Mobility and kinship in the world's first village societies.

Around 10,000 y ago in southwest Asia, the cessation of a mobile lifestyle and the emergence of the first village communities during the Neolithic marked a fundamental change in human history. The first communities were small (tens to hundreds of individuals) but remained semisedentary. So-called megasites appeared soon after, occupied by thousands of more sedentary inhabitants. Accompanying this shift, the material culture and ancient ecological data indicate profound changes in economic and social behavior. A shift from residential to logistical mobility and increasing population size are clear and can be explained by either changes in fertility and/or aggregation of local groups. However, as sedentism increased, small early communities likely risked inbreeding without maintaining or establishing exogamous relationships typical of hunter-gatherers. Megasites, where large populations would have made endogamy sustainable, could have avoided this risk. To examine the role of kinship practices in the rise of megasites, we measured strontium and oxygen isotopes in tooth enamel from 99 individuals buried at Pinarbasi, Boncuklu, and Çatalhöyük (Turkey) over 7,000 y. These sites are geographically proximate and, critically, span both early sedentary behaviors (Pinarbasi and Boncuklu) and the rise of a local megasite (Çatalhöyük). Our data are consistent with the presence of only local individuals at Pinarbasi and Boncuklu, whereas at Çatalhöyük, several nonlocals are present. The Çatalhöyük data stand in contrast to other megasites where bioarchaeological evidence has pointed to strict endogamy. These different kinship behaviors suggest that megasites may have arisen by employing unique, community-specific kinship practices.

Corrigendum: Greater post-Neolithic wealth disparities in Eurasia than in North America and Mesoamerica.

This corrects the article DOI: 10.1038/nature24646.

Changing social inequality from first farmers to early states in Southeast Asia.

When the first rice farmers expanded into Southeast Asia from the north about 4,000 y ago, they interacted with hunter-gatherer communities with an ancestry in the region of at least 50 millennia. Rigorously dated prehistoric sites in the upper Mun Valley of Northeast Thailand have revealed a 12-phase sequence beginning with the first farmers followed by the adoption of bronze and then iron metallurgy leading on to the rise of early states. On the basis of the burial rituals involving interment with a wide range of mortuary offerings and associated practices, we identify, by computing the values of the Gini coefficient, at least two periods of intensified social inequality. The first occurred during the initial Bronze Age that, we suggest, reflected restricted elite ownership of exotic valuables within an exchange choke point. The second occurred during the later Iron Age when increased aridity stimulated an agricultural revolution that rapidly led to the first state societies in mainland Southeast Asia.

Reconstructing herbivore diets: a multivariate statistical approach to interpreting amino acid nitrogen isotope values.

Recent studies have demonstrated that there exists significant variability in amino acid (AA) δ15N values of terrestrial plants, discriminating among plant types (i.e., legume seeds, grasses, tree leaves) as well as tissues of the same plant. For the first time, we investigate the potential of the spacing between the δ15N values of different AAs to differentiate between plant types and thus elucidate their relative importance in herbivore diet. Using principal component analysis, we show that it is possible to distinguish among five plant categories-cereal grains, rachis, legume seeds, herbaceous plants, and woody plants-whose consumption has different implications for understanding herbivore ecology and management practices. Furthermore, we were able to correctly classify the herbaceous plant diet of modern cattle using AA δ15N values of their tooth dentine adjusted for trophic enrichment. The AA δ15N patterns of wild and domestic herbivores from archaeological sites seem to be consistent with diets comprised predominantly of herbaceous plants, but there is variation in AA δ15N values among individuals that may reflect differing inputs of other plant types. The variation in AA δ15N values does not necessarily reflect the variation in herbivore bulk collagen δ13C and δ15N values, indicating that AA δ15N values have the potential to provide additional insights into plant dietary sources compared to bulk tissue isotope values alone. Future work should focus on defining trophic enrichment factors for a wider range of terrestrial herbivores and expanding libraries of primary producer AA δ15N values.

