Tuesday, 27 March 2012

IWGP session topic on archaeogenetics

We have another session proposal for the next IWGP. The title of the session is:

Plant archaeogenetics and archaeogenomics

Session organizers are Angela Schlumbaum, Basel and Terry Brown, Manchester. Those interested in contributing please contact the session organisers.

This can be added to two earlier proposed thematic sessions: 

(Proposal for a thematic session at IWGP 2013, Greece) By Dorian Q Fuller and Soultania Valamoti

Food Globalization in Prehistory Across Eurasia. Chair of a session: Prof. Martin K. Jones

The conference website is now live (but has not been formally announced): it includes a list of session topics.

Monday, 19 March 2012

Predomestication cereal processing and storage

The latest Antiquity includes a detailed treatment by Willcox and Strodeur of Large-scale cereal processing before domestication during the tenth millennium cal BC in northern Syria at Jerf el Ahmar. The archaeobotany of Jerf has featured large in discussion in recent years on Near Eastern domestication, with apparent evidence for an early arable weed flora (see Willcox 2012 for latest), some grain size increase (reported in Willcox 2004, discussed further in Fuller 2007), but with wild-type shattering rachides, mostly of barley and rye. Jerf has been one of the major datasets contributing to a "slowing down" of domestication, from how fast we thought it was before, and of a "de-centring of the fertile crescent." So it is important to understand just how the archaeobotanical evidence fits with the archaeology on this site, and there are some important details to digest. In this paper the present some more details on the spatial patterning of finds, especially rye and barley in relation to crop-processing (mainly later stage dehusking and preparation for grinding), and argue for possible storage in the 'public' multi-room round building in the the site. There is also discussion of rodent dropping, mainly mice (Mus), which argues for on-site cereal stores, the key context for the evolution of commensal rodents.

South Indian aridification press release

The Woods Hole Oceanographic institute has put out a press release on the palaeoclimatic data for India aridification over the late Holocene, based on the GRL paper published a few weeks ago and blogged previously.

Friday, 16 March 2012

Wood charcoal papers online

It recently came to my attention that last year's meet of archaeological charcoal analysts (mainly European), has a nice set of extended abstracts (or short papers) published freely on line as a special number of the Spanish periodical Saguntum. The wood charcoal papers are here, amongst which are number of interesting study, including a Irish study on quantification issues attempting to identify saturation points, the fragment count at which taxa diversity in a sample stops increasing: for Ireland this appear to be around 20 taxa. A French study develops the Dufraisse model for using charcoal ring diameters to model the size of fire wood being collected as a way into human behavioral patterns in wood exploitation (image at left). Eleni Asouti explores the wood charcoal from Catal Hoyuk which fits neither with a straight forward model of climate-driven change in taxa or anthropogenic over-exploitation models. Meanwhile a burnt down building from PPNB Qarassa in Syria provides a glimpse into the construction material used in early villages in the Levant. You can also find a small, but pioneering study of charcoal from Chinese flotation samples taken in a region survey, an analysis of some Yanghao-Longshan charcoal from the Ying valley in Eastern Henan-- which provides evidence for the dominance of oak forests, oak as fuel source, despite a seed record that is dominated by cultivated millets, lacking evidence for acorn consumption. Although we lack good earlier archaeobotanical evidence from this particularly region, it does still suggest a contrast with the earlier predominance of acorns elsewhere in China. By the Yangshao period agriculture had pretty much taken over and wild foods were in decline, although the Yangsaho period still shows a higher range of wild fruits than we find in subsequent periods in the Ying (see Zhang et al in J. Arch Sci 2010).

And there are many other charcoal studies there I have yet to explore.

