viernes, 22 de enero de 2016

Abstracts VIII Southern Connection Congress 2016 (3)


ARATA, J1 , SQUEO, FRANCISCO2 , GAYMER, CARLOS3 , 1 ASESORIA PROCIEN INACH.2 Departamento de Biología, Facultad de Ciencias, Universidad de La Serena.3 Departamento de Biología Marina Universidad Católica del Norte. 

The Antarctic continent is the most isolated continent; yet, it is subject to rapid changes due to anthropogenic impacts such as ozone depletion and climate change. Introduction of alien species and increasing economic uses such as fisheries and tourism are also a matter of concern. The signing of the Antarctic Treaty first and the Madrid Protocol later, which seeks the ‘comprehensive protection of the Antarctic environment and dependent and associated ecosystems’, suggest a clear framework for its conservation. However, recent analyses suggest that current system of protection may not be sufficient, with protected areas needing revision, as they are not inclusive of all habitats or communities and are not as large as to provide resilience to ongoing changes derived from global warming. This diagnosis is even more so for the marine realm. Increasing pressures from human activities requires a change in conservation paradigm, from an approach case-by-case towards a holistic one. Here we illustrate the use of a marine spatial conservation planning process for identifying important areas for ecosystem conservation for the Maritime Antarctica. Results have significance for the resilience of the marine ecosystem, mainly the krill-based ecosystem, under climate change and fisheries. 


ARMESTO, JUAN J.1 , SEGOVIA, RICARDO2 , 1 Departamento de Ecología, Ciencias Biológicas, Instituto de Ecología y Biodiversidad, Pontificia Universidad Católica de Chile.2 Departamento de Ecología, Ciencias Biológicas, Pontificia Universidad Católica de Chile. 

Since the inception of modern biogeography and ecology in the late 19th century, theoretical interpretation of diversity and distribution patterns was strongly influenced by concepts derived from the seminal works of Darwin, Wallace and later Darlington and Simpson. Under this perspective, centers of origin for most lineages and community assembly processes were driven by evolutionary divergence and migration from the larger northern continents. This view, which emphasizes the notions of competitive displacement and dispersal rather than diversification and fragmentation of biotas, dominated the first half of the 20th century, despite early alternative views of Earth history based on the distribution of austral floras (Hooker, Skottsberg) and criticism of the ‘centers of origin’ concept from a South American perspective. The northcentric view was also challenged by geological evidence of the breakup of the ancient southern continent of Gondwana, where much diversification of ancestral biotas also took place. Contemporary analyses of distribution patterns of living and fossil taxa, and molecular evidence of evolutionary radiations of major lineages point to the need for a Gondwanan-based perspective to ecology and biogeography. We propose a re-assessment of altitudinal and latitudinal diversity gradients in relation to new models of tropical and extra-tropical diversification processes in South America. These models highlight the pivotal role for the Antarctic cradle in the history of South American lineages. A biogeographic synthesis from a southern perspective is presently growing under the stimulus of new evidence and discussions at the Southern Connection meetings since the 1990s. 

(Sponsored by PFB-23 (CONICYT), P05-002 (ICM) CONICYT Postdoctoral Fellowship (RS)) 


ARREDONDO-NÚÑEZ, A1 , CHRISTEN, PHILIPPE2 , CRETTON, SYLVIAN3 , TAPIA, JORGE4 , MUÑOZ, ORLANDO4 , BUSTAMANTE, RAMIRO1 , 1 Laboratorio Ecología Terrestre, Facultad de Ciencias, Universidad de Chile.2 Group of Pharmacognosy, Section des Sciences Pharmaceutiques, University of Geneva.3 Group of Pharmacognosy University of Geneva.4 Química, Ciencias, Universidad de Chile. 

Invasive plants can generate significant impacts on biodiversity. The understanding what determine their invasiveness is a central issue in Ecology. When one exotic plant arrives to a new range, they are chemically defended against native predators. If they cannot be recognized by native predators, chemical defenses are no longer adaptive. Then, they can allocate energy to other functions. These responses can vary among different parts of plants as herbivores can be selective. We have worked in the chemical ecology of Eschscholzia californica and invasive plant of Central Chile. We examined total alkaloid content of different plant parts (leaves, shoot and root), comparing native (California) and invasive populations (Central Chile). We found non-significant alkaloid differences between native and invasive populations. However, we found significant differences among populations of Central Chile. Herbivory was almost absent in leaves but some damage can be observed in the flowers. Roots had the highest alkaloid content both in the native and in the invaded range. The absence of regional differences (native vs invaded) suggest that alkaloid concentration is a constitutive defense. Thus, alkaloid content is a conserved trait that does not change irrespective of herbivory pressure.

 (Sponsored by the Iniciativa Científica Milenio (P05-002)) 


ARROYO, MARY T.K.1 , Instituto de Ecología y Biodiversidad (IEB), Facultad de Ciencias, Universidad de Chile, Santiago, Chile. 