Greater post-Neolithic wealth disparities in Eurasia than in North America and Mesoamerica.

How wealth is distributed among households provides insight into the fundamental characters of societies and the opportunities they afford for social mobility. However, economic inequality has been hard to study in ancient societies for which we do not have written records, which adds to the challenge of placing current wealth disparities into a long-term perspective. Although various archaeological proxies for wealth, such as burial goods or exotic or expensive-to-manufacture goods in household assemblages, have been proposed, the first is not clearly connected with households, and the second is confounded by abandonment mode and other factors. As a result, numerous questions remain concerning the growth of wealth disparities, including their connection to the development of domesticated plants and animals and to increases in sociopolitical scale. Here we show that wealth disparities generally increased with the domestication of plants and animals and with increased sociopolitical scale, using Gini coefficients computed over the single consistent proxy of house-size distributions. However, unexpected differences in the responses of societies to these factors in North America and Mesoamerica, and in Eurasia, became evident after the end of the Neolithic period. We argue that the generally higher wealth disparities identified in post-Neolithic Eurasia were initially due to the greater availability of large mammals that could be domesticated, because they allowed more profitable agricultural extensification, and also eventually led to the development of a mounted warrior elite able to expand polities (political units that cohere via identity, ability to mobilize resources, or governance) to sizes that were not possible in North America and Mesoamerica before the arrival of Europeans. We anticipate that this analysis will stimulate other work to enlarge this sample to include societies in South America, Africa, South Asia and Oceania that were under-sampled or not included in this study.

Genetic diversity, distribution and domestication history of the neglected GGAtAt genepool of wheat.

KEY MESSAGE: We present a comprehensive survey of cytogenetic and genomic diversity of the GGAtAt genepool of wheat, thereby unlocking these plant genetic resources for wheat improvement. Wheat yields are stagnating around the world and new sources of genes for resistance or tolerances to abiotic traits are required. In this context, the tetraploid wheat wild relatives are among the key candidates for wheat improvement. Despite its potential huge value for wheat breeding, the tetraploid GGAtAt genepool is largely neglected. Understanding the population structure, native distribution range, intraspecific variation of the entire tetraploid GGAtAt genepool and its domestication history would further its use for wheat improvement. The paper provides the first comprehensive survey of genomic and cytogenetic diversity sampling the full breadth and depth of the tetraploid GGAtAt genepool. According to the results obtained, the extant GGAtAt genepool consists of three distinct lineages. We provide detailed insights into the cytogenetic composition of GGAtAt wheats, revealed group- and population-specific markers and show that chromosomal rearrangements play an important role in intraspecific diversity of T. araraticum. The origin and domestication history of the GGAtAt lineages is discussed in the context of state-of-the-art archaeobotanical finds. We shed new light on the complex evolutionary history of the GGAtAt wheat genepool and provide the basis for an increased use of the GGAtAt wheat genepool for wheat improvement. The findings have implications for our understanding of the origins of agriculture in southwest Asia.

Urban form and scale shaped the agroecology of early 'cities' in northern Mesopotamia, the Aegean and Central Europe.

Agricultural extensification refers to an expansive, low-input production strategy that is land rather than labour limited. Here, we present a robust method, using the archaeological proxies of cereal grain nitrogen isotope values and settlement size, to investigate the relationship between agricultural intensity and population size at Neolithic to Bronze/Iron Age settlement sites in northern Mesopotamia, the Aegean and south-west Germany. We conclude that urban form-in particular, density of occupation-as well as scale shaped the agroecological trajectories of early cities. Whereas high-density urbanism in northern Mesopotamia and the Aegean entailed radical agricultural extensification, lower density urbanism in south-west Germany afforded more intensive management of arable land. We relate these differing agricultural trajectories to long-term urban growth/collapse cycles in northern Mesopotamia and the Aegean, on the one hand, and to the volatility of early Iron Age elite power structures and urban centralization in south-west Germany, on the other.

