Inventory of radiocarbon dates from southern Patagonia and Tierra del Fuego

1980 ◽  
Vol 67 (1) ◽  
pp. 185-212 ◽  
Author(s):  
Omar R. Ortiz-Troncoso.
Keyword(s):  
Tierra Del Fuego ◽  
Radiocarbon Dates ◽  
Southern Patagonia

scholarly journals Late Holocene Glacial Fluctuations of Schiaparelli Glacier at Monte Sarmiento Massif, Tierra del Fuego (54°24′S)

Geosciences ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 340 ◽  
Author(s):  
Meier ◽  
Aravena ◽  
Grießinger ◽  
Hochreuther ◽  
Soto-Rogel ◽  
...  
Keyword(s):  
Late Holocene ◽  
Tierra Del Fuego ◽  
Pioneer Species ◽  
Total Uncertainty ◽  
Radiocarbon Dates ◽  
Terminal Moraine ◽  
Mountain Glaciers ◽  
Southern Patagonia ◽  
Glacial Dynamics ◽  
Western Side

The Magallanes–Tierra del Fuego region, Southern Patagonia (53–56°S) features a plethora of fjords and remote and isolated islands, and hosts several thousand glaciers. The number of investigated glaciers with respect to the multiple Neoglacial advances is based on a few individual studies and is still fragmentary, which complicates the interpretation of the glacial dynamics in the southernmost part of America. Schiaparelli Glacier (54°24′S, 70°50′W), located at the western side of the Cordillera Darwin, was selected for tree-ring-based and radiocarbon dating of the glacial deposits. One focus of the study was to address to the potential dating uncertainties that arise by the use of Nothofagus spp. as a pioneer species. A robust analysis of the age–height relationship, missing the pith of the tree (pith offset), and site-specific ecesis time revealed a total uncertainty value of ±59 years. Three adjacent terminal moraines were identified, which increasingly tapered towards the glacier, with oldest deposition dates of 1749 ± 5 CE, 1789 ± 5 CE, and 1867 ± 5 CE. Radiocarbon dates of trunks incorporated within the terminal moraine system indicate at least three phases of cumulative glacial activity within the last 2300 years that coincide with the Neoglacial phases of the Southern Patagonian Icefield and adjacent mountain glaciers. The sub-recent trunks revealed the first evidence of a Neoglacial advance between ~600 BCE and 100 CE, which so far has not been substantiated in the Magallanes–Tierra del Fuego region.

Hieracium pilosella invasion in the Tierra del Fuego steppe, Southern Patagonia

2009 ◽  
Vol 12 (8) ◽  
pp. 2523-2535 ◽  
Author(s):  
P. A. Cipriotti ◽  
R. B. Rauber ◽  
M. B. Collantes ◽  
K. Braun ◽  
C. Escartín
Keyword(s):  
Tierra Del Fuego ◽  
Hieracium Pilosella ◽  
Southern Patagonia

Salicornia cuscoensis (Amaranthaceae/Chenopodiaceae), a new species from Peru (South America)

Phytotaxa ◽  
2017 ◽  
Vol 319 (3) ◽  
pp. 254 ◽  
Author(s):  
M. ÁNGELES ALONSO ◽  
MANUEL B. CRESPO ◽  
HELMUT FREITAG
Keyword(s):  
New Species ◽  
South America ◽  
Morphological Characters ◽  
Tierra Del Fuego ◽  
South American ◽  
Habitat Distribution ◽  
Closely Related Species ◽  
Molecular Analyses ◽  
Southern Patagonia ◽  
A New Species

