Browsing by Autor "Bronwen S. Whitney"

Now showing 1 - 9 of 9

A 45kyr palaeoclimate record from the lowland interior of tropical South America
(Elsevier BV, 2011) Bronwen S. Whitney; Francis E. Mayle; Surangi W. Punyasena; Katharine Anne Fitzpatrick; Michael J. Burn; René Guillén; Ezequiel Chavez; David G. Mann; R. Toby Pennington; Sarah E. Metcalfe
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
Environmental impact of geometric earthwork construction in pre-Columbian Amazonia
(National Academy of Sciences, 2014) John Carson; Bronwen S. Whitney; Francis E. Mayle; José Iriarte; Heiko Prümers; José D. Soto; Jennifer Watling
There is considerable controversy over whether pre-Columbian (pre-A.D. 1492) Amazonia was largely "pristine" and sparsely populated by slash-and-burn agriculturists, or instead a densely populated, domesticated landscape, heavily altered by extensive deforestation and anthropogenic burning. The discovery of hundreds of large geometric earthworks beneath intact rainforest across southern Amazonia challenges its status as a pristine landscape, and has been assumed to indicate extensive pre-Columbian deforestation by large populations. We tested these assumptions using coupled local- and regional-scale paleoecological records to reconstruct land use on an earthwork site in northeast Bolivia within the context of regional, climate-driven biome changes. This approach revealed evidence for an alternative scenario of Amazonian land use, which did not necessitate labor-intensive rainforest clearance for earthwork construction. Instead, we show that the inhabitants exploited a naturally open savanna landscape that they maintained around their settlement despite the climatically driven rainforest expansion that began ∼2,000 y ago across the region. Earthwork construction and agriculture on terra firme landscapes currently occupied by the seasonal rainforests of southern Amazonia may therefore not have necessitated large-scale deforestation using stone tools. This finding implies far less labor--and potentially lower population density--than previously supposed. Our findings demonstrate that current debates over the magnitude and nature of pre-Columbian Amazonian land use, and its impact on global biogeochemical cycling, are potentially flawed because they do not consider this land use in the context of climate-driven forest-savanna biome shifts through the mid-to-late Holocene.
Pre-Columbian land use in the ring-ditch region of the Bolivian Amazon
(SAGE Publishing, 2015) John Carson; Jennifer Watling; Francis E. Mayle; Bronwen S. Whitney; José Iriarte; Heiko Prümers; José D. Soto
The nature and extent of pre-Columbian (pre-AD 1492) human impact in Amazonia is a contentious issue. The Bolivian Amazon has yielded some of the most impressive evidence for large and complex pre-Columbian societies in the Amazon basin, yet there remains relatively little data concerning the land use of these societies over time. Palaeoecology, when integrated with archaeological data, has the potential to fill these gaps in our knowledge. We present a 6000-year record of anthropogenic burning, agriculture and vegetation change, from an oxbow lake located adjacent to a pre-Columbian ring ditch in north-east Bolivia (13°15′44″S, 63°42′37″W). Human occupation around the lake site is inferred from pollen and phytoliths of maize ( Zea mays L.) and macroscopic charcoal evidence of anthropogenic burning. First occupation around the lake was radiocarbon dated to ~2500 calibrated years before present (BP). The persistence of maize in the record from ~1850 BP suggests that it was an important crop grown in the ring-ditch region in pre-Columbian times, and abundant macroscopic charcoal suggests that pre-Columbian land management entailed more extensive burning of the landscape than the slash-and-burn agriculture practised around the site today. The site was occupied continuously until near-modern times, although there is evidence for a decline in agricultural intensity or change in land-use strategy, and possible population decline, from ~600–500 BP. The long and continuous occupation, which predates the establishment of rainforest in the region, suggests that pre-Columbian land use may have had a significant influence on ecosystem development at this site over the last ~2000 years.
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.
Pre‐Columbian ring ditch construction and land use on a ‘chocolate forest island’ in the Bolivian Amazon
(Wiley, 2016) John Carson; Francis E. Mayle; Bronwen S. Whitney; José Iriarte; José D. Soto
ABSTRACT We present a palaeoecological investigation of pre‐Columbian land use in the savanna ‘forest island’ landscape of the north‐east Bolivian Amazon. A 5700‐year sediment core from La Luna Lake, located adjacent to the La Luna forest island site, was analysed for fossil pollen and charcoal. We aimed to determine the palaeoenvironmental context of pre‐Columbian occupation on the site and assess the environmental impact of land use in the forest island region. Evidence for anthropogenic burning and Zea mays L. cultivation began ∼2000 cal a BP, at a time when the island was covered by savanna, under drier‐than‐present climatic conditions. After ∼1240 cal a BP burning declined and afforestation occurred. We show that construction of the ring ditch, which encircles the island, did not involve substantial deforestation. Previous estimates of pre‐Columbian population size in this region, based upon labour required for forest clearance, should therefore be reconsidered. Despite the high density of economically useful plants, such as Theobroma cacao , in the modern forest, no direct pollen evidence for agroforestry was found. However, human occupation is shown to pre‐date and span forest expansion on this site, suggesting that here, and in the wider forest island region, there is no truly pre‐anthropogenic ‘pristine’ forest.
Reply to Silva: Dynamic human–vegetation–climate interactions at forest ecotones during the late-Holocene in lowland South America
(National Academy of Sciences, 2014) John Carson; Bronwen S. Whitney; Francis E. Mayle; José Iriarte; Heiko Prümers; José D. Soto; Jennifer Watling
Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans the biological, physical, and social sciences.
Sensitivity of Bolivian seasonally-dry tropical forest to precipitation and temperature changes over glacial–interglacial timescales
(Springer Science+Business Media, 2013) Bronwen S. Whitney; Francis E. Mayle; Michael J. Burn; René Guillén; Ezequiel Chavez; R. Toby Pennington