Historical records show high altitude species can escape from global warming by migrating into cooler conditions. However, in seeking cooler conditions, the amount of suitable habitat available for many species could become reduced on account of the geometry of mountainous terrain, the orientation and degree of isolation of mountain ranges and their peaks, and regional changes in precipitation. High elevation, abovetreeline or bioclimatically-equivalent habitats in the north-south trending South American Andes, found at progressively higher altitudes toward the lower latitudes, support a rich flora. Dated phylogenies and the nested positions of some genera within larger clades indicate a fairly recent origin for many clades. An ongoing distributional modelling effort employing Ensemble Forecasting (BIOMOD), two climate models and two climate change scenarios on a pool of high altitude species (presently >300) from the southern Andes (27°-56°S), predicts there will be both winners and losers, but far more losers, even when unlimited dispersal capacity is assumed and a more conservative temperature increase is considered. Whether the severe habitat loss predicted for many species by these models becomes fully manifest will depend on the ability of high altitude species to hold on at the trailing edge and reach favorable thermal microsites within their present altitudinal ranges. Better knowledge of the responses of individual species at the trailing edge and of establishment success at the leading edge is critical to our understanding of the impacts of global warming on high altitude species in the southern Andes. 

(Sponsored by Fondecyt 1140541, ICM-MINECON P05-002 IEB, PBF-23, CONICYT. Diego Alarcón is gratefully acknowledged for his collaboration with the modelling work) 


ARROYO, MARY T.K.1 , PINOCHET, CONSTANZA1 , JARA-ARANCIO, PAOLA1 , FAITH, DANIEL2 , 1 Instituto de Ecología y Biodiversidad (IEB), Facultad de Ciencias, Universidad de Chile, Santiago, Chile.2 Australian National Museum Sydney, Australia. 

Phylogenetic diversity (PD) provides a quantitative measure of evolutionary potential. PD also measures “option value” – the value of diversity in providing future benefits for humans. PD is calculated on a phylogeny as the sum of the branch-lengths of the taxa of interest starting at the root of the phylogeny. Conservation of PD option value focusses on total PD of a region, but conservation of evolutionary potential will focus on maintaining high PD locally. State protected areas in the Chilean biodiversity hotspot are few. We analyzed the spatial distribution of PD for trees and assessed the degree of protection of high PD locations throughout the hotspot. A phylogeny based on rbcl was constructed for tree species using sequences obtained in the laboratory and from GenBank. PD was measured for the full set of trees in each 0.5 x 0.5 degree square. Species richness and generic richness across the grid were obtained from optimized occurrence data obtained from herbarium records, using a fine-scale vegetation scheme. PD, species richness and generic richness are concentrated between 34° to 41°S mainly in the coastal range, with some outstanding pockets in the central valley and southern part of the Andes. PD was strongly correlated with species richness and generic richness. The distribution of protected areas bears little relationship to the locations having highest PD levels at the 0.5 x 0.5 ° square scale. Major disparities are seen in the Coast Range. 

(Sponsored by ICM-MINECON P05-002 IEB, PBF-23, CONICYT)


 BARNARD, P1 , MARON, MARTINE2 (Co-conveners) 1South African National Biodiversity Institute, Private Bag X7, Claremont 7735, South Africa, and the Percy Fitzpatrick Institute of African Ornithology, University of Cape Town, Rondebosch 7700, South Africa, 2 The University of Queensland, Landscape Ecology and Conservation Group, School of Geography, Planning and Environmental Management, Brisbane, Queensland 4072, Australia. 

We propose a break from the symposium structure of Southern Connection by holding an interactive workshop on the nature and importance of bottlenecks. Resource bottlenecks for species – periods of severe restriction in resource availability – are important and little-understood mechanisms through which climate change affects biodiversity. Triggered by increased climate variability and extreme climate events, they can tip species into population declines which precipitate local extinction. Our workshop, building on a recent global review but highlighting Gondwana examples, focuses on global change processes that exacerbate bottlenecks and their effects on animal populations, and how adaptation responses can help buffer the impacts. We outline a framework of factors that increase species’ vulnerability to climate-induced spatial/ temporal bottlenecks in increasingly variable habitats, focusing on the southern hemisphere. Increases in the frequency, severity and/or duration of extreme climate events can trigger bottlenecks that severely limit populations and can exacerbate other human-induced pressures, such as land use change. These may become more frequent and severe, with potentially nonlinear increases in impact. More effective conservation responses include managing protected area networks for complementarity in spatial/ temporal resources. 


 BARNARD, PHOEBE1,2, LEE, ALAN1,2, 1 Percy FitzPatrick Institute of African Ornithology, FUniversity of Cape Town.2 Climate Change BioAdaptation, Kirstenbosch Research Centre, South African National Biodiversity Institute. 