The name Salicornia cuscoensis given to a plant from high Andean saltmarshes near Cusco [Cuzco] and Ayacucho, Peru (South America) is validated by a diagnosis and description. The main morphological characters that separate S. cuscoensis from other closely related species are creeping habit, delicate branches, inflorescence of short and thin spikes, and seed indumentum. The new species clearly differs from other perennial Salicornia taxa growing in high Andean saltmarshes such as S. pulvinata and S. andina. The former forms small compact cushions producing very short, few-flowered inflorescences. The latter shows woody stems and forms larger rounded carpets. Morphologically, S. cuscoensis is also similar to S. magellanica, a species growing along the seashore in southern Patagonia and Tierra del Fuego, but the latter has shorter and wider inflorescences and larger seeds with a different type and arrangement of indumentum. Molecular analyses also supported the separation of S. cuscoensis. Data on habitat, distribution and phylogenetic relationships are presented for the new species and its relatives, and an identification key is given for the South American taxa of the genus Salicornia.

The supposed discovery of South Georgia by Amerigo Vespucci

Polar Record ◽  
1950 ◽  
Vol 5 (40) ◽  
pp. 560-564
Author(s):  
E. W. H. Christie
Keyword(s):  
Tierra Del Fuego ◽  
South Georgia ◽  
Southern Patagonia ◽  
History Of ◽  
Working Out

There have been few more controversial figures in the history of exploration than Amerigo Vespucci, and it is therefore necessary to be extremely cautious in deciding whether he did, or did not, discover the island of South Georgia in the year 1501. Humboldt and Mill believed that he might have done so, but thought that, on the whole, his most likely landfall was southern Patagonia or Tierra del Fuego. Matthews, who devoted considerable attention to working out distances and directions, came to the conclusion that Vespucci very probably arrived at South Georgia after leaving the coast of Brazil and sailing south-westwards, while the Australian map of Antarctica, published in Canberra in 1939, and the Antarctic Pilot (London, second edition, 1948) have respectively described this achievement as a probability and as a possibility.

The Pallid Falcon Falco kreyenborgi Is a Color Phase of the Austral Peregrine Falcon (Falco peregrinus cassini)

The Auk ◽  
1983 ◽  
Vol 100 (2) ◽  
pp. 269-271 ◽  
Author(s):  
David H. Ellis ◽  
Cesar Peres Garat
Keyword(s):  
Tierra Del Fuego ◽  
Peregrine Falcon ◽  
Falco Peregrinus ◽  
Rare Form ◽  
Patagonian Steppe ◽  
Full Species ◽  
Southern Patagonia

Abstract The Pallid Falcon (Falco kreyenborgi), a rare form from southern Patagonia and Tierra del Fuego, has, since its discovery in 1925, gained acceptance as a full species. In 1981, we observed 13 Pallid Falcons on the Patagonian Steppe. Four adult Pallid Falcons were paired with normal Peregrine Falcon (Falco peregrinus cassini) mates. Two normal-phased peregrine pairs produced mixed broods of normal and pallid young. One pair of pallid adults produced only pallid young. These observations lead to the conclusion that the Pallid Falcon is conspecific with and a color phase of the Peregrine Falcon.

Late Quaternary Vegetation and Climate of Southern Tierra del Fuego

1989 ◽  
Vol 31 (3) ◽  
pp. 396-406 ◽  
Author(s):  
Calvin J. Heusser
Keyword(s):  
Late Quaternary ◽  
Pollen Dispersal ◽  
Late Glacial ◽  
Tierra Del Fuego ◽  
Fossil Pollen ◽  
Radiocarbon Dates ◽  
Modern Pollen ◽  
Open Woodland ◽  
Glacial Time ◽  
Vegetation And Climate

