Floristics of the South American Páramo Moss Flora

1990 ◽  
Vol 2 (1) ◽  
pp. 127-132
Author(s):  
Dana Griffin III
Keyword(s):  
South America ◽  
Southern Hemisphere ◽  
Cloud Forest ◽  
South American ◽  
Long Distance Dispersal ◽  
The South ◽  
Long Distance ◽  
Late Pliocene ◽  
Northern Andes ◽  
The Past

The South American paramos appeared in Pliocene times and persist to the present day. The moss flora of this habitat consists of an estimated 400 species that comprise 8 floristic groups. In Venezuela these groups and their percent representation are as follows: neotropical 37%, Andean 26%, cosmopolitan 18%, Andean-African 8%, neotropical-Asiatic 3%, neotropical-Australasian 2%, temperate Southern Hemisphere 2% and northern boreal-temperate 2%. Acrocarpous taxa outnumber pleurocarps by nearly 3:1. The neotropical and Andean floristic stocks likely were present prior to late Pliocene orogenies that elevated the cordillera above climatic timberlines. These species may have existed in open, marshy areas (paramillos) or may have evolved from cloud forest ancestors. Taxa of northern boreal- temperate affinities, including those with Asiatic distributions, probably arrived in the paramos during the Pleistocene, a period which may also have seen the establishment in the Northern Andes of some cosmopolitan elements. Species with temperate Southern Hemisphere and Australasian affinities likely spread first to austral South America thence migrated northward during a cool, moist interval sometime over the past 2.5-3 million years or may have become established in the paramos as a result of long- distance dispersal.

Driftwood on Heard Island

Polar Record ◽  
1989 ◽  
Vol 25 (154) ◽  
pp. 223-228 ◽  
Author(s):  
J. M. B. Smith ◽  
P. Rudall ◽  
P. L. Keage
Keyword(s):  
South America ◽  
South American ◽  
Long Distance Dispersal ◽  
South American Species ◽  
Long Distance ◽  
Heard Island

AbstractSamples from 73 pieces of non-structural driftwood on Heard Island (53°06′S, 73°30′E) were identified to genus or species. Thirty-one belonged to South American species of Nothofagus. The remainder, consisting mostly of conifers especially Picea and Larix, probably came from ships' cargoes. The assemblage is similar to those reported, from smaller samples, on other southern islands. Other items of flotsam, including fishing buoys and drift-cards, are also reported from Heard Island. The significance of driftwood transport from South America to the island in accounting for long-distance dispersal of terrestrial and intertidal organisms is discussed.

Geodynamic study of the north of the Andes block (Colombia, Panama, Ecuador and Venezuela) through gnss-gps: models of displacements, models of deformation and definition of local and regional geodynamic structures.

2020 ◽  
Author(s):  
Berrocoso Manuel ◽  
Del Valle Arroyo Pablo Emilio ◽  
Colorado Jaramillo David Julián ◽  
Gárate Jorge ◽  
Fernández-Ros Alberto ◽  
...  
Keyword(s):  
South America ◽  
Seismic Activity ◽  
Great Part ◽  
Velocity Model ◽  
South American ◽  
The South ◽  
South American Plate ◽  
Northern Andes ◽  
Velocity Models ◽  
The North

<p>The northwest of South America is conformed by the territories of Ecuador, Colombia and Venezuela. Great part of these territories make up the Northern Andes Block (BAN). The tectonic and volcanic activity in the northwest of South America is directly related to the interaction of the South American plate, and the Nazca and Caribbean plates, with the Maracaibo and Panama-Chocó micro plates. The high seismic activity and the high magnitude of the recorded earthquakes make any study necessary to define this complex geodynamic region more precisely. This work presents the velocity models obtained through GNSS-GPS observations obtained in public continuous monitoring stations in the region. The observations of the Magna-eco network (Agustín Codazzi Geographic Institute) are integrated with models already obtained by other authors from the observations of the GEORED network (Colombian Geological Service). The observations have been processed using Bernese software v.52 using the PPP technique; obtaining topocentric time series. To obtain the speeds, a process of filtering and adjustment of the topocentric series has been carried out. Based on this velocity model, regional structures have been defined within the Northern Andes Block through a differentiation process based on the corresponding speeds of the South American, Nazca and Caribbean tectonic plates. Local geodynamic structures within the BAN itself have been established through cluster analysis based on both the direction and the magnitude of each of the vectors obtained. Finally, these structures have been correlated with the most significant geodynamic elements (fractures, faults, subduction processes, etc.) and with the associated seismic activity.</p>

scholarly journals Resolving the northern hemisphere source region for the long-distance dispersal event that gave rise to the South American endemic dung mossTetraplodon fuegianus

