The impact of manuring on nitrogen isotope ratios in cereals: archaeological implications for reconstruction of diet and crop management practices

Recent archaeological studies of human diet have used stable nitrogen isotope ratios (δ¹⁵N) from human bone collagen to infer the relative importance of terrestrial plant and animal foods. This approach is based on widely observed enrichment of δ¹⁵N up the food chain, plants having distinctly lower values than the herbivores that consume them. Studies of early farming diets in Britain, Denmark and Germany have tended to detect relatively high δ¹⁵N values (e.g. c. +9‰), interpreted as evidence of a diet largely based on animal products, though archaeobotanical evidence for crop cultivation (e.g. carbonised cereal grain and chaff) is widespread. This paper investigates the impact of manuring on δ¹⁵N values in modern cereals, and of charring on these cereal values. The results from two long-term experiments demonstrate that manuring significantly raises δ¹⁵N in cereal grain and chaff. Depending on manuring levels and frequency, it appears that human diets with a major component of such grain would conventionally be interpreted as indicating a largely animal-based diet or a mixed plant/animal diet. Moreover, preliminary analyses of experimentally charred grain and chaff from manured and unmanured conditions are promising for the extraction of reliable ancient δ¹⁵N values from archaeobotanical cereal remains. The wider implications of these results, and the need for further work, are discussed.     

Stable isotope analysis of human and animal remains from the Late Upper Palaeolithic site of Balma Guilanyà, southeastern Pre-Pyrenees,Spain

Stable isotope analysis of carbon (¹³C/¹²C) and nitrogen (¹⁵N/¹⁴N) was performed on collagen extracted from three human and five herbivore bone and tooth samples from the Late Upper Palaeolithic site of Balma Guilanyà (Catalonian Pre-Pyrenees, Spain). Contextual and palaeoecological data as well as radiocarbon dates indicate that the studied occupation phase took placed during the Bolling/Allerod interstadial (GI-1a event). The human remains were co-mingled without any anatomical association, corresponding to a minimum number of three individuals, and it was not possible to determine if the three analyzed samples are from one or more individuals. The mean isotope values obtained from the human remains are δ¹³C = −19.8‰ and δ¹⁵N = 6.7‰, while those of the large herbivores (red deer and wild goat) were −19.8‰ and 1.7‰ for δ¹³C and δ¹⁵N respectively. This indicates that the main source of protein in the diet of the Balma Guilanyà human(s) came from terrestrial herbivores. There is no zooarchaeological or isotopic evidence for the consumption of freshwater or marine resources at the site, which lies 80 km from the present Mediterranean coast. The low δ¹⁵N values observed in both human and animal samples correspond to a trend reported by other researchers working in northwestern Europe: a significant δ¹⁵N reduction in collagen from bones datable within 20,000–10,000 BP, followed by a rise to present values in the Early Holocene. This phenomenon, generally attributed to climatic and/or pedological processes, had not been previously observed in the Mediterranean region and, until now, was thought to be restricted to northern Europe.     

Early Neolithic diet and animal husbandry: stable isotope evidence from three Linearbandkeramik (LBK) sites in Central Germany

The first appearance of the Neolithic Linearbandkeramik (LBK) in Central Germany occurred during the 6th millennium BC. However, though LBK sites are abundant in the German loess areas, there are only a few studies that reconstruct the diet of these first farmers using biochemical methods. Here we present the largest study undertaken to date on LBK material using stable isotope analysis of carbon and nitrogen to reconstruct human diet and animal husbandry strategies. We analyzed the bone collagen of 97 human individuals and 45 associated animals from the sites of Derenburg, Halberstadt and Karsdorf in the Middle Elbe–Saale region of Central Germany. Mean adult human values are ?19.9 ± 0.4‰ for δ¹³C and 8.7 ± 0.8‰ for δ¹⁵N. The δ¹³C values are typical for terrestrial, temperate European regions, whereas the δ¹⁵N values fall within an expected range for farming societies with a mixed diet consisting of products from domestic animals and plants. The consumption of unfermented dairy products is unlikely as there is direct palaeogenetic evidence of lactose intolerance available for one of the sites. There are no clear indications for dietary differences in sex. Young children under three years of age are enriched in δ¹⁵N due to breastfeeding indicating that weaning likely occurred around the age of three years. The fauna exhibit mean δ¹³C values of ?20.9 ± 0.8‰ and mean δ¹⁵N values of 7.0 ± 0.9‰ respectively. Variation in the δ¹³C and δ¹⁵N in the domestic animals is probably caused by different livestock managements.     