AbstractVegetation and climate over approximately the past 13,000 yr are reconstructed from fossil pollen in a 9.4-m mire section at Caleta Róbalo on Beagle Channel, Isla Navarino (54°56′S, 67°38′W), southern Tierra del Fuego. Fifty surface samples reflecting modern pollen dispersal serve to interpret the record. Chronologically controlled by nine radiocarbon dates, fossil pollen assemblages are: Empetrum-Gramineae-Gunnera-Tubuliflorae (zone 3b, 13,000–11,850 yr B.P.), Gramineae-Empetrum-assorted minor taxa (zone 3a, 11,850-10,000 yr B.P.), Nothofagus-Gramineae-Tubuliflorae-Polypodiaceae (zone 2, 10,000–5000 yr B.P.), Nothofagus-Empetrum (zone 1b, 5000-3000 yr B.P.), and Empetrum-Nothofagus (zone 1a, 3000-0 yr B.P.). Assemblages show tundra under a cold, dry climate (zone 3), followed by open woodland (zone 2), as conditions became warmer and less dry, and later, with greater humidity and lower temperatures, by closed forest and the spread of mires (zone 1). Comparisons drawn with records from Antarctica, New Zealand, Tasmania, and the subantarctic islands demonstrate broadly uniform conditions in the circumpolar Southern Hemisphere. The influences of continental and maritime antarctic air masses were apparently considerable in Tierra del Fuego during cold late-glacial time, whereas Holocene climate was largely regulated by interplay between maritime polar and maritime tropical air.

scholarly journals Variable retention harvesting influences belowground plant-fungal interactions of Nothofagus pumilio seedlings in forests of southern Patagonia

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5008 ◽  
Author(s):  
Rebecca E. Hewitt ◽  
Donald Lee Taylor ◽  
Teresa N. Hollingsworth ◽  
Christopher B. Anderson ◽  
Guillermo Martínez Pastur
Keyword(s):  
Soil Moisture ◽  
Community Composition ◽  
Conservation Status ◽  
Tierra Del Fuego ◽  
Primary Forest ◽  
Nothofagus Pumilio ◽  
Variable Retention ◽  
Seedling Biomass ◽  
Rdna Sequencing ◽  
Southern Patagonia

Background The post-harvest recovery and sustained productivity of Nothofagus pumilio forests in Tierra del Fuego may be affected by the abundance and composition of ectomycorrhizal fungi (EMF). Timber harvesting alters EMF community structure in many managed forests, but the impacts of harvesting can vary with the management strategy. The implementation of variable retention (VR) management can maintain, increase, or decrease the diversity of many species, but the effects of VR on EMF in the forests of southern Patagonia have not been studied, nor has the role of EMF in the regeneration process of these forests. Methods We evaluated the effects of VR management on the EMF community associated with N. pumilio seedlings. We quantified the abundance, composition, and diversity of EMF across aggregate (AR) and dispersed (DR) retention sites within VR managed areas, and compared them to primary forest (PF) unmanaged stands. EMF assemblage and taxonomic identities were determined by ITS-rDNA sequencing of individual root tips sampled from 280 seedlings across three landscape replicates. To better understand seedling performance, we tested the relationships between EMF colonization, EMF taxonomic composition, seedling biomass, and VR treatment. Results The majority of EMF taxa were Basidiomycota belonging to the families Cortinariaceae (n = 29), Inocybaceae (n = 16), and Thelephoraceae (n = 8), which was in agreement with other studies of EMF diversity in Nothofagus forests. EMF richness and colonization was reduced in DR compared to AR and PF. Furthermore, EMF community composition was similar between AR and PF, but differed from the composition in DR. EMF community composition was correlated with seedling biomass and soil moisture. The presence of Peziza depressa was associated with higher seedling biomass and greater soil moisture, while Inocybe fibrillosibrunnea and Cortinarius amoenus were associated with reduced seedling biomass and lower soil moisture. Seedling biomass was more strongly related to retention type than EMF colonization, richness, or composition. Discussion Our results demonstrate reduced EMF attributes and altered composition in VR treatments relative to PF stands, with stronger impacts in DR compared to AR. This suggests that VR has the potential to improve the conservation status of managed stands by supporting native EMF in AR. Our results also demonstrate the complex linkages between retention treatments, fungal community composition, and tree growth at individual and stand scales.

scholarly journals Cushion bog plant community responses to passive warming in southern Patagonia

