Tuesday, 3 July 2018

In Memoriam, Gordon Hillman (1943-2018)

It’s with great sadness we bring you the news that Gordon Hillman died on Sunday 1st July. He is survived by his daughter Thilaka, and three Grandsons. Gordon Hillman was a pivotal figure in the development of archaeobotany at the Institute of Archaeology, and through his research, publication and teaching he had a major influence on the direction of the field worldwide, especially with regards to the origins of plant domestication in the Near East and late hunter-gatherer economies.

Gordon Hillman joined the Institute of Archaeology as a research associate in 1981 funded by the UK Science and Engineering Research Council and then became a full-time lecturer in a new archaeobotany post from 1983. David Harris was then Professor of Human Environment, and together they launched a MSc in Bioarchaeology at that time which offered intensive practical training in archaeobotany in alternate years. A generation of professional archaeobotanists, both in commercial archaeology and international academic posts, began their careers through this degree. This degree laid the foundations for the current MSc in Environmental Archaeology.

Gordon Hillman carrying out experimental paddle
 harvesting of wild einkorn wheat in Wales, ca. 1980

Gordon's ground-breaking career in Archaeobotany began in 1969, with a year of training in Mainz, Germany with Dr. Maria Hopf, who at that time was studying plant remains from Jericho. Gordon subsequently, and for nearly five years lived in Turkey carrying out ethnobotanical research, building up a seed reference collection and carrying out flotation at various excavations of the British Institute of Archaeology in Ankara, such as at the sites of Can Hassan III and Asvan. This period was critical in Gordon’s pioneering of a ethnoarchaeological approach to archaeobotanical assemblage formation through the study of traditional crop-processing. It was also the period when much of the core seed reference collection was put together for both the BIAA and the Institute of Archaeology. It was also in this period that he came to the attention of Andrew Moore who was embarking on rescue excavations in northern Syria at Tell Abu Hureyra, which was to prove a seminal research project for Gordon, providing insights into broad spectrum wild plant use in the Late Pleistocene, plausible evidence for early pre-domestication cultivation and the nature of early integrated agro-pastoral economies.
George Willcox and Gordon Hillman examining fieldweeds near Asvan in central Turkey, ca. 1977

Gordon Hillman retired from UCL as Reader in Archaeobotany in 1998, but continued his research, especially on potential wild plants collected and processed by hunter-gatherers, as an Honorary Visiting Professor at UCL. Part of this work inspired the BBC program Wild Foods in which he appeared alongside Ray Mears, gathering and processing various plant foods in Britain, in France, and in Australia with aborigines. The program also produced a colourful book Wild Foods (2007). Gordon continued to work on a comprehensive compilation of wild plant foods of Britain up until his death. As this monumental research effort, drawing on a lifetime of teaching, research, and experimentation, remains a work in progress, an effort is being made to bring out his observations on a plant-by-plant basis on the Wild Plant Foods of Britain blog. For a list of Gordon's many publications (upto 2008), see here. A volume of studies in honour of Gordon Hillman was published in 2009

Gordon photographing flowers during the IWGP
excursion near Girona, Spain (2004)

Gordon was an inspiration to his students, his colleagues, and well beyond through his publications and TV appearances. He was always a thoughtful, provocative and supportive senior colleague that will be dearly missed. I always had much learn at his feet.

Do please add you memories and comments on Gordon Hillman as comments to this blog.

Gordon Hillman, Mary Anne Murray, David Harris, and Sue Colledge,
 in office 311, UCL Institute of Archaeology 1998/99

Ehud Weiss, Ramon Buxo, Ahmed Fahmy and Gordon Hillman, in Girona
during  the 2004 International Work Group for Palaeoethnobotany
Dorian Fuller, Gordon Hillman, George Willcox in Girona at the I.W.G.P. 2004

This photo (below) was found dusty in the back of drawer in the UCL archaeobotany lab. I never got to ask Gordon about it,but I think it is from an early I.W.G.P., in Budapest(?), 1969 or 1971(?). A young Gordon Hillman is in the Middle; also pictured Heather Jarmon (left) and Prof Schulz-Motel (right).