Species at the southern edges of Gondwana’s major continents share the same kinds of vulnerabilities to extinction as those at the polar edges of northern continents, but with the added problem of intense human settlement in many areas. In Africa, the fynbos global biodiversity hotspot of South Africa is the world’s smallest and richest floral kingdom, with a Mediterranean-type winter rainfall-summer drought system. Six endemic passerines and one endemic quail, which evolved under mostly cool, moist conditions, face multiple global change drivers which jeopardize their future survival along the southern tip of the continent. These drivers include climate change (including changing rainfall seasonality and frontal systems; changing fire regimes and increasing CO2-driven woody encroachment), land use change (urbanization, agricultural transformation) and biotic invasion. My team has been using the long-term, large-scale citizen science datasets of South Africa, as well as detailed survey, behavioural and epidemiology studies as a basis for climate range modelling, population density and viability assessment. Several of the fynbos endemics show evidence of intolerance to warming temperatures in experimental chamber experiments, and red data list assessment is highlighting increasing concern about their conservation status. 


BECHIS, FLORENCIA1 , ACOSTA, CRISTINA2 , MATHIASEN, PAULA3 , PREMOLI, ANDREA3 , THOMSON, STUART4 , RAMOS, VICTOR5 , 1 IIDyPCa CONICET - Universidad Nacional de Rio Negro.2 IMBIV CONICET - Universidad Nacional de Cordoba.3 Laboratorio Ecotono, INIBIOMA CONICET - Universidad Nacional del Comahue.4 Department of Geosciences, University of Arizona.5 IDEAN CONICET - Universidad de Buenos Aires. 

The Northern and Southern Patagonian Andes show important differences regarding their geological evolution during the Cenozoic Era, which began 66 million years ago. These include important variations in the altitude, style and timing of the mountains’ uplift, and the Pacific vs. Atlantic origin of marine connections, among others. Coincidentally, the geographic distribution of the genetic lineages and haplotypes found for all species within the genus Nothofagus also show important variations between the southern and northern sectors of the Patagonian Andes. Molecular dating has revealed that divergences of the ancestral lineages took place in different times during the Cenozoic associated with paleogeographic changes related to geologic and climatic factors. These previous studies proved that there is a strong link between the tectonic and biological evolution in Patagonia. In this contribution, we outline major latitudinal differences in the geologic evolution of the Patagonian Andes in order to identify key paleogeographic elements that could have acted as barriers, filters or corridors for the dispersion and divergence of Nothofagus species during the Cenozoic. Furthermore, we explore if the available genetic data could help to evaluate competing geological hypotheses, including the location of the Atlantic-Pacific marine connections, or the timing of the Andean uplift. We will particularly focus on the segment between 41° and 42°S, where a complete set of previous and new ages obtained from different techniques (apatite fission track thermochronology and U-Pb LA-ICPMS geochronology) allows a precise dating of the tectonic and paleogeographic evolution, favoring its comparison and integration with the genetic data. 


BERCHEZ, F1 , CONTADOR, T.2 , MASSARDO, F2 , GHILARDI-LOPES , N3 , SCHWINDT, E4 , LEITE, K5 , CABALLERO, P6 , RENDOLL, J6 , OJEDA, J7 , MANSILLA, A8 , KENNEDY, J9 , JIMÉNEZ , J10, ROZZI, R10, 1 Botânica, Instituto de Biociências, Universidade de São Paulo, Brazil.2 Instituto de Ecología y Biodiversidad, Parque Etnobotánico Omora, Universidad de Magallanes, Chile.3 Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, SP, Brazil.4 Grupo de Ecología em Ambientes Costeros Centro Nacional Patagónico (CENPAT, CONICET), Argentina.5 Estação Ecológica Tupinambás ICMBio, Brazil.6 Parque Etnobotánico Omora Instituto de Ecología y Biodiversidad, Chile.7 Laboratorio de Macroalgas Antárticas y Subantárticas, Universidad de Magallanes, Chile.8 Instituto de Ecología y Biodiversidad, Laboratorio de Macroalgas Antárticas y Subantárticas, Universidad de Magallanes, Chile.9 Departament of Biological Sciences, University of North Texas, USA.10Instituto de Ecología y Biodiversidad, Parque Etnobotánico Omora, Universidad de Magallanes, Chile and University of North Texas, USA. 

South American coastal habitats include a wide range of terrestrial, freshwater, and benthic ecosystems, many of which are unique and constitute hotspots of biodiversity. Biosphere reserves, and other categories of protected areas (PA), instituted mostly during the second half of the 20th Century, are considered a key management tool to conserve regional biodiversity. Educational actions to promote changes in basic values, principles, and attitudes, although considered as a main objective for PAs, frequently have a poor conceptual basis. Together with the evaluation of their effectiveness by long-term, site-based socioecological research, efforts should be direct towards a holistic approach, with the development and testing of environmental practices that integrate ecology, economy, ethics, and conflict resolutions on the different uses of biodiversity. However, ecological long-term studies, socio-economic long-term evaluation, and the integration of education and ethics are still incipient. With the recent creation of some independent networks in different South American countries, mainly related to the assessment of biological communities, concern is related to (1) sharing methodologies and data to facilitate comparative and integrated continental analyses, and (2) integrating social components, including not only economic but also ethical values and participatory approaches. Toward this aim, the research network based at Omora Park in the Cape Horn Biosphere Reserve, Chile, has developed the Field Environmental Philosophy methodological approach, which has been adapted to research, educational, and conservation programs in protected areas of other regions of the world. ReBentos Network and CNPq. 

jueves, 21 de enero de 2016


Cuando iba a entrevistar a Benito Baranda, me fuí "conejeando" y pasé por el Parque San Borja y me encontré con este trabajo de Paola Vezzani del año 1996, cuando obtuvo el primer premio del concurso Escultura Joven Chilgener. La obra de la artista magallánica se denomina DANZA

miércoles, 20 de enero de 2016

Abstracts VIII Southern Connection Congress 2016 (2)


ALLOWAY, BRENT1 , MORENO, PATRICIO2 , 1 School of Geography, Environment & Earth Sciences Victoria University of Wellington.2 Department of Ecological Sciences and Millennium Institute of Ecology and Biodiversity Universidad de Chile. 

Ongoing tephra studies in Southern Chile and Argentina (Cono Sur) are currently focused on two important aspects: 1) Elucidating eruptive records and assessing associated hazards for a particular volcano, and 2) Utilisation of tephra as a chrono-stratigraphic marker in wide-ranging Quaternary paleoenvironmental studies. Recent Andean eruptions (i.e. Puyehue-Cordon Caulle (2011), Chaiten (2008/9) and Hudson (1971/91)) have all clearly shown that hazards associated with these eruptions not only pose a risk to adjacent communities but also that ash-fall (tephra) can be quickly distributed over exceptionally large areas and pose a significant and wide-ranging hazard to civil aviation, agriculture and communities located distally. Since a tephra can be extensively distributed through the landscape in a geological instance of time, its value as an isochronous-stratigraphic tool has increasingly been recognised to the point where tephra are now routinely utilised in diverse paleoenvironmental research that focus on high-resolution lake, glacial and marine records. The construction of such records in Cono Sur is fraught with difficulties including: mineralogy and weathering susceptibility that impedes geochemical characterization as well as, pervasive and repeated Andean glaciation that has removed and/or obscured older tephra records. In this presentation, we will provide a number of examples from Cono Sur, where despite these limitations, the utility of tephra can still be clearly demonstrated to assist with the assessment of eruptive records and associated hazards but also, the correlation of equivalent-age sequences for paleoenvironmental comparisions – something of which has great relevance to this forum.   

(Sponsored by a Victoria University of Wellington Science Faculty Research Grant (to BVA); Chilean Fondecyt 1151469 and ICM Grants P05-002 and NC120066 (to PIM)) 


 ALLOWAY, BRENT1 , School of Geography, Environment & Earth Sciences (SGEES), Victoria University of Wellington. 

Tephra is an all-embracing term for the explosively erupted, loose fragmental (pyroclastic) products of a volcanic eruption. The term tephra includes fall deposits (commonly called tephra-fall or tephra fallout) and unconsolidated deposits derived from pyroclastic flows or surges. Tephra deposits have two special features: (1) they are erupted and deposited over very short time periods, geologically speaking, usually a matter of only hours or days to perhaps weeks or months; and (2) they can be spread widely over land and sea to form a thin blanket that (unless reworked) has the same age wherever it occurs. Once a tephra is recognised and dated, it has the ability to effectively connect equivalent-aged sequences in a variety of terrestrial to marine environments wherever it is found. On this basis, tephrochronology has tremendous utility for a wide variety of paleo-environmental studies particularly in, and adjacent to, volcanic regions. In this presentation I will outline ongoing work in Flores, Indonesia, where tephras have been essential for determining the timing of initial human colonisation to the region, as well as the potential speciation from H. erectus to H. floresiensis. I will also show the potential of utilising tephra in long-sediment records retrieved from tropical Australia even though the tephras themselves are not locally sourced. Finally, I will talk about the applications of tephra in paleoenvironmental studies taking place in southern mid-latitude NZ and Chile – countries with similar geological settings and which are more closely connected in a paleoenvironmental sense than one could possibly imagine.

 (Sponsored by Victoria University of Wellington Science Faculty Research Grant and Chilean Fondecyt Grant 1151469) 


 ALVAREZ, CLAUDIO1,2, CHRISTIE, DUNCAN 2,1, VELASQUEZ-ALVAREZ, GONZALO2 , VEBLEN, THOMAS3 , 1 Center for Climate and Relience Reseearch (CR)2, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile2 Laboratorio de Dendrocronologia y Cambio Global, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile.3 Biogeography Lab, Department of Geography, University of Colorado Boulder. 

