Old Crop,New Society: Persistence and Change of Tartary Buckwheat Farming in Yunnan,China

Traditional agricultural systems are important for crop genetic resources conservation. Many scholars have addressed the problem of traditional cultivar replacement by modern varieties, but few have investigated the entire loss of traditional crops from farming systems. Our prior research suggested that tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) agriculture is rapidly decreasing in Yunnan China, the center of the crop’s origin and an important repository of on-farm genetic diversity. Using interdisciplinary methodology to determine whether the crop is indeed in decline and evaluate reasons behind planting trends, we found a combination of interacting agroecological, socio-cultural, and institutional factors influence tartary buckwheat planting in Yunnan. Farmer ethnicity, presence of a commercial market for the crop, and government agricultural policy were particularly important. Low commercial value of the crop compared to other alternatives, reduction of available farmland, and labor shortages were major reasons cited for crop abandonment. Despite an overall reduction in tartary buckwheat planting across a wide spectrum of farms, we also found the crop retains subsistence, rotational and cultural value for many Yunnan farmers. We conclude that although Yunnan farms are increasingly managed commercially rather than for subsistence, tartary buckwheat will continue to occupy a niche in the agricultural landscape.     

Teparies in southwestern North America

Ethnohistorically, wild and domesticated teparies (Phaseolus acutifolius: Leguminosae) are significant native food crops in southwestern North America. Their value rests in adaptations to arid environments, and high protein content and productivity. Use of wild teparies appears to be discontinued, but certain domesticated varieties are still grown by local commercial and subsistence farmers. The recent subsidence of tepary cultivation is related to breakdown of traditional economies and land use, and to the introduction of energy-intensive irrigated agriculture. An earlier and unsuccessful attempt to introduce teparies into modern agriculture was poorly timed. Teparies have considerable potential for low maintenance agriculture in arid and semi-arid lands.     

Recent Origin and Cultural Reversion of a Hunter–Gatherer Group

Contemporary hunter–gatherer groups are often thought to serve as models of an ancient lifestyle that was typical of human populations prior to the development of agriculture. Patterns of genetic variation in hunter–gatherer groups such as the !Kung and African Pygmies are consistent with this view, as they exhibit low genetic diversity coupled with high frequencies of divergent mtDNA types not found in surrounding agricultural groups, suggesting long-term isolation and small population sizes. We report here genetic evidence concerning the origins of the Mlabri, an enigmatic hunter–gatherer group from northern Thailand. The Mlabri have no mtDNA diversity, and the genetic diversity at Y-chromosome and autosomal loci are also extraordinarily reduced in the Mlabri. Genetic, linguistic, and cultural data all suggest that the Mlabri were recently founded, 500–800 y ago, from a very small number of individuals. Moreover, the Mlabri appear to have originated from an agricultural group and then adopted a hunting–gathering subsistence mode. This example of cultural reversion from agriculture to a hunting–gathering lifestyle indicates that contemporary hunter–gatherer groups do not necessarily reflect a pre-agricultural lifestyle.     

Recent origin and cultural reversion of a hunter-gatherer group

Contemporary hunter–gatherer groups are often thought to serve as models of an ancient lifestyle that was typical of human populations prior to the development of agriculture. Patterns of genetic variation in hunter–gatherer groups such as the !Kung and African Pygmies are consistent with this view, as they exhibit low genetic diversity coupled with high frequencies of divergent mtDNA types not found in surrounding agricultural groups, suggesting long-term isolation and small population sizes. We report here genetic evidence concerning the origins of the Mlabri, an enigmatic hunter–gatherer group from northern Thailand. The Mlabri have no mtDNA diversity, and the genetic diversity at Y-chromosome and autosomal loci are also extraordinarily reduced in the Mlabri. Genetic, linguistic, and cultural data all suggest that the Mlabri were recently founded, 500–800 y ago, from a very small number of individuals. Moreover, the Mlabri appear to have originated from an agricultural group and then adopted a hunting–gathering subsistence mode. This example of cultural reversion from agriculture to a hunting–gathering lifestyle indicates that contemporary hunter–gatherer groups do not necessarily reflect a pre-agricultural lifestyle.     