Friday, 9 March 2012

Pre-axumite wheat and barley preference: isotopic evidence

I seem to have overlooked this last year, but was excited to see some stable isotope results, (published last year in J. Arch Science by D'Andrea et al), from northern Ethiopian pre-Axumite  and Proto-Axumite sites (i.e. 800-100 BC). This indicate a strong tendency in human bones towards predominantly (but not necessarily) exclusively C-3 plant diet, i.e. such crops as wheat and barley, but with limited C-4 input. This is of interest since Sorghum, tef and finger millet, all of which might expect to have been around are C-4 plants. So the mystery deepens as to the antiquity of these taxa in agriculture in this region-- or at least they were not very important. If memory serves there is some evidence for tef from around this period (but mainly later)-- treated in some detail by D'Andrea (and blogged previously), where as the earliest finds of finger millet and Sorghum are later and Axumite Also there is an important contrast with the domestic fauna, which have a distinctly different diet form the people. Cattle and donkey have a strongly C4 signature suggesting grazing or foddering mainly from the savannah grasslands. Sheep, goat and gazelle fall in between suggesting C4 grazing mixed with browsing of C3 shrubs etc.

Thursday, 8 March 2012

Domestication of Plants in the [western] Old World, revised.

No doubt all students and researchers of plant domestication and archaeobotany will be pleased to hear that the revised 4th edition of Zohary and Hopf's Domestication of Plants in the Old World (now Zohary, Hopf and Weiss) is hot off the presses in Oxford. I have not seen a copy yet myself but previous editions, the last in 2000, remains the standard reference work on the crops of the Near East and Mediterranean, their wild progenitors and early archaeobotanical evidence. An updated treatment is only to be welcomed.

Wheat museum

It was hard to resist the image at right, of a museum dedicated to wheat, designed with an ear on top. This web site, of an old press release (July 2005), was just brought my attention by a colleague. It claims to celebrate "the earliest known wheat culture" (well that was not in Turkmenistan) the Anau culture (which is pretty late in the Neolithic), and the archaeology of Pumpelly (turn of the last century), who is credited with the first explanatory model of agricultural origins that attributed agricultural origins to climatic change. Good to have that immortalized somewhere. Later announcements indicate that this museum was also to become a national germplasm bank for wheat, which seems a good thing.

Does starch evidence push back foxtail millet domestication?

A recent article in PNAS, by Yang Xiaoyan et al., on starch grains (and some phytoliths) from two early Holocene sites in northern China (approx. 9500-7500 BC), pushes back evidence for the early cultivation of foxtail millet. This builds on recently reported identification criteria for millet starch.  This paper is an important contribution to the earlier prehistory of grass and millet exploitation in Northern China and provides important new evidence for the discussions and debates about the timing, areas and processes of millet exploitation and initial cultivation. For on thing it highlights the importance of grasses, including a large proportion of millet grasses, in the subsistence of later hunter-gatherer, or cultivator transition, northern China. This hints at a contrast with nut-hungry and acquatic-focused south (Yangtze). These new data make foxtail millet exploitation, and possible cultivation, at least as early, if not earlier, than the claimed early Panicum from Cishan (although in the latter case, hard evidence for cultivation rather than gathering remained elusive). Phytolith data indicates the occurrence of Panicum miliaceum types only from late Donghulin. Taken with other recent finds this is suggestive that Panicum and Setaria were not brought into cultivation together, perhaps each more than once, and separately, in different parts on northern China. The bringing together of these two crops, fully domesticated, in an integrated system, would seem to be a key transition, yet to be identified, but which must have happened by the time of the emergence of the Early Yangshao tradition in the first half of the 5th Millennium BC.

The trends that Yang and colleagues have found, towards more of the larger Setaria italica like starches are suggestive a subsistence shift, and potentially as the authors argue, of changes evolving in foxtail millet, as part of the domestication process. More data from more sites and periods are needed, however, to confirm whether this a real trend. It would also be nice to see what these kinds of ratios look like on later sites with clear macro-remains of domesticated foxtail millet.

Nanzhuangtou and Donghulin as early Holocene/terminal Pleistocene transition sites with early pottery are often cited as the precursors of more typically Neolithic miller cultivators but have lacked much of any archaeobotanical evidence. These findings will take on an obvious significance to those interested in the early Holocene or early agriculture in Northern China. This study is also a good example of careful archaeological starch research, and is therefore wider methodological interest. Although starch grain research has become increasingly popular in China, some studies have been rather unconvincing, especially with regards to methodologies for identification and for being clear about uncertainties. That is not the case here, where a clear methodology for identification of millet-type starch grains has been employed which is in part qualitative and in part quantitative and it includes a clear recognition of some of the uncertainties in secure species level identifications, especially of smaller and less fissured starch grains. It is also clear that the reference collection of modern material that has been studied is the most extensive to date for Chinese grasses and this increases greatly the likelihood of their reported identifications. The inclusion of control samples of sediment and loess from Donghulin to check for contamination is also methodologically very important, since modern contamination will always be a concern in starch studies. It is also good to see consideration of the presence of immature starches, since immature millet grains are a significant component of charred assemblages, and significant present on immature/unfilled spikelets has been noted in Chinese agricultural texts throughout history, since records in the Han Dynasty. The recognition of carbonized immature Panicum grains has recently been bolstered by an experimental study blogged previously.

