Friday, 23 July 2010
A very interesting and important approach to mapping global vegetation but including the human activities has just come to my attention. It is the work of "Anthromes Project" of the Landscape Ecology laboratory at University of Maryand Geography Department, lead by Dr. Erle Ellis. Essential they are mapping landuse and vegetation together. Rather than traditional biome and vegetation mapping, which attempts to infer "potential vegetation" on the assumption that such maps represent the world as it would be if there were no humans present, they are explicitly mapping human environments, villages, rice fields, pastoral rangelands, as well as woodlands and 'wild' vegetation. Their results can be found on their website, and are discussed in a fascinating, if somewhat frightening, new paper "Anthropogenic transformation of biomes 1700 to 2000 [AD]" in Global Ecology and Biogeography. Essentially they demonstrate that the proportion of the earth's habitable surface (i.e. not under ice or ocean) has shifted from a majority wild to the majority human-managed and modified in the past 300 years. While we think of the world becoming increasingly urban, certainly true, it is the the expansion of inhabited villages that really stands out-- although as someone who has traveled across much of India and China, this is totally understandable, there is a vast number of sprawling small communities (often with populations in the many thousands) scattered across the landscape, and these are of course surrounded by crops (dry or irrigated), rice fields, and scrub vegetation used for grazing where "potential forests" ought to be. If the Neolithic is about the domestication of a few plants and animals, the plastic-age is about the domestication of the planet Earth.
As an archaeologist interested in past land use and vegetation, one is well aware of the need to factor in human activities in local environments (a point we tried to make in a little book on South Indian woodlands), and to keep in mind that people of have been playing with fire (literally) and modifying vegetation for a long time (at least 50,000 years in Southeast Asia and Australia, to judge by microcharcoal records of biomass burning). Agriculture, of course, represents a major transition in terms of intensifying modification and management of environments, but essentially much of that was still localized in a wider less modified background. The anthromes maps show clearly how precipitously the shift has occurred to a majority managed, modified and inhabited. As they conclude, it is clear that environmental research must focus on better modelling, predicting and managing human-centered ecologies, or as is noted in their blog the "war with nature" has already been won (for better or for worse) by culture, and we better deal with aftermath.
There is a conceptual parallel here with domestication. As seems increasingly clear to me, a key threshold is crossed when domesticated/human dependent crops (such as non-shattering rice) come to dominate the population, and the economy shifts to modifying the landscape and depending on domesticates. This is when agriculture emerges from early pre-domestication cultivation or small scale food production, and in many regional histories there is no going back to hunting-and-gathering after this. For better or worse people become 'trapped' and entangled in agriculture (see one recent exploration of this entanglement in World Archaeology)
Returning to the anthropogenic biosphere, archaeobotany has a role to play in putting an even longer term perspective on these changes in biomes/anthromes. By accessing evidence for earlier periods of human use and modification of landscapes and the construction of agricultural landscapes and economies, we see how current and recent trends compare with and are informed by a longer perspective.
Thursday, 22 July 2010
Both genetics and archaeobotany provide vantage points of reconstructing the early history of crops, where and how they originates, and how they spread. There has been a growing recognition in both fields that some of our previous conclusions were false truths, based on simplistic assumptions. There has been a small, but growing trend, for some true interdisciplinary synthesis, of archaeobotanists teaming up with geneticists to write the history of crops, and a new example comes from the journal Genetic Resources and Crop Evolution, "Geographic distribution and domestication in wild emmer wheat (Triticum dicoccoides)" in which archaeobotanist George Willcox teams up with geneticists (including Ozkan, Salamini and Kilian) to provide an updated compilation of what is know about Emmer and what it might mean for multiple starts of cultivation, gradual domestication, but the possible predominance of one domesticated line at the end of the process. It generally points towards a much more complex picture genetically and biogeographically, and it recognizes the incompleteness of sampled datasets, including the range of modern emmer landraces and wild populations as representatives of what would have been there in the past. This paper hasn't solved all the mysteries of the origins of agriculture in the Near East, nor of emmer, but it represents serious progress through a conversation between archaeology and genetics, rather than just talking past each other.
