ34S consistent with feeding along C3-to-C4 and sulfate-to-sulfide-derived sulfur continuums. Significant correlations between δ13C and δ34S suggests that variation in these isotopic compositions reflects the relative importance of Spartina in past Acadian animal husbandry. These findings indicate that, even in areas where other 13C-eniched food sources are available (e.g., seaweeds, maize), combined δ13C and δ34S analyses should be able to identify Spartina use in coastal regions. A strong negative correlation was also found between δ34S and δ15N, suggesting that processes driving coastal sulfur and nitrogen cycles in the region are coupled (independently of Spartina consumption) and provide new insights into the mechanism behind 15N enrichment observed in saltmarsh plants

ISOTOPIC ANALYSES REVEAL GEOGRAPHICAL AND SOCIOECONOMIC PATTERNS IN HISTORICAL DOMESTIC ANIMAL TRADE BETWEEN PREDOMINANTLY WHEAT- AND MAIZE-GROWING AGRICULTURAL REGIONS IN EASTERN NORTH AMERICA

Historical zooarchaeologists have made significant contributions to key questions about the social, economic, and nutritional dimensions of domestic animal use in North American colonial contexts; however, techniques commonly employed in faunal analyses do not offer a means of assessing many important aspects of how animals were husbanded and traded. We apply isotopic analyses to faunal remains from archaeological sites to assess the social and economic importance of meat trade and consumption of local and foreign animal products in northeastern North America. Stable carbon and nitrogen isotope analyses of 310 cattle and pigs from 18 rural and urban archaeological sites in Upper Canada (present-day southern Ontario, Canada; ca. A.D. 1790-1890) are compared with livestock from contemporary American sources to quantify the importance of meat from different origins at rural and higher- and lower-status urban contexts. Results show significant differences between urban and rural households in the consumption of local animals and meat products acquired through long-distance trade. A striking pattern in urban contexts provides new evidence for the social significance of meat origins in historical Upper Canada and highlights the potential for isotopic approaches to reveal otherwise-hidden evidence for social and economic roles of animals in North American archaeology

Isotopic Evidence for Garden Hunting and Resource Depression in the Late Woodland of Northeastern North America

Resource depression and garden hunting are major topics of archaeological interest, with important implications for understanding cultural and environmental change. Garden hunting is difficult to study using traditional zooarchaeological approaches, but isotopic analyses of animals may provide a marker for where and when people exploited nondomesticated animals that fed on agricultural resources. To realize the full potential of isotopic approaches for reconstructing garden hunting practices—and the impacts of agriculture on past nondomesticated animal populations more broadly—a wider range of species, encompassing many “ecological perspectives,” is needed. We use bone-collagen isotopic compositions of animals (n = 643, 23 taxa, 39 sites) associated with the Late Woodland (~AD 900−1650) in what is now southern Ontario to test hypotheses about the extent to which animals used maize, an isotopically distinctive plant central to subsistence practices of Iroquoian-speaking peoples across the region. Results show that although some taxa—particularly those that may have been hard to control—had substantial access to maize, most did not, regardless of the animal resource requirements of local populations. Our findings suggest that this isotopic approach to detecting garden hunting will be more successful when applied to smaller-scale societies.Le déclin des ressources et la chasse en milieux cultivés sont des sujets d'un grand intérêt archéologique, avec des implications importantes pour la compréhension des changements culturels et environnementaux. La chasse en milieux cultivés est difficile à étudier en utilisant des approches zooarchéologiques traditionnelles, mais les analyses isotopiques des animaux peuvent fournir un marqueur pour savoir où et quand les gens exploitaient des animaux non-domestiqués qui se nourrissaient de produits agricoles. Pour entrevoir le plein potentiel des approches isotopiques pour reconstruire les pratiques de chasse dans les milieux cultivés — et les impacts de l'agriculture sur les populations animales non-domestiquées du passé de manière plus large — un plus large éventail d'espèces, englobant de nombreuses « perspectives écologiques », est nécessaire. Nous utilisons les compositions isotopiques du collagène des ossements d'animaux (n = 643, 23 taxons, 39 sites) associés à la période du Sylvicole supérieur (v. 900−1650 après J.-C.) dans ce qui est maintenant le sud de l'Ontario, afin de tester des hypothèses quant à l'ampleur avec laquelle les animaux ont utilisé le maïs, une plante isotopiquement distincte au cœur des pratiques de subsistance des peuples de langue iroquoienne de la région. Les résultats montrent que bien que certains taxons — en particulier ceux qui peuvent avoir été difficiles à contrôler — avaient un accès substantiel au maïs, la plupart n'en avaient pas, quels que soient les besoins en ressources animales des populations locales. Nos résultats suggèrent que cette approche isotopique de la détection de la chasse dans les milieux cultivés sera plus efficace lorsqu'elle sera appliquée à des sociétés à plus petite échelle.</div

Storing fish?: a dog’s isotopic biography provides insight into Iron Age food preservation strategies in the Russian Arctic

Analysis of individual animal bodies can provide numerous useful insights in archeology, including how humans provisioned such animals, which in turn informs on a variety of other past behaviors such as human dietary patterns. In this study, we conducted stable carbon (δ13C) and nitrogen (δ15N) isotope analysis of collagen and keratin from four types of tissues from a dog burial at the Ust’-Polui site in the Iamal region of Arctic Russia. Ust’-Polui is an Iron Age site located on the Lower Ob River, a major northern fishery characterized by extreme seasonal shifts in fish presence. During a 6-month period stretching over the coldest months of the year, fish are nearly entirely absent in the Lower Ob River. Despite this, the stable isotope compositions of the dog’s bone and dentine collagen and hair and nail keratin all indicate a monotonous diet focusing on local fish. This pattern indicates the dog was provisioned year-round with fish. This was likely accomplished by mass harvesting of fish using nets or traps. Such fish were then processed and frozen for consumption during the non-fishing season. These findings suggest that people in the Ust’-Polui region also relied to some extent on fish throughout the year. Stored fish likely provided a dietary buffer for uneven returns from reindeer and bird hunting, both of which also are well-evidenced at the site