2021 ◽  
Vol 18 (16) ◽  
pp. 4817-4839
Author(s):  
Verónica Pancotto ◽  
David Holl ◽  
Julio Escobar ◽  
María Florencia Castagnani ◽  
Lars Kutzbach
Keyword(s):  
Carbon Dioxide ◽  
Plant Community ◽  
Plant Traits ◽  
Ecosystem Respiration ◽  
Vascular Plant ◽  
Carbon Dioxide Flux ◽  
Tierra Del Fuego ◽  
Near Surface ◽  
Passive Warming ◽  
Southern Patagonia

Abstract. Vascular plant-dominated cushion bogs, which are exclusive to the Southern Hemisphere, are highly productive and constitute large sinks for atmospheric carbon dioxide compared to their moss-dominated counterparts around the globe. In this study, we experimentally investigated how a cushion bog plant community responded to elevated surface temperature conditions as they are predicted to occur in a future climate. We conducted the study in a cushion bog dominated by Astelia pumila on Tierra del Fuego, Argentina. We installed a year-round passive warming experiment using semicircular plastic walls that raised average near-surface air temperatures by between 0.4 and 0.7 ∘C (at the 3 of the 10 treatment plots which were equipped with temperature sensors). We focused on characterizing differences in morphological cushion plant traits and in carbon dioxide exchange dynamics using chamber gas flux measurements. We used a mechanistic modeling approach to quantify physiological plant traits and to partition the net carbon dioxide flux into its two components of photosynthesis and total ecosystem respiration. We found that A. pumila reduced its photosynthetic activity under elevated temperatures. At the same time, we observed enhanced respiration which we largely attribute, due to the limited effect of our passive warming on soil temperatures, to an increase in autotrophic respiration. Passively warmed A. pumila cushions sequestered between 55 % and 85 % less carbon dioxide than untreated control cushions over the main growing season. Our results suggest that even moderate future warming under the SSP1-2.6 scenario could decrease the carbon sink function of austral cushion bogs.

scholarly journals Valve morphology of Didymosphenia geminata (Bacillariophyceae) from Santa Cruz and Tierra del Fuego provinces, Patagonia, Argentina.

2020 ◽  
Vol 55 (4) ◽  
Author(s):  
Noelia M. Uyua ◽  
Silvia E. Sala ◽  
Norma H. Santinelli ◽  
Alicia V. Sastre ◽  
Juan I. Cortés ◽  
...  
Keyword(s):  
Light And Electron Microscopy ◽  
Central Area ◽  
Point Of View ◽  
Tierra Del Fuego ◽  
Santa Cruz ◽  
Didymosphenia Geminata ◽  
Valve Morphology ◽  
Massive Growth ◽  
Southern Patagonia ◽  
Morphology And Morphometry

Background and aims: In 2013, blooms similar to those produced by Didymosphenia geminata (Lyngbye) M. Schmidt around the world, were detected in the Grande River basin, Tierra del Fuego province, and in 2014 in de las Vueltas River in Santa Cruz province. The aim of this paper is to analyze the valve morphology and morphometry of these materials to establish if they correspond to D. geminata or to other species of the genus that is producing the massive growth in southern Patagonia. M&M: Samples were collected at Grande River in 2013 and 2015 and, in de las Vueltas River in 2015 and 2016. Samples were analyzed with light and electron microscopy. For morphometric analyses 100 specimens from each sample were measured and statistical analyses were carried out using the R statistical package. Results: The studied populations have the same fine morphology described for other populations collected in Patagonia. Nevertheless, in some sampling sites from Santa Cruz province, we found a morphotype with a markedly smaller size, subcapitated poles, little marked constrictions of the poles, a broad central area (relative to cell size) and 1 to 3 stigmata, that was never reported in South America. Conclusions: The studied populations correspond to D. geminata ssp. geminata Metzeltin & Lange-Bertalot. From a morphological point of view the smaller morphotype present in Santa Cruz belongs to the same subspecies but can be easily misidentified during the routine monitoring programs carried out with light microscope due its size and valve outline.

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