A picnic in Pevensey, Marsh, 2009: Andy Fairbairn, Dorian Fuller, Gordon Hillman, Ehud Weiss
Receiving instruction from Gordon Hillman on the art of acorn processing (June 2010)

Tuesday, 16 January 2018

In Memoriam Alison Weisskopf (1960-2018)

Alison and Oryza nivara in
Orissa, Sept. 2010
Alison Weisskopf (1960-2018), passed away peacefully in hospice in the presence of her immediate family on 11 January 2018. She was a beloved colleagues at the Institute of Archaeology, a fixture in the archaeobotany laboratory for many years and a leading figure in archaeological phytolith research, respected globally. Her research legacy is substantial as her work takes a distinctively ecological assemblage approach to reconstructing rice cultivation ecology as well as crop processing. This has proved innovative and has proved fruitful, and can be expected to continue to inspire further research and agricultural ecology approaches to phytoliths around the world. Despite first being diagnosed with late stage cancer in 2010, she soldiered on was at her most productive as a researcher over the past half dozen years, which is readily evident from her publications list. 

Bangladesh, Nov. 2013: ethnobotany

She has made lasting empirical contributions on archaeological research in China, Southeast Asia (Vietnam, Thailand, Cambodia), and South Asia (Bangladesh, Sri Lanka, India). Through ethnobotanical fieldwork (in India, Thailand, Laos) and archaeological projects (in China, Bangladesh, Fiji), many further collaborations she was a key colleague in many international networks and she leaves behind many friends around the world.

Alison joined UCL as a BSc Archaeology student in 2000/01, essentially a career reboot as a mid-life adult. She demonstrated a strong affinity for environmental archaeology and archaeobotany from the beginnings of her studies. She took my “Plants and Archaeology” in 2001/02, and a new course on “Origins of Agriculture” the following year. Her BSc dissertation on phytoliths (“A study of the phytoliths from the late Bronze Age site of Krasnoe Smarskoe, Samara Valley, Russia, and the information they provide on agro pastoral economies and environments”) supervised by Dr. Arlene Rosen was passed with distinction in 2003. In receipt of a AHRC scholarship, she continued her studies in the MSc Palaeoecology of Human societies, with a dissertation on “An investigation of the Neolithic ash mound and settlement at Sanganakallu in the south Deccan, India, using phytoliths and macro-archaeobotanical material”, combined analyses of plant macro-remains and phytoliths and received a distinction in 2005.

Liu River, near Huizui, Henan, China, 2006
She began her PhD in 2005, again funded through an AHRC studentship. She submitted her PhD thesis, Vegetation, agriculture and social change in Neolithic north central China, a phytolith study, in 2009 and was awarded her doctorate in 2010. Her doctoral research took her on field to China several times, such as to the sites of Huizui and Xipo, where she worked alongside colleagues including Arlene Rosen (now University of Texas at Austin), Gyoung-Ah Lee (University of Oregon) and Liu Li (Stanford University). Her PhD represents years of dedicated laboratory work. She later published a revised version of her PhD as a monograph in 2014.

Sept 2010: Sampling Oryza rufipogin in Orissa, with
Rabi Mohanty and Mukund Kajale

In 2009 she took up a post-doctoral research associate position funded as part of a NERC project  'The Identification of Rice in Prehistory' (2009-2012), which came to be dubbed the Early Rice Project, and spawned follow on research projects, including 'The Impact of Evolving of Rice Systems from China to Southeast Asia' (2013-2016), and 'The impact of intensification and de-intensification of Asian rice production: transitions between wet and dry ecologies' (2016-2019). During a intermission between the first and second NERC projects she secured funding through a British Academy small grant to explore comparisons between phytoliths and diatoms in rice paddy soils, and she received a travel grant from the Thai Ambassador to the UK for ethnobotanical fieldwork on non-rice plant use in Thailand. Her research, and her development of phytolith approaches to rice cultivation ecology was central to these projects and their success. This sent Alison into the field to study modern rice ecologies, both cultivated and wild, in far flung parts of Asia, from central China to Laos and the highlands of northern Thailand, through Bangladesh and Assam, remote parts of Odisha state in India, and the Western Ghats mountains along western coast of India. Her unique experience and expertise has meant that she attracted archaeological collaborations and samples for analysis from an even wider range of countries. She authored 29 academic papers or book chapters, in addition to 1 monograph, with many more still in the pipeline. For a list her published academic papers and chapters: see here.

