Tierra Del Fuego Island Research Articles

Early peopling and evolutionary diversification in America

Several cranial-functional studies were made to compare the major (neurocranium and face) and minor (anteroneural, midneural, posteroneural, otic, optic, respiratory, masticatory, and alveolar) cranial components in different human populations. In the present study, samples from Paleoamericans and ancient and modern Amerindians from Valley of Mexico, Lagoa Santa, Tierra del Fuego Island, and Minas Gerais (Botocudos) were compared. The aim was to test the hypotheses that (1) “There are non-significant differences in the functional cranial components of different Paleoamerican crania, since they proceeded from a single dispersive effect” and that (2) “The biological variability of Paleoamerican and Amerindian functional cranial components was produced by random diversification evoked—after migration—by stochastic evolution”. Its acceptance will hold the criterion of temporal discontinuity between “megapopulations”, with a high incidence of migration and genetic drift. Its rejection will mean that Paleoamericans were not a morphologically homogeneous substratum, and that further populations could have—at least in part—originated from one or several central nuclei highly diversified by non-stochastic processes, like selection and adaptation. Multivariate (discriminant analysis and hierarchical clusters) were employed to get a general sample distribution. Univariate between-group standardized sD 2 distances were calculated to measure absolute and relative within-component differences. Statistical analyses were performed by the SYSTAT 9 program. Results lead us to reject both null hypotheses, suggesting that: (1) some cranial-functional differences were evident between both Paleoamerican samples, and (2) that several adaptative trends from Paleoamericans to modern Amerindians, and between Amerindians, might have occurred. It was concluded that adaptation could explain a fraction of the non-detectable cranial variation by the non-functional craniometric methods not explained by the “migration-drift” model for the American diversification.

When Patagonia was colonized: people mobility at high latitudes during Pleistocene/Holocene transition

The Pleistocene–Holocene transition was a critical time for the dispersal of human societies all over South America. People looking for places to settle had to accept high environmental variability during the colonizing process. The case studied for this paper is Patagonia (Southern South America), where the oldest dates (ca. 13–10.5 ka BP) have been obtained for the peopling in the Deseado River Basin and Magellan Basin, as well. However, two archaeological sites yielded similar dates on the western side of the Andes (Monte Verde and Tagua Tagua). Following archaeological and palaeoenvironmental data (palynological, faunal, sedimentological and glaciological information), as well as radiocarbon datings, a hypothesis about the colonization of Patagonia is presented. Analysing the ways and time of colonization for this region, it is remarkable the coincidence of these ages in the centre of the steppe and close to the Magellan Strait, even in the present Tierra del Fuego island, though the eastern Andean foothills seems to be occupied at least two millennia later. It is proposed that independent peopling entries would have occurred both through the Atlantic and Pacific facades, and that the Andean foothills were colonized much later, only when the available spaces allowed it.

Invaders without frontiers: cross-border invasions of exotic mammals

We address cross-border mammal invasions between Chilean and Argentine Patagonia, providing a detailed history of the introductions, subsequent spread (and spread rate when documented), and current limits of mammal invasions. The eight species involved are the following: European hare (Lepus europaeus), European rabbit (Oryctolagus cuniculus), wild boar (Sus scrofa), and red deer (Cervus elaphus) were all introduced from Europe (Austria, France, Germany, and Spain) to either or both Chilean and Argentine Patagonia. American beaver (Castor canadensis) and muskrat (Ondatra zibethicus) were introduced from Canada to Argentine Tierra del Fuego Island (shared with Chile). The American mink (Mustela vison) apparently was brought from the United States of America to both Chilean and Argentine Patagonia, independently. The native grey fox (Pseudalopex griseus) was introduced from Chilean to Argentine Tierra del Fuego. Few spread rates are available: the lowest are 10 km/yr and correspond to American beaver and American mink; intermediate rates are observed in muskrat and rather questionably, in grey fox; the highest rates (10–20 km/yr) are found among European hare and European rabbit. Because of their frequent migration, it is difficult to estimate the natural spread rate for wild boar and red deer. Not all mammal invasions in Chilean and Argentine Patagonia have been methodical advances of species; some involve an overlap of invasion fronts, with advances and retreats, and perhaps with re-invasions to different areas of either country. Because national policies with regard to introduced species may differ between countries sharing porous borders, it seems advisable to coordinate such policies in order to prevent the entry of unwelcome invaders.

