Crossing the Wallace Line

Dienekes’ Anthropology Blog has an intriguing map from a paper on human genetic diversity in island South East Asia showing a sharp cline across Wallace’s Line.

The genetic cline corresponds to a cline in phenotype which was actually recognized by Wallace himself. ((And for languages, see this.)) The authors…

…conclude that this phenotypic gradient probably reflects mixing of two long-separated ancestral source populations—one descended from the initial Melanesian-like inhabitants of the region, and the other related to Asian groups that immigrated during the Paleolithic and/or with the spread of agriculture. A higher frequency of Asian X-linked markers relative to autosomal markers throughout the transition zone suggests that the admixture process was sex-biased, either favouring a westward expansion of patrilocal Melanesian groups or an eastward expansion of matrilocal Asian immigrants. The matrilocal marriage practices that dominated early Austronesian societies may be one factor contributing to this observed sex bias in admixture rates.

There’s a map of the same region in the recent paper on pig domestication that’s been in the news lately.

Compare and contrast. Still two quite distinct populations, but the placing of the line of demarcation is somewhat different. This is what the authors have to say about the Pacific pigs, after their main discussion, which is of their separately domesticated Chinese cousins:

This genetic evidence also supports separate domestication pathways (however independent) of one population in India and three wild boar populations indigenous to Peninsular Southeast Asia. Given the relative geographic proximity of the Southeast Asian clades, it is possible that the domesticated haplotypes were all present in a single population of wild boar, as is the case for modern Yaks. Regardless, only the Pacific Clade domestic pigs were transported out of Southeast Asia (to ISEA and the Pacific) before they were replaced in their homeland by domestic pigs derived from nonindigenous populations of wild boar.

So, people and pigs moving together across Wallace’s Line. How about crops? There are also distinct Pacific and Asian genepools in taro, though I could not find a nice map to compare directly with the above. However, the consensus seems to be — as also for crops such as bananas, yams, breadfruit, sugarcane and yams — that domestication happened southeast of the Wallace Line, in Sahul (Melanesia to be exact). As my friend and colleague Vincent Lebot said of these crops a few years back ((And I don’t think he has changed his mind!)):

We now have biomolecular evidence to suggest that most cultivars were not brought by the first settlers from the Indo-Malaysian region, but rather were domesticated from wild sources existing in the New Guinea and Melanesian areas… In other words, the first migrants that went across Wallacea did not embark major domesticated plants if any, in their adventure.

Pigs, in other words, and maybe chickens, but not taro or yams. Banana went in the opposite direction. I wonder why. Or did people bring them on their adventure, and abandon them when they found better varieties?

Incidentally, coconut also shows a bit of a Wallacean dividing line, but of course it doesn’t need humans for its dispersal, at least not everywhere.

Nibbles: Consortium?, Sheep diversity, Sustainable biofuels, Agroforestry, Almonds, Chicken breeding, Restoration, More tree management, Vegetable gardening, Wheat domestication

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The recent history of sustainable agriculture in Thailand deconstructed

We are happy to publish this contribution from our reader Donald R. Strong of the Department of Evolution and Ecology, University of California, Davis.

ResearchBlogging.orgThailand is a cornucopia of agricultural biodiversity. Western visitors like me are astounded by the numbers of kinds, and sheer volume, of fruits and vegetables offered from the densely packed food carts that line city streets. Piles of Asian species — longan, durian, mangosteen, lychee, longkong, salak — as well as unusual melons and herbs, are jumbled together with more familiar food plants — bananas, corn, chilis, onions, citrus, etc. Unlike in many other wet, tropical countries with impressive displays of food in central markets, Thais are generally well fed. Malnutrition and infant mortality are substantially lower than in contiguous countries, and in the region only China rivals Thailand in measures of population well being. ((World Health Organization.)) Thailand has not sacrificed wealth by feeding its people. Food exports have long been high and lucrative, and it is the world’s leading exporter of rice.

The social policies responsible for these positive agricultural outcomes have evolved, sometimes tortuously, over a long period. Thailand had became a major exporter of rice for the global market by the second half of the 19th century, but the wealth from this trade did not trickle down. ((Feeny D. (1982) The political economy of productivity: Thai agricultural development, 1880-1975. University of British Columbia Press, Vancouver.)) Thanks to the Green Revolution, by the late 20th century Thailand had become a model of development. It had progressed from subsistence agriculture, to agribusiness, and then to an industrializing economy. At the same time, low incomes dogged large fractions of the rural population, which provided the labor for agribusiness and practiced small-scale agriculture.