While many have approached phytoliths typologically and metrically to attempt to look at morphological differentiation between domesticated and wild rice (e.g. bulliforms or double-peaks), Alison’s innovation was to focus on the plant communities that occurred with rice and were sampled in harvests, sub-sampled in crop-processing and ended up to systematically recorded, quantified and discriminated in the micro samples from archaeological sediments. In her fieldwork and analyses, her focus on plant communities and how human communities intersected these is evident. It offers a legacy for phytolith archaeology.
Ethnobotanical fieldwork in Thailand,
Nov. 2012: with Katie Manning.
Alison, herself was a key node in our community. Having worked in the archaeobotany lab as a post-graduate student and post-doctoral staff member for some 15 years, she was often the focus of discussions, both of science and of social life. She has also trained and supported numerous students, offered countless cups of tea, words of encouragement, and a warm sense of humour. She is warmly remembered.

I invite comments to be posted to this blog by those who knew and miss here. And I append below various photos of Alison in action.

Gyoung-Ah Lee and Alison on the Liu river, Henan, China (2006)

Alison collecting rice weeds in Bangladesh, Nov. 2013.

Nov 2011: Northern Thailand: Cristina Castillo (Left) and ALISON (right) with Karen rice farmers in Northern Thailand

Ellie Kingwell-Banham and ALISON WEISSKOPF in Maharashtra, India (Sept. 2010)

14 July 2004, IoA foyer on lab botanical shirt day: Phil Austin, Emma Harvey, Meriel McClatchie, Jon Digby, ALISON WEISSKOPF, Emma Jenkins. Alison was an MSc student at the time, and was apparnelty the original source of the idea for this day.  Below a full photos of the whole lab group.

Dorian, ALISON, and Deepika Tripathi at the IWGP in Thessaloniki (2014)

Indo-Pacific Prehistory Association conference, Siem Reap, Jan. 2014. Participants in session on "Foraging and Farming". Alison fifth from Left.

Early Rice and Its Weed Flora, Symposium at Peking University May 2011

Rice bulliform phytoiths and morphological change

In preparing for a recent Bangkok workshop on the archaeology of rice, I have collected some thoughts of the proposed methodology for tracking rice domestication using rice bulliform phytoliths.

Fan shaped bulliform phytoliths form along the veins of rice leaves. Rice (genus Oryza) has a distinctive shape although some fanlike bulliforms do occur in other grasses, but with different shapes. These are also sometimes referred to “motor cells” as these cells function, when alive, to fold and unfold the leaf and thus to control sunlight exposure, which in turn relates to amounts of photosynthesis and water evaporation from the leave. Once they are silicified and have become phytoliths they stop functioning so this tend to mean that the phytoliths come from older rather than younger leaves.

These are relatively large for single celled phytoliths (28-40 µm) and therefore fairly easy to recover and to spot in phytolith slides. Bulliforms have suggested to be useful for tracking domestication, separating subspecies japonica and indica, and for studying crop processing. Identification approaches relies on measurements and/or counting variation in the number of chips along the scalloped edge of the fan. In terms of crop-processing they are an indicators of leaf presence (i.e. straw), i.e from harvested rice and/or threshing by-production as opposed to husk phytoliths that represent dehuksing waste.