Nutritional consequences of the transformation from subsistence to commercial agriculture in Tabasco,Mexico

Recent changes in the area of the Plan Chontalpa in Tabasco have greatly reduced the production of subsistence crops by rural families, resulting in decreased crop diversity and a concomitant increase in the degree of dependence on outside sources of food. Results from a nutrition survey of 149 families demonstrate that dietary diversity, dietary quality, and nutritional status of preschool children are negatively associated with lower crop diversity and increased dependence on purchased foods. Dietary deterioration is illustrated by the negative relationship found between nutritional status and increased sugar consumption. The assumption that a rise in income accompanying the adoption of commercial production will automatically lead to improved nutrition is challenged: income levels were not found to be consistently related to nutritional status. Children of families that have converted to cattle production, despite greater land availability and family incomes, do not have improved nutritional status. In the study area, where wages are low and food prices are very high, the value of a higher degree of self-sufficiency in food is recognized, yet families continue to switch to cash crops due to the environmental, economic, and time constraints imposed by the system of commercial agriculture in which they participate. The solution is not to return to traditional subsistence farming, however, but to determine under what conditions a more progressive form of agricultural change can occur.     

Positive effects of wheat variety mixtures on aboveground arthropods are weak and variable

Although modern agriculture generally relies on homogeneous varieties that are usually grown in pure stands, crop variety mixtures have been used for a long time, notably to improve resistance to fungal diseases. A growing number of studies suggest that intraspecific plant diversity may also enhance the abundance and diversity of wild species and thereby some ecosystem services such as biological control by natural predators. However, positive effects of the genetic diversity of plant species on the diversity of associated communities have mostly been documented in natural systems, with only a handful of studies targeting crop species in agroecosystems. Here, we investigated the ecological effects of the number of winter wheat varieties (Triticum aestivum) on aboveground arthropods and particularly predatory species. We manipulated the number of wheat varieties (1, 2, 4 or 8) in 120 plots (80 m² each) to examine how wheat diversity and stand characteristics impact communities of three dominant aboveground arthropod groups that include many predatory species: ground beetles, rove beetles and spiders. The number of wheat varieties had a weak, but positive effect on predator abundance, notably spider abundance. In contrast, wheat functional diversity, as assessed by the number of wheat functional groups, was only negatively related to the diversity of spiders. Among wheat stand characteristics, the variance in plant height, wheat biomass and the Green Area Index were weakly correlated with ground beetle, rove beetle and predatory diversity, respectively. The Green Area Index was also weakly correlated with ground beetle abundance. Our study suggests that wheat variety mixtures have variable and limited effects on aboveground arthropods and probably low effectiveness to enhance biological control, but these results should be further tested under low-input agriculture in real fields.     

Deployment of diversity for enhanced crop function

Mixtures of genotypes are the norm in natural and seminatural ecosystems and subsistence agriculture but have been replaced by pure genotypes in modern agriculture to maximise profitability in high-input systems. However, crop function with respect to the stability of yield and quality in particular tends to be lost in this process. Diversity can be reintroduced into cropping systems as a trait not only to confer stability but also to exploit synergies between component genotypes, compensating for potential performance losses against the best performing genotype in any given season or location. Quality need not be compromised, and research has demonstrated practical development and deployment approaches, which challenge the assumed benefits of current approaches to agronomy and achieve enhanced crop function.     

Sexual dimorphism in stature and women's work: a phylogenetic cross-cultural analysis.

The following cultural variables were tested for their association with sexual dimorphism: sexual division of labor, type of subsistence (hunting and agriculture), and polygyny. The transmission of these traits among populations was investigated. All the traits were found to be associated with phylogeny, indicating that they are inherited from mother to daughter populations. A cross-cultural comparative method was used which controls for the statistical effects of similarity due to common ancestry (Galton's problem). Cross-cultural variation in sexual dimorphism in stature is negatively associated with women's contribution to subsistence. Women are taller, relative to men, in societies where women contribute more to food production. This may be because female nutritional status is better in these societies. No relationship was found between sexual dimorphism and other aspects of subsistence or polygyny. These results are discussed in relation to other studies of sexual dimorphism in modern and archaeological populations, and in relation to cross-cultural variation in sex-biased parental investment.     

