Tierra Del Fuego Research Articles

La acción de los expertos en contexto: La aplicación de la política de protección de bosques nativos en cuatro provincias argentinas

In the light of the technical complexity required for the design of environmental policies, we ask: What are the factors that influence the role of experts and the use of their knowledge in the design of an environmental policy? How is the political and economic context linked to the role of experts? We distinguish between two types of experts (proactive and advisory) and depart from the working hypothesis that experts will be more proactive in contexts of greater economic-environmental conflict over land uses and greater political plurality. To answer our questions, we compare the application of the National Law on Native Forests in the Argentine provinces of Formosa, Mendoza, Santa Cruz and Tierra del Fuego between 2008 and 2012. Our findings show that experts play a proactive role in contexts of greater economic-environmental conflict but not necessarily in contexts of greater political plurality.

Paleomagnetic Constraints From South Georgia on the Tectonic Reconstruction of the Early Cretaceous Rocas Verdes Marginal Basin System of Southernmost South America

AbstractSouth Georgia exists as a microcontinent along the North Scotia Ridge ∼1,700 km east of Cape Horn. The tectonostratigraphic units of South Georgia have long been correlated with those of the Fuegian Andes of southernmost South America. Accordingly, South Georgia has been regarded as a continuation of the Late Jurassic–Early Cretaceous Rocas Verdes marginal basin system, formerly situated south of Burdwood Bank and east of Cape Horn. To test this, paleomagnetic analysis of samples from the Larsen Harbour Complex, Drygalski Fjord Complex, and Annenkov Island Formation of South Georgia showed that 21 sites yield a mean direction of D = 328.5°, I = −62.1° (a95 = 3.5°) and a paleomagnetic pole at 068.2°E, 67.2°N, A95 = 4.7°. The consistency of directions and strong polarity bias, plus indications of a negative differential tilt test, point to a secondary magnetization acquired in the Late Cretaceous. Comparison of predicted versus observed directions for South Georgia relative to stable South America indicate 27.2 ± 11.2° of counter‐clockwise rotation (and 10.5° ± 4.5° of northward tilting) since the acquisition of magnetization. These results are consistent with paleomagnetic studies from the Fuegian Andes and support a paleoposition of the South Georgia microcontinent south of Burdwood Bank as strongly indicated by the geologic evidence. Partitioning this rotation between oroclinal bending during the Rocas Verdes basin collapse in the Late Cretaceous and left‐lateral translation along the North Scotia Ridge is not possible on paleomagnetic grounds, but the co‐linearity of Andean structures between the restored microcontinent and Tierra del Fuego indicates the former.

Mercury transfer in coastal and oceanic food webs from the Southwest Atlantic Ocean

The dynamics of contaminants, such as mercury (Hg), in marine trophic webs is a critical topic in the scientific community due to the high concentrations encountered in organisms. In this study we attempted to provide information on total Hg accumulation patterns and possible pathways of trophic transfers assessed in combination with δ13C and δ15N to understand how this contaminant permeates three sub-Antarctic food webs: the Beagle Channel (BC), the Atlantic coast of Tierra del Fuego (AC-TDF) and Burdwood Bank (BB). We found a site-specific pattern of Hg transfer and biomagnification processes, while the oceanic BB showed major Hg transfer through the pelagic domain, coastal sectors (BC and AC-TDF) indicate a general biodilution process but with Hg concentrations incrementing with the benthivory grade. This represents a dissimilar Hg bioavailability for marine consumers that rely on different diet and forage in different habitats, and may become an issue of important conservation concern for these southern areas.

