Pre-Columbian land use and human impact in the Bolivian Amazon

There is a polarised debate amongst Neotropical archaeologists and ecologists over the extent of Pre-Columbian (pre-AD 1492) anthropogenic environmental impacts in Amazonia. While some maintain the old paradigm of pre-Columbian Amazonia as a “pristine wilderness”, which was sparsely populated by humans, others point to the discovery of an increasing number of archaeological sites across the Amazon basin as evidence for large, complex societies, supported by intensive agriculture and management of forest and aquatic resources. Under this model, pre- Columbian people had profound impacts on biogeochemical cycles through largescale deforestation and biomass burning, and left an indelible legacy on Amazonian ecosystems by altering edaphics, geomorphology, hydrology, and the distribution of plant taxa. However, so far this debate has continued amongst a paucity of palaeoecological data, meaning that we have little evidence to indicate the scale of impact, and often no palaeoenvironmental context in which to place these societies. Other aspects of pre-Columbian cultures, such as their chronology, land use practices and subsistence strategies, are also poorly understood. In this thesis, palaeoecological methods are applied to improve our understanding of the scale, nature, and legacy of land use associated with pre- Columbian geometric earthwork cultures in north-east Bolivia. The methodology employs analysis of fossil pollen and macroscopic charcoal from lake core sediments. In total 110 pollen and 628 charcoal samples were analysed from four lakes: Laguna Isireri (14°49’18”S, 65°40’57”W), Laguna Orícore (13°20’44”S, 63°31’31”W), Laguna Granja (13°15’44”S, 63°42’37”W) and Laguna La Luna (13°21’20”S, 63°35’2”W). Chronologies were built for these cores from 12 AMS 14C dates. Results are presented in four chapters (thesis chapters 2-5), in the form of academic papers. Chapter 2 describes a new laboratory technique co-developed with Whitney et al., which improves the recovery of cultigen pollen grains from sediments from large, Neotropical lake basins. This technique was applied in the laboratory preparations of sediments analysed for Chapters 3-5. Chapter 3 employs palaeoecological reconstructions from differently sized lakes (L. Granja and L. Orícore) in the same earthwork region, to obtain both a regional- and a local-scale history of environmental change/human impact around the archaeological site. Key findings of this paper are: 1) earthworks were built in an originally open savannah landscape, which existed under drier-than-present climatic conditions in the mid-to-late-Holocene; 2) forest expanded into this region from ~ 2000 (cal yrs) BP and was supressed locally around the settlement to maintain an open landscape; therefore, 3) earthwork construction across southern Amazonia, may not have required extensive deforestation, and pre-Columbian impacts on biogeochemical cycling may have been much less than some authors have suggested. Chapter 4 looks more closely at the local scale record provided by L. Granja. These data are integrated with phytolith data analysed by co-author J. Watling and existing archaeological data, to discuss the chronology of settlement on the site, the agricultural/land use strategies employed by its inhabitants, and the spatial scale and distribution of impacts locally around the site. Key findings are that: 1) first occupation of the site is much earlier than previously dated from archaeological contexts, beginning ~2500 BP; 2) maize was the staple crop grown on site; 3) land use involved more extensive and intensive burning of the landscape than compared to modern slash-and-burn agriculture; 4) site decline occurred ~ 500 BP, and may have been related to the Columbian Encounter of AD1492; 5) the close integration of local scale palaeoecological records with archaeology, is highly useful in discerning aspects of chronology and spatial variability of land use. Chapter 5 presents a 6000 year record of palaeoenvironmental change and land use on a pre-Columbian forest island site. Key findings are that: 1) As in Chapter 3, inhabitants exploited an originally open landscape and practiced forest suppression to maintain that open landscape; 2) the earliest recorded evidence for maize agriculture in the region is found at 2100 BP; 3) the economically useful species Theobroma cacao, which is abundant on the site today, is not detectable in the pollen record; 4) clear-cutting was not practiced on the site and previous population estimates, based on labour for deforestation, must be reconsidered. The work in this thesis reveals a new model of human-environment interactions, demonstrating that pre-Columbian earthwork cultures in southern Amazonia occupied and adapted to a region of dynamic, climatically controlled forest-savannah transition during the mid-to-late-Holocene. Obtaining a palaeoenvironmental context for archaeological landscapes, is shown to be a vital pre-requisite to inferring past environmental impacts. Furthermore, we demonstrate the valuable contribution that palaeoecology can make to a better understanding of the chronology and land use practices of pre-Columbian cultures

Pre-Columbian ring ditch construction and land use on a “chocolate forest island” in the Bolivian Amazon

We present a palaeoecological investigation of pre-Columbian land use in the savannah “forest island” landscape of north-east Bolivian Amazonia. 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 savannah, 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

Environmental impact of geometric earthwork construction in pre-Columbian Amazonia

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

Out of Amazonia: Late Holocene Climate Change and the Tupi-Guarani Trans-Continental Expansion

