Tuesday, 12 July 2016

A multidisciplinary view of pre-Columbian Amazonia

In June 2016 a multidisciplinary group of researchers working in Amazonia got together in Barcelona to discuss to what extent and in what way pre-Columbian populations changed the landscape of ancient Amazonia.  The meeting was funded by the INQUA Commission for Humans and the Biosphere and SIMULPASTHere you can find the talks that were given on the 8th of June. Unfortunately, the first talk, given by Marie-Pierre Ledru, was not recorded due to technical problems.

Marie-Pierre Ledru - Palaeoecologist: Paleoecological changes in the Amazon basin during the Holocene

Abstract:
Amazonia supports the largest rainforest system in the world. However this rainforest-dominant basin is composed of several types of vegetation including savanna, dry forests and mangrove mostly found on the transition zones. We will examine the different responses of the plant assemblages that characterize each of these vegetal communities and, how the global climate and the sea level changes  affected Amazonian landscape and plant diversity throughout the Holocene. Observed differences in tree cover, biomass, elevation, climate all over the territory altered the plant responses in different manners thus increasing the range of environmental responses.We will review and compare pollen records located in each vegetation type that compose the Amazon Basin. Hiatuses in sedimentation are common to all pollen records, although at different time intervals in function of their location. Expression of the environmental responses in northern, eastern, western and coastal Amazonia will be examined and compared to their adjacent biome evolution. Drier climate or drier soil conditions prevailed until the early Holocene although he re-start of lacustrine sedimentation is observed at different time intervals throughout Amazonia. The mid Holocene drought 8 to 5 kyr was prolongated in south and eastern Amazon until 3 kyr. Alternance of wet and dry episodes characterized the last millennia. We will also examine how the predicted increase of sea level and the global warming may affect this extremely moist and warm region in the future.

Umberto Lombardo - Geographer: El paisaje antrópico de la Amazonia Boliviana (In Spanish)

Abstract:
Los Llanos de Moxos, en la Amazonia Boliviana, son un conjunto de sabanas inundables ubicadas en la parte más meridional de la cuenca Amazonia. Esta región se caracteriza por la presencia de numerosas obras de tierra pre-Colombinas, como lomas monumentales, terraplenes, canales de irrigación y drenaje, campos agrícolas elevados (camellones) e islas de monte. Todos estos restos arqueológicos son la expresión de sociedades de cazadores recolectores antes y agrícolas después, que vivieron allí antes de la llegada de los españoles, desde hace 10000 años. A lo largo de estos 10.000 años, estás sociedades pre-Colombinas han sido afectadas por cambios medioambientales, y al mismo tiempo, han afectado el medio ambiente de manera permanente, tanto que el increíble paisaje de los Llanos de Moxos es el resultado de las complejas interacciones entre gente, ríos y clima. En mi charla exploraré estas dinámicas y interacciones entre pre-Colombinos y medioambiente en distintos lugares de la Amazonia Boliviana, intentando mostrar como la variabilidad espacial de las obras pre-Colombinas se corresponde con cambios en las características del paisaje y en las propiedades del los suelos.


Eduardo Góes Neves - Archaeologist: En búsqueda del año 6K en la Amazonia Antigua: Evidencias Tempranas de Cambios Paisajísticos (In Spanish)

Abstract:

Investigaciones arqueológicas recientes en la cuenca amazónica enseñan que esta región estuvo densamente ocupada en el pasado precolombino y que las poblaciones que allá vivían hicieran cambios en las condiciones ecológicas de la región. Si correcta, tal hipótesis sugiere que lejos de prístinos, los ambientes amazónicos tienen una larga historia de manejo hecho por los pueblos indígenas. Aunque tales formas de cambio sean visibles en los hallazgos arqueológicos relacionados a ocupaciones de pasado relativamente reciente, al rededor de 2 mil años BP, poco sabemos sobre ocupaciones mas antiguas fechadas al rededor de 6 mil años BP, o 6K. De hecho, por razones que todavía no son claras, en la arqueología amazónica asimismo como de otras partes de las tierras bajas de Sudamérica, parece más fácil encontrarse evidencias de ocupación humanas fechadas de la transición Pleistoceno-Holoceno, al rededor de 12-10 K BP, que del Holoceno medio, alrededor de 6K. Esta charla presentará los resultados preliminares de un proyecto de investigaciones el SW de la Amazonía, donde contextos fechados al rededor del año 6K han sido identificados. Los resultados preliminares nos permiten identificar algunas formas tempranas de manejo en la Amazonía e proponer hipótesis más amplias sobre la relación de largo plazo entre cambios climáticos y dinámicas culturales en la Amazonia antigua.




