Browsing by Autor "Francis E. Mayle"

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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
A simple and effective methodology for sampling modern pollen rain in tropical environments
(SAGE Publishing, 2003) William D. Gosling; Francis E. Mayle; Timothy J. Killeen; Marcelo E. Siles; Lupita Sanchez; Steve Boreham
To gain a better insight into the nature of palaeovegetation change in tropical ecosystems, more information needs to be gleaned from the limited number of fossil pollen records that exist. To achieve this, a detailed understanding of modern tropical ecosystems and the pollen they produce is required. To facilitate this, a practicable and effective mechanism for sampling modern pollen rain from the tropics is required. This paper presents a modified field methodology based upon three years of trapping experience in Noel Kempff Mercado National Park, Bolivia, and improved laboratory preparation methodologies. We demonstrate here a simple and very effective way to sample modern pollen rain in tropical environments using a funnel trap mounted on a stake containing cotton fibre as the trapping medium.
Characterisation of Bolivian savanna ecosystems by their modern pollen rain and implications for fossil pollen records
(Elsevier BV, 2011) Huw T. Jones; Francis E. Mayle; R. Toby Pennington; Timothy J. Killeen
Differentiation between Neotropical rainforest, dry forest, and savannah ecosystems by their modern pollen spectra and implications for the fossil pollen record
(Elsevier BV, 2008) William D. Gosling; Francis E. Mayle; Nicholas Tate; Timothy J. Killeen
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.
Fifty-thousand-year vegetation and climate history of Noel Kempff Mercado National Park, Bolivian Amazon
(Cambridge University Press, 2004) R. Burbridge; Francis E. Mayle; Timothy J. Killeen
Pollen and charcoal records from two large, shallow lakes reveal that throughout most of the past 50,000 yr Noel Kempff Mercado National Park, in northeastern lowland Bolivia (southwestern Amazon Basin), was predominantly covered by savannas and seasonally dry semideciduous forests. Lowered atmospheric CO 2 concentrations, in combination with a longer dry season, caused expansion of dry forests and savannas during the last glacial period, especially at the last glacial maximum. These ecosystems persisted until the mid-Holocene, although they underwent significant species reassortment. Forest communities containing a mixture of evergreen and semideciduous species began to expand between 6000 and 3000 14 C yr B.P. Humid evergreen rain forests expanded to cover most of the area within the past 2000 14 C yr B.P. coincident with a reduction in fire frequencies. Comparisons between modern pollen spectra and vegetation reveal that the Moraceae-dominated rain forest pollen spectra likely have a regional source area at least 2–3 km beyond the lake shore, whereas the grass- and sedge-dominated savanna pollen spectra likely have a predominantly local source area. The Holocene vegetation changes are consistent with independent paleoprecipitation records from the Bolivian Altiplano and paleovegetation records from other parts of southwestern Amazonia. The progressive expansion in rain forests through the Holocene can be largely attributed to enhanced convective activity over Amazonia, due to greater seasonality of insolation in the Southern Hemisphere tropics driven by the precession cycle according to the Milankovitch Astronomical Theory.
Localised land-use and maize agriculture by the pre-Columbian Casarabe Culture in Lowland Bolivia
(SAGE Publishing, 2025) Joseph Hirst; Marco F. Raczka; Umberto Lombardo; Ezequiel Chavez; Lorena Becerra‐Valdivia; McKenzie R. Bentley; Christopher Bronk Ramsey; Miros Stavros James Charidemou; Suzanne Maclachlan; Francis E. Mayle
Multiple pre-Columbian (pre-1492 CE) archaeological sites now challenge the traditional portrayal of Amazonia as a ‘pristine wilderness’. This is especially true within the forest-savanna mosaic landscapes of lowland Bolivia, where the pre-Columbian Casarabe Culture constructed hundreds of settlement mounds, integrated with a dense causeway-canal network – one of the most complex, stratified societies yet discovered in Amazonia. Excavations at previous sites indicate that this culture sustained itself by practicing large-scale, maize-based agriculture. However, the Casarabe Culture’s mounds have also been found within the riparian forests abutting major river systems, where their inhabitants could have benefitted from greater access to forest resources and local fish species. To determine whether these differences influenced how the Casarabe Culture utilised the landscape, we conducted palaeoecological analysis on the sediments collected from Laguna Loma Suarez (LLS), an oxbow lake situated adjacent to a monumental habitation mound within these riparian forests. Our analysis reveals that, despite significant differences in natural resource availability, the Casarabe Culture continued to cultivate maize locally around LLS for over a millennium, between 280 BCE and 1130 CE, with anthropogenic fires largely restricted to the open savannas. Our record also suggests that the Casarabe Culture possibly delayed either forest recovery or natural forest encroachment until after the nearby settlement mound was abandoned. These findings, when compared with those of other sites in the region, show that maize was an important crop in pre-Columbian times, irrespective of major differences in natural resource availability across the complex forest-savanna mosaic settings of Amazonian Bolivia.
Millennial-Scale Dynamics of Southern Amazonian Rain Forests
(American Association for the Advancement of Science, 2000) Francis E. Mayle; R. Burbridge; Timothy J. Killeen
Amazonian rain forest-savanna boundaries are highly sensitive to climatic change and may also play an important role in rain forest speciation. However, their dynamics over millennial time scales are poorly understood. Here, we present late Quaternary pollen records from the southern margin of Amazonia, which show that the humid evergreen rain forests of eastern Bolivia have been expanding southward over the past 3000 years and that their present-day limit represents the southernmost extent of Amazonian rain forest over at least the past 50,000 years. This rain forest expansion is attributed to increased seasonal latitudinal migration of the Intertropical Convergence Zone, which can in turn be explained by Milankovitch astronomic forcing.
Modern Pollen-Rain Characteristics of Tall <i>Terra Firme</i> Moist Evergreen Forest, Southern Amazonia
(Cambridge University Press, 2005) William D. Gosling; Francis E. Mayle; Nicholas Tate; Timothy J. Killeen
Abstract The paucity of modern pollen-rain data from Amazonia constitutes a significant barrier to understanding the Late Quaternary vegetation history of this globally important tropical forest region. Here, we present the first modern pollen-rain data for tall terra firme moist evergreen Amazon forest, collected between 1999 and 2001 from artificial pollen traps within a 500 × 20 m permanent study plot (14°34′50″S, 60°49′48″W) in Noel Kempff Mercado National Park (NE Bolivia). Spearman's rank correlations were performed to assess the extent of spatial and inter-annual variability in the pollen rain, whilst statistically distinctive taxa were identified using Principal Components Analysis (PCA). Comparisons with the floristic and basal area data of the plot (stems ≥10 cm d.b.h.) enabled the degree to which taxa are over/under-represented in the pollen rain to be assessed (using R-rel values). Moraceae/Urticaceae dominates the pollen rain (64% median abundance) and is also an important constituent of the vegetation, accounting for 16% of stems ≥10 cm d.b.h. and ca. 11% of the total basal area. Other important pollen taxa are Arecaceae (cf. Euterpe ), Melastomataceae/Combretaceae, Cecropia , Didymopanax , Celtis , and Alchornea . However, 75% of stems and 67% of the total basal area of the plot ≥10 cm d.b.h. belong to species which are unidentified in the pollen rain, the most important of which are Phenakospermum guianensis (a banana-like herb) and the key canopy-emergent trees, Erisma uncinatum and Qualea paraensis .
Pollen-based differentiation of Amazonian rainforest communities and implications for lowland palaeoecology in tropical South America
(Elsevier BV, 2010) Michael J. Burn; Francis E. Mayle; Timothy J. Killeen
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