Seed size, number and strategies in annual plants: a comparative functional analysis and synthesis.

BACKGROUND AND AIMS: Plants depend fundamentally on establishment from seed. However, protocols in trait-based ecology currently estimate seed size but not seed number. This can be rectified. For annuals, seed number should simply be a positive function of vegetative biomass and a negative function of seed size. METHODS: Using published values of comparative seed number as the 'gold standard' and a large functional database, comparative seed yield and number per plant and per m2 were predicted by multiple regression. Subsequently, ecological variation in each was explored for English and Spanish habitats, newly calculated C-S-R strategies and changed abundance in the British flora. KEY RESULTS: As predicted, comparative seed mass yield per plant was consistently a positive function of plant size and competitive ability, and largely independent of seed size. Regressions estimating comparative seed number included, additionally, seed size as a negative function. Relationships differed numerically between regions, habitats and C-S-R strategies. Moreover, some species differed in life history over their geographical range. Comparative seed yield per m2 was positively correlated with FAO crop yield, and increasing British annuals produced numerous seeds. Nevertheless, predicted values must be viewed as comparative rather than absolute: they varied according to the 'gold standard' predictor used. Moreover, regressions estimating comparative seed yield per m2 achieved low precision. CONCLUSIONS: For the first time, estimates of comparative seed yield and number for >800 annuals and their predictor equations have been produced and the ecological importance of these regenerative traits has been illustrated. 'Regenerative trait-based ecology' remains in its infancy, with work needed on determinate vs. indeterminate flowering ('bet-hedging'), C-S-R methodologies, phylogeny, comparative seed yield per m2 and changing life history. Nevertheless, this has been a positive start and readers are invited to use estimates for >800 annuals, in the Supplementary data, to help advance 'regenerative trait-based ecology' to the next level.

Trade-offs between seed and leaf size (seed-phytomer-leaf theory): functional glue linking regenerative with life history strategies and taxonomy with ecology?

Background and Aims: While the 'worldwide leaf economics spectrum' (Wright IJ, Reich PB, Westoby M, et al. 2004. The worldwide leaf economics spectrum. Nature : 821-827) defines mineral nutrient relationships in plants, no unifying functional consensus links size attributes. Here, the focus is upon leaf size, a much-studied plant trait that scales positively with habitat quality and components of plant size. The objective is to show that this wide range of relationships is explicable in terms of a seed-phytomer-leaf (SPL) theoretical model defining leaf size in terms of trade-offs involving the size, growth rate and number of the building blocks (phytomers) of which the young shoot is constructed. Methods: Functional data for 2400+ species and English and Spanish vegetation surveys were used to explore interrelationships between leaf area, leaf width, canopy height, seed mass and leaf dry matter content (LDMC). Key Results: Leaf area was a consistent function of canopy height, LDMC and seed mass. Additionally, size traits are partially uncoupled. First, broad laminas help confer competitive exclusion while morphologically large leaves can, through dissection, be functionally small. Secondly, leaf size scales positively with plant size but many of the largest-leaved species are of medium height with basally supported leaves. Thirdly, photosynthetic stems may represent a functionally viable alternative to 'small seeds + large leaves' in disturbed, fertile habitats and 'large seeds + small leaves' in infertile ones. Conclusions: Although key elements defining the juvenile growth phase remain unmeasured, our results broadly support SPL theory in that phytometer and leaf size are a product of the size of the initial shoot meristem (≅ seed mass) and the duration and quality of juvenile growth. These allometrically constrained traits combine to confer ecological specialization on individual species. Equally, they appear conservatively expressed within major taxa. Thus, 'evolutionary canalization' sensu Stebbins (Stebbins GL. 1974. Flowering plants: evolution above the species level . Cambridge, MA: Belknap Press) is perhaps associated with both seed and leaf development, and major taxa appear routinely specialized with respect to ecologically important size-related traits.

Crop manuring and intensive land management by Europe's first farmers.