This is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this recordThe late Holocene expansion of the Tupi-Guarani languages from southern Amazonia to SE South America constitutes one of the largest expansions of any linguistic family in the world, spanning ~ 4000 km between latitudes 0°S and 35°S at about 2500 yr B.P. However, the underlying reasons for this expansion are a matter of debate. Here, we compare continental-scale paleoecological, paleoclimate, and archaeological datasets, to examine the role of climate change in facilitating the expansion of this forest-farming culture. Because this expansion lies within the path of the South American Low-Level Jet, the key mechanism for moisture transport across lowland South America, we were able to explore the relationship between climate change, forest expansion, and the Tupi-Guarani. Our data synthesis shows broad synchrony between late Holocene increasing precipitation and southerly expansion of both tropical forest and Guarani archaeological sites – the southernmost branch of the Tupi-Guarani. We conclude that climate change likely facilitated expansion of the Guarani forest-farming culture by increasing the area of forested landscape that they could exploit, showing a prime example of ecological opportunism.The ideas and themes developed in this paper stem from a European Research Council project ‘Pre-Columbian Amazon-Scale Transformations’ (ERC-CoG 616179) to JI. The University of Reading’s ‘Centre for Past Climate Change’ funded a writing workshop for this paper. RS was funded by an NERC ‘Scenario’ DTP PhD award. JGS was funded by a CAPES PhD scholarship (Ministry of Education, Brazil). JFC and MLC received postdoctoral funding from the University of Reading and the Arts and Humanities Research Council, respectively

Out of Amazonia: late-Holocene climate change and the Tupi–Guarani trans-continental expansion

The late Holocene expansion of the Tupi-Guarani languages from southern Amazonia to SE South America constitutes one of the largest expansions of any linguistic family in the world, spanning ~ 4000 km between latitudes 0°S and 35°S at about 2500 yr B.P. However, the underlying reasons for this expansion are a matter of debate. Here, we compare continental-scale palaeoecological, palaeoclimate, and archaeological datasets, to examine the role of climate change in facilitating the expansion of this forestfarming culture. Because this expansion lies within the path of the South American Low-Level Jet, the key mechanism for moisture transport across lowland South America, we were able to explore the relationship between climate change, forest expansion, and the Tupi-Guarani. Our data synthesis shows broad synchrony between late Holocene increasing precipitation and southerly expansion of both tropical forest and Guarani archaeological sites – the southernmost branch of the Tupi-Guarani. We conclude that climate change likely facilitated the agricultural expansion of the Guarani forest-farming culture by increasing the area of forested landscape that they could exploit, showing a prime example of ecological opportunism

Mindfulness for irritable bowel syndrome: protocol development for a controlled clinical trial

<p>Abstract</p> <p>Background</p> <p>Irritable bowel syndrome (IBS), a functional bowel disorder with symptoms of abdominal pain and disturbed defecation experienced by 10% of U.S. adults, results in significant disability, impaired quality of life, and health-care burden. Conventional medical care focusing on pharmacological approaches, diet, and lifestyle management has been partially effective in controlling symptoms. Behavioral treatments, such as cognitive-behavioral therapy and hypnosis, are promising. This paper describes an on-going feasibility study to assess the efficacy of mindfulness training, a behavioral treatment involving directing and sustaining attention to present-moment experience, for the treatment of IBS.</p> <p>Methods/Design</p> <p>The study design involves randomization of adult women with IBS according to Rome II criteria, to either an eight-week mindfulness training group (based on a Mindfulness-based Stress Reduction [MBSR] format) or a previously validated IBS social-support group as an attention-control condition. The primary hypothesis is that, compared to Support Group participants, those in the Mindfulness Program will demonstrate significant improvement in IBS symptoms as measured by the IBS Symptom Severity Scale <abbrgrp><abbr bid="B1">1</abbr></abbrgrp>.</p> <p>Discussion</p> <p>214 individuals have been screened for eligibility, of whom 148 were eligible for the study. Of those, 87 were enrolled, with 21 withdrawing after having given consent. 66 have completed or are in the process of completing the interventions. It is feasible to undertake a rigorous randomized clinical trial of mindfulness training for people with IBS, using a standardized MBSR protocol adapted for those experiencing IBS, compared to a control social-support group previously utilized in IBS studies.</p> <p>Trial Registration</p> <p>Clinical Trials.gov Identifier: NCT00680693</p

Association between neighborhood socioeconomic status and screen time among pre-school children: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Sedentary behavior is considered a separate construct from physical activity and engaging in sedentary behaviors results in health effects independent of physical activity levels. A major source of sedentary behavior in children is time spent viewing TV or movies, playing video games, and using computers. To date no study has examined the impact of neighborhood socioeconomic status (SES) on pre-school children's screen time behavior.</p> <p>Methods</p> <p>Proxy reports of weekday and weekend screen time (TV/movies, video games, and computer use) were completed by 1633 parents on their 4-5 year-old children in Edmonton, Alberta between November, 2005 and August, 2007. Postal codes were used to classified neighborhoods into low, medium or high SES. Multiple linear and logistic regression models were conducted to examine relationships between screen time and neighborhood SES.</p> <p>Results</p> <p>Girls living in low SES neighborhoods engaged in significantly more weekly overall screen time and TV/movie minutes compared to girls living in high SES neighborhoods. The same relationship was not observed in boys. Children living in low SES neighborhoods were significantly more likely to be video game users and less likely to be computer users compared to children living in high SES neighborhoods. Also, children living in medium SES neighborhoods were significantly less likely to be computer users compared to children living in high SES neighborhoods.</p> <p>Conclusions</p> <p>Some consideration should be given to providing alternative activity opportunities for children, especially girls who live in lower SES neighborhoods. Also, future research should continue to investigate the independent effects of neighborhood SES on screen time as well as the potential mediating variables for this relationship.</p

Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires

The production of tt‾ , W+bb‾ and W+cc‾ is studied in the forward region of proton–proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fb−1 . The W bosons are reconstructed in the decays W→ℓν , where ℓ denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of $t\overline{t}$, $W+b\overline{b}$ and $W+c\overline{c}$ is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 $\pm$ 0.02 \mbox{fb}^{-1}. The $W$ bosons are reconstructed in the decays $W\rightarrow\ell\nu$, where $\ell$ denotes muon or electron, while the $b$ and $c$ quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions