Production risk, inter-annual food storage by households and population-level consequences in seasonal prehistoric agrarian societies

Abstract

Using complementary behavioural and population ecological models, we explore the role of production risk, normal surplus and inter-annual food storage in the adaptations of societies dependent on seasonal agriculture. We find that (a) household-level, risk-sensitive adaption to unpredictable environmental variation in annual agricultural yields is a sufficient explanation for the origins of normal agrarian surplus and, consequently, of household-level incentives for inter-annual food storage; and, (b) at the population level, density-dependent Malthusian processes tightly constrain the circumstances under which this same mechanism can be effective in smoothing inter-annual fluctuations in household food availability. Greater environmental variation and higher levels of fixed set-asides such as seed requirements or transfer obligations to political authorities lead to more severe, periodic famines; however, outside of famine events, these same factors improve average population welfare by suppressing population density to levels at which Malthusian constraints have lessened impact. The combination of behavioural and population ecological modelling methods has broad and complementary potential for illustrating the dynamic properties of complex, coupled human-natural systems.

Rain, Sun, Soil, and Sweat: A Consideration of Population Limits on Rapa Nui (Easter Island) before European Contact

“…In practice, population control via fertility control or other coordinated approaches may have been difficult to achieve. Also, environmental stochasticity could have played a role in maintaining populations at levels lower than stable equilibria predict, and achieved some of the benefits of fertility control, including average food availability and life expectancy, at the cost of occasional famines (Winterhalder et al, 2015). However, we have limited ourselves in this study to stable seasonal variation, meaning that seasonality is included, but each year is the same as the next.…”

“…Many of the ecological transitions initiated by human occupation of the island would be well under way at that point, including changes to the soil organic matter pools and deforestation. Winterhalder et al (2015) discuss some of the consequences of a food-limited population's agricultural yield becoming elevated and then returning to a lower level; these consequences include potential famine and social upheaval.…”

“…The demographic model has been used to examine the linkages between early agricultural populations and their food supply (e.g., Lee et al, 2009;Puleston et al, 2014;Winterhalder et al, 2015) and has been applied to Polynesian contexts in particular (Puleston and Tuljapurkar, 2008;Kirch et al, 2012). The model requires input of a potential yield, which we identified earlier, and calculates per capita food availability based on the amount of arable land, labor supply and the size and structure of the population.…”

Resilience of small-scale societies: a view from drylands

“…In the context of small-scale societies and early agricultural systems, the boundary between subsistence storage and surplus storage has been assessed to be the amount of foodstuff needed to cover three consecutive years with scarce harvests (Angourakis et al 2015). Past those limits, storage can no longer be considered as a mere risk-reduction strategy, but rather a wealth-accumulation strategy, as emerging from the study of the evolution of Neolithic food storage in the Near East and in Europe (Kuijt 2015, O'Brien and Bentley 2015, Winterhalder et al 2015. In such contexts, the production of surplus is in most cases directly related to the existence of effective storage structures and capabilities .…”

<em>Longhouses</em>, biografía de la casa y complejidad social en el noroeste peninsular en la alta edad media

“…Y aunque, como en el caso de Gasteiz, existe la posibilidad de que algunos de ellos estuviesen en uso a la vez siguiendo las informaciones proporcionadas por las relaciones estratigráficas, la disposición espacial o los rellenos secundarios o terciarios (p. e. en Zornoztegi la serie de silos alineados ue 4100,4102,4013;en Zaballa ue 3902,3904,3905,3911), este extremo no es siempre fácil de demostrar de forma indiscutible. Es también posible sugerir que los grupos de silos hallados en Gasteiz, interpretados en términos de silos de renta (Azkarate y Solaun 2015: 557), fuesen estructuras destinadas al almacenaje de 'excedente normal' por parte de productores con el fin de reducir el riesgo interanual (Halstead 1989;Wintherhalder et al 2015) y que hayan tenido un ritmo de uso y reemplazo similar al observado en otros yacimientos.…”