The life history of human foraging: Cross-cultural and individual variation.

Human adaptation depends on the integration of slow life history, complex production skills, and extensive sociality. Refining and testing models of the evolution of human life history and cultural learning benefit from increasingly accurate measurement of knowledge, skills, and rates of production with age. We pursue this goal by inferring hunters' increases and declines of skill from approximately 23,000 hunting records generated by more than 1800 individuals at 40 locations. The data reveal an average age of peak productivity between 30 and 35 years of age, although high skill is maintained throughout much of adulthood. In addition, there is substantial variation both among individuals and sites. Within study sites, variation among individuals depends more on heterogeneity in rates of decline than in rates of increase. This analysis sharpens questions about the coevolution of human life history and cultural adaptation.

Challenges to conservation: land use change and local participation in the Al Reem Biosphere Reserve, West Qatar.

One response to humanity's unsustainable use of natural resources and consequent degradation, even destruction of the environment, is to establish conservation areas to protect Nature and preserve biodiversity at least in selected regions. In Qatar, the government has shown strong support for this approach, confronted by the environmental consequences of oil and gas extraction and rapid urban development, by designating about one-tenth of the country a conservation area. Located in the west of the peninsula, it comprises the Al Reem Reserve, subsequently declared a UNESCO Biosphere Reserve. Several approaches have figured in conservation, currently popular is co-management featuring participation of the local population, which recognises that people's activities often contribute to today's environment, with the promotion of bio-cultural diversity. However, these assumptions may not hold where rapid social and cultural change occurs, as in Qatar. We explore the implications of such change, notably in land use. We detail changes resulting with the move from nomadic to sedentary lifestyles: in land access, which now features tribal-state control, and herding strategies, which now feature migrant labour and depend on imported fodder and water, underwritten by the country's large gas and oil revenues. Current stocking arrangements - animals herded in much smaller areas than previously - are thought responsible for the degradation of natural resources. The place of animals, notably camels, in Qatari life, has also changed greatly, possibly further promoting overstocking. Many local people disagree. What are the implications of such changes for the participatory co-management of conservation areas? Do they imply turning the clock back to centrally managed approaches that seek to control access and local activities?

After the 'affluent society': cost of living in the Papua New Guinea highlands according to time and energy expenditure-income.

What is the cost of living in the Papua New Guinea highlands? An answer is sought using a time and energy accounting approach. The subsistence regime of Wola-speaking highlanders, the subjects of this investigation, comprises three components. The principal one is horticulture: people clearing gardens from forest and grassland, with tuberous crops predominating, notably sweet potato. The second component comprises animal rearing, notably of domestic pigs. The third, and least important, is hunting and gathering for food in the forest. The calculated returns on investments in these subsistence domains vary considerably. Gardens return in their crops between ten and fifteen times the energy expended in cultivation. Pigs may also give a good return, of four to five times the energy invested in rearing them, if slaughtered when adult, but people regularly keep animals for years and may incur negative energy returns on their labour investments. This relates to the high cultural premium put on pigs. Foraging for food is also energetically costly, the Wola expending four times more energy on these activities than they gain in return from the food they secure. This analysis of energy gains and losses challenges the relative notion of affluence as applied to foragers, by reviewing it in the comparative context of subsistence horticulture.