Wednesday, 7 March 2012

Dating archaeobotanical treasure troves from Armenia and Peru

The arrival of a new issue of Antiquity is always a welcomed event. The issue that arrived in my mail box this week a particular trove of treasures of an archaeobotanical sort. Not so much for archaeobotanical reports as such (the only such is the study by Willcox and  Strodeur on the details of Jerf el Ahmar), but for tantalizing new information of sites that have exceptional plant assemblages, or that one expects will in the future, like the Han era Pompeii, Sanyanzhuang (blogged below). Two sites, which are well-known for exceptional preservation are the Areni-1 cave complex in Aremenia (Areshian et al in Antiquity), left, and Huaca Prieta mound in coastal peru, below right (Dillehay et al.). 
     Areni made the news a couple of years ago for its early leather footwear, from ca. 3500 BC (Pinhasi et al in PLOSone), but it also has dessicated plant remains of many sorts: emmer and free-threshing wheat and barley, of course, but also lentil, grasspea, grapes, plums, walnuts, almonds and pears. How many of these fruit and nuts represent species that were available wild in the region, were under cultivation or introduced as cultivars still needs to be clarified. The site has produced features indicating on-site wine production, so presumably grapes were cultivated, from at least, from around 4000 BC. 4000 BC is associated with the earliest material reported so far, but the site still has much to yield to excavation, presumably including earlier material. Late samples from the past 2000 years include cotton and textiles.

     Huaca Prieta also boasts exceptional archaeobotanical preservation, and with a long sequence it provides information that suggests the chronology of cultivar introductions in this region. Few plants are likely to be native here and so their introductions point earlier cultivation and domestication elsewhere. This includes Cucurbita sqaush, avocado and lima bean at 7000-5500 BC, and thereafter the appearance of chillis and bottlegourds. Cotton cultivation was established around 4800 BC, and after 4500 BC maize was added to the repertoire. This is some of the best dated and documented early maize in South America, detailed of which were published earlier this year (see previous blog). Peanut, sweet potato and quinoa also come from later levels. Full details are not yet published but some summary can be found in the on-line supplement. This site has also produced coca leaves, indicating the long traditions of chewing this drug plant. Dillehay and colleagues reported the earliest for use of this drug, back to ca. 6000 BC, from elsewhere in northern Peru about a year and half ago, also in Antiquity. Intriguingly this drug plant, plausibly from across the Andes, appeared to already have domestication features at this date.

Monday, 5 March 2012

Han period 'Pompeii' includes farmland

In the latest Antiquity Kidder, Liu and Li report on Sanyanzhuang, a settlement buried by catastrophic Yellow River floods around AD 23. This is a essentially a central Chinese Pompeii but without the burning. So far little of the settlement occupation area has been excavated but it appears that field systems around the site were preserved as well. Some exceptional preservation includes leaf megafossils (leaf casts), in this case of mulberry and elm trees. The report is basically descriptive and notes sampling for pollen. One can hope that in the future systematic flotation and phytolith sampling will be carried out, because a site like this provides an amazing opportunity to ground truth the reliability and biases of the (limited) textual sources on Han agriculture. Despite the fact that written sources refer to "row crop cultivation" (p. 46), as found here.