Our research examines the relationships between climate variability and tree growth, and the potential colonization of tree individuals above the present treeline in a Nothofagus pumilio forest at the Choshuenco volcano (40o S) in the northern Patagonian Andes. Based on treeline control theory which indicates that the low temperatures determines the altitudinal position worldwide, we would expect a temporal increment in the establishment of N. pumilio above the present treeline as a result of increasing temperatures in the Andes of northern Patagonia. We address the following questions: 1) are the temporal patterns of climate (temperature and precipitation) influencing the establishment of N. pumilio above the present treeline? 2) If so, is the relation between tree establishment and climate conditions the same than tree-growth and climate? To answer these questions, we dated the establishment of seedlings, saplings and small trees of N. pumilio (n=664) collected above the present adult treeline. Preliminary results indicate that the N. pumilio establishment above treeline has been continuous over the last three decades. This period coincide with an increase of temperatures, decrease of precipitation and a decrease on tree growth at the adult forest in the treeline. This finding would indicates that responses of tree growth and treeline advance to climatic conditions were not similar at the Choshuenco volcano, and it supports the idea that temperatures increase and precipitation decrease in northern Patagonia may be producing a successful establishment of N. pumilio above treeline but decreasing tree growth. 

(Sponsored by FONDAP1511009, FONDECYT 1120965) 


ANTONELLI, A1 , ZIZKA, ALEXANDER1 , Department of Biological and Environmental Sciences, Faculty of Sciences, University of Gothenburg. 

No single taxon gives a pattern: the historical assembly of the world’s biomes can only be inferred through cross-taxonomic analyses. In this talk we will present our recent work in ‘comparative biogeography’, focusing on i) data-driven identification and delimitation of biogeographical regions instead of opiniongenerated classifications; ii) spatial coding of species into regions and altitudinal ranges for biogeography and macroecology; and iii) the estimation of historical range shifts and region-specific diversification. Our studies indicate that the application of network methods on species occurrence data can extract considerably stronger biogeographical signal than hitherto realized; that bioinformatic tools are able to provide rapid assessments of biodiversity patterns; that Neotropical angiosperms have speciated and gone extinct at significantly higher rates than in other tropical regions; that the Great American Biotic Interchange occurred millions of years earlier than assumed; and that fossils play a major role in reducing uncertainties in biogeographical analyses. Tropical America has acted as a species pump to the rest of the world, but it also received considerable input from temperate regions in South and North America. Likewise, the tropical and temperate Andes have exchanged a substantial amount of plant and animal lineages with Amazonia in the last 30 million years, with peaks correlating in time with major phases of mountain uplift. These examples showcase how old questions can be addressed by new methods and more data, and identify future directions in biogeographical research. 


ARACENA, C1 , KILIAN, ROLF2 , LANGE, CARINA6 , BERTRAND, SEBASTIEN3 , LAMY, FRANK4 , ARZ, HELGE5 , DE POL-HOLZ, RICARDO6 , BAEZA, OSCAR2 , PANTOJA, SILVIO6 , KISSEL, CATHERINE7 , 1 Instituto de Ciencias Marinas y Limnologicas, Ciencias, Universidad Austral de Chile.2 Lehrstuhl fur Geologie, Fachbereich VI, Geowissenschaften, Universitat Trier, University of Trier.3 Renard Centre of Marine Geology, Sciences, University of Gent.4 Am Alten Hafen 26, 27568 Bremerhaven, Germany AWI.5 Marine Geology, Seestrasse 15, D 18119 Rosto Leibniz Institute for Baltic Sea Research Warnemundeck.6 Department of Oceanography, Faculty of Science, University of Concepción.7 Av de la Terrasse, 91198 Gif-sur Yvette Cedex, France Lab. Sc. Climat et de l Environnement/IPSL. 

One of the most important factors controlling fjord primary production in southernmost Patagonia is the variability in the thermohaline structure of the water column. In the present day environment, thermal stratification is related to freshwater input and in particular to the seasonal melting of glaciers. Here we assess whether this relation between fjord productivity and freshwater input holds true for the Holocene, using a sediment record from the central basin of the Strait of Magellan (MD07-3132, 53 ◦44.17’S; 70 ◦ 19.03’W). Our approach relies on a proxy based reconstruction of fjord sea surface temperature (SST), paleosalinity, freshwater input, and paleoproductivity. The results indicate that, during the early Holocene, productivity was low (accumulation rates of marine organic carbon (AR marOC) (≦ 20 kg m−2 kyr−1), likely due to high freshwater contribution resulting in low salinity and low SSTs. After 8.5 kyr BP and during the mid and late Holocene all the productivity proxies increase. The AR marOC (˜30 kg kg m−2 kyr−1), CaCO3 (˜60 kg kg m−2 kyr−1) and opal (425 kg kg m−2 kyr−1) reached the highest values during the last millennium. This increase was probably driven by the marine transgression during which marine macronutrient-rich waters entered into the central basin. The late Holocene rise in productivity was interrupted by a low salinity phase between 3.2 and 2.2 kyr BP, during which productivity returned to early Holocene conditions in response to increased input of glacial clays from Cordillera Darwin, as suggested by high values of K/Si ratio (˜1.2).