The evolution of social and economic conditions for small farmers following the Green Revolution, and the subsequent movement toward sustainable agriculture, is the subject of a fascinating recent study by Yuichiro Amekawa of Iowa State University. ((Amekawa, Y. (2010). Rethinking Sustainable Agriculture in Thailand: A Governance Perspective Journal of Sustainable Agriculture, 34 (4), 389-416 DOI: 10.1080/10440041003680254)) Manned by surplus labor in rural regions, and trained by agricultural extension funded by the World Bank, industrial agriculture employed new varieties, inorganic fertilizers, and machinery. Great increases in yields followed. Skillful marketing of the bounty by agribusiness boosted Thailand’s capital. GNP increased to drive industrialization.

While the Green Revolution was promulgated throughout Thailand, however, only in the irrigated central part of the country did rice yields rise a great deal. In many areas that rely upon rainfed cultivation, impoverishment persisted for small farmers, and market prices did not rise to match costs of the technology. Small farmers on marginal lands faced drought, soil salinization, pest resurgence, poisoning due to ignorance of proper handling of pesticides, and many were overwhelmed by debt. In upland areas of northern and northeastern regions of the country, indigenous people were displaced by the deforestation that came with the push for cash crops other than rice. Bereft of land, these people became the pool of dependent labor. Government reforestation efforts displaced poor farmers who then moved into the remaining forest seeking places to farm. ((Sadoff, C. W. 1991. The Value of Thailand’s Forests. TDRI Quarterly Review Vol. 6 No. 4, December 1991, pp. 19-24.))

The thrust of Amekawa’s work concerns the outcome of the sustainable agriculture movement in Thailand meant to counter the economic insecurity, pollution from inorganic fertilizers and pesticides, harm to the environment, and erosion of biodiversity caused by industrial agriculture brought by the Green Revolution. He addresses governance, following the approach of the 2009 Nobel Prize in economics to Eleanor Elinor Ostrom, one of the two co-awardees. She and others have focused upon what might be termed bottom-up, self-management by local communities. The examples of successful management of such “common property regimes” contradict the original assertion of Hardin’s Tragedy of the Commons that the only means of avoiding over-exploitation and the tragedy of the commons is top-down control by private ownership of the property or by government .

Amekawa learned Thai and based his study upon data that he collected over a ten year period before 2009, which was an advance upon previous purely theoretical analyses of the prospects for smallholder sustainable agriculture in Thailand. His study was in Chaiyaphum Province, in the northeastern region, locally called Isan and considered the least developed of Thailand’s four regions. It has low agricultural productivity, drought, soils that have become saline, and farmers with low incomes. They grow a range of fruits and vegetables as well as sugar cane, taro, cassava, pummelo citrus, and corn. He concentrates on the case of the “SAO: Industrial Organic Agriculture,” which was promoted by a Japanese NGO with efforts at democratic local governance in 13 villages.

They raised diverse vegetables in small gardens, with manure, organic pest management, and crop rotation — and received guaranteed high prices from subscribing Japanese households in Bangkok. The operation collapsed after a few years under a burden of oversupply driven by “increasingly opportunistic entry of producers.” Control of supply is a crucial element of common property theory and practice, and its absence from SAO operation contributed to the tragedy of the collapse of the SAO operation.

This was not an orthodox tragedy of the commons, however. Overexploitation in this case was of the limited market rather than a natural resource. Subsequent rescue schemes by the government and private parties were not successful.

The failure of SAO not withstanding, Amekawa concludes that sustainable agriculture as it exists in the complicated government polices and procedures — which do contain some elements of local, shared governance — are indeed valuable to small-scale farmers. However, consistent with the SAO story, the domestic markets for many Thai crops, especially those for fresh fruits and vegetables, are saturated. He finds no wisdom in “encouraging less competitive groups to newly enter the markets…” Amekawa is making an important statement about the complex relationship between agricultural biodiversity, sustainability, and economic sociology.

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