Making a living in the tropical forest: Yuquí foragers in the Bolivian Amazon

Questions concerning the availability of resources in tropical rain forests have given rise to the current debate centering on whether human subsistence based solely on foraging is possible in these biomes without agricultural subsidies. This paper takes the position that changing perspectives on ecological pattern and process in tropical forests and the significant variation among tropical forests on a worldwide as well as regional scale must be taken into consideration. Human disturbance is also proposed as a cause of dependence on agriculture by modern human foragers rather than as a necessary precondition for successful exploitation of the tropical forest. These issues are discussed against the background of a case study of the Yuquí, who, until very recently, were true foragers in the Bolivian Amazon. For the Yuquí, the sustainability of their subsistence system depended on a finegrained knowledge of their environment and the freedom of movement over a large territory to access resources within it.     

Stature and robusticity during the agricultural transition: Evidence from the bioarchaeological record

The population explosion that followed the Neolithic revolution was initially explained by improved health experiences for agriculturalists. However, empirical studies of societies shifting subsistence from foraging to primary food production have found evidence for deteriorating health from an increase in infectious and dental disease and a rise in nutritional deficiencies. In Paleopathology at the Origins of Agriculture (Cohen and Armelagos, 1984), this trend towards declining health was observed for 19 of 21 societies undergoing the agricultural transformation. The counterintuitive increase in nutritional diseases resulted from seasonal hunger, reliance on single crops deficient in essential nutrients, crop blights, social inequalities, and trade. In this study, we examined the evidence of stature reduction in studies since 1984 to evaluate if the trend towards decreased health after agricultural transitions remains. The trend towards a decrease in adult height and a general reduction of overall health during times of subsistence change remains valid, with the majority of studies finding stature to decline as the reliance on agriculture increased. The impact of agriculture, accompanied by increasing population density and a rise in infectious disease, was observed to decrease stature in populations from across the entire globe and regardless of the temporal period during which agriculture was adopted, including Europe, Africa, the Middle East, Asia, South America, and North America.     

Development policy,forests, and peasant farms: Reflections on Huastec-managed forests’ contributions to commercial production and resource conservation

The Huastec Indians of northeastern Mexico manage their forests in an indigenous system that integrates commercial and subsistence production. Elements of primary and secondary forest coexist with introduced species in this diverse silvicultural structure which complements the swidden and permanent agriculture fields of the Huastec farmstead. The forest’s direct production of the food, timber, and fuel resources discussed here buffers the Huastec peasant family against market fluctuations and the failed harvest of a single crop. The Huastec system of forest management offers an alternative pattern to the agroforestry and plantation schemes now being suggested for development in the tropics. It is an alternative that provides protection for wild genetic resources while it contributes to the combination of commercial and subsistence agriculture so important for the successful modernization of peasant agriculture. The documentation of this system demonstrates that ethnobotanists and economic botanists have an important but unrealized role to play in the protection of biotic resources and in the development of sustained yield agroecosystems for peasants. The contributions of ethnobotanists are particularly valuable because they can find where and why useful wild species persist in agroecosystems. A greater effort to direct the attentions of policy makers to the value of ethnobotanical knowledge is needed.     

Increases in crop pests caused by Wasmannia auropunctata in Solomon Islands subsistence gardens

The impacts of Wasmannia auropunctata (the little fire ant) on the native biota and subsistence agriculture in the Solomon Islands are poorly understood. This species was originally introduced as a biological control against nut‐fall bugs (Amblypelta sp.) around 30 years ago and in the intervening time has spread throughout the Solomon Islands, aided movement of produce and planting material. It is now itself a major pest of coconut, cocoa and subsistence agriculture. In this study, we show the negative effects of this invasive ant on subsistence agriculture in the Solomon Islands. We do this by (i) assessing the presence of insect pests that develop a mutual relationship with W. auropunctata on four common subsistence crops; and (ii) measuring the impact of a significant pest (Tarophagus sp.) and its natural predator the bug Cyrtohinus fulvus, in the presence and absence of W. auropunctata on taro crops. The existence of insect pests that form a mutual relationship with W. auropunctata was measured in a total of 36 gardens of the four subsistence crops. This was conducted through standardized visual searches, plus identification and collecting from randomly selected plants within the gardens. A number of additional insect pests causing major problems to subsistence crops have also developed mutual relationships with W. auropunctata. Infested taro gardens have more Tarophagus sp. compared with taro plants that are free of the little fire ant. The presence and abundance of Wasmannia therefore has the potential to inflict considerable crop loss in rural subsistence gardens in the Solomon Islands.     