Chemical analyses of organic residues in archaeological pottery from Arbon Bleiche 3, Switzerland – evidence for dairying in the late Neolithic

Fatty acids distribution and stable isotope ratios (bulk δ¹³C, δ¹⁵N and δ¹³C of individual fatty acids) of organic residues from 30 potsherds have been used to get further insights into the diet at the Late Neolithic (3384–3370 BC) site of Arbon Bleiche 3, Switzerland. The results are compared with modern equivalents of animal and vegetable fats, which may have been consumed in a mixed ecology community having agrarian, breeding, shepherd, gathering, hunting, and fishing activities. The used combined chemical and isotopic approach provides valuable information to complement archaeological indirect evidence about the dietary trends obtained from the analysis of faunal and plant remains. The small variations of the δ¹³C and δ¹⁵N values within the range expected for degraded animal and plant tissues, is consistent with the archaeological evidence of animals, whose subsistence was mainly based on C₃ plants. The overall fatty acid composition and the stable carbon isotopic compositions of palmitic, stearic and oleic acids of the organic residues indicate that the studied Arbon Bleiche 3 sherds contain fat residues of plant and animal origin, most likely ruminant (bovine and ovine). In several vessels the presence of milk residues provides direct evidence for dairying during the late Neolithic in central Europe.     

Isotopic evidence of dietary variability in subadults at the Usu-moshiri site of the Epi-Jomon culture,Japan

This study reconstructs adult and subadult diets of a hunter-gatherer population of the Epi-Jomon culture (approximately 2300–1700 years BP) in Japan, using the stable isotopic analysis of carbon and nitrogen. The results suggest that the Usu-moshiri adults were highly dependent on marine resources such as seals for their dietary protein intake and that no significant dietary differences existed between the sexes. Among subadults we found two types of diet on the basis of different isotopic signatures. One group consisted of individuals with δ¹³C values below than those of the adult female mean minus two standard deviations and δ¹⁵N values lower than those of subadults in the other groups. These low-δ¹³C subadults indicated relatively less enriched δ¹⁵N values by 3.5 years of age at the latest. They probably consumed more ¹³C-depleted foods during weaning than in the ordinary adult diet. In the other high-δ¹³C group, their enriched δ¹⁵N values start to decline by four years of age and fall within the two-standard-deviations range of the total adult mean around five to six years of age. Isotopic values of children in this high-δ¹³C group suggest that they would have been fed ordinary adult diets during weaning. Perinates could also be divided into two groups on the basis of the similar patterns in their carbon and nitrogen isotope ratios. Our results indicate variabilities in the diets of subadults, and similar variabilities were also seen in ethnographic studies of the Ainu populations.     

Isotopic anthropology of rural German medieval diet: intra- and inter-population variability

This study investigates the diet of an eleventh century CE parish community located in northwestern Germany. We assessed the isotopic compositions of human (n = 24) and faunal (n = 17) bone collagen (δ ¹³C_col, δ ¹⁵N_col) and human structural carbonate (δ ¹³C_sc) using skeletal material recovered from the Dalheim cemetery. Traditional interpretation of the isotopic data indicates that Dalheim residents likely relied on a C₃ plant-based diet and consumed some terrestrial animal products without evidence of marine resource input in the diet. Bivariate and multivariate models used as an additional means to assess diet indicate minor consumption of C₄ plant foods in this community. The multivariate-isotope model identified regional similarities and differences in C₄ plant/marine food consumption and in dietary protein sources by comparing data from Dalheim with those of other medieval sites from the published literature. We did not observe sex differences in this population but differences in δ ¹⁵N_col suggest that juveniles consumed the lowest trophic level protein.     

