The Physical Geography of South America

Author(s):  
Thomas Veblen ◽  
Kenneth Young ◽  
Antony Orme

The Physical Geography of South America, the eighth volume in the Oxford Regional Environments series, presents an enduring statement on the physical and biogeographic conditions of this remarkable continent and their relationships to human activity. It fills a void in recent environmental literature by assembling a team of specialists from within and beyond South America in order to provide an integrated, cross-disciplinary body of knowledge about this mostly tropical continent, together with its high mountains and temperate southern cone. The authors systematically cover the main components of the South American environment - tectonism, climate, glaciation, natural landscape changes, rivers, vegetation, animals, and soils. The book then presents more specific treatments of regions with special attributes from the tropical forests of the Amazon basin to the Atacama Desert and Patagonian steppe, and from the Atlantic, Caribbean, and Pacific coasts to the high Andes. Additionally, the continents environments are given a human face by evaluating the roles played by people over time, from pre-European and European colonial impacts to the effects of modern agriculture and urbanization, and from interactions with El Niño events to prognoses for the future environments of the continent.

Author(s):  
Cameron Jones

While it is certainly true that more academic studies have focused on the North American missions, in terms of their historical impact South American missions were just as important to the frontiers of Spain and Portugal’s American empires. The massive size alone of the frontier region, stretching from the upper reaches of the Amazon basin to the headwaters of the Paraná as well as stretching across the lower Southern Cone, meant numerous missionary enterprises emerged in an attempt to evangelize the peoples who inhabited these regions. While small handfuls of Dominicans, Mercedarians, and Augustinians would engage in such efforts, most missions were established by the Jesuits or Franciscans. Certainly, for the Jesuits, or the Society of Jesus as they are properly known, American missions represented an extension of the Counter-Reformation for which they were created. Starting in the mid-16th century, this relatively new organization, founded in 1534, began in earnest to “reduce” the Indigenous peoples into their missions. These activities, however, abruptly ended when the Jesuits were expelled from both the Portuguese and Spanish empires in 1759 and 1767 respectfully. The much older Franciscan order had extensive experience in popular missions in Europe and was one of the first orders of regular clergy in the Americas. Franciscans, like the Jesuits, engaged in evangelizing activities throughout both North and South America from the colonial period to the present. The expulsion of the Jesuits, however, pushed them further to the forefront of missionizing efforts in the late colonial period. This acceleration of Franciscan missionary activity was aided by the establishment of the Apostolic Institute in 1682. The Institute created a pipeline of missionaries from Spain to come directly to frontier areas with funding from the crown. While this aided missionary efforts throughout South America, particularly in areas abandoned by the Jesuits, it embroiled the missionaries in the politics of the Bourbon reforms and their obsession with limited clerical power. Ultimately, while missionizing efforts continued into the Republican period, their association with the Spanish and Portuguese crowns led to widespread suppression and secularization following independence. The historiographical divide in the field tends to lie between usually older, Eurocentric histories by scholar-clerics which focus on the missionaries themselves, and newer studies carried out by more secular professional historians that examine how Indigenous populations were affected by the inherent imperialism of the missions, though exceptions abound.