The spread of farming from western Asia to Europe had profound long-term social and ecological impacts, but identification of the specific nature of Neolithic land management practices and the dietary contribution of early crops has been problematic. Here, we present previously undescribed stable isotope determinations of charred cereals and pulses from 13 Neolithic sites across Europe (dating ca. 5900-2400 cal B.C.), which show that early farmers used livestock manure and water management to enhance crop yields. Intensive manuring inextricably linked plant cultivation and animal herding and contributed to the remarkable resilience of these combined practices across diverse climatic zones. Critically, our findings suggest that commonly applied paleodietary interpretations of human and herbivore δ(15)N values have systematically underestimated the contribution of crop-derived protein to early farmer diets.

Impact of contamination and pre-treatment on stable carbon and nitrogen isotopic composition of charred plant remains.

RATIONALE: Stable isotope analysis of archaeological charred plants has become a useful tool for interpreting past agricultural practices and refining ancient dietary reconstruction. Charred material that lay buried in soil for millennia, however, is susceptible to various kinds of contamination, whose impact on the grain/seed isotopic composition is poorly understood. Pre-treatment protocols have been adapted in distinct forms from radiocarbon dating, but insufficient research has been carried out on evaluating their effectiveness and necessity for stable carbon and nitrogen isotope analysis. METHODS: The effects of previously used pre-treatment protocols on the isotopic composition of archaeological and modern sets of samples were investigated. An archaeological sample was also artificially contaminated with carbonates, nitrates and humic acid and subjected to treatment aimed at removing the introduced contamination. The presence and removal of the contamination were investigated using Fourier transform infrared spectroscopy (FTIR) and δ(13)C and δ(15)N values. RESULTS: The results show a ca 1‰ decrease in the δ(15)N values of archaeological charred plant material caused by harsh acid treatments and ultra-sonication. This change is interpreted as being caused by mechanical distortion of the grains/seeds rather than by the removal of contamination. Furthermore, specific infrared peaks have been identified that can be used to detect the three types of contaminants studied. We argue that it is not necessary to try to remove humic acid contamination for stable isotope analysis. The advantages and disadvantages of crushing the grains/seeds before pre-treatment are discussed. CONCLUSIONS: We recommend the use of an acid-only procedure (0.5 M HCl for 30 min at 80 °C followed by three rinses in distilled water) for cleaning charred plant remains. This study fills an important gap in plant stable isotope research that will enable future researchers to evaluate potential sources of isotopic change and pre-treat their samples with methods that have been demonstrated to be effective.

Seeing the fields through the weeds: introducing the WeedEco R package for comparing past and present arable farming systems using functional weed ecology.

The functional ecology of arable weeds provides a way of comparing present-day and past farming regimes. This paper presents the R package WeedEco, an open-source resource which allows users to compare their archaeobotanical dataset against three previously published arable weed models to understand fertility, disturbance or a combination of both. The package provides functions for data organisation, classification and visualisation, allowing users to enter raw archaeobotanical data, obtain trait values from the functional trait dataset, conduct discriminant analysis and plot the results against the relevant present-day model. Using data from the early medieval site of Stafford in the UK, the paper provides a detailed example of the use of the package, demonstrating its different functions, as well as how the results can be interpreted. Supplementary Information: The online version contains supplementary material available at 10.1007/s00334-023-00964-8.

Roman to early medieval cereal farming in the Rhineland: weeds, tillage, and the spread of the mouldboard plough.