 (Sponsored by PROYECTO DID-UACh S-2015-28) 

martes, 19 de enero de 2016

Investigador del INACH se adjudica proyecto Fondecyt para el estudio de esponjas marinas en la Antártica

cesar cardenas

Hoy en día el mundo de la investigación científica es cada vez más competitivo a la hora de optar a la adjudicación de becas y fondos para proyectos. César Cárdenas, biólogo marino e investigador del Instituto Antártico Chileno (INACH), pudo superar las dificultades y obtener el financiamiento por tres años para su proyecto “Evaluando la utilidad de las esponjas antárticas para estudiar el cambio climático: desde el nivel de especies al nivel de comunidades”, gracias al Fondo para el Desarrollo de la Ciencia y Tecnología (Fondecyt).
Cárdenas agrega que “adjudicarse un fondo como éste es algo no menor considerando lo complicado y competitivo que se ha tornado con el tiempo el sistema de becas y fondos para investigación”.
El investigador del INACH añade que en el ámbito de la biología se adjudicaron solo diez proyectos, es decir, un tercio de los postulantes. Cabe destacar que, en la región de Magallanes y Antártica Chilena, Cárdenas fue el único beneficiado. “La idea de este estudio es generar mayor conocimiento sobre las esponjas marinas, que son componentes muy importantes de las comunidades bentónicas antárticas y, a través de este conocimiento, ver si se pueden utilizar como una manera de detectar el cambio climático observando el aumento de la temperatura del agua. Lo anterior se refiere no solamente a nivel de especies y cómo son afectadas, sino que si se puede transformar en un efecto cascada con la comunidad en general y cómo podría afectar a todo el ecosistema antártico”, acotó Cárdenas.
El biólogo marino apuntó que el proyecto intenta ver el cambio climático en las esponjas en distintos niveles. Será bastante el trabajo por hacer, ya que es necesario estudiar los patrones actuales de distribución y la interacción con otros organismos. “La primera temporada se va a desarrollar por más de un mes en la base antártica ‘Yelcho’ y a partir de marzo nos tenemos que preocupar del trabajo de laboratorio donde analizaremos los datos, así como las fotografías y el estudio de las comunidades bacterianas asociadas”, puntualizó Cárdenas.
César Cárdenas es biólogo marino (Universidad Austral de Chile, 2003), magister en Manejo y Conservación de Recursos Naturales (Universidad de Magallanes, 2009) y doctor con mención en Biología Marina (Victoria University of Wellington, Nueva Zelandia, 2014). Actualmente, integra el Departamento Científico del INACH.




1 Laboratorio de Dendrocronología y Estudios Ambientales, Instituto de Geografía, Pontificia Universidad Católica de Valparaíso.2 Departamento de Ciencias Agronómicas y Recursos Naturales, Facultad de Ciencias Agropecuarias y Forestales, Universidad de la Frontera.3 Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile.4 Centro de Aplicaciones de Tecnología Nuclear en Agricultura Sostenible (Uruguay), Universidad de la República.

 High precipitation reductions have been observed in south central Chile during the last 50 years, however the effect of climate variability on the processes and functions of tree species is still not well understood. Utilizing 27 years of seed production records and δ13C from growth rings, we evaluated the effect of precipitation variability on seed production and water-use efficiency on Nothofagus obliqua trees in the San Martin Experimental Forest (BESM) (39° 38’ S y 73° 07’ W) in Chile. Seed production was positively correlated with precipitation during summer months of two years before the seeds fall to the forest ground. Moreover, the water-use efficiency inferred from δ13C in the growth rings of N. obliqua, was also positively correlated with the summer months during one and two years prior to the ring formation. These results suggest that precipitation reduction in this area could have a strong effect in reproductive and functional processes of N. obliqua. More information about changes in water availability and its relationship with the resources allocation in N. obliqua forests would help to estimate its responses to projected climate change scenarios for this region. 

(Sponsored by CATNAS - Centro de Aplicaciones de Tecnología Nuclear en Agricultura Sostenible (Uruguay); Universidad Austral de Chile) 


 AH-PENG, C1 , MEEK, SARAH2 , HEDDERSON, TERRY2 , WILDING, NICHOLAS2 , STRASBERG , DOMINIQUE1 , FLORES, OLIVIER1 , 1 UMR PVBMT, Faculty of Science, Human and Environment, University of La Réunion.2 Biological Sciences, University of Cape Town. 

Analysing functional traits along environmental gradients can improve our understanding of the mechanisms involved in plant community assembly. Elevational gradients as major environmental gradients provide model systems to study the factors that generate and structure biodiversity. While literature has explored community-level trait responses to environmental changes for vascular plants, functional diversity and the role of functional traits of bryophytes in ecosystem services and processes remain largely unexplored. In this study, we measured species abundance and the distribution of 12 traits related to vegetative growth of epiphytic liverworts along an elevational gradient (350-2750 m) on La Réunion island (Mascarenes). We use functional diversity indices (Villéger et al., 2008) and related them to elevation and climatic variables along the gradient. Processes implied in community assembly were investigated using both the mean and variance of trait values weighted by species abundance and compared to a null model based on species abundance randomizations. Results of this study will shed light on the drivers of community assembly of liverworts on islands and the role of this plant group in insular ecosystem processes. This work is embedded in a large- scale research program across tropical and subtropical islands (MOVECLIM) aiming at studying the different components of diversity (species richness, functional and phylogenetic diversity) to better understand the current and future distribution of bryophytes under a changing environment. 

