Linking subsistence harvest diversity and productivity to adaptive capacity in an Alaskan food sharing network.

BACKGROUND: Although anthropogenic climate change poses existential challenges for Indigenous communities in the Arctic, these challenges are not entirely unprecedented. Over many generations, Arctic peoples have developed a wide range of behavioral strategies to navigate environmental change and uncertainty, and these strategies provide a foundation for contemporary adaptation. AIMS: In this article, we focus on mixed cash-subsistence economies and the social networks that underlie them in Alaska. The patterns of food production, labor exchange, and food sharing in subsistence-oriented communities throughout Alaska are driven by the productivity of keystone households who regularly harvest and share resources within and between communities. MATERIALS & METHODS: Building on previous research suggesting the critical importance of these networks to community resilience, we use network analysis to investigate whether patterns in resource transfers between households are associated with subsistence harvest diversity-the diversity of species harvested by a household unit. We use exponential random graph models to describe the structure of a sharing network from Aniak, Alaska, and model the links between harvest productivity, harvest diversity, and household position in this network. RESULTS: Our results indicate that both productivity and diversity are positively associated with network connections, and that productivity alone provides an incomplete model of network structure. DISCUSSION: We suggest that subsistence harvest diversity may play a unique role in supporting adaptive capacity and resilience by maintaining the productivity of keystone households despite changing environments and sustaining social network structures that circulate resources throughout the community. Harvest diversity may also serve as a broad indicator of Indigenous ecological knowledge and a tangible representation of cultural practices, values, and worldviews that underlie subsistence in Alaska. CONCLUSION: Greater attention to harvest diversity is important for understanding how subsistence networks adapt to environmental change and uncertainty linked to social and ecological dynamics of anthropogenic climate change.

Indirect Reciprocity, Resource Sharing, and Environmental Risk: Evidence from Field Experiments in Siberia.

Integrating information from existing research, qualitative ethnographic interviews, and participant observation, we designed a field experiment that introduces idiosyncratic environmental risk and a voluntary sharing decision into a standard public goods game. Conducted with subsistence resource users in rural villages on the Kamchatka Peninsula in Northeast Siberia, we find evidence consistent with a model of indirect reciprocity and local social norms of helping the needy. When participants are allowed to develop reputations in the experiments, as is the case in most small-scale societies, we find that sharing is increasingly directed toward individuals experiencing hardship, good reputations increase aid, and the pooling of resources through voluntary sharing becomes more effective. We also find high levels of voluntary sharing without a strong commitment device; however, this form of cooperation does not increase contributions to the public good. Our results are consistent with previous experiments and theoretical models, suggesting strategic risks tied to rewards, punishments, and reputations are important. However, unlike studies that focus solely on strategic risks, we find the effects of rewards, punishments, and reputations are altered by the presence of environmental factors. Unexpected changes in resource abundance increase interdependence and may alter the costs and benefits of cooperation, relative to defection. We suggest environmental factors that increase interdependence are critically important to consider when developing and testing theories of cooperation.

Skills, division of labour and economies of scale among Amazonian hunters and South Indian honey collectors.

In foraging and other productive activities, individuals make choices regarding whether and with whom to cooperate, and in what capacities. The size and composition of cooperative groups can be understood as a self-organized outcome of these choices, which are made under local ecological and social constraints. This article describes a theoretical framework for explaining the size and composition of foraging groups based on three principles: (i) the sexual division of labour; (ii) the intergenerational division of labour; and (iii) economies of scale in production. We test predictions from the theory with data from two field contexts: Tsimane' game hunters of lowland Bolivia, and Jenu Kuruba honey collectors of South India. In each case, we estimate the impacts of group size and individual group members' effort on group success. We characterize differences in the skill requirements of different foraging activities and show that individuals participate more frequently in activities in which they are more efficient. We evaluate returns to scale across different resource types and observe higher returns at larger group sizes in foraging activities (such as hunting large game) that benefit from coordinated and complementary roles. These results inform us that the foraging group size and composition are guided by the motivated choice of individuals on the basis of relative efficiency, benefits of cooperation, opportunity costs and other social considerations.

Estimating the absolute wealth of households.

OBJECTIVE: To estimate the absolute wealth of households using data from demographic and health surveys. METHODS: We developed a new metric, the absolute wealth estimate, based on the rank of each surveyed household according to its material assets and the assumed shape of the distribution of wealth among surveyed households. Using data from 156 demographic and health surveys in 66 countries, we calculated absolute wealth estimates for households. We validated the method by comparing the proportion of households defined as poor using our estimates with published World Bank poverty headcounts. We also compared the accuracy of absolute versus relative wealth estimates for the prediction of anthropometric measures. FINDINGS: The median absolute wealth estimates of 1,403,186 households were 2056 international dollars per capita (interquartile range: 723-6103). The proportion of poor households based on absolute wealth estimates were strongly correlated with World Bank estimates of populations living on less than 2.00 United States dollars per capita per day (R(2) = 0.84). Absolute wealth estimates were better predictors of anthropometric measures than relative wealth indexes. CONCLUSION: Absolute wealth estimates provide new opportunities for comparative research to assess the effects of economic resources on health and human capital, as well as the long-term health consequences of economic change and inequality.

What is a group? Conceptual clarity can help integrate evolutionary and social scientific research on cooperation.

Smaldino argues that evolutionary theories of social behavior do not adequately explain the emergence of group-level traits, including differentiation of roles and organized interactions among individuals. We find Smaldino's account to be commendable but incomplete. Our commentary focuses on a simple question that has not been adequately addressed: What is a group?