A new model for gauging levels of soil disturbance (i.e. tillage) by analysing arable weed assemblages from archaeological contexts is applied to an extensive Roman-to-early medieval archaeobotanical sequence from the region west of Cologne. It tests the hypothesis that increasing use of the mouldboard plough, especially in a three-field system, would result in increased levels of soil disturbance which would be reflected in the kinds of weeds that grew in arable fields. The results point to clear differences in tillage regimes during the Roman period, providing support for the view that military sites were not provisioned by the same networks that supplied the civilian market. They also reveal generally low disturbance levels for the fifth and sixth centuries, indicating a continuing predominance of ard cultivation in the post-Roman period. The majority of seventh- to eighth-century samples had, however, been grown in 'high disturbance' conditions, a pattern that continued through the eighth and ninth centuries. Although use of the mouldboard plough within a fully developed three-field system may not have become widespread until the tenth or eleventh century, our evidence suggests that a plough capable of turning over the soil was in use in the Rhineland at a much earlier date.

The experimental heating of rye, oat, spelt, wheat and barley between 215 and 300 °C: the stable carbon and nitrogen isotope data and the photographic evidence of changes to the morphology of the grains.

The effect that heating has on cereal grain morphology and isotopic values has far reaching consequences for archaeobotanical research and palaeodietary reconstructions. Stable carbon and nitrogen isotopic data and mass loss percentages on, and photographs of, rye, oat, barley, wheat and spelt from a heating experiment are presented and support Stroud et al. (2023). The experiment heated rye, oat, and spelt at 215 °C, 230 °C, 245 °C, 260 °C and 300 °C for 4 h, 8h and 24 h, with each temperature/duration condition consisting of 3 samples of 10 grains per sample. The mass loss of the grains, the %C and %N, and δ13C and δ15N values are presented. Furthermore, photographs of the grains' external and internal morphology for each temperature/duration combination are provided. The wheat and barley data of samples charred between 215 °C and 260 °C/ 4-24 h were obtained from the published and unpublished dataset of Nitsch et al. (2015) and it is this dataset which the new data builds upon. This article also provides the published and unpublished data and photographs from Nitsch et al. (2015), bringing together a dataset of nine crop species. This article provides the raw data from two cereal grain heating experiment, which will enable further research into understanding the impact of heating on both grain isotopic values and grain morphology. It also allows users to construct charred-uncharred isotopic offsets for a combination of species relevant to their research.

Practical considerations in the determination of compound-specific amino acid δ15N values in animal and plant tissues by gas chromatography-combustion-isotope ratio mass spectrometry, following derivatisation to their N-acetylisopropyl esters.

RATIONALE: Stable nitrogen isotope (δ(15)N) values of bone collagen are routinely used to inform interpretations of diet and trophic positions within contemporary and ancient ecosystems, yet the underlying physiological and biochemical factors which contribute to the bulk collagen δ(15)N value remain little understood. Determination of individual amino acid (AA) δ(15)N values in animal and plant proteins can help to elucidate the cycling of nitrogen and inform predictions of palaeodiet and ecology. METHODS: In this study we present a methodology for the measurement of amino acid δ(15)N values using gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). Amino acid standards of known δ(15)N values were derivatised to their N-acetylisopropyl (NAIP) esters and purified through Dowex ion-exchange resin to determine any isotopic fractionation associated with derivatisation and ion-exchange chromatography. The effect of starch on AA δ(15)N values was also determined by hydrolysing bone collagen with and without the presence of starch. RESULTS: The amino acids derivatised to their NAIP esters give values within ±0.8‰ of their δ(15)N values measured separately by elemental analyser (EA)-IRMS, with a precision of better than 0.8‰. The δ(15)N values of AAs after Dowex ion-exchange chromatography were within ±0.9‰ of their values prior to ion-exchange chromatography. The AA δ(15)N values of bone collagen hydrolysed with and without starch were within ±0.8‰. CONCLUSIONS: Hydrolysis of lipid-extracted plant material followed by purification of AAs using Dowex ion-exchange resin and derivatisation to their NAIP esters is a suitable protocol for the accurate determination of individual plant and animal AA δ(15)N values by GC-C-IRMS.

A new functional ecological model reveals the nature of early plant management in southwest Asia.