(Sponsored by Era NetBiome Project (ANR MOVECLIM)) 


AIZEN, MARCELO1 , TUR, CRISTINA2 , SÁEZ, AGUSTÍN3 , TRAVESET, ANNA4 , 1 Departamento de Ecología, Centro Regional Universitario Bariiloche, Universidad Nacional del Comahue - INIBIOMA.2 Institut Mediterrani d´Estudis Avançats (CSIC-UIB) IMEDEA.3 Laboratorio ECOTONO-INIBIOMA, Centro Regional Universitario Bariloche, Universidad Nacional del Comahue.4 Institut Mediterrani d´Estudis Avançats (CSICUIB) IMEDEA. 

Although plant-plant facilitation via the nurse effects seems to be common in Alpine environments, similar information for plant-plant facilitation via shared pollinators is limited. Pollinator sharing often implies interspecific pollen transfer (IPT). We studied IPT among a total of ~50 plant species distributed across three high-Andean communities at 1600, 1800 and 2000 m a.s.l. in Cerro Challhuaco (Nahuel Huapi NP) to construct networks depicting plant-plant, pollinator-mediated interactions. We analysed the relation between the (a) number of conspecific and number of heterospecific pollen grains deposited on stigmas (quantitative effect), and (b) proportion of germinated pollen and number of heterospecific pollen grains on stigmas (qualitative effect). Using GLMMs, we estimated the sign (positive, neutral or negative) of quantity and quality effects of pollinator sharing for each recipient species and each recipient-donor species pair. Communities were characterized by the presence of pollen hub-donors acting as “magnet species”. In general, facilitative and neutral pollinator-mediated interactions among plants prevailed over competition. Thus, the benefits from pollinator sharing (i.e. increased visitation and conspecific pollen deposition) seem to outweigh the costs (i.e. heterospecific deposition and conspecific pollen loss). The largest proportion of facilitated species was found in the highest elevation community, suggesting that facilitation can be even more common at lower plant densities and under unfavourable conditions for pollination. This evidence indicates that widespread facilitation in stressful environments can not only occur via increasing availability of limited abiotic resources, but also increasing attraction of scarce mutualists

Magallanes reunirá a cerca de 300 científicos de todo el mundo en torno a las ciencias naturales del Hemisferio Sur


Hoy se inicia uno de los eventos más importantes de la ciencia mundial: el Congreso Southern Connection que, en su octava versión y por segunda vez, se realizará en Chile. Serán 5 intensas jornadas de divulgación sobre las investigaciones que se están llevando a cabo entre las latitudes 0 y 90°S, en torno al cambio global.
A la reunión científica – organizada por la Universidad de Magallanes, el Instituto de Ecología y Biodiversidad (IEB) y el Instituto Antártico Chileno (INACH) – llegarán científicos de más de 20 países, en su mayoría, biólogos y ecólogos interesados en los ecosistemas del hemisferio sur, con énfasis en los de carácter templado. Ellos compartirán sus experiencias de estudio en temas como la biogeografía, el paleoclima, la ecología, la conservación biocultural, la biología reproductiva de las plantas, la paleontología y los procesos oceánicos, entre otros. 
Durante una semana, habrá presentación de posters, 16 simposios y 10 charlas plenarias a cargo de connotados investigadores, como la Premio Nacional de Cs. Naturales 2010, Mary Kalin, y el Dr. Juan Armesto de la Pontificia Universidad Católica. El evento se llevará a cabo en Punta Arenas, en dependencias del Cordenap y de la Universidad de Magallanes, tras lo contempla 4 visitas a terreno, con viajes a los parques nacionales Torres del Paine y Pali Aike, al Fuerte Bulnes y al Parque Omora en Puerto Williams.
El investigador Juan Carlos Aravena de la Universidad de Magallanes, quien forma parte del Comité Organizador Local, destacó el potencial de la zona para ser sede de esta importante conferencia internacional. “Somos la región subantártica que es la única representación de las latitudes más australes. No hay ningún otro continente que cubra esta franja del Hemisferio del Sur, por lo tanto, lo que pase aquí, es único en el mundo”, dijo. Y puso un ejemplo: “a un investigador de Nueva Zelandia le interesa muchísimo saber qué está pasando acá, para poder comparar lo que está encontrando allá. Se trata de una ligación muy importante, porque formamos parte de ese gran continente que fuimos alguna vez y que se llamó Gondwana, y también porque conoceremos que está haciendo cada uno a lo menos desde hace cuatro años atrás”.
En lo que refiere al escenario mundial, Aravena afirmó que es la gran oportunidad para decir qué está pasando en el Hemisferio Sur respecto al Cambio Global, en un momento estratégico, pues acaba de conocerse el acuerdo climático de París. “Creo que es la ocasión para que tomemos las conclusiones de esta reunión, y se pueda hacer una declaración. No nos podemos hacer los locos; no me imagino a la gente viniendo acá y hablando de ecología sin tocar este tema”, concluyó.