It is not everyday that archaeobotany received much 'mainstream' attention. But recently it did: Science on 2 July 2010 includes a profile of Dolores Piperno, one of our fields seniors figures in phytolith work and a pioneer in applying starch grains to the archaeology of the Neotropics.
Tuesday, 20 July 2010
A important study has recently come out in the journal Molecular Ecology, on "Ecological divergence in the face of gene flow in two closely related Oryza species (Oryza rufipogon and O. nivara" by Zheng and Ge. In it they have sequenced a few chloroplast and nuclear DNA loci (7 in total) across 26 populations of these two wild rices. Nivara and rufipogon represent two ends of a adaptive spectrum in the wild genepool of Asian domesticated rice, with O. nivara being an annual adapted to seasonal water from the monsoon and lacking daylength seaonsality controls (so its life cycle is driven by water availability), while O. rufupogon sensu stricto is a perennial occurring in perennial wetlands, and is often highly structured in terms of the seasonality of seed set (especially important in its northern range in China). As I have discussed previously in a 2009 World Archaeology paper, these differing ecologies had important consequences for how these plants would have been utilized by hunter-gatherers, with the perennial rufipogon requiring more environmental manipulation to force it to produce more grain.
In this study Zheng and Ge show that these two wild rice ecotypes are well diverged overall, and they estimate a last common ancestor about 160,000 years ago, but they also show evidence for recurrent gene flow. This strongly suggests that these have diverged as ecological adaptations despite being in continued genetic contact, providing a nice case of the strength of natural selection in pushing divergence even when species ranges overlap (i.e. a case of sympatric speciation). It is interesting to note that the divergence time they have calculated is very similar that those calculated for the last common ancestor of indica and japonica domesticated rices, which have ranged in various studies between 86,000 and ~400,000 years ago, but most focus on 100,000-200,000, much like nivara and rufipogon. As many have argued (see for example the recent "Rice consilience" review article), indica and japonica appear to have different origins in cultivation from different maternal ancestors, one from a nivara-like annual and the other from Chinese rufipogon perennials-- although they also have undergone recurrent geneflow (see McNally et al 2009 on SNPs and hybridization), which has introduced selected domestication traits amongst others. Thus the process of differentiation in cultural ecologies in the rice crop, despite continued geneflow, continues that ecological and genetics dynamics of the wild progenitors.
Friday, 9 July 2010
A recent issue of the Chinese Science Bulletin contains an archaeobotanical paper from what appears to be a new archaeobotanical research group. An ChengBang et al. report evidence from survey archaeobotany in Qinan and Li counties, and as such follows in the path laid by flotation as part of field surveys published previously from the Yiluo Survey (Lee et al 2007) and the Ying Survey (Fuller and Zhang 2007; see also our GIS study in Journal of Archaeological Science). This new study is based on 96 samples, from something like about 40 sites (although this is not entirely clear). Unfortunately the full dataset is not published, and we are given a glimpse of it through summary data presented as bar chart of absolute counts of Panicum and Setaria grains. Not the most informative means of comparing across sites and periods with very different sample sizes. The presence of rice (7 grains in the Late Yangshao) and wheat and barley (from the Western Zhou period) are only referred to in the text description. No reference is made to any other species, whether pulses, fruits or weeds. One novel addition to the study was a stable carbon isotope study of the millet grains, which shows that Setaria tends to have a somewhat higher value than Panicum, as expected since although both are C4 plants they have different forms of the C4 mechanism. A novel technique but the results are still close enough that this is unlikely to replace morphological identification! While it is nice to see more archaeobotanical research being carried out in China, the attention to only cereals, the lack of discussion of archaeological context (it is even unclear which sites numbers are which period), a less helpful method of quantification, and the lack of full details makes this study a rather frustrating addition.