Author(s):  
Thomas T. Veblen ◽  
Kenneth R. Young

An important goal of this book has been to provide a comprehensive understanding of the physical geography and landscape origins of South America as important background to assessing the probabilities and consequences of future environmental changes. Such background is essential to informed discussions of environmental management and the development of policy options designed to prepare local, national, and international societies for future changes. A unifying theme of this book has been the elucidation of how natural processes and human activities have interacted in the distant and recent past to create the modern landscapes of the continent. This retrospective appreciation of how the current landscapes have been shaped by nature and humans will guide our discussion of possible future trajectories of South American environments. There is abundant evidence from all regions of South America, from Tierra del Fuego to the Isthmus of Panama, that environmental change, not stasis, has been the norm. Given that fact, the history, timing, and recurrence intervals of this dynamism are all crucial pieces of information. The antiquity and widespread distribution of changes associated with the indigenous population are now well established. Rates and intensities of changes related to indigenous activities varied widely, but even in regions formerly believed to have experienced little or no pre-European impacts we now recognize the effects of early humans on features such as soils and vegetation. Colonization by Europeans mainly during the sixteenth century modified or in some cases replaced indigenous land-use practices and initiated changes that have continued to the present. Complementing these broad historical treatments of human impacts, other chapters have examined in detail the environmental impacts of agriculture (chapter 18) and urbanism (chapter 20), and the disruptions associated with El Niño–Southern Oscillation events. The goal of this final synthesis is to identify the major drivers of change and to discuss briefly their likely impacts on South American environments and resources in the near and medium-term future. Our intent is not to make or defend predictions, but rather to identify broad causes and specific drivers of environmental change to inform discussions of policy options for mitigating undesirable changes and to facilitate potential societal adaptations to them.


2019 ◽  
Vol 27 (2) ◽  
pp. 87-101
Author(s):  
Charlotte M. Taylor ◽  
David A. Neill ◽  
Melissa Calderón Cruz

This paper reviews Hippotis Ruiz & Pav. and Schradera Vahl, two Rubiaceae genera with centers of diversity in western South America. Both are inadequately known and in need of field study. Recent authors’ circumscriptions of H. albiflora H. Karst. and H. mollis Standl. are narrowed here, and four new species of Hippotis are described: H. antioquiana C. M. Taylor from northwestern Colombia, H. ecuatoriana C. M. Taylor from central-southern Ecuador, H. elegantula C. M. Taylor & M. Calderón from the western Amazon basin in Ecuador, and H. vasqueziana C. M. Taylor from lowland northeastern Peru. Four new species of Schradera Vahl are also described here: S. cernua C. M. Taylor and S. francoae C. M. Taylor from western Colombia, S. condorica C. M. Taylor & D. A. Neill from southern Ecuador, and S. morindoides C. M. Taylor from southern Ecuador and northern Peru. Schradera condorica at least sometimes is a free-standing tree, a habit newly documented for this genus.


2010 ◽  
Vol 15 (18) ◽  
Author(s):  
M C Receveur ◽  
M Grandadam ◽  
T Pistone ◽  
D Malvy

Mayaro virus (MAYV) disease is a mosquito-borne zoonosis endemic in humid forests of tropical South America. MAYV is closely related to other alphaviruses that produce a dengue-like illness accompanied by long-lasting arthralgia. A French tourist developed high-grade fever and severe joint manifestations following a 15-day trip in the Amazon basin, Brazil, and was diagnosed with MAYV infection in January 2010. This case is the first reported in a traveller returning from an endemic South American country to Europe.


2020 ◽  
Vol 70 (1) ◽  
pp. 1-13
Author(s):  
Dawson M White ◽  
Jen-Pan Huang ◽  
Orlando Adolfo Jara-Muñoz ◽  
Santiago MadriñáN ◽  
Richard H Ree ◽  
...  

Abstract Coca is the natural source of cocaine as well as a sacred and medicinal plant farmed by South American Amerindians and mestizos. The coca crop comprises four closely related varieties classified into two species (Amazonian and Huánuco varieties within Erythroxylum coca Lam., and Colombian and Trujillo varieties within Erythroxylum novogranatense (D. Morris) Hieron.) but our understanding of the domestication and evolutionary history of these taxa is nominal. In this study, we use genomic data from natural history collections to estimate the geographic origins and genetic diversity of this economically and culturally important crop in the context of its wild relatives. Our phylogeographic analyses clearly demonstrate the four varieties of coca comprise two or three exclusive groups nested within the diverse lineages of the widespread, wild species Erythroxylum gracilipes; establishing a new and robust hypothesis of domestication wherein coca originated two or three times from this wild progenitor. The Colombian and Trujillo coca varieties are descended from a single, ancient domestication event in northwestern South America. Huánuco coca was domesticated more recently, possibly in southeastern Peru. Amazonian coca either shares a common domesticated ancestor with Huánuco coca, or it was the product of a third and most recent independent domestication event in the western Amazon basin. This chronology of coca domestication reveals different Holocene peoples in South America were able to independently transform the same natural resource to serve their needs; in this case, a workaday stimulant. [Erythroxylum; Erythroxylaceae; Holocene; Museomics; Neotropics; phylogeography; plant domestication; target-sequence capture.]