A study of bulliforms from Lower Yangtze archaeological sites suggest that they became large and more pronounced in their japonica morphological metrics over time, 5000 and 2000 BC, over the period when domestication was completed and grain size increased (Zheng et al 2003a). Measurements on controlled experimental crosses indicate the bulliform shape is influenced by numerous genes, with 16 genes (QTLs) suggested, but these QTLs only explain somewhere between 37% and 54% of the variation, suggesting the environment (growing conditions) play a major role (Zheng et al 2003b). No QTLs were correlated with the b/a ratio suggesting this may be largely environmental.

Bottom line on metrics: May be useful for separating indica from japonica when it can be assumed that rice was fully domesticated; and trends may be found alongside domestication. Further work is needed, especially on aus and more variation found in South Asia and more tropical varieties in Southeast Asia.

Bulliform scalloped margins: scale counts and domestication. Another approach to documenting bulliforms is to count the “scale-like” facets along the rounded edge of the “fan”. The fans in domesticated rices tend to have more facets. Initially Lu et al (2002) proposed that phytoliths with 9 or more facets are likely domesticated, while less than 9 are wild. This has been backed up by field comparisons of wild and cultivated rices in South China (Huan et al 2015) These studies indicate that example with less than 9 facets occur in cultivated rice and more than 8 occur in wild rice but the frequency differences are substantial (see below). 

This means in in time series data assemblages can be used to track changes over time (below). This is nicely demonstrated in a time series through the Early and Middle Holocene for the Lower Yangtze by Ma et al (2016). It should be noted also that current approach of Ma et al (2016) exclude from counts any assymetric phytoliths.

Time series of rice bulliform facet counts (% of ≥9) from Lower Yangtze sites (Ma et al 2016).
These data show a direction of travel over time that is similar to non-shattering, grain size increase and other indicators. However, much variation is hidden by the fact that difference between 8 facets (very common in wild rices) and 9 facets (probably the most common value in domesticated rices).
In addition, an explanatory mechanism is not yet firmly established, unlike established domestication traits such as non-shattering and seed size. While ~16 genes may affect bulliform shape, environmental factors are also essential, and domestication is ultimately about genetic changes that differentiate domesticates from their wild ancestors. Therefore it is essential to understand how much of this shift phenotypic response to environmental conditions as opposed to evolution. Huan et al (2015) suggest that the increase faceting in domesticated rice is due to increased use of leaf folding to control evaporation from leaves. They hypothesis that the erect growth habit of rice and drier growing conditions than wild rice would lead to increased faceting. If this is merely a phenotypic response then it becomes a less useful domestication indicator. But this can also be questioned, as ecological indices (see below) suggest that early rice in China was grown under wet, wild-like conditions (at least at Tianluoshan) and that erect growth habit and drier conditions occurred only from the later Majiabang period, and then returned to very wet conditions (Weisskopf et al 2015). So further work is needed to understand genetic and phylogenetic signal in bulliform facet variation as opposed to difference to due with habitat.

The bottom line: on the whole this looks like a promising and worthwhile complementary dataset, but it remains no substitute for morphological domestication data from macro-remains, as other environmental factors seem to be at play. In addition it is worth noting some studies that question the reliability of this approach.

Applications in India that raise questions over the universal applicability of this approach.   Harvey (2006 PhD, UCL) counted this chips on bulliforms from Chalcolithic sites in Orissa (Golbai Sassan and Gopalpur, dating 1500-1000 BC), both of which have domesticated rice (based on spikelet base data), and wet field ecology (further work by Kingwell-Banham 2015, PhD UCL). In this material the average number of chips is 8.6 and thus “wild “ according chip count standards used by Chinese researchers.This is out of agreement with the non-shattering spikelet base data, weed flora and the large village context all of which indicate fully domesticated, wet-rice based agricultural economies.

Saxena et al (2006) applied this to phytoliths from the lake sedimentary sequence at Lahuradewa, next to a Neolithic site in the Ganges plain of the same name. They reported both wild and domesticated bulliforms through the core is roughly equal proportions between 8600 and 3500 BP after which wild forms declined. While Lahuradewa is often discussed an an early site of rice cultivation in India, critical review suggest this was primarily wild rice gathering prior to ca. 2000 BC or so after domesticated rice became available through hybridization with japonica (the proto-indica hypothesis) (Fuller and Qin 2009; Choi et al. 2017; Murphy and Fuller 2017). Thus the phytolith data here appear out of agreement with macro-remains and rice genetics.