2017 ◽  
Vol 104 (11) ◽  
pp. 1651-1659 ◽  
Author(s):  
Lily R. Lewis ◽  
Elisabeth M. Biersma ◽  
Sarah B. Carey ◽  
Kent Holsinger ◽  
Stuart F. McDaniel ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Source Region ◽  
South American ◽  
Long Distance Dispersal ◽  
The South ◽  
Long Distance

scholarly journals Unenlagiinae revisited: dromaeosaurid theropods from South América

2011 ◽  
Vol 83 (1) ◽  
pp. 163-195 ◽  
Author(s):  
Federico A. Gianechini ◽  
Sebastian Apesteguia
Keyword(s):  
South America ◽  
South American ◽  
The South ◽  
Important Data ◽  
The Past

Over the past two decades, the record of South American unenlagiine dromaeosaurids was substantially increased both in quantity as well as in quality of specimens. Here is presented a summary review of the South American record for these theropods.Unenlagia comahuensis, Unenlagia paynemili, and Neuquenraptor argentinus come from the Portezuelo Formation, the former genus being the most complete and with putative avian features. Neuquenraptor is more incomplete and exhibits pedal features resembling those of Unenlagia. The earliest and most complete South American dromaeosaurid is Buitreraptor gonzalezoru, whose preserved cranial remains, provides important data in the characterization of unenlagiines. The most recently described,Austroraptor cabazai also with cranial remains, allows further comparisons with Laurasian lineages and a better characterization of unenlagiines. The possible synonymy between nenlagia and Neuquenraptor is discussed. Additional evidences from Brazil and Colombia show that dinosaurs with similar dentition to that of unenlagiines were present in the whole South America. However, it is not possible to discart that these remains may belong to other unknown maniraptoran lineages, considering the increasing number of taxa of this group found in South America.

scholarly journals The Influence of Orbital Forcing of Tropical Insolation on the Climate and Isotopic Composition of Precipitation in South America

2015 ◽  
Vol 28 (12) ◽  
pp. 4841-4862 ◽  
Author(s):  
Xiaojuan Liu ◽  
David S. Battisti
Keyword(s):  
South America ◽  
Isotopic Composition ◽  
General Circulation ◽  
Circulation Model ◽  
Ocean Model ◽  
Northeastern Brazil ◽  
Convergence Zone ◽  
South American ◽  
The South ◽  
Northern Andes

Abstract The δ18O of calcite (δ18Oc) in speleothems from South America is fairly well correlated with austral summer [December–February (DJF)] insolation, indicating the role of orbitally paced changes in insolation in changing the climate of South America. Using an isotope-enabled atmospheric general circulation model (ECHAM4.6) coupled to a slab ocean model, the authors study how orbitally paced variations in insolation change climate and the isotopic composition of precipitation (δ18Op) of South America. Compared with times of high summertime insolation, times of low insolation feature (i) a decrease in precipitation inland of tropical South America as a result of an anomalous cooling of the South American continent and hence a weakening of the South American summer monsoon and (ii) an increase in precipitation in eastern Brazil that is associated with the intensification and southward movement of the Atlantic intertropical convergence zone, which is caused by the strengthening of African winter monsoon that is induced by the anomalous cooling of northern Africa. Finally, reduced DJF insolation over southern Africa causes cooling and the generation of a tropically trapped Rossby wave that intensifies and shifts the South Atlantic convergence zone northward. In times of low insolation, δ18Op increases in the northern Andes and decreases in northeastern Brazil, consistent with the pattern of δ18Oc changes seen in speleothems. Further analysis shows that the decrease in δ18Op in northeastern Brazil is due to change in the intensity of precipitation, while the increase in the northern Andes reflects a change in the seasonality of precipitation and in the isotopic composition of vapor that forms the condensates.

scholarly journals The South American Monsoon Variability over the Last Millennium in CMIP5/PMIP3 simulations

2015 ◽  
Vol 11 (6) ◽  
pp. 5651-5681 ◽  
Author(s):  
M. Rojas ◽  
P. A. Arias ◽  
V. Flores-Aqueveque ◽  
A. Seth ◽  
M. Vuille
Keyword(s):  
South America ◽  
Large Scale ◽  
Model Simulation ◽  
Ice Age ◽  
South American ◽  
Last Millennium ◽  
The South ◽  
South American Monsoon ◽  
The Past ◽  
Intercomparison Project