2014 ◽  
Vol 14 (23) ◽  
pp. 13337-13359 ◽  
Author(s):  
D. C. Zemp ◽  
C.-F. Schleussner ◽  
H. M. J. Barbosa ◽  
R. J. van der Ent ◽  
J. F. Donges ◽  
...  

Abstract. Continental moisture recycling is a crucial process of the South American climate system. In particular, evapotranspiration from the Amazon basin contributes substantially to precipitation regionally as well as over other remote regions such as the La Plata basin. Here we present an in-depth analysis of South American moisture recycling mechanisms. In particular, we quantify the importance of cascading moisture recycling (CMR), which describes moisture transport between two locations on the continent that involves re-evaporation cycles along the way. Using an Eulerian atmospheric moisture tracking model forced by a combination of several historical climate data sets, we were able to construct a complex network of moisture recycling for South America. Our results show that CMR contributes about 9–10% to the total precipitation over South America and 17–18% over the La Plata basin. CMR increases the fraction of total precipitation over the La Plata basin that originates from the Amazon basin from 18–23 to 24–29% during the wet season. We also show that the south-western part of the Amazon basin is not only a direct source of rainfall over the La Plata basin, but also a key intermediary region that distributes moisture originating from the entire Amazon basin towards the La Plata basin during the wet season. Our results suggest that land use change in this region might have a stronger impact on downwind rainfall than previously thought. Using complex network analysis techniques, we find the eastern side of the sub-tropical Andes to be a key region where CMR pathways are channeled. This study offers a better understanding of the interactions between the vegetation and the atmosphere on the water cycle, which is needed in a context of land use and climate change in South America.


2020 ◽  
Author(s):  
Paul-Arthur Monerie ◽  
Amulya Chevuturi ◽  
Peter Cook ◽  
Nick Klingaman ◽  
Christopher E. Holloway

Abstract. We assess the effect of increasing horizontal resolution on simulated precipitation over South America in a climate model. We use atmosphere-only simulations, performed with HadGEM3-GC31 at three horizontal resolutions: N96 (~ 130 km, 1.88° × 1.25°), N216 (~ 60 km, 0.83° × 0.56°), and N512 (~25 km, 0.35° × 0.23°). We show that all simulations have systematic biases in annual mean and seasonal mean precipitation over South America (e.g. too wet over the Amazon and too dry in northeast). Increasing horizontal resolution improves simulated precipitation over the Andes and north-east Brazil. Over the Andes, improvements from horizontal resolution continue to ~ 25 km, while over north-east Brazil, there are no improvements beyond ~ 60 km resolution. These changes are primarily related to changes in atmospheric dynamics and moisture flux convergence. Over the Amazon basin, precipitation variability increases at higher resolution. We show that some spatial and temporal features of daily South American precipitation are improved at high resolution, including the intensity spectra of rainfall. Spatial scales of daily precipitation features are also better simulated, suggesting that higher resolution may improve the representation of South American mesoscale convective systems.


