National University of Tierra del Fuego

Santiago del Estero, Argentina

National University of Tierra del Fuego

Santiago del Estero, Argentina
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Llompart F.M.,CONICET | Llompart F.M.,National University of Tierra del Fuego | Colautti D.C.,CONICET | Colautti D.C.,Institute Limnologia Dr Raul A Ringuelet | And 2 more authors.
Fisheries Research | Year: 2017

Recreational and artisanal fisheries are common activities in Latin America often interpreted as competitors due to the use of common-pool resources in coastal areas. Conflicts between the (historical) artisanal fisheries (AF) and recreational fisheries (RF) in Anegada Bay resulted in the prohibition of the former. This study addresses key fisheries characteristics to detect the degree of spatio-temporal overlap between them considering the annual dynamic of the coastal fish assemblage and proposed management alternatives. Both fisheries exerted different fishing effort coinciding with the dynamic of the fish assemblages but partial temporal and spatial overlap where apparent especially during one month. However, both fisheries focused their catches on different target species thus greatly reducing the overlap in resource use. Moreover, the low proportion of juveniles caught, limited fishing effort using selective bottom gillnets and scarce total harvest (168 tonnes/years) for AF compared with those of RF harvest (631 tonnes/years) in Anegada Bay poorly justifies the actual prohibition. However, the vulnerability index of AF landings resulted in higher values than the RF. To resolve conflicts, a co-management including AF, RF and industrial (trawl) stakeholders and non-fishing community is suggested. Because of the economic importance of fishing for local people, an efficient inter and intra-sector communications process and new fisheries guidelines are urgent for the equitable use of fisheries resources without compromising the goals of a protected area. © 2017 Elsevier B.V.

Anderson C.B.,National University of Tierra del Fuego | Anderson C.B.,CONICET | Anderson C.B.,Omora Sub Antarctic Research Alliance | Vanessa Lencinas M.,CONICET | And 4 more authors.
Diversity and Distributions | Year: 2014

Aim: Ecological theory predicts that invasive ecosystem engineers like the American beaver (Castor canadensis) in Tierra del Fuego (TDF) affect landscape-level biodiversity and ecosystem function (BEF) when engineered habitats are novel or extensive. We tested these hypotheses on freshwater BEF, sampling benthic habitat and macroinvertebrates in natural lotic (forest and grassland streams) and natural lentic habitats (bogs, lakes) and beaver-modified lentic ecosystems (active and abandoned ponds). Location: Tierra del Fuego Archipelago (Chile and Argentina). Methods: To determine effects on patch-scale BEF, we assessed two drivers: substrate diversity (H′) and benthic organic matter standing crop (BOM, g m-2). Extent of impact was estimated as relative stream length (%) for each patch type in four 1000 ha images. Results: The freshwater landscape was 56% free-flowing streams (natural lotic), 13% bogs and lakes (natural lentic) and 31% active and abandoned beaver ponds (beaver lentic). While engineering significantly modified lotic habitats (converting them to ponds), the beaver ponds were largely similar to natural lentic systems, but engineered lentic patches retained more BOM. While benthic biodiversity in beaver ponds was less than streams, the assemblage contained no habitat-specific taxa and was a subset of the natural lentic community. Main conclusions: Invasive beavers engineer habitats whose biodiversity is similar to the landscape's natural lentic habitats, but by increasing the surface area and unit area retention of BOM via its impoundments, this invasion augments carbon standing stock approximately 72% in watersheds. While this invasion is considered the largest alteration to TDF's forested biome in the Holocene, here we discover that its impact is to ecosystem function, rather than biodiversity in the aquatic landscape. © 2013 John Wiley & Sons Ltd.