The Relative Decline in Women's Contribution to Agriculture with Intensification

This paper suggests why the intensification of agriculture is associated with a relative decline in women's participation in agriculture. The statistical evidence described here is consistent with the theory that women contribute relatively less to agriculture when it becomes intensive because their domestic work and fertility have increased. It is also argued that most men may be able to contribute more to agriculture in societies cultivating intensively because hunting, warfare, and trade are not so likely to pull them away from crop production [women's contribution to subsistence, agricultural intensification, time allocation, fertility, cross-cultural]     

A craniometric perspective on the transition to agriculture in Europe

Debates surrounding the nature of the Neolithic demographic transition in Europe have historically centered on two opposing models: a "demic" diffusion model whereby incoming farmers from the Near East and Anatolia effectively replaced or completely assimilated indigenous Mesolithic foraging communities, and an "indigenist" model resting on the assumption that ideas relating to agriculture and animal domestication diffused from the Near East but with little or no gene flow. The extreme versions of these dichotomous models were heavily contested primarily on the basis of archeological and modern genetic data. However, in recent years a growing acceptance has arisen of the likelihood that both processes were ongoing throughout the Neolithic transition and that a more complex, regional approach is required to fully understand the change from a foraging to a primarily agricultural mode of subsistence in Europe. Craniometric data were particularly useful for testing these more complex scenarios, as they can reliably be employed as a proxy for the genetic relationships among Mesolithic and Neolithic populations. In contrast, modern genetic data assume that modern European populations accurately reflect the genetic structure of Europe at the time of the Neolithic transition, while ancient DNA data are still not geographically or temporally detailed enough to test continent-wide processes. Here, with particular emphasis on the role of craniometric analyses, we review the current state of knowledge regarding the cultural and biological nature of the Neolithic transition in Europe.     

新石器时代关中地区人类生业模式演变的生物考古学证据

农业的起源与发展,改变了人类食物资源的获取方式。作为史前文化发展的中心,关中地区史前人类生业模式演变规律与影响因素的探索,将为北方地区农业的起源、发展与传播,文化交流对农业发展的影响,人类对环境变迁的适应等热点问题研究提供重要依据。本文对关中地区史前不同文化、不同遗址人与动物骨骼的稳定同位素以及动植物遗存进行了综合分析。结果显示,受文化的发展与交流、区域地理环境的差异、气候的演变等因素影响,关中地区史前先民生业模式呈现时空差异。老官台文化先民的生业模式中旱作农业与狩猎采集并重。仰韶文化早期,旱作农业成为先民生业模式的主体,但不同区域发展水平不同;另外,家畜饲养的发展速度要滞后于农作物。仰韶文化中、晚期至龙山文化早期,水稻与小麦先后传入,形成以粟、黍旱作农业为主,兼营水稻、大豆等的多元化农业结构;水稻对仰韶文化中期先民的食谱产生影响,而同时期家畜饲养主要依赖于粟黍类农作物。龙山文化,黍、粟农业比重下降,水稻含量相对增加,并对先民与家畜的食谱产生影响;肉食获取方式以饲养活动为主,渔猎活动为辅。     

农作物遗传多样性农家保护的现状及前景

农作物地方品种的有效保护是农业生物多样性的可持续利用的基础。由于现代农业的集约化生产方式使大量农作物地方品种被少数高产改良品种所取代,造成农作物基因库的严重“基因流失”（genetic erosion)。农家保护是在农业生态系统中进行的动态保护,被保护的生物多亲性可在其生境中继续进化而产生新的遗传变异,在而是农业生物多样性就地保护的重要途径。然而,尽管人们对作物品种资源农家保护的兴趣不断增长,也有大量有关农家的保护的研究和案例分析,但目前为止还没有比较成功的农家保护实例报道。因此,对农家保护的机制及科学问题进行深入的研究,并寻求一条新的途径来充分发挥农家保护应有的作用,显得格外重要。利用生物多样性布局的水稻混合间栽的生产模式,不仅解决了病害控制的问题,而且也保护了水稻地方品种的多样性。这种混合间栽的生物多样性布局和生产方式可能成为农保护的一条新途径。     