AN INVESTIGATION INTO DIET AT THE SITE OF YARNTON, OXFORDSHIRE, USING STABLE CARBON AND NITROGEN ISOTOPES

This paper reports the results of stable isotopic analyses conducted upon animal and human bones recovered from Yarnton, Oxfordshire. Spanning the Neolithic to Saxon periods, it is in many ways a typical site, but is unusual in that a small Middle Iron Age cemetery was discovered.
All of the data presented here lie within the expected isotopic ranges for the European Holocene, although both faunal and animal δ¹⁵N values are higher than is commonly found. The faunal data show the expected pattern for the animals studied (horse, cattle, sheep/goat, pig and dog), with pigs being more omnivorous than ruminants, and dogs eating an isotopically similar diet to humans. The animals' diets had higher δ¹⁵N values during the Roman period as compared to the Iron Age, although it is unclear if this reflects an environmental change or alteration in animal management practices. Despite the site's riverine location, there is no isotopic evidence for fish consumption. No distinctions were found based on gender or burial position within the Iron Age cemetery. Age-based distinctions were found in δ¹³C values, although these cannot be fully explained. As expected, infants have a higher nitrogen isotopic value than other individuals, reflecting the consumption of their mother's milk.     

Diet and mobility in Middle Archaic Florida: stable isotopic and faunal evidence from the Harris Creek archaeological site (8Vo24), Tick Island

We explore diet and mobility in Middle Archaic Florida using human burials and faunal remains from the Harris Creek archaeological site (8Vo24) on Tick Island. We conducted stable carbon and oxygen isotopic (δ¹³C, δ¹⁸O) analyses of 50 human enamel samples and strontium isotopic (⁸⁷Sr/⁸⁶Sr) analysis of a subset of 10. Most individuals (46/50) subsisted on local freshwater and terrestrial resources, with relatively depleted δ¹³C values (C₃) and δ¹⁸O values matching those of central and north Florida water resources within the St. Johns River valley. Eight of 10 burials have local, within valley ⁸⁷Sr/⁸⁶Sr values. Two human burials yield marine δ¹³C and ⁸⁷Sr/⁸⁶Sr values, which we interpret as evidence for across valley movement from the coast. Another two individuals show depleted δ¹⁸O values, likely obtained from northern rivers. We also identified potential food resources and non-local foods from the Harris Creek faunal assemblage. We found six species with estuarine and marine habitat preferences; two of which, whelk and quahog, indicate that people of Harris Creek traveled to or traded with coastal areas.     

Fast or feast: reconstructing diet in later medieval England by stable isotope analysis

In this pilot-study, which was designed to assess the range of isotopic variation in English medieval populations, we present the results of stable isotope analysis of carbon and nitrogen of human and animal bone collagen from three later medieval sites in Northern England.The isotopic values observed for the rural hospital of St. Giles by Brompton Bridge (N. Yorks.), the Augustinian Friary at Warrington and a mass-grave with casualties from the Battle of Towton (N. Yorks.) are significantly different from those reported for other archaeological populations in Britain, namely by their very enriched δ¹⁵N ratios which are combined with almost entirely terrestrial carbon signals. We discuss possible explanations for the unusual human data and argue on grounds of the available faunal data, that a mixed diet of terrestrial, marine and freshwater resources is most likely. This may indicate the significant impact of the medieval fasting regulations on everyday subsistence. We conclude that stable isotope analysis can complement the available historical information on diet in the Middle Ages.     

Stable carbon and nitrogen isotope ratios of bone collagen: Variations within individuals,between sexes,and within populations raised on monotonous diets

The stable carbon and nitrogen isotope ratios of collagen of seven bones from each of three rabbits raised on a monotonous diet, and of two bones from each of eight female and seven male mink raised on another monotonous diet, were determined. The ranges of δ¹³C values and δ¹⁵N values were 0·5‰ and 0·6‰ for the rabbit bones and 1·0‰ and 1·4‰ for the mink bones. Uncertainties in the δ¹³C and δ¹⁵N values for prehistoric human diets estimated from the isotopic composition of collagen from the small numbers of bones which are typically available for analysis, and thus likely to be of the order of ±1‰.     