Anderson C.B.,CONICET | Anderson C.B.,National University of Tierra Del Fuego | Monjeau A.,Fundacion Bariloche | Monjeau A.,CONICET | And 2 more authors.
BioScience | Year: 2015

To achieve a global brain circulation, many Latin American countries have incentivized training abroad and publishing in high impact factor journals. Such internationalization strategies are valuable, but we argue that a knowledge dialogue is a better model for global science to overcome North-South disparities and to achieve both excellence and relevance. Circulation implies transmitting into a system, but dialogue highlights the individuals involved in the exchange. Although extant policies are theoretically adequate means of achieving brain circulation, broader impact criteria (e.g., integrating research and education, enhancing underrepresented groups' participation, linking science with national goals) would help attain genuine knowledge dialogue. Using the Argentine and Chilean science systems as case studies, particularly regarding environmental inquiry, we found that these principles are not systematically used but that nascent efforts exist. Lessons from home and experiences elsewhere offer guidance to promote and evaluate science in a manner that reconciles the need for global excellence and local socioecological relevance. © 2015 The Author(s) 2015. Published by Oxford University Press on behalf of the American Institute of Biological Sciences. All rights reserved. For Permissions, please e-mail:

Janches D.,NASA | Close S.,Stanford University | Hormaechea J.L.,Estacion Astronomica Rio Grande | Hormaechea J.L.,National University of Tierra Del Fuego | And 8 more authors.
Astrophysical Journal | Year: 2015

We present an initial survey in the southern sky of the sporadic meteoroid orbital environment obtained with the Southern Argentina Agile MEteor Radar (SAAMER) Orbital System (OS), in which over three-quarters of a million orbits of dust particles were determined from 2012 January through 2015 April. SAAMER-OS is located at the southernmost tip of Argentina and is currently the only operational radar with orbit determination capability providing continuous observations of the southern hemisphere. Distributions of the observed meteoroid speed, radiant, and heliocentric orbital parameters are presented, as well as those corrected by the observational biases associated with the SAAMER-OS operating parameters. The results are compared with those reported by three previous surveys performed with the Harvard Radio Meteor Project, the Advanced Meteor Orbit Radar, and the Canadian Meteor Orbit Radar, and they are in agreement with these previous studies. Weighted distributions for meteoroids above the thresholds for meteor trail electron line density, meteoroid mass, and meteoroid kinetic energy are also considered. Finally, the minimum line density and kinetic energy weighting factors are found to be very suitable for meteroid applications. The outcomes of this work show that, given SAAMER's location, the system is ideal for providing crucial data to continuously study the South Toroidal and South Apex sporadic meteoroid apparent sources. © 2015. The American Astronomical Society. All rights reserved..

Estevez R.A.,University of Melbourne | Estevez R.A.,University of Santiago de Chile | Anderson C.B.,National University of Tierra del Fuego | Anderson C.B.,CONICET | And 2 more authors.
Conservation Biology | Year: 2015

Decision makers and researchers recognize the need to effectively confront the social dimensions and conflicts inherent to invasive species research and management. Yet, despite numerous contentious situations that have arisen, no systematic evaluation of the literature has examined the commonalities in the patterns and types of these emergent social issues. Using social and ecological keywords, we reviewed trends in the social dimensions of invasive species research and management and the sources and potential solutions to problems and conflicts that arise around invasive species. We integrated components of cognitive hierarchy theory and risk perceptions theory to provide a conceptual framework to identify, distinguish, and provide understanding of the driving factors underlying disputes associated with invasive species. In the ISI Web of Science database, we found 15,915 peer-reviewed publications on biological invasions, 124 of which included social dimensions of this phenomenon. Of these 124, 28 studies described specific contentious situations. Social approaches to biological invasions have emerged largely in the last decade and have focused on both environmental social sciences and resource management. Despite being distributed in a range of journals, these 124 articles were concentrated mostly in ecology and conservation-oriented outlets. We found that conflicts surrounding invasive species arose based largely on differences in value systems and to a lesser extent stakeholder and decision maker's risk perceptions. To confront or avoid such situations, we suggest integrating the plurality of environmental values into invasive species research and management via structured decision making techniques, which enhance effective risk communication that promotes trust and confidence between stakeholders and decision makers. © 2015, Society for Conservation Biology.