Applications in Southeast Asia and China that raise questions over the universal applicability of this approach. The initial introduction of this approach (Lu etal 2002) included a dataset on a see floor core between China and Taiwan, an area that would have been flooded after the Last Glacial. This palaeoenvironmental sequence produced rice phtyoliths- and rice would be expected in fresh water wetlands in such areas when they were above sea level. However, this included substantial numbers of the “domesticated” type. Is it realistic to believe that domesticated rice was already cultivated in flooded regions of Southeast China during the Last Glacial (LGM)? If so, then it must have been a dead-end experiment, as the evolution of domesticates rice is documented over the course the Early and Middle Holocene, starting anew apparently. However, if the bulliform faceting is responding to environmental conditions this LGM population may have nothing to do with human selection and domestication

The Loagan Bonut pollen core on Borneo near Niah Cave produced substantial quantities of rice bulliforms with high facet counts (i.e. “domesticated”) around 8000-7500 BP, but not later (Hunt and Premathilake2012). Is this also to be interpreted as a lost domestication of rice? Or could this be a particular situation in terms of environmental conditions that encouraged wild rice and more leaf folding and bulliform faceting?

Most of the above cases have all been presented as evidence of early farming, which would represent “stealth domestication” without other clear indicators for cultivation over the millennia leading to these nor continuing into subsequent period. In all cases phenotypic plasticity in response to environmental change needs to be considered, and realistically dismissed before domestication can be adequately diagnosed.

Rice husk phytoliths and morphological change

In preparing for a recent Bangkok workshop on the archaeology of rice, I have collected some thoughts of the proposed methodology for tracking rice domestication using rice husk phytoliths (the "double peaked" cells from lemma and palea).

The husks of rice are full of silica and often all the cells of silicified. The rows of cells on the rice husk include trapezoidal phytoliths the upper corners of which often form into peaks, as in the image below. These are diagnostic of the genus Oryza, although a few similar forms may occur more rarely in other grasses. These are often the most frequent form of rice phytolith. Because these derive from husk, disposed of after dehusking, they are an indicator of dehusking waste and useful in crop-processing studies. (See Harvey and Fuller 2005)

Size and shape of these varies and has been suggested to be useful in tracking domestication through measurements on populations (Zhao et al (1998)), although these are not definitive because of large degrees of overlap and because cell size is also impacted by environmental conditions. An explanatory mechanism for how these change during domestication has never been satisfactorily elaborated, although some relationship to grain size change seem plausible.

The proposed method for looking at double peak cells and domestication uses 5 measurement on each phytolith as defined below, left (from Zhao et al 1998)- note that H is measured twice on each side of the phytolith. Some of these are then used in squared form. These are combined in discriminant functions that are meant to assign individual phytoliths to like domesticated or wild (i.e. if the domesticated score is greater than the wild score: formula at right).

As originally developed, Zhao et al (1998) reported correct classification in their modern reference set was correct in >70% of test cases. The formulae were developed by taking Bayesian approach to discriminant function analysis. In an attempt to employ and extend this work, we attempted to replicate this in London with modern rice accessions, but found a correct identification in only 44% of cases (Harvey 2006). In addition measurements on phytoliths from Chalcolithic sites in Orissa (Gopalpur and Golbai Sassan) predicted a majority wild rice and on 39% domesticated. However these sites (dating 1500-1000 BC) have spikelets bases that indicate fully domesticated rice (100% non-shattering at Gopalpur and ~70% at Golbai out of a small sample size: unpublished UCL data from Kingwell-Banham 2015). This indicates that this phytolith discrimination method is unlikely to work in India, raising questions about what biogeographic contexts it would be useful in, if at all. One problem is that some of the variation in ancient cultivars may not be well represented in modern landraces. Indeed some of the measurements on archaeological phytoliths from Orissa fell outside the range of modern material, both wild and domesticated.

Also, against this method are two applications in China that have yielded results that are illogical with regards to what is known about rice domestication. As applied by Zhao (1998) to Diaotonghuan cave in Jiangxi and change from predicted wild in pre-ceramic layers and predicted domesticated dominance in early ceramic layers was found. At the time Zhao wrote this it was assumed the that advent of pottery was Neolithic and sometime in the early Holocene, but recent dating work on nearby Xianrendong and another South Chinese cave, Yuchanyuan, indicate the ceramics began to be produced around the Last Glacial Maximum or just after 18,000-16,000 BP. The ceramics at Daiotonghuan are comparable and thus this would re-date the alleged rice domesticated to ~18,000-16,000 BP, nearly 10,000 years earlier than potential sedentary, agricultural villages. An more plausible alternative explanation is that rice husk cells (and grains) changes shape in response to the major and rapid change in climate and atmospheric carbon dioxide levels that took place after the LGM.

As applied by Itzein-Davey et al (2007) in the Lower Yangtze region to a stratigraphic sequence of Qingpu rice bulliforms dating between 2300 BP and 1800 BO (i.e. Warring State through Han Dynasty era), they found the majority of double peaks were predicted as wild, often as much as 80% in some samples. Rice was certainly morphologically domesticated in the Lower Yangtze long before this and we would expect fairly intensive rice agriculture during Han times. These results also call into question this index.

Nevertheless plotting double peak measurements over a time series may provide a line of evidence for rice that is changing and evolving morphologically. This has recently been applied in South America to argue for a lost rice domesticationin the Amazon (Hilbert et al 2017). In the context of Chinese rice domestication the study of Wu et al (2014) demonstrated both that wild and domesticated predictions are very mixed on sites of early cultivation but also that there is trend for more double peak cells to fall towards the apparently domesticated end of the spectrum through time.

The bottom line: Variation in husk phytoliths exists but its significance in terms of domestication, varietal changes, cultivation ecology remains unclear and deserved further study.

Saturday, 9 December 2017

Buckwheat origins remain elusive

Harriet Hunt and colleagues have provided a new critical assessment of data and potential data on origins of the buckwheats (Fagopyrum esculentum and F. tartaricum) in a Vegetation History and Archaeobotany article. Buckwheat is an important carbohydrate crop at high elevations in Asia, as well as parts of Japan and Europe, but it has remained quite elusive archaeobotanically.

It is absent from the many large charred seed assemblages in central China, or the charred and Fagopyrum identifications as distinct from many other Polygonaceae. Even if we accept all identifications of Fagopyrum, there are several wild taxa in this genus that will have nothing to do with the cultivtion of the crop. They consider how reliable stratigraphic dating controls are for many of pollen sequences, but even so, pollen never allows for the direct dating nor direct association with human activities that archaeobotany does.
waterlogged assemblages of the Lower Yangtze. In the Indian Himalayas where it is traditionally an important crop, finds have been few, restricted to later First Millennium BC and medieval finds in Nepal. The new review by Hunt et al has compiled evidence from archaeobotanical macro-remains, a few reported based on apparent archaeological starch remains, and the many more reports from pollen diagrams. They take a threshold of fairly high quantities in pollen diagrams, but less clear is whether one can always rely on