20,000 yr old huts from Jordan

This report on Kharaneh IV, published in PLoSone  a couple of weeks ago, has a lot of people excited: well-preserved hut features from the early epipalaeolithic of the southern Levant, over 20,000 years old, are a pretty uncommon archaeological find. Most sits of such age provide a bunch of chipped stone, some animal bones and if one is lucky some wood charcoal. Of course, this period has already produced the remarkable Ohalo 2 over in Israel, with amazing plant preservation in burnt down huts of similar age, partial details of which were published in J. Arch Science by Ehud Weiss et al in 2008. One of the problems of Ohalo 2 has been there is so little to compare it with, apart from sites of much later periods. Now there is the opportunity. No plant evidence from Karaneh IV has been reported yet, although colleague here in London are working on it, Sue Colledge on the flotation samples, and a PhD student Monica Nicolaides is working on phytoliths and starch samples. We can expect some important results id due course, although it is unlikely to come close to Ohalo in terms of quantity and preservation in macros, but supplemented by much more systematically collected micros. Other exciting work on the faunal remains is taking place down the hall here, by Lousie Martin, Liz Henton, and Anna Spyrou, which will provide insights into mobility and seasonality.

The archaeology of this site has received plenty of media attention on-line already, and a useful summary at about.com.

Sunday, 4 March 2012

Permafrost anceint DNA

One of the most remarkable, and unusual, pieces of archaeobotany I have seen lately is the report of bringing back to life Pleistocene campion (Silene) flowers, published by Yashina et al in a recent PNAS. Ancient seeds did not themselves germinate, but their genetic material, from immature fruits, was cultured in vitro and then propagated clonally. So the images at right are clones of a plant that was trapped in frost some 31,800 years ago. It is not strictly archaeological, there is no report of a human site there. Direct AMS dates put fruits, apparently from ancient rodent (squirrel) burrows back to over   30,000 years old. 

There are of course periodic reports of extremely old seeds germinating, although in most cases is unlikely that seeds of more than about a century or so, with germinate. See, for example, Barbara Youngman's old review on the germination of old seeds (in Kew Bulletin 1951). "Mummy wheats" are a myth. In general,  longevity may decrease rapidly for many seeds after a decade or so. But natural ice mummy seeds, would appear to be a reality, or at least a source of genetic material that might be propagated by lab methods. As seed banks have learned freezing temperatures can keep seeds longer, slowing down all manner of  enzymatic and decay processes-- part of the rationale for Norway's Svalhard ice burrowing seedbank. 

Will such approaches become more common place? Elephantid phylogenetics have certainly been aided by the ancient DNA from frozen remains of mammoths (see Alan Cooper's 2006 "Year of the Mammoth" in PLOSone): is there is a similar set of phylogenetic surprises in store as more permafrost Pleistocene plants are dug up? Of course permafrost regions are too far north for much in the way of agriculture to be practiced-- taking crops north was a challenge as the archaeobotany of Norway reveals-- so  there is unlikely to be much in the way of agricultural crops.

Early plant cords in rock art?

In the lastest Antiquity project gallery, "fibre technology depicted in archaic art" is a re-interpretion of some rock art from Borneo, as depicting a twisted cord, presumably of some plant fibre, with frayed ends. The image is more than 8000 years old, and also includes human and apparent orangutan figures. Rather than being some sort of symbolic pathway, Judith Cameron, suggests that it represents something material, and she can point towards, admittedly later, evidence for plant cordage from Neolithic burials at Niah Cave. Of course, throughout the Palaeolithic, or at least the later Palaeolithic associated with modern human use of plant fibres, cordage, weaving of baskets must have been quite widespread. In addition to rare finds of actual cordage, such as at Ohalo 2 at >21000 years BP, other plant finds that suggest the use of plant cordage may be seen in the phytolith record: phytoliths of palms and from wild banana (Musa) leaves occur throughout the sequence at Batadomba-Lena rock shelter in Sri Lanka by to 36,000 BP [Perera et al. 2011 People of the Rainforest...]. And as phytolith sampling, and some exceptional examples of preservation, at Catal Hoyuk demonstrate there silica skeletons can provide evidence for Plants as material culture (Ryan 2011 in J. Anthro. Arch.), and so it is not too much of a strecth to think about phytolith, such as those from palms, Musa and many other fibrous monocots, as likely to represent past human gathering for raw materials, perhaps even more so than use as food.

One is reminded of Karen Hardy's impassioned plea for giving more consideration to the importance of string in early evolution on human technology ("String Theory" in Antiqiuty 2008). This reexamining of rock art appears to be step in that direction.