Dell'Osa A.H.,National University of Tierra del Fuego
IFMBE Proceedings | Year: 2016

Electrical Impedance Tomography (EIT) techniques elaborate two dimensions images from average spatial distribution of resistivity within a three-dimensional structure. In the fracture and healing process of long bones, the limb has changes of bioimpedance values. This paper review varius works in bone electrical impedance and tomographic reconstruction, and proposes potential improvements for clinical applications of the current technology to apply in first emergency attention in difficult access areas (p.e.: mountains areas). © Springer Science+Business Media Singapore 2016.

Valenzuela A.E.J.,Southern Patagonia Coordination Office | Anderson C.B.,National University of Tierra del Fuego | Anderson C.B.,OSARA Omora Sub Antarctic Research Alliance | Anderson C.B.,CONICET | And 2 more authors.
Acta Oecologica | Year: 2013

Understanding processes and impacts of biological invasions is fundamental for ecology and management. Recent reviews summarized the mechanisms by which invasive species alter entire ecosystems, but quantitative assessments of these mechanisms are lacking for actual assemblages to determine their relative importance, frequency and patterns. We updated information on introduced vertebrates in the Tierra del Fuego Archipelago (TDF) via an exhaustive literature review and new data to evaluate ecosystem impact mechanisms and provide management recommendations. To date, 24 exotic vertebrates have naturalized in TDF, outnumbering natives nearly 2:1, with the North American beaver (Castor canadensis) and muskrat (Ondatra zibethica) being the most widely distributed species and also impacting the ecosystem through the greatest number of mechanisms. Introduced vertebrates occupied most parts of the archipelago with human-inhabited islands having greater taxa richness. All exotics potentially altered ecosystems by one or more mechanisms: 100% food webs, 92% invasional meltdown, 42% habitat modification, 38% disease or parasite transmission, 21% soil property and disturbance regime changes. Impact to habitat structure was the main clustering criterion for this assemblage. Within the species that physically alter habitats, we found two sub-groups: 1) large herbivores and 2) "others" including beavers and muskrats. Species that did not alter habitat were divided further into those with predatory trophic effects (carnivorous mammals and trout, sub-group 4) and the rest with assorted impacts (sub-group 3). By establishing high quality information on archipelago-wide assemblage, distribution, impacts and mechanisms for exotic vertebrates, we recommend, based on ecological criteria, prioritizing the management of sub-group 2. A secondary priority might be given to the carnivores in sub-group 4, while species in sub-groups 1 and 3 are less urgent. As the first systematic survey of introduced fauna on an archipelago-scale, we identified knowledge gaps, such as population abundance and dynamics for specific species, which are needed to orient future work, but the notable progress made to date is highlighted. © 2013 Elsevier Masson SAS.

Henn J.J.,CONICET | Henn J.J.,University of Wisconsin - Madison | Anderson C.B.,CONICET | Anderson C.B.,National University of Tierra del Fuego | Martinez Pastur G.,CONICET
Biological Invasions | Year: 2016

Understanding the amount of impact and distribution of invasive species is important for both basic ecological research and making management decisions. Because of their extensive impacts in southern Patagonia, invasive North American beavers (Castor canadensis) are considered both a scientific and conservation priority. However, little is known about the landscape-scale effects of these exotic ecosystem engineers. Using satellite imagery, we estimated the impact of beavers in the Argentine portion of Tierra del Fuego Island and determined the habitat factors (vegetation cover, forest type, stream presence and topography) related to their presence using both non-parametric statistical and information-theoretic approaches. Results indicated that more than 31,000 ha (1.6 % of the study area) were impacted by beavers and that the presence, but not the amount, of beaver impacts were spatially clustered. Impacts were greater in the Mountain ecoregion (2.8 % of the ecoregion) and lower in the Steppe (0.1 %). The best model for predicting beaver presence included variables related to water availability (presence of peatlands and streams), forage availability (forest type cover), and topography (slope and elevation). These findings support previous assertions that this invasion is the largest alteration to the sub-Antarctic forests in the Holocene. They also serve as a foundation for the development of maps based on habitat- and landscape-scale conditions to assist with the orientation of control, eradication, and restoration efforts currently being planned. © 2016 Springer International Publishing Switzerland