The extensive set of direct dates, on the largest early assemblage of wheat and barley in China, provides important new evidence on the arrival of West Asian crops, and western stimulus, into China. Rowan Flad, Li Suicheng, Wu Xiaohung and Jimmy Zhao, have recently reported new archaeobotanical evidence and AMS dates from the Gansu corridor site of Donhuishan in short article in The Holocene, "Early wheat in China: Results from new studies at Donghuishan in the Hexi Corridor." Importantly, the evidence includes the first large assemblage of wheat rachis remains. These provide the first clear confirmation of what has long been taken for granted, that the early wheat in China is only hexaploid bread wheat, leaving the eastern margins of tetraploid naked wheats (durum) somewhere in central Asia and to the south in India. This article also provides an updated review of all the early wheat finds that have been published from China.
In my version of their map (left), I have colour-coded wheat reports by broad period. First of all, it can be seen that finds line up along the eastern line of the classical silk road, running through the Gansu corridor and along the Lower Yellow river basin. It should noted that while the earliest finds are all attributed to 2500-2000 BC, or even more than 2500 BC in the case of Xishanping, none of these earliest finds is directly AMS dated. The case on Donghuishan reported by Flad et al., provides a warning call against putting too much faith in single or few or associated dates, as the earlier evidence from Donghuishan has suggested the wheat could be closer to 2500 BC rather than the 1600-1500 BC age indicated by numerous dates, including 4 directly on barley (but not wheat). Nevertheless it still seems plausible that wheat and barley entered China by ca. 2500 BC, even if the wheat crop did not take off until closer to 2000 BC. This period of arrival ion China is paralleled by the adoption from the west also of sheep, cattle and probably copper metallurgy (with a possible parallel spread to Southeast Asia-- as argued recently by Whyte and Hamilton). The counter current was provided by Chinese millets, as both Panicum miliaceum and probably Setaria italica arrive in northwestern India around this period, and Panicum is also reported in Yemen (ca. 2200 BC) and in Sudan by ca. 1700 BC. On the dispersal of westwards and southwards through the Indus to Arabia and Nubia, see discussion the paper "Cattle, Crops and Commensals" that I recently published with Nicole Boivin in the French periodical Etudes Ocean Indien [pdf]. I have also argued that japonica rice followed this route west from the Yellow river and in India (see discussion in my article in the recent rice issue of Archaeological and Anthropoloigical Sciences)
Interestingly the barley from Donghuishan, like that from Xishanping, is notable since most sites in China that have yielded wheat have lacked barley. This indicates that the adoption of wheat went through a strong cultural filter in which is was only wheat rather than wheat and barley that was adopted in much of central China. This provides a curious contrast from other regions of Asia, whether west Asia, central Asia of South Asia where wheat and barley are almost always found together archaeologically. In India these two winter cereals are also often found with evidence for pulses crops like lentils, peas or chickpeas. None of these Southwest Asia crops appears to have made it into prehistoric China. Thus the diffusion of crops into (and out of) China was selective process of cultural choice.
Thursday, 8 July 2010
I received the following queries about rice, posted on the Indo-Eurasian discussion list. Which I will endeavour to answer here. This queries arise from a colleague having read my recent “consilience” review article on rice.
- Does this new evidence (of proto-Indica and japonica entering fromChina via a precursor of the silk road) conclusively rule out the association of rice cultivation with a hypothetical 'Austric' package(I mean, dispersal of Munda-speakers INTO India)?
No. These processes are not mutually exclusively. The genetics of rice is complex and implies many episodes of hybridization between indica and japonica lineages, and with the aus and tropical japonica groups which are now increasingly seen of distinct subgroups of indica and japonica, respectively. Just have a look at the genomic data published by McNallay et al last year, and you will see how recurrent and extensive hybridization has been. A single entry of japonica into South Asia is inandequate, and we tried to reflect this in our ‘Thrust 10’, but there is also presumably some mixing between thrusts 6 and 8 in the Assam region. Indeed it is the aus-rices of Assam and Bangladesh that shows that highest levels of hybirdization in McNally’s study.
- Does this lend credence to the theories of South Asian homeland forAustroasiatic languages (including perhaps pre-proto-Munda and ancestral language of Mon-Khmer languages)?