Sexual Division of Labor in African Agriculture: A Network Autocorrelation Analysis

A model of causes and consequences of sexual division of labor in agriculture is tested using a sample of African societies. Crop type and the presence or absence of slavery are shown to be effective predictors of the degree of female contribution to agricultural subsistence, and the degree of polygyny is shown to be affected by female agricultural contribution and the form of residence. Autocorrelation effects are found and are shown to be a consequence of Bantu societies having higher female participation in agriculture than would otherwise be expected. This effect is an example of one of the kinds of phenomena that anthropologists have referred to as Galton's problem . [sexual division of labor, cultural ecology, Galton's Problem, Africa]     

Novel genes for disease-resistance breeding

Plant disease control is entering an exciting period during which transgenic plants showing improved resistance to pathogenic viruses, bacteria, fungi and insects are being developed. This review summarizes the first successful attempts to engineer fungal resistance in crops, and highlights two promising approaches. Biotechnology provides the promise of new integrated disease management strategies that combine modern fungicides and transgenic crops to provide effective disease control for modern agriculture.     

Landraces of maize in Central Mexico: an altitudinal transect

Conservation of crop genetic resources is now considered an important component of sustainable agricultural development. If conservation of genetic resources for agriculture is to be successful, a more complete understanding of the dynamics affecting traditional (landrace) crop populations is needed. We conducted a study of maize-based agriculture in the Central Highlands of Mexico in communities at 2400, 1700, 1400, and 1200 masl to assess the status of traditional varieties in an area characterized by thorough integration into the national economy. Our research contradicts the view that modern varieties persist because of marginal conditions, deficient infrastructure, weaker markets, or traditional attitudes. One or two landraces dominated highland maize populations and farmers appeared to be more conservative in terms of their emphasis on traditional maize varieties than at lower elevations. The dominance of traditional varieties in the highlands is well known but poorly explained, and the coexistence of traditional and modern varieties in the mid-elevations was unexpected. Our highland study area has good roads, is near Mexico City, and is less than 50 km away from four major crop research institutes that have done maize breeding since 1950’s. We suggest that in situ conservation of maize genetic resources in the highlands is sustained because the landraces there have good agronomic performance and are highly valued by farmers for their end-use qualities. At the mid-elevations, competition between local and modern maize was sharpest, and farmers have found that both landraces and improved varieties suit their needs, hence enhancing genetic diversity. Interventions and incentives would appropriately be carried out here to assure in situ conservation of locally adapted landraces of maize.     

The effects of agriculture and the availability of edge habitat on populations of Helmeted Guineafowl Numida meleagris and on the diversity and composition of associated bird assemblages in KwaZulu-Natal province, South Africa

We investigated the effects of agriculture and the availability of edge habitat on populations of Helmeted Guineafowl Numida meleagris and associated avian diversity and species composition in woodland and grassland biomes in the Midlands of KwaZulu-Natal province, South Africa. Study sites within woodland biome had greater species diversity than those in grassland, whereas adjacent, high-quality, protected habitat in grassland sites, enhanced diversity within this biome. Both guineafowl populations and overall avian diversity declined with increasingly intensive agriculture and disappearance of edge habitat and associated, optimally fragmented habitat mosaic. Furthermore, traditional agriculture in the form of contouring in a pesticide-free environment, resulted in extensive edge habitat that appeared to provide additional food and cover for birds. This, in turn, caused an increase in overall bird diversity, and in guineafowl populations in particular. The widespread decline in Helmeted Guineafowl populations in the Midlands that started in the 1980s, and possibly the decline in species associated with this variegated landscape, was therefore caused by the loss of the habitat mosaic to intensive, modern, monoculture, crop agriculture. Maintaining species diversity and healthy guineafowl populations within these habitats requires the persistence or re-creation of a habitat mosaic and the resulting edge habitat on a landscape scale.