Browsing by Author "Gurruchaga, Andone"

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    1000 years of population, warfare, and climate change in pre-Columbian societies of the Central Andes
    (2023) Lima, Mauricio; Gayo, Eugenia M.; Gurruchaga, Andone; Estay, Sergio A.; Santoro, Calogero M.
    Different Andean societies underwent processes of expansion and collapse during propitious or adverse climate conditions, resource boost or depletion along with population variations. Previous studies have emphasized that demographic collapses of polities in the Central Andes Area were triggered by warfare and the negative impacts of fluctuating climate (droughts) on crop productivity. Nevertheless, the interactions between climatic variability, demography and warfare have been less thoroughly evaluated. We develop population dynamic models to test feedback relationships between population growth, climate change and warfare in the Central Andes, where considerable regional hydroclimate variations have occurred over a millennium. Through population models, we found out that the rise and demise of social polities in the northern coast of the Central Andes appear to be a consequence of climate change. In contrast, for the highlands of Peru and the Titicaca basin, population models suggest that warfare intensity has a negative effect on population growth rates.
  • Thumbnail Image
    Item
    Positive feedbacks in deep-time transitions of human populations
    (2024) Lima, Mauricio; Gayo, Eugenia M.; Estay, Sergio A.; Gurruchaga, Andone; Robinson, Erick; Freeman, Jacob; Latorre, Claudio; Bird, Darcy
    Abrupt and rapid changes in human societies are among the most exciting population phenomena. Human populations tend to show rapid expansions from low to high population density along with increased social complexity in just a few generations. Such demographic transitions appear as a remarkable feature of Homo sapiens population dynamics, most likely fuelled by the ability to accumulate cultural/technological innovations that actively modify their environment. We are especially interested in establishing if the demographic transitions of pre-historic populations show the same dynamic signature of the Industrial Revolution transition (a positive relationship between population growth rates and size). Our results show that population growth patterns across different pre-historic societies were similar to those observed during the Industrial Revolution in developed western societies. These features, which appear to have been operating during most of our recent demographic history from hunter-gatherers to modern industrial societies, imply that the dynamics of cooperation underlay sudden population transitions in human societies.This article is part of the theme issue 'Evolution and sustainability: gathering the strands for an Anthropocene synthesis'.
  • Thumbnail Image
    Item
    Towards understanding human-environment feedback loops: the Atacama Desert case
    (2024) Gayo, Eugenia M.; Lima, Mauricio; Gurruchaga, Andone; Estay, Sergio A.; Santoro, Calogero M.; Latorre, Claudio; Mcrostie, Virginia
    The overall trajectory for the human-environment interaction has been punctuated by demographic boom-and-bust cycles, phases of growth/overshooting as well as of expansion/contraction in productivity. Although this pattern has been explained in terms of an interplay between population growth, social upscaling, ecosystem engineering and climate variability, the evoked demographic-resource-complexity mechanisms have not been empirically tested. By integrating proxy data for population sizes, palaeoclimate and internal societal factors into empirical modelling approaches from the population dynamic theory, we evaluated how endogenous (population sizes, warfare and social upscaling) and exogenous (climate) variables module the dynamic in past agrarian societies. We focused on the inland Atacama Desert, where populations developed agriculture activities by engineering arid and semi-arid landscapes during the last 2000 years. Our modelling approach indicates that these populations experienced a boom-and-bust dynamic over the last millennia, which was coupled to structure feedback between population sizes, hydroclimate, social upscaling, warfare and ecosystem engineering. Thus, the human-environment loop appears closely linked with cooperation, competition, limiting resources and the ability of problem-solving.This article is part of the theme issue 'Evolution and sustainability: gathering the strands for an Anthropocene synthesis'.