Author(s):  
Carol P. Harden ◽  
Glenn G. Hyman

People have manipulated the natural environments of South America for agricultural purposes for several millennia. While agriculture is strongly affected by the physical attributes of a place—soil, water, climate, biota, and topography—agriculture changes a landscape’s physical and biological characteristics and processes. Agriculture may involve short- and long-term conversion of forest to cropland and pasture, modification of topography and drainage, and the introduction and propagation of exotic species. Soil erosion, much of which is caused by agriculture, is a major concern in South America. This chapter introduces the patterns of agriculture in South America and examines agricultural trends. It then reviews the causes and consequences of soil erosion at continental to local scales, providing examples from research conducted across the continent. As population grows and demand for agricultural production increases, knowledge of the physical geography of soil erosion will be even more critical for the sustainability of agriculture in South America. Agriculture is broadly defined here to encompass annual and permanent crops, tree crops, and livestock. Agricultural patterns of South America today reflect great differences in the continent’s natural environments. They also reflect the influence of international and global markets, the impacts of national policies, and the imprints of preand post-colonial settlement patterns, preferred species, and cultural preferences. The wide range of climates in South America allows a great variety of temperate and tropical fruits, vegetables, and grains to flourish. Historically, the diverse agricultural capabilities of different parts of the continent have been fundamental influences in the development of pre- and post-colonial human habitation and economic patterns (U.S. Agency for International Development, 1993; see chapters 16 and 17). At the continental scale, agriculture occurs across almost all regions of South America. It is notably absent only in the Gran Chaco, rugged portions of the high Andes, and desert landscapes along the Pacific coast of northern Chile and southern Perú. In practice, there is little cropland in sparsely populated regions, especially in the Amazon basin, and in densely populated urban areas, even where the lands and climates of those places are capable of supporting agriculture.


2015 ◽  
Vol 31 (3) ◽  
pp. 285-289 ◽  
Author(s):  
Christopher M. Heckscher ◽  
Matthew R. Halley ◽  
Pamela M. Stampul

Abstract:Recent advances in tracking technology have revealed significant intratropical movement of Nearctic–Neotropical migratory songbirds during their non-breeding season. We report the movement of 25 veeries (Catharus fuscescens) over multiple seasons (2009–2013) through equatorial rain forests of South America. Veeries initially settled on the Brazilian Shield geological formation but undertook an intratropical migration to a second South American region in January, February or March. Consequently, our study is the first to track individual forest passerines to document an annual migration from the Brazilian Shield to the Guiana Shield and into lowland regions of Amazonia. The movement and settlement patterns showed no spatiotemporal relationships with Nearctic–Neotropical migration, remained in accordance with the flood pulse of the Amazon basin, and were spatially and temporally complex suggesting relatively ancient ancestral origins. The ability to isolate the migration event from Nearctic–Neotropical migration is an important contribution to the ongoing discourse regarding the evolution of trans-hemispheric migration in the genus Catharus.


2016 ◽  
Vol 29 (4) ◽  
pp. 1429-1449 ◽  
Author(s):  
Marília Guedes do Nascimento ◽  
Dirceu Luis Herdies ◽  
Diego Oliveira de Souza

Abstract To study the climatology of the water balance over South America and analyze the influence of low-level jets (LLJs), a climate study of the water balance and its main components was performed, specifically in the Amazon and La Plata basin (LPB) region, from 1979 to 2008. The results showed that on average for the analysis period, the Amazon basin and LPB performed as a sink of moisture (ET < P) and as a moisture convergence for the regions, which accounted for approximately 62% and 43% of the precipitation, respectively. During the study period, 884 days with an occurrence of LLJs were observed, occurring most frequently during the winter and around 0000 and 0600 UTC. When considering the water balance for the days with LLJs, it was observed that the Amazon acts as a source of moisture, especially in the dry season, and that the LPB behaves as a sink during all months. The influence of the LLJ as a modulator for precipitation on the LPB is clear, as the precipitation is 32% higher during the LLJ events compared with days without LLJs. This main pattern shows that the moisture convergence trough of the LLJs is crucial for the water balance on the LPB, whereas evapotranspiration is a more important variable of the water balance on the Amazon basin with or without the LLJs.


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