What goes in does not always come out: The impact of the ruminant digestive system of sheep on plant material,and its importance for the interpretation of dung-derived archaeobotanical assemblages

Abstract

On archaeological sites where livestock dung was a major fuel source, plant material that survives digestion intact may well be preserved in the remnants of dung-fuelled fires. Preserved plant remains which were derived from dung relate to the diet of animals, and thus provide a way of investigating the agro-pastoral economies of the past. In order to improve our understanding of the taphonomic processes to which plant material is exposed to during digestion, we applied archaeobotanical methods to the analysis of dung from sheep fed a known diet of cereal and wild plant material. Two clear patterns emerge from these investigations. First, cereal material (grain or chaff) survives digestion poorly and was rarely found in the dung analysed. Second, large proportions of seeds of various wild species survive digestion in an identifiable form, probably due to their small size and/or protective coating. These findings are crucial for reliable interpretation of dung-derived plant material in archaeological settings.     

Variable Ovicaprid Diet and Faecal Spherulite Production at Amara West,Sudan

ABSTRACT

This paper presents the results of integrated geoarchaeological and archaeobotanical analyses of desiccated and charred ovicaprid dung pellets from the New Kingdom pharaonic settlement of Amara West (Sudan). These analyses reveal diagnostic phytolithic evidence for considerable variations in plant diet amongst the site’s ovicaprid population. These data shed light on aspects of ancient animal husbandry practice, the settlement’s subsistence economy and residents’ exploitation of natural resources. We also observe that specific phytolith types correlate with the presence (and quantity) or absence of calcium carbonate faecal spherulites in analysed dung pellets. This evidence, augmented by experimental analysis of analogous modern plant material, suggests that dietary Ca intake is implicated in faecal spherulite crystallization within the ovicaprid digestive system.     

Agricultural change in Copper Age Croatia (ca. 4500–2500 cal B.C)?

The Copper Age in the Carpathian Basin is marked by a distinct change in settlement patterns, material culture, social traditions and subsistence practices; however, few studies address the nature of crop cultivation in the region. This paper examines new archaeobotanical data from 13 Copper Age (ca. 4500–2500 cal BC) sites located in continental Croatia, in order to assess the extent to which crop agriculture may have changed and contributed to overall subsistence economies in the Copper Age. From the archaeobotanical results, a dominance in einkorn and emmer is seen followed by barley. Less frequently millet, naked wheat and spelt/new glume wheat are also recovered, but due to their limited numbers, it is less clear whether they were grown as crops or represent weeds. Pulses (e.g. lentil, pea and grass pea), fruit remains (e.g. cornelian cherry and chinese lantern) and wild plant and weed species are also recovered, although more commonly from the late Copper Age sites. The archaeobotanical results show a clear reduction in the quantity and range of plant species recovered during the early/middle Copper Age; however, this is likely the result of taphonomic bias rather than a reduction in crop cultivation. The results therefore highlight problems of recovery bias in the region, which makes comparisons between sites as well as the reconstruction of crop husbandry regimes difficult. Overall, the results from continental Croatia suggest that the type of crops cultivated continued relatively unchanged from the late Neolithic, although it is clear that more research is desperately needed to explore the relationship between crop agriculture and the changing socio-economic environment of the Copper Age in the region.     

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.     

The effect of charring and burial on the biochemical composition of cereal grains: investigating the integrity of archaeological plant material

