DSpace Angular :: Browsing by Author "Gayo, Eugenia M."

Browsing by Author "Gayo, Eugenia M."

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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.
A modeling approach to estimate the historical population size of the Patagonian Kawesqar people
(2022) Estay, Sergio A.; Lopez, Daniela N.; Silva, Carmen P.; Gayo, Eugenia M.; McRostie, Virginia; Lima, Mauricio
The study of human-gatherers societies' demography used to be a difficult task due to the lack of direct evidence to support the estimations. This is the case of several human groups from Pacific Patagonia whose historical population size estimations are controversial. This study estimated the historical population size for the Kawesqar people using direct and indirect evidence. Thus, we collated past estimations from experts and encounter rates distribution in time and space to generate a statistical approximation for population size. We used weights to include the reliability of such past estimations under three modeling scenarios. Our results indicate that the historical population ranged roughly between 3700 and 3900 individuals before the massive contact with Chileans and European people. The approach developed here for combining and integrating different evidence for estimating population in Kawesqar people, emerges as a promising and valuable tool to study the demography of other hunter-gatherer societies in South America.
Acta de Tarapacá: pueblo sin agua, pueblo muerto
(2018) Latorre Hidalgo, Claudio; Marquet Iturriaga, Pablo Angel; McRostie, Virginia; Maldonado, Antonio; Santoro, Calogero M.; Valenzuela, Daniela; Jofré, Daniela; Angelo, Dante; Gayo, Eugenia M.; Hamamé, Eva; Correa, Jacqueline; Barraza, José; Capriles, José M.; Porras, María Eugenia de; Uribe, Mauricio; Castro, Victoria; Standen, Vivien G.
El “Acta de Tarapacá” constituye un llamado de atención sobre la necesidad de cambiar la manera como las sociedades humanas han estado utilizando el agua en el Desierto de Atacama, mediante una perspectiva histórica a lo largo de milenios. El Acta, una iniciativa que resume los resultados del proyecto CONICYT/PIA Anillo SOC1405 “Cambios Sociales y Variabilidad Climática a Largo Plazo en el Desierto de Atacama”, está dirigida a la sociedad civil y a distintas instancias políticas con miras a que se generen cambios tecnológicos y culturales para detener y mitigar los efectos causados por las actividades antrópicas en uno de los desiertos más antiguos y áridos del mundo. En el transcurso del proyecto se constató la necesidad urgente de sensibilizar a la sociedad acerca del desmesurado y mal uso del agua en el Desierto de Atacama; un recurso no renovable con relación a las escalas económicas de extracción ya que depende, fundamentalmente, de aguas fósiles que fueron acumuladas durante milenios en las zonas altas del desierto. De esta manera queremos evitar que este conocimiento científico se encapsule en las universidades y hacer eco de lo señalado por Victoria Castro (2003): Para crecer hay que educar.
Camelids from hunter-gatherer contexts of the Dry Puna in the Atacama Desert (Northern Chile): towards understanding human-animal interactions over time
(2022) Castillo, Camila; Sepulveda, Marcela; Gayo, Eugenia M.; Dufour, Elise; Goepfert, Nicolas; Osorio, Daniela
The Dry Puna in extreme northern Chile lies between the Andean region's two main camelid domestication centers, a location that makes it particularly important to the study of human-animal relationships. This article presents a first synthesis of the archeozoological analysis of fourteen hunter-gatherer sites in the Andean foothills near Arica (Chile), the preliminary results of stable isotope analyses from two locations, and 35 associated radiocarbon dates. Researchers contrasted this data with other regional studies of lithic materials and rock art paintings. In synthesis, the article recognizes changes in consumption throughout Archean up to the Formative Period. It identifies the use of animals from the same area or with the same foraging pattern in the Puna and explores a "conservative" mobility pattern within the highlands. Finally, the changes in human-camelid interactions portrayed in rock art complement the vision drawn from bone fragment analysis, reflecting the importance of integrating different material and visual registers into discussions of these issues.
Camelids in the hyperarid core of the Atacama desert 12,000-11,000 years ago? A stable isotope study and its consequences for early human settlement
(2024) Ugalde, Paula C.; Gayo, Eugenia M.; Labarca, Rafael; Santoro, Calogero M.; Quade, Jay
How did hunter-gatherers initially settle and move across extreme environments? We conducted a multi-disciplinary study to tackle this question, focusing on how Paleoindigenous populations inhabited the hyperarid core of the Atacama Desert. Particularly, we examined the stable isotopic values of similar to 12,000-11,200-year-old camelid and rodent bones and hair samples retrieved from low-elevation archaeological sites (Pampa del Tamarugal basin - PdT, 800-1200 masl). By integrating novel and existing data into a regional stable isotope ecology, we offer a baseline for interpreting our results. delta C-13 and delta N-15 values on archaeological remains show animals with different geographical origins. A first group includes camelids and rodents with lower delta N-15 values and delta C-13 values indicating a dominantly C-3 diet, corresponding to animals either local to the PdT or from the Andean Steppe, at least similar to 80 km away and between 4000 and 4500 masl. Most of these remains, however, come from residential sites and belong to young camelids, indicating a local origin. A second group presents a higher delta N-15 signal and delta C-13 values indicative of a mixed C-3-C-4 based diet. These animals were not local but source to the Puna at least similar to 60 km away between 3200 - 4000 masl. We hypothesize that the first would correspond to animals associated with hunter-gatherer bands settled around a wetland and grove environment in the PdT. The second group could correspond to remains brought by humans from the Puna to the PdT. Our results demonstrate that during the Late Pleistocene/Early Holocene the Atacama was very different than today, supporting life that included large and mid-size game. These results also show that the core of the Atacama attracted animals and people and counters the notion of this ecosystem as a barren passageway from the Andes to the coast.