Banded vegetation patterning in a subantarctic forest of Tierra del Fuego, as an outcome of the interaction between wind and tree growth

Abstract Banded patterns have been investigated in a Nothofagus betuloides primeval forest from Bahia del Buen Suceso, on the eastern edge of Tierra del Fuego island (Argentina). These forests grow on spodosols developed upon silicic shales, in a cold oceanic climate, with 5 °C mean annual temperature and 600 mm mean annual rainfall. Bands are oriented perpendicular to the prevailing wind direction, with older and dying trees in the windward edge and a seedling regrowth in the lee side of each band. Forest structure, species composition and relevant soil properties were sampled in a wind-affected forest and in an undisturbed stand. In the former, samples were obtained in transects across the banding and along a hill-slope gradient. Results show that wind causes about 50 % reduction of stand basal area and of size of overstorey trees. Stand growth processes, such as self-thinning, basal area and height growth, and specific composition of the understorey, occur in a windward direction, as well as changes in soil properties such as C/N ratio and redox potential increase. Based on field observations, we have developed an hypothesis of how wind is able to generate this pattern. Its core is that bands develop when vulnerability of trees to wind damage increases with age and with lack of protection from older windward trees. In such conditions, bands are the outcome of a tuning between tree growth rates and wind killing capacity. On the basis of this hypothesis, a simulation model, based on the cellular automata approach, was constructed. Simulated patterns that arise from heterogeneous forests with random age distributions match successfully with those observed in nature. Increasing tree growth rates lead to longer wavelengths and higher wave propagation rates, while increasing wind killing potential leads to shorter wavelengths and lower propagation rates. This interpretation of banded patterning involves a resonance between a directional disturbance and an oscillatory process, such as stand regeneration, growth and decay.

The potential for production of high quality seed potatoes in Tierra del Fuego Island, Argentina

In Argentina, different areas are suitable for seed potato production: however, each has particular problems, mainly related to different pest and diseases. Tierra del Fuego Island is well isolated from traditional potato growing areas. Therefore, it was tested for its potential for seed production. The cultivars Achatt. Mailen INTA. Pampeana INTA and Spunta were grown in Rio Grande, San Pablo and Ushuaia from 1991–1994. Nematode presence and aphid population dynamics were recorded. Average tuber yield ranged from 20.1–37.6 t ha−1. After three years PVY and PLRV remained low (0–1% for different cultivars and locations). Moreover, seed tubers obtained were physiologically young. Long days, early frosts and strong winds may limit tuber yield in some years. The island can be considered as an ecological “safe haven” and is very suitable to obtain healthy and physiologically adequate seed potatoes.

Foraminíferos uniloculares calcáreos del Eoceno medio-superior y Oligoceno inferior, Isla Grande de Tierra del Fuego y plataforma continental adyacente, Argentina

Unilocular calcareous Foraminifera of the middle-upper Eocene and lower Oligocene from Tierra del Fuego Island and adjacent continental platform, Argentina. The calcareous unilocular Foraminifera of the Leticia Formation (upper middle Eocene), Cerro Colorado Formation (upper middle Eocene-upper Eocene) and the Cabo Peña Formation (lower Oligocene) from Tierra del Fuego Island are described. The Leticia Formation yields scarce unilocular foraminifers that are characterized by species described from the Maastrichtian and the lower Eocene, including Conolagena argentina , C . acuticosta and Sipholagena sp. The Cerro Colorado Formation bears 29 species, almost the half of which (both individuals and species) belong to the Genus Fissurina , with Fissurina bisulcata occurring as the most abundant taxon. The formation also contains species characteristic of either Antarctic waters or the Malvinas current, reflecting the temperature decrease in the oceanic waters during the middle-late Eocene. The Cabo Peña Formation, which contains the Spirosigmoilinella-Martinottiella Assemblage typical of the Antarctic region, yielded 19 species; the dominant unilocular species belong to the genera Fissurina and Parafissurina , and the most conspicuous are fimbriate forms, such as F. fimbriata and F. fueguina, which are associated with Antarctic waters.