Stable isotope analysis of charred archaeobotanical cereal grains has the potential to provide direct evidence of crop growing conditions in the past and to refine palaeodietary predictions. If isotope values of archaeobotanical material are to be considered robust, it is necessary to characterise the compositional changes associated with their charring and burial. This study used a suite of analytical techniques, including FT-IR and solid state ¹³C NMR, to characterise changes in the biochemical composition of modern einkorn grains with heating at 230 °C for 2 h, 4 h, 8 h and 24 h, encompassing conditions that replicate their undistorted ancient counterparts. The biochemical composition of archaeobotanical charred einkorn grains was also investigated by FT-IR and solid state ¹³C NMR in order to assess the changes in composition which occur during burial. Results of FT-IR and solid-state ¹³C NMR show that heating of modern einkorn grains resulted in Maillard reactions between cereal proteins and starch, forming high molecular weight melanoidins, which contain both alkyl and aromatic carbon. Loss of low molecular weight carbon and nitrogen-containing volatiles resulted in a slight but non-systematic increase in the δ¹³C values and a systematic increase of 0.8‰ in the δ¹⁵N values of the charred einkorn grains. Solid-state ¹³C NMR shows that the ancient charred einkorn grains consisted entirely of aromatic carbon and retained a similar proportion of nitrogen to their modern 24 h charred counterparts, despite a significantly lower concentration of amino acids. This indicates that the amino acid nitrogen in the ancient charred grains was retained in the stable melanoidins whose polymeric structure makes them resistant to subsequent degradation.     

Variations in the C/C ratios of modern wheat grain, and implications for interpreting data from Bronze Age Assiros Toumba, Greece

Variations in the ¹³C/¹²C ratios of wheat grain at different spatial and temporal scales are examined by analysis of modern samples, including harvests of einkorn and durum wheat from Greece, and serve as a guide to interpreting data for Bronze Age grains from Assiros Toumba. The normal distribution and low variability of δ¹³C values of einkorn from 24 containers in the Assiros storerooms are consistent with pooling of local harvests, but less likely to represent the harvest of several years or include grain imported from further afield. Correlation between emmer and spelt δ¹³C values provides strong support for other evidence that these were grown together as a maslin crop. ¹³C discrimination (Δ) for the Bronze Age samples is estimated to be 2.5‰ larger than at present, and would be consistent with an intensive, horticultural regime of cereal cultivation, possibly involving some watering.     

Book Reviews

Abstract

Plant macroremains were recovered during the renewed excavation at Grap?eva ?pilja, a cave on the island of Hvar in Croatia. This is the first archaeoboatnical investigation on an eastern Adriatic island to use flotation samples. Samples were taken from layers dating from the Early Neolithic to the Middle Bronze Age (ca. 6000–1500 B.C.). Sixteen radiocarbon dates obtained from wood charcoal date the samples precisely. Detailed archaeobotanical analyses of plant macroremains reveal plant use during the occupation of the cave, with the highest density of plant remains in the Neolithic. Oak acorns were the most abundant plant remains. Finds of two types of juniper berry cones, various parts of gymnosperm cones, and cypress seeds and leaves indicate that the Mediterranean evergreen woodland was exploited. Remains of cultivated plants are rare. A small number of cereal grains, including emmer, einkorn, and possibly bread wheat were recovered from the Neolithic layers, as well as a few wheat grains from later horizons. Remains of typical wild Mediterranean fruits included almond nutshell fragments, a grape pip, and a fig seed. These finds indicate that the occupants of Grap?eva utilized processed crops but also gathered plants from the wild for food, fuel, and perhaps ritual. Fourier Transform Infrared Spectroscopy (FTIR) analysis was performed in order to assess charred versus mineralized preservation. Macroplant remains from Grap?eva were compared to the few available plant analyses from the eastern Adriatic. This comparison provides evidence that caves had different functions both from each other and from open-air sites. The plant remains are discussed in the context of the spread of farming on both sides of the Adriatic.     

Neolithic and Bronze Age Agriculture in Southern Scandinavia – Recent Archaeobotanical Evidence from Denmark

Abstract

This paper presents archaeobotanical studies from the Danish regions of Thy, northern Schleswig and Djursland. The data are discussed in the light of developments in the landscape and in house architecture; comparisons are made with the contemporary situation in southern Sweden. Pollen analysis reveals that Thy was more or less treeless by the end of the Neolithic, whereas Djursland maintained its forests for a further 1500 years; the situation in northern Schleswig lies somewhere in between. Developments in house architecture are very similar in the three areas. The shift from two-aisled to three-aisled houses occurred in period I/II of the Bronze Age and phosphate analyses suggest that the earliest Danish byre dates from the beginning of period II.

Crop plant assemblages are dominated by naked barley and emmer and remain remarkably stable from the Single Grave Culture to the Late Bronze Age in Thy, from the Middle Neolithic to the middle of the Bronze Age in northern Schleswig, and from the Late Neolithic to the Late Bronze Age on Djursland. Other crops come and go – einkorn, bread wheat, spelt, millet, flax, oats and gold of pleasure. Hulled barley is largely conspicuous by its absence. Well-developed arable weed floras appear first in the Early Bronze Age – arable weeds are very scarce at Neolithic sites. There is evidence of improvement of arable soils using fen peat and household refuse and manure. The situation appears somewhat more complex in Denmark than that described for Sweden. The most striking difference is seen in the behaviour of hulled barley, which becomes massively dominant in Sweden in the course of the Bronze Age, whereas its role in Denmark is much more modest.     

4500-Year old domesticated pearl millet (Pennisetum glaucum) from the Tilemsi Valley,Mali: new insights into an alternative cereal domestication pathway

We report here new evidence from the Lower Tilemsi Valley in northeastern Mali, which constitutes the earliest archaeobotanical evidence for domesticated pearl millet (Pennisetum glaucum), predating other finds from Africa or India by several centuries. These materials provide further morphological details on the earliest cultivated pearl millet. Our results demonstrate that pearl millet non-shattering evolved earlier than the start of grain size increases and that once domesticated, pearl millet spread widely and rapidly. Additional attention is given to the dating of these materials, highlighting potential flaws in the use of organic chaff tempered pottery to date occurrences of pearl millet. A revised chronology, based on detailed Bayesian modelling, is presented for the Lower Tilemsi region.     

Ground cereal food preparations from Greece: the prehistory and modern survival of traditional Mediterranean ‘fast foods’

Archaeobotanical remains of ground cereals from prehistoric northern Greece are discussed in this paper within the context of ethnographic and textual evidence for similar food preparations encountered in countries of the Mediterranean and the Middle East. The archaeobotanical remains consist of ground einkorn and barley grain, stored in this form, from the sites of Mesimeriani Toumba and Archondiko respectively, located in the region of central Macedonia, northern Greece. The results of published pilot studies involving macroscopic, experimental, and scanning electron microscopic examination of these archaeological finds seem to suggest that these products correspond to preprocessed cereals, stored in this form. It is also likely that some at least of these finds were produced from boiled and subsequently ground cereal grains. This practice identified in the prehistoric material is similar to various forms of processing cereals still widely encountered in rural areas of modern Greece and other circum-Mediterranean countries. These products are known in Greece under the names of pligouri (bulgur) and trachanas. Through a combined examination of archaeobotanical, ethnographic, and textual evidence it is argued that the idea of pre-processing cereals for piecemeal consumption throughout the year is of considerable antiquity in this part of the world. Drawing information from food science research on similar, modern traditional preparations of the same geographical region, the paper highlights the advantages of pre-processing cereals for later consumption, which offers insights into likely prehistoric subsistence practices. Parboiling cereal grains or mixing grains with milk products in the summer would have made excellent use of seasonally available ingredients by converting them into nutritious and storable foodstuffs, which could then be consumed as part of daily meals with very little additional cooking effort and fuel. This ease of conversion into a filling meal may justify us considering them as ‘traditional fast foods’.     

Plant economy of the northern Alpine lake dwellings — 3500–2400 cal. BC

Abstract

Considerable changes are observed in the abundance of cultivated plants in the northern Alpine foreland between 3500 and 2400 cal. BC. The importance of tetraploid naked wheat (Triticum durum Desf./turgidum L.) and opium poppy (Papaver somniferum L.) declines whereas that of glume wheat (mainly emmer, Triticum dicoccum Schübl.) and flax (Linum usitatissimum L.) increases progressively. The hypothesis presented here is that these developments are mainly due to changing cultural spheres of influence. Many of these changes are, however, not fully traceable due to the very heterogeneous and, in part, very poor state of research in this area.     

Phytolith-rich layers from the Late Bronze and Iron Ages at Tel Dor (Israel): mode of formation and archaeological significance

The presence of many phytolith-rich layers in late Bronze and Iron Age deposits at Tel Dor, Israel, are indicative of specific locations where plants were concentrated. Detailed studies of six of these phytolith-rich layers and associated sediments from Tel Dor show that the phytoliths were derived mainly from wild and domestic grasses. The most common domestic grass was the cereal Triticum aestivum (bread wheat). Three of these layers have a microlaminated microstructure, associated dung spherulites and phosphate nodules; characteristics that all point to the phytolith-rich layers having formed from dung in animal enclosures. In two of the layers, the microlaminated structure is absent while dung spherulites and phosphate nodules are present, suggesting that these too originate from dung that was not deposited in an enclosure. The sixth layer is microlaminated but does not contain spherulites. We thus cannot suggest a parsimonious explanation of its observed properties. Concentrations of burnt phytoliths are present in three locations, implying that dung was either burnt in situ or the ashes from burnt dung were redeposited. The transformation of dung accumulations into phytolith-rich layers involves a loss of organic material and hence a significant reduction in sediment volume, which is clearly apparent in the stratigraphy of some of the locations examined. The volume reduction can be observed in the macrostratigraphy and has important implications with regard to macrostratigraphic interpretation. The presence of abundant phytolith-rich layers on the tell has significant implications for the concept of ‘urbanism’ during these periods.     

Preliminary report on the archaeobotanical investigations at Tell Abraq with special attention to chaff impressions in mud brick

Examination of impressions from chaff-tempered mud brick proved rewarding, given the poor preservation of carbonised seed and grain material at Tell Abraq. Individual chaff elements were found to be recognisable from the impressions and it was shown that naked wheat and barley chaff were used as a tempering medium. Charcoal samples indicate that two species of mangrove were present, one of which is no longer found in the area. Tamarisk and Ziziphus were also present. Date charcoal was common. This study remains preliminary, and further sampling and analyses have been planned for the future.     

Archaeobotanical remains from the mid-first millennium AD site of Kaerdong in western Tibet

In this study, we present the preliminary result of archaeobotanical investigation at Kaerdong in western Tibet. The result shows that agropastoralism with combined strategies of foraging, hunting and fishing was in practice at the location between approximately 455 and 700 cal. AD. Our results also show that herding animals grazed at meadows above 4300 m above sea level (masl), and dung was used as fuel. The presence of a rice grain together with spikelet bases indicates that rice was a component of food resources possibly as a result of a trade and exchange system. In addition, tatary buckwheat grains were also recovered at the site.     

Next generation sequencing of DNA in 3300-year-old charred cereal grains

We investigated whether ‘next generation’ methods can be used to sequence ancient DNA molecules in charred cereal grains. We prepared a DNA extract from a mixed sample of barley, einkorn, emmer and broomcorn millet, taken from a 3300-year-old assemblage of charred cereal grains from Assiros Toumba, Greece. Using the SOLiD 5500 system, we obtained 21,112,844 unique sequence reads. Of these, 178,779 had a 75% or greater nucleotide sequence similarity with one or more entries in the full nucleotide sequence database; 496 of these matches were to previously reported sequences from barley, einkorn, emmer, broomcorn millet or related species such as hexaploid wheat. The unique reads were also compared with a database comprising only wheat sequences. This analysis identified 1658 charred grain sequences that had 90% or greater similarity with segments of the wheat genome. The presence of barley, wheat and millet sequences in the next generation dataset confirms the presence of ancient DNA in this charred grain assemblage. Enrichment of extracts by hybridization capture or equivalent methods is likely to enable sequences to be obtained for entire genes and other genomic regions of interest.     

Early Hominin Paleoecology

Abstract

This paper reports on the zooarchaeological and archaeobotanical remains from the initial season of excavations at the Norse period site at Undir Junkarinsfløtti in the Faroe islands. These remains represent the first zooarchaeological analysis undertaken for the Faroes and only the third archaeobotanical assemblage published from the islands. The excavated deposits are described and the key findings from the palaeoenvironmental remains highlighted within the context of the wider North Atlantic environmental archaeology of the Norse period.     