Diet in Medieval Gaelic Ireland: A multiproxy study of the human remains from Ballyhanna, Co. Donegal

This study investigates the nature of diet in a predominantly Late Medieval Gaelic Irish skeletal population and explores whether any sex-based and/or age differences were evident in the population. A smaller sub-sample was also examined to determine whether there was any evidence for dietary change over time between the Early Medieval (c.700–c.1200) and Late Medieval periods (c.1200–c.1600). The dietary evidence was derived using a multiproxy approach that combined information from dental palaeopathology (n = 356 adults) and analysis of carbon (δ13C) and nitrogen (δ15N) stable isotope compositions (n = 72 individuals). A higher proportion of females were affected by carious lesions when compared to males. This is possibly suggestive of differing levels of carbohydrate consumption between the sexes, although other factors such as eating habits, and genetic and physiological differences may also have influenced the patterns in the data. The isotopic values indicated that both sexes were consuming similar amounts and types (marine vs. terrestrial) of dietary protein. Elevated δ15N indicated breastfeeding among the youngest in society but, once children had been weaned, the dietary protein was isotopically similar across the different age categories. Among a smaller radiocarbon-dated sub-sample (n = 37), there was an increase in both the percentage of individuals affected by dental caries and the percentage of teeth affected by dental caries between the Early Medieval and Late Medieval periods. This increase may indicate a greater inclusion of plant-based carbohydrates, such as cereals, in the diet over time, although it may also reflect the younger age distribution of the Early Medieval sample. Interpretations for each of these patterns are discussed with reference to the historical and archaeological evidence. Multiproxy palaeodietary studies for Medieval Ireland are limited and this is the first substantial study of evidence derived from both dental palaeopathology and stable isotope analysis.<br

Ancient dog diets on the Pacific Northwest Coast: zooarchaeological and stable isotope modelling evidence from Tseshaht territory and beyond

Abstract Domestic dogs are frequently encountered in Indigenous archaeological sites on the Northwest Coast of North America. Although dogs depended on human communities for care and provisioning, archaeologists lack information about the specific foods dogs consumed. Previous research has used stable isotope analysis of dog diets for insight into human subsistence (‘canine surrogacy’ model) and identified considerable use of marine resources. Here, we use zooarchaeological data to develop and apply a Bayesian mixing model (MixSIAR) to estimate dietary composition from 14 domestic dogs and 13 potential prey taxa from four archaeological sites (2,900–300 BP) in Tseshaht First Nation territory on western Vancouver Island, British Columbia, Canada. Two candidate models that best match zooarchaeological data indicate dogs predominantly consumed salmon and forage fish (35–65%), followed by nearshore fish (4–40%), and marine mammals (2–30%). We compared these isotopic data to dogs across the Northwest Coast, which indicated a pronounced marine diet for Tseshaht dogs and, presumably, their human providers. These results are broadly consistent with the canine surrogacy model as well as help illuminate human participation in pre-industrial marine food webs and the long-term role of fisheries in Indigenous economies and lifeways

Postglacial relative sea-level history of the Prince Rupert area, British Columbia, Canada

This paper presents a history of relative sea level (RSL) change for the last 15,000 years in the Prince Rupert region on the northern coast of British Columbia, Canada. One hundred twenty-three radiocarbon ages of organic material from isolation basin cores, sediment sequence exposures, and archaeological sites having a recognized relation to past sea levels constrain postglacial RSL. The large number of new measurements relating to past sea-level provides a well constrained RSL curve that differs in significant ways from previously published results. After deglaciation following the Last Glacial Maximum, the region experienced an isostatically-induced rapid RSL drop from as much 50 m asl to as low as −6.3 m asl in as little as a few centuries between 14,500 BP and 13,500 BP. After a lowstand below current sea level for about 2000 years during the terminal Pleistocene, RSL rose again to a highstand at least 6 m asl after the end of the Younger Dryas. RSL slowly dropped through the Holocene to close to its current position by 2000-1500 BP, with some potential fluctuations between 3500 and 1500 BP. This study highlights variation in RSL histories across relatively short distances, which must be accounted for by local RSL reconstructions such as this one. This RSL curve aided in the identification of an 8000–9000 year old archaeological site on a 10–12 m asl terrace, which is currently the earliest dated archaeological site in the area, and it provides guidance for searching for even older archaeological remains. We highlight the utility and potential of this refined RSL history for developing surveys for other archaeological sites associated with paleoshorelines

Anthropogenic changes to the Holocene nitrogen cycle in Ireland

Humans have always affected their ecosystems, but finding evidence for significant and lasting changes to preindustrial landscapes is rare. We report on human-caused changes to the nitrogen cycle in Ireland in the Bronze Age, associated with intensification of agriculture and animal husbandry that resulted in long-term changes to the nitrogen isotope values of animals (wild and domesticates) during the Holocene. Major changes to inputs and cycling of soil nitrogen occurred through deforestation, land clearance and management, and more intensive animal husbandry and cereal crop cultivation in the later Bronze Age; after this time, the Irish landscape took on its current form. Within the debate concerning the onset of the Anthropocene, our data suggest that human activity in Ireland was significant enough in the Bronze Age to have long-term impact, thereby marking a profound shift in the relationship between humans and their environment