No. The current archaeobotanical evidence can fit with Austroasiatic origins either to the East to the West. In my own writings I have gone back and forth from supporting the immigration ofMunda (my 2003 paper on Dravidian [pdf]) or emigration from pre-Proto-Munda (my 2007 paper in the Petraglia/Allchin volume). I have actually shifted back more towards seeing the Munda coming into India from the Northeast. In either case Proto-Munda agriculture was not particularly rice focused, indeed reconstructible rice vocabulary is meagre, but focused on tubers (including taro), millets (and it is unlcear if these are the Chinese or Indian millets originially), and pulses, water buffalo and maybe pig. It seems clear that Proto-Munda is heavily influenced by Dravidian and pre-existing Indian agriculture through the adoptions of sheep/goat, zebu, and Indian pulses. The archaeological and archaeobotanical evidence, however, is strongly against an “Austric” hypothesis (sensu Blust) that see one origin of rice driving all the major language expansions of SE Asia.
- With this new evidence, could we say anything about the familial affiliations of Language X and Harappan languages (Kubha-vipas and Melluha -- let's call them Language Y and Language Z; I personally don't like the terms like Para-Dravidian, Para-Munda, Para-IA etc.)?
No. I increasingly think that Para-Munda is highly misleading. Kubha-vipas seems to have as uch in common (in not more) with Mon-Khmer and even Austronesian as it does with Munda (this is clear from vocabulary comparisons used by Kuiper, which as Osada has pointed out often include Austronesian words; and from the “rising” versus “falling” order of the language (sensu Donegan and Stampe 2004). These might all be labelled as broadly “Austricoid” but I can not see how these can be connected with agriculture and presume that shared ancestry must be much older than that…. But this is probably a discussion for another time….
has a different history than that of rice, and agriculture predates the introduction of rice in all regions of civilization viz., Indus Valley, Gangetic plains, eastern India and Neolithic southern region of Andhra-Karnataka- Is it correct to assume that the dispersal of agriculture in India
The patterns are different in different regions: there is neither one story of agriculture in India (e.g. my Journal of World Prehistory paper of 2006 [pdf]), nor one story of rice in India. Agriculture clearly precedes rice in the northwest (the Indus), in the west (Gujarat and Rajasthan), in the northern and southern Deccan. Through most of the Indian savannahs (Gujarat through the South Deccan) early farming was based on indigenous millets and pulses, rice came late (mainly after 500 BC) and even in historic times rice was a relatively minor component of overall agriculture: I take this for example from my recent research on the archaeobotany at Paithan in Maharashtra—in the early Early Historic and Early Medieval period rice is presence but millets are dominant, and wheat and barley are also more frequent than rice. Of interest is that kodo millet (Paspalum scrobiculatum) is hand down the most dominant crop on the site, with the African millets including sorghum, which are so prominent today, making only a minor show. Agriculture and diet has been dynamic, and we do a dis-service to that variety by obsessing about rice. As explored in an interesting paper by Monica Smith (The Archaeology of Food Preference), rice does appear to have been a preferred crop of higher status and for culinary reasons, and probably also by states as it is highly productive and is therefore a favoured by state taxation. A similar point has been made compellingly in a recent history of political ecology and shifting cultivation in southeast Asia, James Scott’s book The Art of Not Being Governed—in which he explores how the lowland states of mainland Southeast Asia have always been built on fairly intensive, and easily taxable rice agriculture, while the unruly and difficult to govern peripheries have been the realm of shifting cultivators and those fleeing oppressive states.