Colautti D.,CONICET | Baigun C.,CONICET | Llompart F.,CONICET | Llompart F.,National University of Tierra del Fuego | And 5 more authors.
Hydrobiologia | Year: 2015

Pampean lakes are characterised by the alternation of flood and drought periods, but little is known about its effects on fish assemblage in an extended temporal scale. This study analyses the temporal variability of the fish assemblage in Chascomús Lake, and discusses the role of temperature and precipitation as potential drivers of fish composition shifts. Data acquisition was based on experimental fishing performed from 1999 to 2013 and from historical fishing records. Two alternative fish assemblage configurations were identified by cluster analysis. Odontesthes bonariensis, Parapimelodus valenciennis and Cyphocharax voga were the dominant species, which accounted for 70–80% of the relative abundance. The species O. bonariensis showed temporal fluctuations in its representativeness, changing from dominant to almost absent, whereas C. voga and P. valenciennis changed their abundance following a similar pattern along time. When historical data were considered, Platanichthys platana appeared as the fourth most relevant species. Precipitation, critical temperatures and fish mortalities were identified as the main drivers of species abundance shifts. This study highlights the importance of long-term assessments to understand the influence of climatic factors and the need to maintain or restore natural ecological processes as the basis to support dynamic sustainable fisheries in Pampean shallow lakes. © 2014, Springer International Publishing Switzerland.

Rabassa J.,CONICET | Rabassa J.,National University of Tierra del Fuego | Ponce J.F.,CONICET
Quaternary International | Year: 2013

Marine Isotope Stage 3 (MIS 3) was an interstadial stage, a relatively warm climatic period which developed roughly between 60 and 50 and 30 cal. ka BP. Several very cold periods, known as Heinrich (H) events, developed during MIS 3 as a result of partial collapse of the North American ice sheet margins, with formation of huge amounts of icebergs which, after melting in more temperate latitudes, would have inundated the North Atlantic Ocean with low salinity waters which would have impeded the reach of the Gulf Stream into the North Atlantic Ocean. Several paleoclimatic moments with relatively warmer conditions, known as the Dansgaard-Oeschger (D-O) events, took place in between the Heinrich (H) events, throughout MIS 3. These H and D-O cycles would have been very short (perhaps even only around 1ky each in some cases) and intense, with mean annual temperatures in the area of Beringia ca. 5-8C° higher than those active at the Last Glacial Maximum (LGM; ca. 24 cal. ka B.P.) and perhaps close to those occurring in past interglacial periods, respectively. Even though climate was warmer, total melting of the continental ice sheets did not take place; thus, global sea level was perhaps still low enough to allow the persistence of the Beringia land bridge between Siberia and North America, without any interruptions throughout the entire MIS 3. The aims of this paper are to present paleoclimatic and paleogeographic information about MIS 3 and to discuss the most favorable chronology for human displacement through Beringia. At the times of MIS 3, there would have been no coalescence between the Laurentide and Cordilleran ice sheets; thus, both the hinterland path from Beringia southwards and the coastal route would have been open and enjoying moderate climate ecosystems, and thus available for humans. In this case, it is now possible to suggest possible moments for human penetration in North America, sometime between ca. 60-50 to 28cal.ka B.P, during one or more D-O events (most likely sometime between the D-O 16 and D-O 3 events) throughout MIS 3. Other routes of human colonization of the Americas following other routes rather than that of Siberia-Beringia, if they ever existed, are not discussed in this paper. © 2013 Elsevier Ltd and INQUA.

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