Charles R. Clement - Biologist: Plant domestication and dispersal in Amazonia (In English)


Abstract:

Throughout history, humans have developed uses for some 5000 native Amazonian plant species, and at least 85 of them have also been selected and propagated, which is the beginning of domestication. Domestication is a process in which humans select and propagate plant populations with traits that are useful to them; the interaction between human agency and natural selection results in anthropogenic plant populations embedded in landscapes that are increasingly useful to humans. In these populations, domestication can create subtle or dramatic changes in morphology, biochemistry and genetics. Likewise, landscape domestication may be subtle or dramatic, from modest changes in forest species composition to complete transformation of the landscape in swiddens and settlements. In recent years, studies combining molecular genetics and biogeography have allowed the identification of centers of domestication and routes of dispersal of some important Amazonian domesticates. Manioc (Manihot esculenta) was domesticated in southwestern Amazonia and selected for minimum toxicity; this ‘sweet’ manioc was widely dispersed quite early, arriving in Pacific coastal Peru by 8000 BP. ‘Bitter’ manioc appears to have been selected later in swiddens and was important in central and northern Amazonia. Cacao (Theobroma cacao) was semi-domesticated by 5000 BP in Amazonian Ecuador for the sweet pulp around the seeds and was dispersed both to Mesoamerica (where chocolate was invented) and to eastern Amazonia, which went unnoticed until recently because there was no chocolate there! Peach palm (Bactris gasipaes) was also domesticated in southwestern Amazonia and dispersed both northwestward to Central America, becoming a major starch crop used for fermented drinks, and northeastward to central and eastern Amazonia, where it was used as a snack. Guaraná (Paullinia cupana) is a stimulant and the only crop known to be domesticated in central Amazonia; it is a high level polyploid with very little genetic diversity, suggesting a very recent domestication (1000 BP). Brazil nut (Bertholletia excelsa) was used by 11,200 BP, and is incipiently domesticated and widely dispersed across central and eastern Amazonia in forest stands associated with archaeological sites. Its center of domestication is not yet confirmed, with southwestern and northeastern Amazonia being considered. Future integration with archaeology, especially archaeobotany, and palaeoecology will increase the relevance of these studies to understand the history of Amazonian crops, people and landscapes.




Manuel Arroyo-Kalin - Archaeologist: Los Suelos Antrópicos de la Amazonía: algo más que tierra negra… (In English)




Stéphen Rostain - Archaeologist: Amazonía, el dinamismo de un paisaje tropical único (In Spanish)


Abstract:

Se admite hoy en día que los paisajes en los cuales vivimos son resultado tanto de antiguas actividades humanas como de procesos naturales. Los ecosistemas amazónicos, al igual que otras tierras antiguamente ocupadas por el hombre, han evolucionado en función de las acciones de este. Así, solo la asociación de las ciencias de la Vida y de la Tierra permite una evaluación de las contribuciones respectivas del  hombre y de la naturaleza en la construcción del paisaje ecuatorial. Es el caso de un proyecto llevado a cabo en las sabanas costeras de las Guyanas, el mismo que contó con la colaboración de arqueólogos, arqueobotánicos, ecólogos, pedólogos, etc. Si bien la arqueología alimenta a las ciencias de la naturaleza con temas de estudio cruzados, para la lectura del pasado se  nutre también  de  otras  ciencias que  le proporcionan nuevos métodos complementarios de los clásicos y la ayudan a reconstruir de manera mucho más completa el contexto medio ambiental en el cual la cultura antigua se hallaba inserta. Es entonces, una nueva historia del paisaje la que se dibuja poco a poco. 



Maximilien Guèze - Ethnobotanist: Shifts in indigenous culture relate to forest tree diversity: A case study from the Tsimane’, Bolivian Amazon (In Spanish)


Abstract:

Understanding how indigenous peoples’ management practices relate to biological diversity requires addressing contemporary changes in indigenous peoples’ way of life. This study explores the association between cultural change among a Bolivian Amazonian indigenous group, the Tsimane’, and tree diversity in forests surrounding their villages. We interviewed 86 informants in six villages about their level of attachment to traditional Tsimane’ values, our proxy for cultural change. We estimated tree diversity (Fisher’s Alpha index) by inventorying trees in 48 0.1-ha plots in old-growth forests distributed in the territory of the same villages. We used multivariate models to assess the relation between cultural change and alpha tree diversity. Cultural change was associated with alpha tree diversity and the relation showed an inverted U-shape, thus suggesting that tree alpha diversity peaked in villages undergoing intermediate cultural change. Although the results do not allow for testing the direction of the relation, we propose that cultural change relates to tree diversity through the changes in practices and behaviors that affect the traditional ecological knowledge of Tsimane’ communities; further research is needed to determine the causality. Our results also find support in the intermediate disturbance hypothesis, and suggest that indigenous management can be seen as an intermediate form of anthropogenic disturbance affecting forest communities in a subtle, non-destructive way.