Isotopic evidence for the reconstruction of diet and mobility during village formation in the Early Middle Ages: Las Gobas (Burgos,northern Spain)

Strontium, carbon, and nitrogen isotopes of human bone and tooth remains have been used to reconstruct residential mobility and diet of early medieval populations at Las Gobas from the sixth to eleventh centuries. Most non-local individuals correspond to the tenth to eleventh centuries and were mostly women and infants. This residential mobility coincided with the formation of Laño village and the abandonment of artificial cave settlement. Carbon and nitrogen isotope ratios of bone collagen indicate an omnivorous homogenous diet based on terrestrial plant resources, with few animal-derived proteins from livestock. Millet consumption was restricted to an earlier period of time (seventh to ninth centuries); and in later periods (tenth to eleventh centuries), mainly C₃ plants such as wheat and barley were consumed. In general, there were no dietary differences between individuals according to sex or age. Sex-related dietary differences have only been observed in the tenth to eleventh centuries, when females consumed a more vegetarian diet and less animal protein. The higher δ ¹⁵N values in infants reflect the weaning effect, while the differences in δ ¹⁵N values between young adult men and young adult women can be explained as a physiological factor related to pregnancy or different origins. In a comparison with contemporaneous medieval populations in the northern Iberian Peninsula, both δ ¹³C and δ ¹⁵N values suggest similar foodstuff resources and diet among Christian and Muslim populations.     

Isotopic investigation of pre-Hispanic macaw breeding in Northwest Mexico

The pre-Hispanic settlement of Paquimé (ca. 1200–1450 AD) lay outside of urban Mesoamerica in arid northern Chihuahua, Mexico, yet the excavated remains of 322 scarlet macaws, tropical parrots whose northernmost habitat is 500 km to the south, suggest that Paquimé had relationships with distant communities. Here, carbon and oxygen stable isotope analysis of 30 macaw bones determines whether the Paquimeños actively bred these parrots or traded with Mesoamerican groups to obtain the birds. The δ¹³C values indicate that the macaws ate a diet of C₄ plants, foods that were unavailable to wild macaws. In addition, δ¹⁸O data suggest that the majority of the macaws spent their entire lives at Paquimé. We conclude that the ancient Paquimeños were in fact breeding scarlet macaws, although one bone with δ¹⁸O values outside the local range suggests that the breeders also maintained exchange ties with the source areas of the birds. By confirming that Paquimeños implemented a system of local macaw reproduction outside the Mesoamerican region itself, this analysis provides new evidence about the economic and ideological interdependence of pre-Hispanic societies in the Americas. It is also suggestive of the pre-industrial capabilities of humans to extend the natural ranges of animal species.     

Stable isotopes and diet at Ancient Kerma,Upper Nubia (Sudan)

Carbon and nitrogen stable isotope values were measured from bone collagen extracted from archaeological Nubian human (n = 54) and faunal (n = 61) populations from the site of Kerma, Sudan. Collagen suitable for isotopic analysis was extracted from 22 faunal and 48 human samples from the Eastern cemetery site, dated to the Middle Kerma (c. 2050–1750 BC) and Classic Kerma (c. 1750–1500 BC) periods respectively. The isotopic data indicate that the human dietary regimen included a mix of C₃ and C₄ plant-derived components, with a larger C₄ component than previously reported in archaeological Egyptian Nile Valley populations. Elevated δ¹⁵N values are attributed to consumption of dietary resources from a ¹⁵N-enriched terrestrial ecosystem. The faunal isotope data also indicate the consumption of C₃ and C₄ plants. The large range of δ¹³C values measured in both the human and faunal samples supports previous work suggesting that a significant portion of the populations buried at Kerma may have originated elsewhere, further confirming the Nile Valley as a major corridor for population movement in the region.     