ariki, arici (tamil), brinj (persian) etc. [as discussed in Witzel 2006. South Asian agricultural terms in Indo-Aryan, and Southworth 2005]?- What about the rice related terms like vrihi (vedic), vari (telugu),
Many of these terms probably are related, although I am less then convinced that all of them are. Some of the Dravidian terms look like they may be semantic shift from words that originally names of millet. But whatever the case the spread of rise and its rise in importance in economic and prestige terms means that names of rice would have been widely borrowed. Clearly the spread of rice into the Persian world came from India (although the preferred fragrant rice varieties of Persian had their ultimate genetic origins in Southeast Asia—as did most fragrant rices, as indicated by genetics of the most-common BADH2 mutation-- but must have moved via cultivation India). This could have been as much a process of elite dominance, in regions like much of South India where rice was initially a fairly minor crop, and have little to do with population movements as such. I would look to parallels in things like the spread, borrowing and diversification of terms of pepper in European and Western Indian Ocean languages—which testified to the long importance of this plant product in trade—it appears broadly related from Thai Phrikthiy, Swahili Pilipili (hence Brazilian periperi), Portuguese pimento, Turkish biber, Greek piperi, all ultimately from Sanskrit. Oddly from Sanskrit and not Tamil as black pepper is clearly indigenous to Southwest India. A similar pattern holds for names of coconut, far more prominent as a crop in Southern India than in the Sanskrit north. But these patterns must have some reflection of trade routes and social valuation. On the other hand most of the world has taken its names for Mango from Dravidian, yet the mango is not originally native there, but most cultivated mangos have their origins in Assam or thereabouts, but I know of no linguistic trail. Instead it was Tamil and/or Malay sailors who had borrowed from Tamil who did the most to spread knowledge of this fruit around the Indian Ocean. …I would note that putting together histories such as these and anchoring them in archaeobotanical evidence and genetics is a major focus of the Oxford based SEALINKS project, in which we have started new archaeobotanica sampling in Kerala, Sri Lanka, and coastal Kenya and Tanzania…
- Is it still correct to assume that the South Dravidian form 'arici' has been transmitted westwards, probably by maritime trade to result in Greek oryza, oryzon and Arab. ruz, English rice? You see, 'arici' is one of those words that compels people like Karunanidhi, the current CM of Tamil Nadu, to bombastically claim that "Tamil is the mother of all languages in the world!" (tamizh ulaga mozhigaá¸·ukkellaam taay mozhi ennum perumai peRukiRatu)!
Certainly the term for rice has been translated Westward from Tamil, but as the examples of pepper and mango indicate this has much to do with patterns of early historic trade, and which middlemen give commodities their name, than anything else, and perhaps little to do with ultimate ‘origins’ or Linguistic superiority. South India played a major role in Indian ocean trade throughout the 1st Millennium AD and upto the European colonial era, and thus many Tamil names have become attached to things; so too Portuguese and Spanish played the major role in transmitting the names of New World crops throughout Eurasia.
(These queries come from Suresh Kolichala, who is researching ancient Indian recipes and cookbooks, which I very much look forward to learning more about!)
Sunday, 4 July 2010
Archaeological & Anthropological Sciences volume 2(2), is a special issue on the topic of early rice agriculture in Asia. It brings together recent statements about the state of the art of rice archaeology in China, Korea, Thailand, and to a lesser extent Japan and India. It has articles on genetics, including the first published ancient DNA extraction targeting the occluded cell nuclei trapped with phytoliths (although admittedly from a remarkable context of preservation that included visible waterlogged leaves). One accomplishment is getting authors from Japan, China and Korea to publish all in one place in English. It also has a large review on the domestication process and spread of rice (see example of one map above), which comes out of a team effort, mostly here at the Institute in London. So if you want my latest views on early rice then you must read Consilience of genetics and archaeobotany in the entangled history of rice. [pdf] This includes domestication processes, and when they are finished in both India and China, how I think indica and japonica met (and hybridized) for the first time (in northwest India or Pakistan!), and when upland dry rice and paddyfield systems came to various parts of Asia. But for a taster of the volume as a whole it is, of course, worth starting with the short editorial. [pdf]
A couple of enterprising Harvard students have built a facebook of seeds, or rather a kind of networking platform for uploading images of archaeobotanical specimens, or reference materials. http://paleobot.org/
Just a quick note, to record a link to a free, on-line book about plants in Europe (mainly Medieterranean and eastern Europe): Plants and Culture. Seeds of Cultural Heritage of Europe, edited by Jean-Paul Morel and Anna Maria Mercuri; the chapters or whole can be downloaded in PDF for free.
Drawing on historical sources and archaeobotany, various chapters deal with vegetables, fruits, gardens and recipes. Topics ranges from a history of peaches in Italy, to a detailed archaeobotanical consideration of Portulaca oleracea (purslane), to a reconstruction of food preparation (recipes) in prehistoric Greece, to renaissance era archaeobotany of Ferrera, Italy.
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