Eocene Stratigraphy of Southeastern Tierra del Fuego Island, Argentina

Recognizing folded and thrusted Eocene foreland strata of the oil-producing Austral Basin provides new insights on the Paleogene evolution of Tierra del Fuego Island and the adjacent Atlantic shelf. Field mapping and petrographic and micropaleontologic studies at the Punta Torcida anticline depict an Eocene composite section about 1600 m thick assigned to the La Despedida Group. This group is divided into three formations: Punta Torcida (215 m), Leticia (520 m), and Cerro Colorado (855 m). These formations are subdivided into informal members. In the Punta Torcida Formation the lower member is composed of dark-gray mudstones with thin sandstone beds. The middle member of the Punta Torcida contains mudstones with small sandstone lenses. Both the lower and middle members have a high radiolarian content. The upper member contains mudstones. Lithologic succession, presence of pyrite, and a well-preserved benthic assemblage having little diversification suggest a regressive sequence formed in shelf settings with a dysaerobic to anoxic bottom. Planktonic foraminifera indicate a Ypresian age (equivalent to upper Zone P6 to basal Zone P9 tropical planktonic zones). In the Leticia Formation the lower and upper members are glauconite rich, highly bioturbated sandstones; in the middle member, rich in pyrite and carbonized plant material, the glauconite is rare or absent. Large channels, filled with cross-stratified sandstone lenses and having a general absence of planktonic foraminifera, suggest estuarine, restricted-marine settings. Planktonic foraminifera indicate a late-middle Eocene age (basal Zone P12 to middle of Zone P14) indicating a hiatus with the underlying Punta Torcida Formation. The Cerro Colorado Formation, a coarsening- and thickening-upward succession of mudstones and sandstones, is a major, shelfal transgressive-regressive sequence punctuated by minor deepening and shallowing. Its four members record different benthic assemblages that reflect cooling waters. The uppermost member bears abundant radiolarians and planktonic foraminifera typical of an oxygen-minimum habitat and indicating a late Eocene age (upper Zone P15 to upper Zone P16). The microfauna and stratigraphic position of the lower three members are consistent with a latest middle Eocene age (middle of Zone P14 to lower Zone P15). In preliminary observations on the outcrop area of Late Cretaceous-Paleogene strata between Cabo San Pablo and Bahia Thetis, two important angular unconformities were recorded: one at the contact between the Estratos de Policarpo and the Rio Bueno-La Despedida Group, and the other at the contact between the La Despedida Group and the Cabo Pena-Rio Leona formations.

Some spores and pollen from the Cullen formation (upper Eocene to middle Oligocene), Tierra del Fuego, Argentina

Abstract The Cullen Formation is exposed in the northeastern part of Tierra del Fuego Island; it is dated as Late Eocene to middle Oligocene on the basis of palynology. In this paper, 21 palynomorphs from the type locality of the formation are recorded, 13 of which have been previously described. Notable taxa include Baculatisporites comaumensis (Cookson 1953) Potonie 1956, Catinipollis geiseltalensis Krutzsch 1966, Crassiorites australis gen. et sp. nov., Lycopodiumsporites eminulus Dettmann 1963, Malvacipollis argentina sp. nov., Nothofagidites suggatei (Couper 1953) Hekel 1972, Phyllocladidites mawsonii Cookson 1947 ex Couper 1953, and Reboulisporites fuegiensis gen. et sp. nov. All of these species can be assigned to extant families with a high degree of confidence. The occurrence of M. argentina and C. australis is consistent with the hypothesis of a southern origin of Malvaceae and Onagraceae.

Rabbit and fox introductions in tierra del fuego: history and assessment of the attempts at biological control of the rabbit infestation

Four European rabbits Oryctolagus cuniculus were introduced in the Chilean side of Tierra del Fuego island in 1936. At the height of the rabbit infestation (1953) they numbered about 30 million. Twenty-four foxes Dusicyon griseus were released in Tierra del Fuego in 1951, three years before the myxoma virus decimated the rabbit populations. We document the history of the introductions of both rabbits and foxes in Tierra del Fuego, and evaluate the role of foxes as biological-control agents for the rabbits.

Influence of Man on the Distribution of Reptiles and Mammals in Patagonia and Fuegia

Previous articleNext article FreeNotes and LiteratureInfluence of Man on the Distribution of Reptiles and Mammals in Patagonia and FuegiaJ. B. HatcherJ. B. Hatcher Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 38, Number 448Apr., 1904 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/278402 Views: 85Total views on this site Citations: 1Citations are reported from Crossref PDF download Crossref reports the following articles citing this article:William L. Franklin Guanaco colonisation of Tierra del Fuego Island from mainland Patagonia: Walked, swam, or by canoe?, Geo: Geography and Environment 9, no.22 (Jul 2022).https://doi.org/10.1002/geo2.110