Diet in medieval Denmark: a regional and temporal comparison

The aim of this research is to explore regional and temporal patterning in diet in medieval Danish populations. δ¹⁵N, δ¹³C_coll, δ¹³C_ap values were obtained from 154 human bone samples from three sites located in the Jutland peninsula of Denmark. These sites span the medieval period. The results suggest that the medieval Danish diet was composed of C₃ plants, terrestrial animals, and freshwater and marine fish in varying amounts. The data also suggest some regional patterning in diet, but little temporal differences in the composition of diet.     

Dietary reconstruction in Migration Period Central Germany: a carbon and nitrogen isotope study

This study presents bone collagen carbon and nitrogen isotope data from the Migration Period cemeteries (fifth/sixth century AD) of Obermöllern and Rathewitz in Central Germany. The human average δ ¹³C ratios of ?19.8?±?0.3 ‰ and δ ¹⁵N ratios of 9.6?±?0.9 ‰ (n?=?43) reflect a mixed diet in a temperate C3-based ecosystem without significant difference between the two sites. The average offset between human and faunal δ ¹³C and δ ¹⁵N values indicates a significant contribution of plant food to the human diet that has different isotope ratios from the forage of the animals. It furthermore suggests the influence of land management on the δ ¹⁵N values. One adult male from Obermöllern stands out due to his elevated nitrogen isotope ratio, body height, grave goods, and burial position. The collagen isotope data of this study are comparable with data from other central European sites and confirm rather stable communities with moderate variation in the environmental conditions of arable land.     

Human and animal diet at Conchopata, Peru: stable isotope evidence for maize agriculture and animal management practices during the Middle Horizon

This paper reports δ¹³C and δ¹⁵N values for human and animal skeletal remains from the Middle Horizon (AD 550–1000) site of Conchopata in the Peruvian highlands. The data indicate that maize was the dietary staple for both humans and the majority of animals at this urban site. Camelids at the site segregated into two groups according to δ¹³C values, reflecting two distinct animal management strategies. Human infants were found to have elevated δ¹⁵N values, reflecting the trophic level effect of breastfeeding. No sex based differences in diet were observed.     

Paleodiet reconstruction of Bronze Age Siberians from the mortuary site of Khuzhir-Nuge XIV,Lake Baikal

Paleodiet reconstruction using stable isotopes of carbon and nitrogen was carried out on individuals from the Bronze Age cemetery, Khuzhir-Nuge XIV on the western shore of Lake Baikal, Russian Federation. The cemetery contained 79 graves with 89 individuals and was in use between approximately 2700 and 2000 cal. B.C. with the exception of one burial, dated to around 4000 B.C. Archaeological and ethnographic evidence indicates that hunting and fishing were the main subsistence activities while gathering was less important. δ¹³C from collagen and carbonate apatite was analysed, along with δ¹⁵N from collagen. Bone mineral preservation was evaluated using Fourier transform infrared spectroscopy. δ¹³C and δ¹⁵N of collagen are positively correlated and reflect varying reliance on terrestrial mammals, fish, and seals from Lake Baikal. Lake Baikal biota exhibit considerable variation in δ¹³C at the base of the food web thus; there is variation in human δ¹³C (−20.1‰ to −16.2‰) despite the fact that there are no C₄ plants in the region. δ¹⁵N results (range 10.3‰–16.5‰) indicate that fish, and possibly seals, made up some of the diet for everyone, but in varying amounts relative to terrestrial herbivores. δ¹³C from carbonate is not correlated with δ¹³C from collagen, a situation that has been found in remains from other coastal sites. A mixed diet from both terrestrial and freshwater ecosystems is the most likely explanation. Analysis of mortuary variables within the cemetery reveals three distinct clusters of graves with variations in burial treatment among the clusters. δ¹⁵N values are significantly different among these clusters, suggesting an association between diet and mortuary customs.     