The protracted domestication model posits that wild cereals in southwest Asia were cultivated over millennia before the appearance of domesticated cereals in the archaeological record. These 'pre-domestication cultivation' activities are widely understood as entailing annual cycles of soil tillage and sowing and are expected to select for domestic traits such as non-shattering ears. However, the reconstruction of these practices is mostly based on indirect evidence and speculation, raising the question of whether pre-domestication cultivation created arable environments that would select for domestic traits. We developed a novel functional ecological model that distinguishes arable fields from wild cereal habitats in the Levant using plant functional traits related to mechanical soil disturbance. Our results show that exploitation practices at key pre-domestication cultivation sites maintained soil disturbance conditions similar to untilled wild cereal habitats. This implies that pre-domestication cultivation did not create arable environments through regular tillage but entailed low-input exploitation practices oriented on the ecological strategies of the competitive large-seeded grasses themselves.

The potential of stable carbon and nitrogen isotope analysis of foxtail and broomcorn millets for investigating ancient farming systems.

Foxtail and broomcorn millets are the most important crops in northern China since the early Neolithic. However, little evidence is available on how people managed these two crops in the past, especially in prehistory. Previous research on major C3 crops in western Eurasia demonstrated the potential of stable carbon and nitrogen isotope analysis of charred archaeobotanical remains to reveal the management of water and manure, respectively. Here, we evaluate the feasibility of a similar approach to C4 millets. Foxtail and broomcorn millet plants grown in pots in a greenhouse under different manuring and watering regimes were analysed to test the effects of management on stable carbon and nitrogen isotope values of grains. Stable nitrogen isotope values of both millets increased as manuring level increased, ranging from 1.7 ‰ to 5.8 ‰ in different conditions; hence, it appears a feasible tool to identify manuring practices, in agreement with results from recent field studies. However, the two millets exhibit opposing trends in stable carbon isotope values as watering level increased. The shift in stable carbon isotope values of millets is also smaller than that observed in wheat grown in the same experimental environment, making it difficult to identify millet water status archaeologically. In addition, we charred millet grains at different temperatures and for varying durations to replicate macro-botanical remains recovered archaeologically, and to evaluate the offsets in carbon and nitrogen isotope values induced by charring. We found that the stable nitrogen isotope values of foxtail millet and broomcorn millet can shift up to 1-2 ‰ when charred, while the stable carbon isotope values change less than 0.3 ‰. Overall, we demonstrate that stable nitrogen isotope values of charred foxtail and broomcorn millet seeds could provide insight into past field management practices, and both carbon and nitrogen isotope values can together inform palaeodietary reconstruction.

Abundance of 13C and 15N in emmer, spelt and naked barley grown on differently manured soils: towards a method for identifying past manuring practice.

The shortage of plant-available nutrients probably constrained prehistoric cereal cropping but there is very little direct evidence relating to the history of ancient manuring. It has been shown that the long-term addition of animal manure elevates the δ(15)N value of soil and of modern crops grown on the soil. We have examined the δ(15)N and δ(13)C values of soil and of the grain and straw fractions of three ancient cereal types grown in unmanured, PK amended and cattle manured plots of the Askov long-term field experiment. Manure increased biomass yields and the δ(15)N values of soil and of grain and straw fractions of the ancient cereal types; differences in δ(15)N between unmanured and PK treatments were insignificant. The offset in straw and grain δ(15)N due to manure averaged 7.9 and 8.8 ‰, respectively, while the soil offset was 1.9 ‰. The soil and biomass δ(13)C values were not affected by nutrient amendments. Grain weights differed among cereal types but increased in the order: unmanured, PK, and animal manure. The grain and straw total-N concentration was generally not affected by manure addition. Our study suggests that long-term application of manure to permanently cultivated sites would have provided a substantial positive effect on cereals grown in early agriculture and will have left a significant N isotopic imprint on soil, grains and straw. We suggest that the use of animal manure can be identified by the (15)N abundance in remains of ancient cereals (e.g. charred grains) from archaeological sites and by growing test plants on freshly exposed palaeosols.