Cultivation of Naked Barley by Early Iron Age Agro-pastoralists in Xinjiang,China

ABSTRACT

We report an archaeobotanical analysis of flotation samples taken from Shirenzigou, an Early Iron Age agro-pastoralist site dated between the fourth and first century BC, located on the northern slope of the Tianshan Mountains in Xinjiang, China. The charred macro-botanical assemblage is dominated by naked barley grains with a few broomcorn and foxtail millet grains. In the context of Trans-Eurasian exchange of cereal crops, southwest Asian crops (wheat and barley) and two Asian millets (broomcorn and foxtail) were introduced to Xinjiang a few centuries to a millennium before Shirenzigou was occupied. The choice of barley cultivation in preference to wheat and millet may have been possibly driven by the relatively extreme local environment and the scheduling requirements of mobile pastoralism. Barley is well suited to this environment, and the choice of naked barley in preference to hulled barley may have been driven by the whole grain tradition prevailing in East Asia.     

Dung matters: An experimental study into the effectiveness of using dung from hay-fed livestock to reconstruct local vegetation

This paper explores the relationship between standing vegetation and dung from hay-fed cattle and sheep. In an experimental study, hay is retrieved from a known hay field, surrounded by a semi-open landscape of hedgerows, forests and heather fields. The hay is fed to cattle and sheep, after which the dung is collected and from which the botanical remains are analysed, according to archaeobotanical standards. The results from the macro-remains are compared to vegetation relevés from the hay field. The pollen analysis is compared to both the hay field and the surrounding vegetation. Results from the plant macro remains provide an excellent representation of the vegetation in the field itself on the presence/absence level. Pollen analysis reflects the regional vegetation very well and are comparable with ‘surface samples’.     

Length of the Cubit

Abstract

From excavations of Bronze Age Levantine sites only rarely has there been archaeobotanical evidence of a specific dietary event which may be seen to reflect the daily life of the people against the background of their farming economy. Even more rare is one that may be examined scientifically for evidence of dried or preserved foodstuffs. An Early Bronze Age archaeobotanical assemblage at Tell es-Sa'idryeh in the Jordan valley has provided an opportunity for such an investigation on food remains burnt by the sudden conflagration of the room in which they were found. Scanning electron microscopic examination and experimental replication of the charred remains have provided new and vital information regarding the role of pickled and stored plant foods within the diet at the site during the period. The results have also contributed towards a revised interpretation of the room containing the plant remains as well as a wider understanding of agricultural practices at the site.     

Changes in crop cultivation during the last five centuries before the Roman conquest: archaeobotanical investigation in the Clermont-Ferrand basin,Massif Central,France

For several decades, a growing number of protohistoric sites in Auvergne (Massif Central, France)—mostly excavated through preventive archaeology—have been subject to the collection of archaeobotanical analysis. This study presents the archaeobotanical results from ten La Tène sites dating from the last five centuries before the Roman conquest. In addition to providing an inventory of taxa, this paper concerns crops and crop cultivation methods. These results are interpreted in a wider context, dealing with crop husbandry, arable farming, storage and consumption practices. The sites are located in the Limagne plain within a 50-km radius around the city of Clermont-Ferrand. A total of 23,579 carpological remains were identified from 163 sediment samples totalizing a volume of 1096 l. Comparable to other sites in Gaul, the spectrum of cereals and pulses is restricted. Spelt (Triticum spelta), einkorn (Triticum monococcum) and foxtail millet (Setaria italica) are disappearing or becoming rare. A better control of agricultural techniques and increased yields is supposed during the ca. five centuries of the La Tène period. Mixed cultivation is hereby replaced by the sowing of monocrops. At the beginning of this period, farming systems are dominated by a polyculture of cereals and pulses. They become more specialized during the last two centuries before the Roman conquest; diversity of cereals and pulses is decreased.