Dietary diverstiy in the Atacama desert during the Late intermediate period of northern Chile
(2019) Alfonso-Durruty, Marta P.; Gayo, Eugenia M.; Standen, Vivien; Castro, Victoria; Latorre, Claudio; Santoro, Calogero M.; Valenzuela, Daniela
The Pacific Ocean that flanks the hyperarid Atacama Desert of Northern Chile is one of the richest biomass producers around the world. Thus, it is considered a key factor for the subsistence of prehistoric societies (including mixed-economy groups), that inhabited its coastal ecosystems as well as the neighboring inland areas. This study assesses the Arica Culture groups' diet (Late Intermediate Period; 1000-1530 CE), through stable isotope (on bone-collagen; delta C-13 and delta N-15) and dental pathology data. Seventy-seven (n = 77) individuals from two inland (LLU54 and AZ8) and one coastal (CAMS) archaeological sites were studied. Results show an important, but lower than predicted by earlier studies, contribution of marine resources in the diet of all three groups. Dental pathologies and stable isotopes indicate that these groups' diet varied in correlation with their distance to the Pacific Ocean as well as group and individual preferences. The results challenge the idea that Arica Culture groups depended heavily on marine resources for their subsistence. In contrast, this study shows both that the Arica Culture groups' diet was diverse, and that the terrestrial resources consumed were mostly contributed by C-3/CAM plants instead of maize. (C) 2019 Elsevier Ltd. All rights reserved.
FROM THE PACIFIC TO THE TROPICAL FORESTS: NETWORKS OF SOCIAL INTERACTION IN THE ATACAMA DESERT, LATE IN THE PLEISTOCENE
(2019) Santoro, Calogero M.; Gayo, Eugenia M.; Capriles, Jose M.; Rivadeneira, Marcelo M.; Herrera, Katherine A.; Mandakovic, Valentina; Rallo, Monica; Rech, Jason A.; Cases, Barbara; Briones, Luis; Olguin, Laura; Valenzuela, Daniela; Borrero, Luis A.; Ugalde, Paula C.; Roihhanuner, Francisco; Latorre, Claudio; Szpak, Paul
The social groups that initially inhabited the hyper arid core of the Atacama Desert of northern Chile during the late Pleistocene integrated a wide range of local, regional and supra regional goods and ideas for their social reproduction as suggested by the archaeological evidence contained in several open camps in Pampa del Tamarugal (PdT). Local resources for maintaining their every-day life, included stone raw material, wood, plant and animal fibers, game, and fresh water acquired within a radius of similar to 30 km (ca. 1-2 days journey). At a regional scale, some goods were introduced from the Pacific coast (60-80 km to the west, ca. 3-4 days journey), including elongated rounded cobbles used as hammer stones in lithic production, and shells, especially from non-edible species of mollusks. From the Andes (ranging 80-150 km to the east, ca. 5-8 days of journey), they obtained camelid fiber, obsidian and a high-quality chalcedony, in addition to sharing knowledge on projectile point designs (Patapatane and Tuina type forms). Pieces of wood of a tropical forest tree species (Ceiba spp.) from the east Andean lowlands (600 km away, ca. 30 days of journey) were also brought to the PdT. While local goods were procured by the circulation of people within the PdT, the small number of foreign items would have been acquired through some sort of exchange networks that integrated dispersed local communities throughout several ecosystems. These networks may have been a key factor behind the success exhibited by these early huntergatherers in the hyper arid ecosystems of the Atacama Desert at the end of the Pleistocene.
Late Quaternary hydrological and ecological changes in the hyperarid core of the northern Atacama Desert (∼21°S)
(2012) Gayo, Eugenia M.; Latorre, Claudio; Jordan, Teresa E.; Nester, Peter L.; Estay, Sergio A.; Ojeda, Karla F.; Santoro, Calogero M.