Abstract. In this paper we assess South American Monsoon System (SAMS) variability throughout the Last Millennium as depicted by the Coupled Modelling Intercomparison Project version 5/Paleo Modelling Intercomparison Project version 3 (CMIP5/PMIP3) simulations. High-resolution proxy records for the South American monsoon over this period show a coherent regional picture of a weak monsoon during the Medieval Climate Anomaly period and a stronger monsoon during the Little Ice Age (LIA). Due to the small forcing during the past 1000 years, CMIP5/PMIP3 model simulations do not show very strong temperature anomalies over these two specific periods, which in turn do not translate into clear precipitation anomalies, as suggested by rainfall reconstructions in South America. However, with an ad-hoc definition of these two periods for each model simulation, several coherent large-scale atmospheric circulation anomalies were identified. The models feature a stronger Monsoon during the LIA associated with: (i) an enhancement of the rising motion in the SAMS domain in austral summer, (ii) a stronger monsoon-related upper-troposphere anticyclone, (iii) activation of the South American dipole, which results to a certain extent in a poleward shift in the South Atlantic Convergence Zone and (iv) a weaker upper-level sub tropical jet over South America, this providing important insights into the mechanisms of these climate anomalies over South America during the past millennium.

scholarly journals The South American monsoon variability over the last millennium in climate models

2016 ◽  
Vol 12 (8) ◽  
pp. 1681-1691 ◽  
Author(s):  
Maisa Rojas ◽  
Paola A. Arias ◽  
Valentina Flores-Aqueveque ◽  
Anji Seth ◽  
Mathias Vuille
Keyword(s):  
South America ◽  
Large Scale ◽  
Model Simulation ◽  
Ice Age ◽  
South American ◽  
Last Millennium ◽  
The South ◽  
Model Simulations ◽  
South American Monsoon ◽  
The Past

Abstract. In this paper we assess South American monsoon system (SAMS) variability in the last millennium as depicted by global coupled climate model simulations. High-resolution proxy records for the South American monsoon over this period show a coherent regional picture of a weak monsoon during the Medieval Climate Anomaly and a stronger monsoon during the Little Ice Age (LIA). Due to the small external forcing during the past 1000 years, model simulations do not show very strong temperature anomalies over these two specific periods, which in turn do not translate into clear precipitation anomalies, in contrast with the rainfall reconstructions in South America. Therefore, we used an ad hoc definition of these two periods for each model simulation in order to account for model-specific signals. Thereby, several coherent large-scale atmospheric circulation anomalies are identified. The models feature a stronger monsoon during the LIA associated with (i) an enhancement of the rising motion in the SAMS domain in austral summer; (ii) a stronger monsoon-related upper-tropospheric anticyclone; (iii) activation of the South American dipole, which results in a poleward shift of the South Atlantic Convergence Zone; and (iv) a weaker upper-level subtropical jet over South America. The diagnosed changes provide important insights into the mechanisms of these climate anomalies over South America during the past millennium.

scholarly journals Impact of enriched analyses on regional numerical forecasts over southeastern South America during SALLJEX

2014 ◽  
Vol 29 (3) ◽  
pp. 315-330
Author(s):  
Yanina García Skabar ◽  
Matilde Nicolini
Keyword(s):  
Data Assimilation ◽  
South America ◽  
Atmospheric Modeling ◽  
South American ◽  
The South ◽  
Low Level ◽  
Positive Effects ◽  
Accumulated Rainfall ◽  
Low Level Jet ◽  
The Impact

During the warm season 2002-2003, the South American Low-Level Jet Experiment (SALLJEX) was carried out in southeastern South America. Taking advantage of the unique database collected in the region, a set of analyses is generated for the SALLJEX period assimilating all available data. The spatial and temporal resolution of this new set of analyses is higher than that of analyses available up to present for southeastern South America. The aim of this paper is to determine the impact of assimilating data into initial fields on mesoscale forecasts in the region, using the Brazilian Regional Atmospheric Modeling System (BRAMS) with particular emphasis on the South American Low-Level Jet (SALLJ) structure and on rainfall forecasts. For most variables, using analyses with data assimilated as initial fields has positive effects on short term forecast. Such effect is greater in wind variables, but not significant in forecasts longer than 24 hours. In particular, data assimilation does not improve forecasts of 24-hour accumulated rainfall, but it has slight positive effects on accumulated rainfall between 6 and 12 forecast hours. As the main focus is on the representation of the SALLJ, the effect of data assimilation in its forecast was explored. Results show that SALLJ is fairly predictable however assimilating additional observation data has small impact on the forecast of SALLJ timing and intensity. The strength of the SALLJ is underestimated independently of data assimilation. However, Root mean square error (RMSE) and BIAS values reveal the positive effect of data assimilation up to 18-hours forecasts with a greater impact near higher topography.