Distribution of wild Fagopyrum species (Campbell 1997, IPGRI)
One of their key conclusions is that the past distribution of wild Fagopyrum species, including the wild progenitor of F. esculentum, was more widespread. Extending further north, even to the north of Sichuan. This certainly seems plausible and could support a domestication in Sichuan north of where modern wild populations (in NW Yunnan) have tended to suggest domestication. They point to a few pollen cores from Shaanxi and Gansu apparently 5000 years old or more, as perhaps relating to early cultivation-- although the absence of grain finds in these regions which have had considerable archaeobotanical sampling in recent years surely calls into question the paper's tentative conclusion that cultivation had begun before 5000 BP.  Another problem with many of these pollen cores is the reliability of dating. For example, the pollen sequence at Xishanping, which was collected through an archaeological sequence, has a number of inverted radiocarbon dates, suggesting reworked residual materials, but the short (and old) chronology followed by Hunt et al. removes the out of sequence dates-- which would make sense if this were a lake core with constant sedimentation, rather than a sequence 5 varied archaeological layers. A safer, and archaeologically logical reading of the original stratigraphy (see raw data in Li et al 2007) date makes the buckwheat pollen occurrence only slightly older than 3000 BP. (The short chronology also implies that wheat was present at this Gansu site before 2600 BC, which does not fit with the accumulated evidence on wheat's arrival in Gansu (as noted already in a previous blog), especially AMS dates (see Stevens et al 2006).

A more critical reading of the dates in the sequence of the earlier pollen cores find little support for any substantial quantities of Fagopyrum pollen before around 4000 years ago, so I stand by previous inferences of domestication taking place around this period. Nevertheless from the Second Millennium BC onwards, some archaeological seeds of Fagopyrum, possible supported by starch finds points to cultivation of this crop, with a focus on west Central China and southwest China, consistent with early dispersal around the eastern front of the Tibetan plateau. Nevertheless with central and eastern China, the lower reaches of the Yellow and Yangtze basins buckwheat appears to have been absent, from macro-remains (and supported by early Chinese written sources). In this regard some of the apparent pollen reports from natural cores in the Lower Yangtze seem unlikely to represent cultivation. Despite being clearly present among the crops known in early Tibetan languages (and many related Burmic languages), and having likely been loaned from a Tibetan language into Chinese since the Han dynasty period (see Bradley 2011), buckwheat remains elusive in Asian archaeology.

This new paper by Hunt et al. provides a solid starting point for new research on buckwheat origins, with a thorough compilation of pollen and archaeobotanical evidence (in China)long with some critical thinking on the rather limited genetic data.

Friday, 8 December 2017

Neolithic wine drinkers in Georgia or wishful thinking

Strong inference I was always taught comes from thinking through multiple working hypotheses and assessing which hypothesis is best supported by available evidence and trying to falsify alternatives. It is unfortunate if the quest for headlines and high profile publication gets in the way of clear thinking and an scientific approach. Of course sometimes evidence and conclusions are only partly certain, but when that is the case it should not be carefully hidden in online supplementary text and onreference claims of background fact as is the case in this study. I have to conclude weak inference reigns in the recent headline grabbing claim that the first grape wine makers anddrinkers were to be found in the Neolithic Georgia. While McGovern et al present a compelling read in their PNAS paper, and some apparently very technical scientific support, their presentation seems to me aimed to grab headlines and appeal to journalist or generalist and not really to convince scientifically the specialist. The fine print in the supplement raises many unanswered questions that undermine their conclusion. The failure to reject alternative plausible hypotheses for their result, the lack of reference to scientific names, regional flora inventories or vegetation surveys, as these would so clearly support alternative hypotheses…

Here is the claim: some interesting liquid storage vessels that could well be for wine storage have produced tartaric acid residues. This would indeed constitute part of an evidential base to argue for early wine, but on its own this is necessary but not sufficient evidence for the claim. Tartaric acid occurs as background in the soil—thus one learns in the supplement that some 11 sherds were rejected as having levels not sufficiently above background soil levels. What is more tartaric acid occurs in many fruits, not only grapes. Oddly they reject other sources with a flippant line in their supplement, “Other plants with high tartaric acid–e.g., hawthorn fruit and star fruit from east Asia, tamarind from the Indian sub-continent, and yellow plum from the New World—can be ruled out”- notable for being without any Latin names, without any citation of botanical sources on  these taxa, their chemistry, or on the regional flora from which to based claims about their distribution. What is worrying here is the inclusion of hawthorns (Crataegus spp.), and plums in this list. They claim that “yellow plum” is exclusively American—and while this is ture if what they mean is the species Prunus americana, but the broader Prunus genus, including numerous Cerasus cherries and Padus bird cherries, has high endemic diversity in the Caucusus regions, as well as numerous Crataegus species. There are ~70 species of Prunus native to Eurasia: are we really to believe that none contains tartaric acid in contrast their common American cousin? If so, how have these been excluded. Contrary to the dismissive statement in the supplement there are half a dozen Crataegus reported form the Caucasus region in the old Flora of the USSR, and several more to the South or to the north in Ukraine! (Flora of the USSR Vol. IX. Rosales and Sarraceniales, by Botisova et al 1939, English Language 1971 from Jerusalem, online here)