The hyperarid core of the Atacama Desert possesses important reserves of "fossil" or ancient groundwater, yet the extent and timing of past hydrologic change during the late Quaternary is largely unknown. In situ and/or short-distance transported leaf-litter deposits abound along relict fluvial terraces inserted within four dry and unvegetated valleys that drain into the endorheic basin of Pampa del Tamarugal (PDT, 21 degrees S, 900-1000 m), one of the largest and economically important aquifers in northern Chile. Our exceptional archive offers the opportunity to evaluate the response of low-elevation desert ecological and hydrological systems to late Quaternary climate variability. Three repeated expansions of riparian/wetland ecosystems, and perennial rivers occurred along the southernmost PDT basin between 17.6-14.2 ka, 12.1-11.4 ka and from 1.01-0.71 ka. Both early and late archaic archaeological artefact are present in clear association with our fossil riparian/wetland assemblages, which suggests that these palaeoenvironmental changes facilitated past human occupations in the hyperarid core of the Atacama Desert. Using modern analogues, we estimate that these ecological and hydrological changes were triggered by a threefold increase in rainfall along the headwaters of what are presently inactive canyons. Comparisons with other regional palaeoclimatic records from the central Andes indicate that these changes were synchronous with the widespread pluvial stages now termed the Central Andean Pluvial Event (CAPE- 17.5-14.2 ka and 13.8-9.7 ka). In addition, we summarize new evidence for perennial runoff, riparian ecosystems and a major human settlement during the latest Holocene. Our findings clearly show that local hydrological changes in the PDT were coupled with precipitation variability in the adjacent eastern highlands during the late Quaternary. The long-term dynamics of low-elevation desert ecological and hydrological systems are likely driven by changes in moisture sources, with one source tied to the Amazon region (N-NE mode) and the other to the Gran Chaco region (SE mode). We conclude by linking ENSO-like variability and moisture variations over the Gran Chaco to the three major regional-scale recharge events over the last 18 ka in the PDT basin. We conclude by asserting that an important portion of the groundwater resources in the PDT is indeed fossil, inherited from past pluvial events. We recommend that the relationship between ancient recharge, together with palaeoclimate records of past headwater rainfall fluctuations should be incorporated into future water-balance models and evaluation of groundwater potential in northern Chile. (C) 2012 Elsevier B.V. All rights reserved.
Population dynamics and cultural niche construction during the Late Holocene in a mediterranean ecosystem (central Chile, 32°S-36°S)
(2024) Godoy-Aguirre, Carolina; Frugone-Alvarez, Matias; Gayo, Eugenia M.; Campbell, Roberto; Lima, Mauricio; Maldonado, Antonio; Latorre, Claudio
Understanding socio-ecological systems over the long term can shed light on past adaptive strategies in environmentally sensitive regions. Central Chile is an emblematic case study for mediterranean ecosystems, where a progressive and sustained population increase began approximately 2000 years ago alongside significant landscape changes. In this work we analyzed regional paleo-demographic trends by compiling a new database of archaeological dates over the last 3000 years, and integrating population dynamics theory with an analysis of the spatio-temporal variation of regional cultural stages. Results show three moments of marked acceleration in population growth: just before agricultural adoption, during the Archaic Period (c. 700-300 BCE); during the second half of the ECP (500-900 CE); and during the Late Intermediate Period (1200-1400 CE). We also identified periods of deceleration in per capita growth rates, although population size continued to increase (300 BCE-500 CE, 900-1200 CE and after 1400 CE). These large shifts in the per capita growth rates coincide with major cultural changes associated with social and economic aspects. The pulses of major occupation show in general terms a more intensive use of the valleys as the population size increased, although the remaining ecosystems never ceased to be occupied with different economic and symbolic emphases.
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'.
The first peoples of the Atacama Desert lived among the trees: A 11,600-to 11,200-year- old grove and congregation site
(2024) Ugalde, Paula C.; Joly, Delphine; Latorre, Claudio; Gayo, Eugenia M.; Labarca, Rafael; Simunovic, Mikhaela; Mcrostie, Virginia; Holliday, Vance T.; Quade, Jay; Santoro, Calogero M.
In deserts, water has been singled out as the most important factor for choosing where to settle, but trees were likely an important part of the landscape for hunter - gatherers beyond merely constituting an economic resource. Yet, this critical aspect has not been considered archaeologically. Here, we present the results of mapping and radiocarbon dating of a truly unique archaeological record. Over 150 preserved stumps around five Late Pleistocene/ Early Holocene archaeological campsites (12,800 to 11,200 cal BP) show that trees were key features in the creation of everyday habitats for the first inhabitants of the Atacama Desert. At two of these sites, QM12 and QM35, the spatial and chronological correlation between trees and hearths reveals that people located their homes under the tree canopy. At residential site QM35, artifact distribution coincides with a grove dated to - 11,600 to 11,200 cal BP. A third residential area (QM32) occurred along the grove margins - 12,000 to 11,200 cal BP. Based on the distinct cultural material of these two camps, we propose that two different groups intermittently shared this rich wetland - grove environment. The tree taxa suggest a preference for the native Schinus molle, a tree scarcely present on the landscape today, over the endemic, nitrogen - fixing Strombocarpa tamarugo , both for toolmaking and firewood and even though the S. tamarugo was locally more abundant. Together with the spatial and chronological coincidence of campsites, hearths, and trees, we propose that people spared the most abundant and resilient species to create their homes, in turn promoting fertility oases amid the Atacama's hyperaridity.
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'.

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