Evert Thomas - Biologist: Spatial patterns in the natural and human history of Brazil nut across the Amazon Basin: megarodents, glacial refugia, terra preta and geoglyphs (In Spanish)




Amy Goldberg - Mathematician and Anthropologist: Post-invasion human demography in prehistoric South America: a continental view (In English)


Abstract:

As the last habitable continent colonized by humans, the site of multiple domestication hotspots, and the location of the largest Pleistocene megafaunal extinction, South America is central to human prehistory. Yet remarkably little is known about human population dynamics during colonization, subsequent expansions, and domestication. Here we reconstruct the continental-scale spatiotemporal patterns of human population growth in South America using a database of 1,147 archaeological sites and 5,464 calibrated radiocarbon dates spanning fourteen thousand to two thousand years ago (ka). Notably, our database demonstrates substantial regional variation in coverage, suggesting further work for Northeastern South America and Amazonia.
We demonstrate that early human expansions showed the same pattern characteristic of invading animal populations, with resource-limited growth. Only with widespread sedentism, beginning ~5 ka, did a second demographic phase begin, with evidence for exponential population growth in cultural hotspots, characteristic of the shift to agriculture worldwide.



Carla Jaimes Betancourt - Archaeologist: La dinámica cultural al suroeste de la Amazonia a la luz del registro arqueológico (In Spanish)


Abstract:

La arqueología amazónica enfrenta grandes cuestionamientos paradigmáticos. Al mismo tiempo que aumentan las evidencias de monumentalidad y manejo de recursos naturales, se devela una enorme diversidad de contextos culturales y patrones de transformación del paisaje. Aunque los procesos históricos y sociales de cómo se generaron estas manifestaciones en el paisaje cultural amazónico se encuentran todavía en discusión, la mayoría de estas transformaciones son atribuidas por lo general a la dispersión de la familia lingüística Arawak. En esta ponencia, se coteja el registro arqueológico de dos áreas culturalmente distintas de los Llanos de Mojos, con algunos de los modelos planteados que intentan explicar el proceso de “arawakización” en la Amazonía. Comprobándose que en Mojos y de manera coetánea, se desarrollaron diferentes procesos culturales locales, en escenarios multiétnicos y posiblemente plurilingües, que desembocaron en la creación de sociedades con características inalienables a las supuestas influencias Arawak. Dejando al descubierto, que únicamente mediante el estudio de los desarrollos culturales locales durante el holoceno medio, podremos entender el surgimiento de estos complejos procesos ocupacionales.



Philip Riris - Archaeologist: Dates and Dispersions: examining the spatio-temporal boundaries of the Guaraní expansion into the La Plata basin with Monte Carlo methods (In English)


Abstract:

he direction and timing of the Guaraní expansion into the La Plata basin from an Amazonian origin is a matter of no small debate in the study of South American indigenous cultures. The short timeframe of the Guaraní expansion (2000 – 500 BP) during the late Holocene, as well as the distances involved, are both used to explain it as the result of the migration of significant numbers of people in a classic “wave of advance”. The process is further broken down into “pulses” punctuated by periods of relative stasis in which colonization through the valleys of major rivers was halted or slowed. These factors, combined with a broad base of empirical data from decades of research, provide the impetus for refining established chronologies of the Guaraní dispersal. 
We use a published database of georeferenced dates to model the its spread at the beginning of the Common Era from a presumed entry point until the time of European contact at its known limits at the La Plata delta and Atlantic coast of Brazil. Using Monte Carlo methods, we examine the dispersal as a function of time and distance in order to constrain the probable start dates for entry into different zones. Additionally, we investigate the notion that Guaraní groups enveloped large sectors of terrain contiguously as the result of demographic pressures that were interspersed, as noted, with hiatuses of comparatively little movement. We place our findings in the context of preceding archaeological, ethnographic, and ethnohistorical knowledge on this uniquely South American process of indigenous dispersal. Suggestions for further work to improve the scenarios we present are offered, following the note by Brochado (1984) that in the study of Guaraní archaeology, “computer modelling is probably the only way to achieve refined estimates of population growth” in the La Plata basin. 




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