Grape pip with measurements (from
Bouby & al 2013 PLOSone
One might support an argument for grape wine production on archaeobotanical grounds if flotation samples were rife with grape pips and no other fruits, but in fact we learn that all AMS dates run grape pips turn out to be intrusive, Bronze Age and later. This does not support major use of grapes for wine in the Neolithic but quite the opposite! For Neolithic grape finds one must go to the Fertile Crescent, or indeed to parts of Mediterranean Europe, like Greece or Italy! While some of the co-authors have have done some cutting age work on the geometric morphometrics on grapes, e.g. Laurent Bouby, whose work on archaeological grape diversity in France is indeed cutting edge (e.g. the Vegetation History and Archaeobotany paper by Bacilieri, Bouby et al earlier this year), the deployment of these techniques on Georgian grapes from the Bronze Age and later (based on direct dates) does little to support a sequence of grape domestication in the Neolithic Caucausus.

Some sort of fermented fruit wine—the conclusion is plausible. But grape wine? That still seems wishful thinking. At best the sloppy and journalistic presentation of the evidence might be attributed to weak editing and inadequate peer reviewing combined with authors’ excitement, but at worst it represents obfuscation of the science to claim headlines and citations indices.

Thursday, 23 November 2017

The earliest wheats of Ukraine (5400 BC)

The eastern areas of Europe and their transition to the steppe that lead to Central Asia remains one of the less well-studied regions archaeobotanically. The sparseness of reliable evidence has meant that the region is sometime discussed in terms of an alternative eastern source of crops from Europe, in addition to the main thrust from Anatolia through Greece and the Balkans, and it is sometimes mooted as a region of some crop origins, such as spelt wheat. New data is always welcome, especially of a high empirical calibre, from systematic sampling and backed up by AMS dating.

New data from the Ratniv-2 site in Western Ukraine, near the eastern frontiers of the Linear Pottery (LBK) culture, has been published by Motuzaite Matuzeviciute and Telizhenko in Archaeologia Lituana. This is an important record of early crops, and as the authors point out, it clearly points to similarities to the West and Southwest in Neolithic  Europe and suggest a spread towards Ukraine from the West in the Neolithic, rather than the east. The assemblage consists of wheats, barley, flax, lentil and pea. Two direct AMS radiocarbon dates on emmer wheat grains place these assemblages between 5400 and 5200 cal.BC. Of particular interest is that the wheats here include not just einkorn and emmer but apparently at some of the socalled "new type glume wheat," which these and other authors sometimes equate with Triticum timopheevi, and 20th century relict wheat found north of the Caucasus (western Georgia). That the archaeological "new type" has the AAGG genome of timopheevi remains unproven-- although I agree it is likely. It is perhaps more accurate to regard T. timopheevi as the relict remnant of what was a once a much more diverse and widespread species of wheat, which in all likelihood originated in the Anatolia and spread through many part of Europe and east through northern Iran in the Neolithic. I have sometimes offered the name "striate emmeroid" as a descriptive alternative to  "new type", as it is hard to think of something that has been largely extinct since the Bronze Age as new, and this wheat type has been in discussion by archaeobotanists for around 20 years...

In any case, what is notable about this assemblage is that is corresponds to those crops that are most common in the Neolithic of southwest Europe, supporting the ceramic and settlement evidence that attributes to the origins of agriculture in western Ukraine to spread from the west.