A new bee genus from the pampas of eastern Argentina, with appended notes on the classification of “paracolletines” (Hymenoptera: Colletidae)

A new genus and species are described and figured from the eastern pampas of Tandil, Argentina. Aenarete roigi Engel & Gonzalez, new genus and species, is quite similar to Spinolapis Moure (here used in a restricted sense), occurring in southern Chile, and particularly Patagoniapis Engel, new genus (type species: Pasiphae cyanea Cockerell) from further southward in Argentina (Rio Negro to Tierra del Fuego). The genus is distinguished from these two genera and other South American “paracolletines”. Given the employment of different concepts for “paracolletine” genera herein and in recent published works relative to the classification outlined by Michener, a revised key to these groups is appended based on the genera as envisioned by the authors. This necessitates making available the following new taxa (eight new subtribes, 20 new genera, 13 new subgenera): Aageocolletes Engel, new genus; Aglaocolletes Engel, new genus; Asciocolletes Engel, new genus; Baeocolletina Engel, new subtribe; Bicolletopsis Engel, new subgenus of Bicolletes Friese; Calloproctus Engel, new genus; Chilicolletina Engel, new subtribe; Chrysopasiphae Engel, new genus; Conospermapis Engel, new genus; Cyanopasiphae Engel, new subgenus of Bicolletes; Cygnella Engel, new subgenus of Euryglossidia Cockerell; Cyranocolletes Engel, new genus; Damocrateia Engel, new genus; Donovanapis, new subgenus of Leioproctus Smith; Eremocolletes Engel, new genus; Erythropasiphae Engel, new subgenus of Bicolletes; Hexaproctus Engel, new genus; Houstoniella Engel, new subgenus of Eremocolletes; Kanakapis Engel, new subgenus of Lamprocolletes Smith; Leucopasiphae Engel, new subgenus of Perditomorpha Ashmead; Lonchorhynchina Engel & Gonzalez, new subtribe; Manocolletes Engel, new subgenus of Euryglossidia; Machaerocolletes Engel, new genus; Maoricolletes Engel, new subgenus of Leioproctus; Maynardapis Engel, new genus; Nanopasiphae Engel, new genus; Niltoniina Engel, new subtribe; Notinopasiphae Engel, new subgenus of Euryglossidia; Packercolletes Engel, new genus; Perditomorphina Engel, new subtribe; Phenacolletina Engel, new subtribe; Rhamphocolletes Engel, new genus; Ruzopria Engel, new subgenus of Belopria Moure; Sarocolletidion Engel, new genus; Spinolapina Engel, new subtribe; Sthenele Engel, new genus; Stilbopasiphae Engel, new genus; Stoclele Engel, new subgenus of Lamprocolletes; Torocolletina Engel, new subtribe; Walkerapis Engel, new genus; Zyzzocolletes Engel, new genus.

Updated distribution of the diatom Didymosphenia geminata (Lyngbye) Schmidt in Tierra del Fuego, Patagonia

In this study, we report new observations on the distribution of the invasive diatom Didymosphenia geminata on the island of Tierra del Fuego, southern Patagonia. We present new findings as well as data collected by the monitoring programme of the Government of the Tierra del Fuego. Didymosphenia geminata was first reported from the island in 2013, in the watershed of the Rio Grande, northeast of the island. In 2017, it was found in the Lapataia River, within the Tierra del Fuego National Park. More recently, we detected its presence at two more sites; one in Lake Fagnano, and in the Arroyo Grande, near the city of Ushuaia. Hence, in eight years, this invasive diatom has spread and reached the southern part of the island despite prevention measures applied in protected areas since 2014. Although D. geminata is already in Tierra de Fuego, the island is home to many water bodies with high conservation value. Monitoring the range expansion of this invasive diatom should continue since prevention is the only tool to prevent further expansion. This is particularly important because Ushuaia, in the southern part of the island, is a port from which many tourist companies depart for Antarctica, a continent not yet impacted by D. geminata.

Horizontal and Vertical Deformation Rates Linked to the Magallanes‐Fagnano Fault, Tierra Del Fuego: Reconciling Geological and Geodetic Observations by Modeling the Current Seismic Cycle

AbstractWe integrate geodetic, geological and seismological observations in Tierra del Fuego, into a consistent and quantitative analysis, to better understand the current crustal deformation associated to the Magallanes‐Fagnano Fault, that is, the transform boundary between the South American and Scotia plates at the southern tip of Patagonia. To obtain reliable geodetic estimates of the thickness of the seismogenic layer, we model the current seismic cycle from the great 1949 Mw ≃ 7.7 earthquake to the present, including the lasting effects of postseismic relaxation. The model parameters are constrained by Global Navigation Satellite System velocities obtained by reprocessing 24 years of observations in the island with up‐to‐date models and satellite products. We combine the observed deformation rates with long‐term geological estimates of the slip rate in this transform system during the Holocene. The modeling results point to a seismogenic layer thickness of 15 ± 3 km and to fault planes inclined 63° ± 4°, dipping to the South. Along the sections of the Magallanes‐Fagnano Fault in the island these results are consistent with a seismic moment deficit rate, per unit of length, of 3.2 ± 0.8 × 1012 N m a−1 km−1, and a cumulative seismic moment, to date, equivalent to an earthquake of magnitude Mw ≃ 7. The postseismic viscoelastic relaxation, probably related to viscous flow in the mantle, affects the entire region up to ∼200 km away from the Magallanes‐Fagnano Fault, and more than 60 years after the earthquake.

En los confines del mundo: etnografía histórica de la migración transnacional de chilotes en Ushuaia, Tierra del Fuego, Argentina

The article shows etnhographic findings on the migratory experiences of chilotes in Ushuaia, Tierra del Fuego, Argentina, between the years 1947-2018. The objective of this work is to understand the creative strategies that the chilotes designed in their settlement processes, associated with the formation of communities, the re-signification of the notion of home and the circulation of nostalgia merchandise. The methodological approach followed the perspective of multi-sited ethnography, wich consisted in the development of fieldwork between Chiloé and Ushuaia, collecting information through the review of Historical documents, in-depth interviews and round tables. The results show the stage of chilote settlement after the closure of the prisión in 1947 and its effects on the consolidation processes of the community in the middle 1990’s.

Colección de referencia de maderas para el estudio del registro antracológico del litoral Atlántico Patagonia Sur de la República Argentina (Provincias de Santa Cruz y Tierra del Fuego)

In the archaeological sites of hunter-gatherer societies in Patagonia, carbonized woody plant macro-remains are the most frequent and ubiquitous of the archaeobotanical record. For this reason, it is essential to create a reference collection that allows a correct identification and interpretation of anthracological remains and to infer collection and management practices. The objective of this work is to present the reference collection of woods potentially used by hunter-gatherer societies of the southern coast of Patagonia and the island of Tierra del Fuego. In addition, to create dichotomous keys and to apply the results obtained to the identification of archaeological charcoals from two archaeological sites of the late Holocene of the southern Atlantic coast of Patagonia and Tierra del Fuego (Palo Alto and CSP2017). The importance of this work is due to the few anatomical descriptions for many of the species of the Atlantic coast of Patagonia, especially for taxa that do not have commercial use.

Submerged landscape evolution of the Beagle Channel: context of the first record of underwater archaeological evidence

ABSTRACT We analyze the finding of a lithic projectile point at more than 100 meters depth in the Beagle Channel (Tierra del Fuego, Argentina) in relation to submerged landscapes. On the one hand, this underwater evidence is examined as part of an inundated archaeological landscape supporting the hypothesized Pleistocene coastal dispersion in southern South America. On the other hand, the lithic projectile point is evaluated as a submerged isolated artefact as the result of human movements through aquatic environments due to foraging and transport practices in the sea during the Holocene. Technological properties and post-depositional modifications of the projectile point are described, and the artefact location is assessed in light of paleogeographic models. The presented evidence does not support an early human occupation in the region, but the particular archaeological detection offers insights to the alternative explanation, and to the potential of underwater explorations in the region.

Mercury exposure driven by geographic and trophic factors in Magellanic penguins from Tierra del Fuego

Mercury exposure driven by geographic and trophic factors in Magellanic penguins from Tierra del Fuego

Immature stages of the limnephilid caddisfly Verger lutzi (Navás 1918) (Trichoptera: Limnephilidae ): description and larval life-history traits in seasonal forested wetlands of Northwestern Patagonia

The genus Verger Navás 1918 (Trichoptera: Limnephilidae), is a Neotropical genus exclusive to the Andean region, with most of its species distributed from Tierra del Fuego to north central Chile and Argentina. Currently, 20 species of the genus have been described from adults and only six larvae have been associated and diagnosed. The ecology of the species is completely unknown. In this work, we describe and illustrate the immature stages of Verger lutzi (Navás 1918) and study its breeding phenology, larval growth and adult emergence. The main characters that enable the separation of this species are the coloration the body, shape of the anterior ventral apotome, shape and distribution of metanotal setal areas, distribution of tracheal gills and number of accessory teeth in the anal prolegs. Reproduction occurs during the summer and females lay their eggs on the wetland basin formed by humid leaf litter and organic debris, covered by herbaceous vegetation. Larvae hatch after flooding and overwinter in the wetland. Larvae develop fast during spring and emergence begins in December before the wetland dries up. Description of the immature stages is helpful for use of macroinvertebrates biomonitoring, ecological studies and understanding their ecosystem services in seasonal-lentic habitats.

Hemerobiidae from Deceit Island: the Southernmost Neuroptera in the Americas

The Neuropteran fauna on the most meridional part of South America is relatively scarce. Two families, Hemerobiidae and Coniopterigydae, have been recorded so far. Accordingly, only a few species have reached the south of Tierra del Fuego. Currently, the southernmost records of these species, Hemerobius chilensis Nakahara, 1965 and Megalomus flinti (Nakahara, 1965), are from Puerto Williams, Navarino Island (54°56′S 67°37′W), which makes them the southernmost distributed neuropterans in the continent. Here we provide the first records for two Neuroptera species, Hemerobius nekoi Monserrat, 1996 and Megalomus flinti; from Deceit Island, a remote subantarctic island within the Cape Horn archipelago (55°51′41″S 67°08′31″W). The records provided makes these species the southernmost recorded lacewings in the continent; extending the known distribution of neuropterans in South America nearly 110km towards the south.

Language in the Americas: Out of Beringia

Linguistically, the Western Hemisphere harbors a great typologicaldiversity, by some estimates, the greatest in the world. Controversyregarding classification aside, much work lies ahead to identify themovements up through to include the final leg of the journey ofmodern humans, in terms of distance travelled from our continent oforigin, to Tierra del Fuego. This article will briefly summarize theadvances that the language sciences have made in describing thesemigrations and the languages that accompanied them, to then discussviable proposals for collaboration with other fields. Such an interdisciplinaryprogram of study is necessary because the tools of linguisticsdo not suffice. Continuing work on the processes of origin, dispersionand convergence will help us better understand fundamentalproperties of language. Research on the description of individuallanguages and how they can be classified will contribute to thisunderstanding. For speakers and students of the American languages,these advances will also contribute to the recovery of the culturalheritage that is associated with historical language change.

Antifouling Diterpenoids from the Sponge Dendrilla antarctica.

Two nor-diterpenes, 9,11-dihydrogracilin A (1) and the previously unreported 9,11-dihydrogracillinone A (2), were isolated from the sponge Dendrilla antarctica. The sponge was collected by trawling at a depth of 49 m, from the research vessel Puerto Deseado, near the coast of Tierra del Fuego, farther north than the reported habitat for this species. Since these compounds were particularly abundant and the sponge was free from epibionts, both 1 and 2 were included in soluble-matrix paints and tested for antifouling activity in the ocean. The results obtained from these experiments clearly indicated a potent antifouling activity for both compounds against a variety of colonizing organisms, and established a probable role as natural antifoulants for these abundant secondary metabolites and other structurally related compounds previously isolated from Dendrilla spp.

Zircon U–Pb ages in El Chaltén Jurassic rhyolites (Chon Aike Silicic LIP, Argentina) reveal xenocrystic remnants of an unexposed lower basement of the Paleo-Pacific Gondwana margin

We investigate the Jurassic volcanic rocks of the El Quemado Complex in the El Chaltén region (Argentina), which correlate with the youngest eruptive event of the Chon Aike Silicic LIP in southern Patagonia. New zircon crystallization ages of the various silicic units were obtained using U–Pb geochronology measured by in-situ Laser Ablation Inductively Coupled Plasma Mass Spectrometry. The average ages for 12 samples range from 147 to 152 Ma. Xenocrystic zircon cores of Jurassic igneous zircons are characterized by complex cathodoluminescent textures wherein growth surfaces are truncated by dissolution surfaces that are in turn overgrown by euhedral growth zones that exhibit oscillatory magmatic zoning. The cores have a wide range of ages, from 185 Ma to 1.3 Ga. We combine our analyzed xenocryst zircon ages preserved in the El Quemado Complex rhyolites with a compilation of published xenocryst zircon ages documented from Cenozoic to Paleozoic volcanic and plutonic rocks throughout southern Patagonia. The combined datasets suggests three prominent geologic features not currently exposed on the present day surface: (1) widespread abundant Triassic through Permian (200–300 Ma) xenocrystic ages throughout the present day Andean region, which connect to current exposures in Northern Patagonian and that of the Antarctic Peninsula, marking the Paleo-Pacific Gondwanan margin, (2) the existence of widespread Early-Middle Ordovician to Cambrian ages throughout southern Patagonia, and (3) the presence of an old (∼1.0 Ga) crust below that of the Deseado Massif and Tierra del Fuego, which likely extends beneath the present-day Andes.

Human-nature connection and soundscape perception: Insights from Tierra del Fuego, Argentina

Human disconnection from nature is thought to have contributed to the environmental crises we currently face, and increasing connection with nature has been proposed as one way of promoting pro-environmental behavior, nature conservation, and social-ecological sustainability. Some efforts to increase connection with nature (“nature relatedness”) have centered on exploring the social-ecological importance of soundscapes, but there is a paucity of empirical evidence supporting the theoretical linkage between soundscape perception and nature relatedness. Using prerecorded and in situ soundscape prompts, we conducted a street intercept survey in Ushuaia, Tierra del Fuego, Argentina to assess: 1) the relative importance of senses in experiences of nature, 2) the relationship between nature relatedness and soundscape perception, 3) differences in soundscape perception between various soundscapes, and 4) possible sociodemographic influences on sense importance, nature relatedness, and soundscape perception. Participants reported that hearing was of secondary importance to vision in experiences of nature. We also found that nature relatedness was positively correlated with the valuation of soundscapes—particularly more natural ones—but not with the discernment of soundscapes or identification of where soundscapes were recorded. Valuation of more natural soundscapes was higher than valuation of more technophonically dominated soundscapes, while soundscape discernment and location identification were higher for soundscapes that were likely more familiar to listeners. Sociodemographic influences on these variables were minor, but women reported higher sense importance, and having a nature-based occupation was associated with higher nature relatedness and valuation of a soundscape from a penguin colony. Our study highlighted a number of potential research areas concerning soundscape perception, including differences between prerecorded and in situ soundscape prompts, defining various aspects of soundscape perception, and the relative influences of sound sources and quantitative acoustic parameters on soundscape perception. Further research is certainly needed to account for global diversity in cultures and soundscapes, but we found some promising empirical support for the use of natural-soundscape-focused educational programs in efforts to promote nature relatedness.

First record of overlap between two species of Pinguicula in the Andean Patagonian forest

In Argentina there are two species of carnivorous plants of the genus Pinguicula, P. antarctica, and P. australandina. These species, also present in Chile, have a distribution in Argentina limited to the Andean Patagonian Forest ecoregion, which ranges from southern Neuquén to Tierra del Fuego and Isla de los Estados. To date, no cases of overlap between these two Pinguicula species have been reported. Knowing the distribution of species is a key component to understanding their ecology and conservation. The study of the carnivorous plants of Argentina contributes to increase the knowledge of the native flora.

Bone density and genomic analysis unfold cold adaptation mechanisms of ancient inhabitants of Tierra del Fuego

The Fuegians, ancient inhabitants of Tierra del Fuego, are an exemplary case of a cold-adapted population, since they were capable of living in extreme climatic conditions without any adequate clothing. However, the mechanisms of their extraordinary resistance to cold remain enigmatic. Brown adipose tissue (BAT) plays a crucial role in this kind of adaptation, besides having a protective role on the detrimental effect of low temperatures on bone structure. Skeletal remains of 12 adult Fuegians, collected in the second half of XIX century, were analyzed for bone mineral density and structure. We show that, despite the unfavorable climate, bone mineral density of Fuegians was close to that seen in modern humans living in temperate zones. Furthermore, we report significant differences between Fuegians and other cold-adapted populations in the frequency of the Homeobox protein Hox-C4 (HOXC4) rs190771160 variant, a gene involved in BAT differentiation, whose identified variant is predicted to upregulate HOXC4 expression. Greater BAT accumulation might therefore explain the Fuegians extreme cold-resistance and the protection against major cold-related damage. These results increase our understanding of how ecological challenges have been important drivers of human–environment interactions during Humankind history.

Mercury exposure driven by geographic and trophic factors in Magellanic penguins from Tierra del Fuego

Penguins accumulate mercury due to their long-life span together with their high trophic position. We sampled adult and juveniles' feathers from three colonies of Spheniscus magellanicus from Tierra del Fuego along an inshore-offshore corridor. We integrated toxicological information (mercury concentrations) and foraging biomarkers (δ13C, δ15N) into a common data analysis framework (isotopic niche analysis) to evaluate the influence of age, location, and foraging behaviors on mercury concentrations. Adults had higher feather mercury concentrations, δ13C, and δ15N values compared to juveniles. Also, adult and juvenile feather mercury concentrations differed between colonies, with lower mercury concentrations at the nearest inshore colony relative to the farther offshore colonies. Trophic position and the isotopic niche analyses suggest that this geographic gradient in mercury concentrations is due to differences in colonies' foraging areas. Understanding penguins' exposure to mercury derived from local food webs is a crucial first step in evaluating the impacts of this heavy metal on their conservation status.

Genetic structure in the nonbreeding range ofrufaRed Knots suggests distinct Arctic breeding populations

AbstractAn understanding of the migratory connectivity between breeding and nonbreeding areas is fundamental to the management of long-distance migrants under pressure from habitat change along their flyways. Here we describe evidence for genetic structure within the nonbreeding range of the endangered Arctic-Canadian rufa subspecies of Red Knots (Calidris canutus). Using blood and tissue samples from the major nonbreeding regions in Argentina (Tierra del Fuego and Río Negro), northern Brazil (Maranhão), and southeastern USA (Florida), we estimated genetic structure in 514 amplified fragment length polymorphism (AFLP) loci, applying cluster assignment analyses in DAPC, assignPOP, and STRUCTURE. Using a priori location information, individuals could be correctly re-assigned to their nonbreeding regions, which validated that the assignment accuracy of the data was sufficient. Without using a priori location information, we detected 3–5 genotype clusters, and posterior assignment probabilities of samples to these genotype clusters varied among the three regions. Lastly a chi-square test confirmed that allele frequencies varied significantly among nonbreeding regions, rejecting the hypothesis that samples were drawn from a single gene pool. Our findings hint at undescribed structure within the Red Knot rufa breeding range in the Canadian Arctic and indicate that each rufa nonbreeding area in this study hosts a different subsample of these breeding populations. The observation that nonbreeding sites of rufa Red Knots contain different genetic pools argues for separate conservation management of these sites.