scholarly journals Problems and prospects of MERCOSUR as a civilizational political project of South America

2020 ◽  
pp. 1-8
Author(s):  
Mikhail Valer'evich Gorbachev
Keyword(s):  
South America ◽  
The Political ◽  
South American ◽  
Core State ◽  
The South ◽  
Project Approach ◽  
Political Project ◽  
Key Participants ◽  
Further Development

  This article discusses the political projects of civilizational level, which are designed and implemented in South America. The author examines MERCOSUR as the largest regional civilizational political project, its sociocultural foundation and institutional superstructure; functionality of the “core state” in formation and maintenance of the South American civilizational political project; problems of development and future implementation. The article reveals conflict potential of MERCOSUR, as well as sociocultural capabilities for its overcoming by the “core state” of the project. The research was conducted via application of civilizational-project methodology of interpretation of policy, which is based on methodological synthesis of the principles of project approach with provisions of the theory of civilizations. The author was able to determine the value grounds of MERCOSUR, which comprise its sociocultural foundation; identify the countries competing for status of the “core state” within the framework of this project. The nature of commonality between the key participants of the projects is identified. Problems and prospect of further development of MERCOSUR civilizational projects are defined.  

scholarly journals The impact of the subtropical South Atlantic SST on South American precipitation

2008 ◽  
Vol 26 (11) ◽  
pp. 3457-3476 ◽  
Author(s):  
A. S. Taschetto ◽  
I. Wainer
Keyword(s):  
South America ◽  
Southern Oscillation ◽  
South Atlantic ◽  
Empirical Orthogonal Functions ◽  
Convergence Zone ◽  
South American ◽  
The South ◽  
Inter Tropical Convergence Zone ◽  
The Impact ◽  
Sst Anomalies

Abstract. The Community Climate Model (CCM3) from the National Center for Atmospheric Research (NCAR) is used to investigate the effect of the South Atlantic sea surface temperature (SST) anomalies on interannual to decadal variability of South American precipitation. Two ensembles composed of multidecadal simulations forced with monthly SST data from the Hadley Centre for the period 1949 to 2001 are analysed. A statistical treatment based on signal-to-noise ratio and Empirical Orthogonal Functions (EOF) is applied to the ensembles in order to reduce the internal variability among the integrations. The ensemble treatment shows a spatial and temporal dependence of reproducibility. High degree of reproducibility is found in the tropics while the extratropics is apparently less reproducible. Austral autumn (MAM) and spring (SON) precipitation appears to be more reproducible over the South America-South Atlantic region than the summer (DJF) and winter (JJA) rainfall. While the Inter-tropical Convergence Zone (ITCZ) region is dominated by external variance, the South Atlantic Convergence Zone (SACZ) over South America is predominantly determined by internal variance, which makes it a difficult phenomenon to predict. Alternatively, the SACZ over western South Atlantic appears to be more sensitive to the subtropical SST anomalies than over the continent. An attempt is made to separate the atmospheric response forced by the South Atlantic SST anomalies from that associated with the El Niño – Southern Oscillation (ENSO). Results show that both the South Atlantic and Pacific SSTs modulate the intensity and position of the SACZ during DJF. Particularly, the subtropical South Atlantic SSTs are more important than ENSO in determining the position of the SACZ over the southeast Brazilian coast during DJF. On the other hand, the ENSO signal seems to influence the intensity of the SACZ not only in DJF but especially its oceanic branch during MAM. Both local and remote influences, however, are confounded by the large internal variance in the region. During MAM and JJA, the South Atlantic SST anomalies affect the magnitude and the meridional displacement of the ITCZ. In JJA, the ENSO has relatively little influence on the interannual variability of the simulated rainfall. During SON, however, the ENSO seems to counteract the effect of the subtropical South Atlantic SST variations on convection over South America.

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