Stable isotope palaeodietary study of humans and fauna from the multi-period (Iron Age,Viking and Late Medieval) site of Newark Bay,Orkney

We report here on stable carbon and nitrogen isotope measurements of human and faunal bone collagen from the Iron Age, Viking Age, and Late Medieval site of Newark Bay, Orkney, Scotland. We found a wide range of results for humans in both δ¹³C (−15.4‰ to −20.3‰) and δ¹⁵N (8.6‰–15.6‰) values. The enriched carbon and nitrogen values indicate the consumption of significant amounts of marine protein, which is very unusual for post-Mesolithic (e.g. 4000 cal BC) UK and European populations. Also of interest is a statistically significant difference in δ¹³C (t = −2.48, p = 0.011) and δ¹⁵N (t = −2.44, p = 0.011) values, and therefore diets, between adult males and females at this site, with males (δ¹³C = −17.8 ± 1.2‰, δ¹⁵N = 13.2 ± 1.6‰) having, on average, a higher proportion of marine protein than females (δ¹³C = −18.9 ± 1.1‰, δ¹⁵N = 11.8 ± 1.8‰). The weaning age of the sub-adults was difficult to interpret due to the large isotopic variation in the adult females, but nearly all individuals between birth and 1.25 years have elevated δ¹⁵N values indicating that they were breastfed to some extent.     

Paleonutritional and paleodietary survey on prehistoric humans from Las Cañadas del Teide (Tenerife,Canary Islands) based on chemical and histological analysis of bone

The aim of the present study is to perform a paleodietary and paleonutritional survey on 17 individuals buried in accordance with the prehispanic ritual in the central plateau of the island Tenerife, called Las Cañadas del Teide. We recorded hydrogen, nitrogen and carbon isotope compositions of human bone collagen, bone barium and strontium, and histomorphometrically assessed trabecular bone mass (TBM). Bone trace elements and TBM were compared with reference data derived from a modern sample consisting of 13 individuals. In addition, δ¹⁵N and δ¹³C values were determined in several modern indigenous plants, bone collagen of prehistoric domestic animals (goat and pig), and prehistoric wild animals (a giant lizard, Gallotia goliath and a giant rat, Canaryomis bravoi), which represent food sources potentially consumed by the prehistoric population of the Island. The carbon stable isotope composition of bone collagen ranged between ?20.5 and ?18.6‰ (VPDB), indicating a diet based on C₃ plants. Nitrogen isotope values ranged from 8.2 to 12.4‰ (AIR), suggesting a general meat-enriched diet, most likely domestic goats, of higher level consumers. Hydrogen isotope values ranged from ?18 to +4‰, whereas log Ba/Sr was greater than ?0.40 in the vast majority of cases. TBM showed a tendency to osteoporosis in 30% of the individuals analyzed. C-14 dating showed that two burial sites, including 5 individuals, belonged to the post-conquest era (after the 15th century), despite a fully “prehispanic” burial ritual, which lends credenceto the oral tradition that some of the prehispanic population fled to the highlands at the time of the Spanish conquest, and lived there during decades or even centuries. These individuals showed lower δD, δ¹³C and δ¹⁵N, and higher log Ba/Sr values than those buried before the Spanish conquest, suggesting dietary differences between the two groups. Also, women showed a trend to a higher consumption of vegetables than men.     

Dietary change in Fijian prehistory: isotopic analyses of human and animal skeletal material

We examine evidence for prehistoric diet in the Fiji Islands through the analysis of stable isotope ratios (δ¹³C and δ¹⁵N) for 26 samples of human and animal bones from various archaeological sites, time periods, and local environments. The oldest individuals in this study, dating to about 2700 BP and living on the small island of Waya, consumed a predominantly marine-based diet. Subsequent populations on this island showed reduced consumption of marine resources, with greater reliance on terrestrial ones, throughout the cultural sequence. In contrast, populations of humans and pigs living inland on Viti Levu, the largest island, relied on terrestrial resources since at least 1500 BP. Thus, our results suggest that human and pig diets throughout Fijian prehistory relied variably on marine or terrestrial resources, and this distinction is largely a product of geography. This finding and our analyses provide a model for understanding ancient diets in Remote Oceania.