Browsing by Autor "Ruth Dickau"

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Differentiation of neotropical ecosystems by modern soil phytolith assemblages and its implications for palaeoenvironmental and archaeological reconstructions
(Elsevier BV, 2013) Ruth Dickau; Bronwen S. Whitney; José Iriarte; Francis E. Mayle; José D. Soto; Phil Metcalfe; F. Alayne Street‐Perrott; Neil J. Loader; Katherine J. Ficken; Timothy J. Killeen
Pre-Columbian landscape impact and agriculture in the Monumental Mound region of the<i>Llanos de Moxos</i>, lowland Bolivia
(Cambridge University Press, 2013) Bronwen S. Whitney; Ruth Dickau; Francis E. Mayle; José D. Soto; José Iriarte
We present a multiproxy study of land use by a pre-Columbian earth mounds culture in the Bolivian Amazon. The Monumental Mounds Region (MMR) is an archaeological sub-region characterized by hundreds of pre-Columbian habitation mounds associated with a complex network of canals and causeways, and situated in the forest–savanna mosaic of the Llanos de Moxos . Pollen, phytolith, and charcoal analyses were performed on a sediment core from a large lake (14 km 2 ), Laguna San José (14°56.97′S, 64°29.70′W). We found evidence of high levels of anthropogenic burning from AD 400 to AD 1280, corroborating dated occupation layers in two nearby excavated habitation mounds. The charcoal decline pre-dates the arrival of Europeans by at least 100 yr, and challenges the notion that the mounds culture declined because of European colonization. We show that the surrounding savanna soils were sufficiently fertile to support crops, and the presence of maize throughout the record shows that the area was continuously cultivated despite land-use change at the end of the earth mounds culture. We suggest that burning was largely confined to the savannas, rather than forests, and that pre-Columbian deforestation was localized to the vicinity of individual habitation mounds, whereas the inter-mound areas remained largely forested.
Pre-Columbian raised-field agriculture and land use in the Bolivian Amazon
(SAGE Publishing, 2014) Bronwen S. Whitney; Ruth Dickau; Francis E. Mayle; John H. Walker; José D. Soto; José Iriarte
We present an integrated palaeoecological and archaeobotanical study of pre-Columbian raised-field agriculture in the Llanos de Moxos, a vast seasonally inundated forest–savanna mosaic in the Bolivian Amazon. Phytoliths from excavated raised-field soil units, together with pollen and charcoal in sediment cores from two oxbow lakes, were analysed to provide a history of land use and agriculture at the El Cerro raised-field site. The construction of raised fields involved the removal of savanna trees, and gallery forest was cleared from the area by ad 310. Despite the low fertility of Llanos de Moxos soils, we determined that pre-Columbian raised-field agriculture sufficiently improved soil conditions for maize cultivation. Fire was used as a common management practice until ad 1300, at which point, the land-use strategy shifted towards less frequent burning of savannas and raised fields. Alongside a reduction in the use of fire, sweet potato cultivation and the exploitation of Inga fruits formed part of a mixed resource strategy from ad 1300 to 1450. The pre-Columbian impact on the landscape began to lessen around ad 1450, as shown by an increase in savanna trees and gallery forest. Although agriculture at the site began to decline prior to European arrival, the abandonment of raised fields was protracted, with evidence of sweet potato cultivation occurring as late as ad 1800.
RECONSTRUCTING PRE-COLOMBIAN AGRICULTURAL PRACTICES IN THE BOLIVIAN SAVANNAH: STRATIGRAPHIC AND PHYTOLITH EVIDENCE FROM RAISED FIELDS AT CAMPO ESPAÑA, WESTERN LLANOS DE MOXOS
(Federal University of Pelotas, 2016) Ruth Dickau; José Iriarte; Timothy A. Quine; Daniel P. Soto; Francis Mayle
Abstract: Pre-Columbian inhabitants of the western Llanos de Moxos, Bolivia, transformed large expanses of seasonally flooded savannah into a complex agricultural landscape. Extensive raised field systems, along with associated canals and causeways, suggest a sophisticated approach to managing land and water resources for permanent, intensive, agricultural production. However, the detailed construction history, specific crops, and palaeoenvironmental impacts of these fields are poorly known. To investigate these issues, we analyzed stratigraphy and phytoliths from two raised fields (camellones) at the site of Campo España, western Beni, Bolivia. Results indicate that prior to field construction, vegetation was mainly palm savannah. A decline in arboreal phytolith frequencies is associated with human clearing and initial field construction. A peak in burnt grass phytoliths followed by an increase of Asteraceae, suggests a period of regular field maintenance and intensive agricultural use. Maize (Zea mays) and manioc (Manihot esculenta) were grown. A small increase in arboreal phytoliths suggests some forest recovery after field abandonment. This study demonstrates the utility of phytolith and stratigraphic analyses in reconstructing construction, cultivation, and palaeoenvironmental histories of raised field systems, and assessing their role within the advanced agricultural landscape management practiced by pre-Columbian populations in the Bolivian Amazon. Resumo: Os habitantes pré-colombianos de Llanos de Moxos ocidental, Bolívia, transformaram grandes áreas de uma savana sazonalmente inundada em complexas paisagens agrícolas. Extensos campos de plantação, assim como canais e caminhos associados, sugerem uma abordagem sofisticada para o manejo da terra e dos recursos aquáticos para produção agrícola intensiva e permanente. No entanto, detalhes sobre suas histórias construtivas, plantações específicas e os impactos paleoambientais destes campos são pouco conhecidos. Para investigar estas questões, analisamos a estratigrafia e os fitólitos de dois destes campos elevados (camellones) do sítio Campo España, oeste de Beni, Bolívia. Os resultados indicam que antes da construção dos campos, a vegetação era majoritariamente uma savana com palmeiras. O declínio na frequência de fitólitos arbóreos é associado com uma limpeza da área pela ação humana e o início das construções dos campos. Um pico nos fitólitos de grama queimada seguido porum aumento de Asteraceae, sugere um período de manutenção regular dos campos e uso agrícola intensivo. Eram cultivados milho (Zea mays) e possivelmente mandioca (Manihot esculenta). Um pequeno aumento dos fitólitos arbóreos sugere certo grau de recuperação da floresta após o abandono dos campos. Este estudo demonstra a utilidade de análises de fitólitos e estratigráficas na reconstrução dos processos de construção, cultivo e história paleoambiental dos sistemas de campos elevados e na avaliação de seus papeis dentro do avançado manejo de paisagens agrícolas praticadas por populações pré-colombianas na Amazônia boliviana.