Si quieres conocer el programa completo, ingresa aquí

viernes, 15 de enero de 2016

El agujero en el corazón del explorador antártico

El agujero en el corazón del explorador antártico
Rescate de la expedición Imperial Trans-Antártica, capitaneada por Ernest Shackleton (Hemeroteca)

  • Confirman la patología cardiaca congénita que sufrió Ernest Shackleton
«Se buscan hombres para viaje peligroso. Sueldo escaso. Frío extremo. Largos meses de completa oscuridad. Peligro constante. No se asegura el regreso. Honor y reconocimiento en caso de éxito».
Fue el anuncio de Ernest Shackleton en el Times al que respondieron más de 5.000 aspirantes. Más impresionante aún si se sabe que el explorador autor de este llamamiento padecía un problema cardíaco que empeoraba con el frío y cuyos achaques sufrió en sus expediciones y hasta su muerte a los 47 años.
Líder ejemplar
Hace ahora 100 años, Ernest Shackleton y sus hombres estaban varados en el hielo, en el mar de Weddell. La expedición Imperial Transantártica, que puso en marcha apenas unos días ante que estallara la I Guerra Mundial, tenía como objetivo cruzar a pie el continente helado por primera vez. Pero el intenso frío detuvo al barco Endurance cuando apenas faltaban 160 kilómetros para comenzar la caminata.
Los bloques de hielo, finalmente, destruyeron el barco y los expedicionarios tuvieron que escapar sobre el océano congelado empujando los botes salvavidas. Acamparon en la llanura helada y cuando el hielo se resquebrajó, navegaron a la isla Elefante, en el Pacífico Sur. Allí Shackleton instaló a la mayoría de sus hombres y se echó de nuevo al maren un bote abierto con apenas seis marineros, rumbo a Georgia del Sur, donde esperaba recabar ayuda en una estación ballenera.
Tras un viaje infernal de más de 1.000 kilómetros en 16 días en un mar tormentoso, arribó finalmente, aunque aún restaba cruzar a pie la cordillera y los glaciares que atraviesan la isla. Finalmente, Shackleton consiguió llegar a su objetivo y volver a la isla Elefante para recoger viva a toda su tripulación. Su perseverancia, liderazgo y gestión de equipos ante la adversidad lo ha convertido en un aventurero mítico y un ejemplo en las escuelas de negocios.
Shackleton realizó cuatro expediciones antárticas y en tres de ellas sufrió serios problemas de salud. Curiosamente, en la más dura –y por la que ha pasado a la historia– no se ha registrado ningún evento de este tipo. El anestesista Ian Calder y la cardióloga Jan Till han publicado un artículo en Journal of the Royal Society of Medicine. En él, describen la dolencia que afectó al explorador y que finalmente acabaría causándole la muerte en 1922, a los 47 años, cuando estaba a punto de atracar en Georgia del Sur e iniciar su cuarta expedición antártica.
Ernest H. Shackleton (1874 - 1922)
Ernest H. Shackleton (1874 - 1922) (Gettyimages)

Como explica Calder por correo electrónico, “siempre me interesó esta historia, desde que era pequeño. Hace unos años tuve la oportunidad de ir a una expedición a Georgia del Sur con Stephen Venables, un famoso montañero. Decidí entonces repasar las expediciones de Shackleton y saber por qué tuvo estos achaques. Le pregunté a mi amiga Jan, que inmediatamente dio un diagnóstico: debía sufrir una comunicación interauricular (CIA), un defecto cardíaco congénito conocido comoagujero en el corazó n. Los síntomas y signos de la enfermedad los confirmé repasando los archivos del Instituto Scott de Investigación Polar, en Cambridge. Fue un trabajo muy interesante”.
Tras una expedición a Georgia del Sur decidí investigar los achaques de Shackleon y confirmé la enfermedad en los archivosIAN CALDER

Bucear en los archivos
Ya en el diario de la primera expedición, en 1903 a bordo del Discovery y junto a Robert Scott, Shackleton tuvo un primer episodio registrado en el diario del médico y achacado “a un tipo de asma” que le causó debilidad y le dejó sin aliento. En el segundo viaje antártico, en el Nimrod, se produjeron dos ataques, atribuidos a “un murmullo sistólico pulmonar”, de los que se acabó recuperando, ya que terminó la expedición siendo uno de los hombres más fuertes.
El doctor James McIlroy, médico en la tercera y cuarta expedición, consignó en sus diarios las negativas de Shackleton a que le reconociera. Para Calder, era evidente que el explorador “sabía que tenía un problema de tipo cardiaco, pero la necesidad de buscar mecenas para financiar sus viajes le llevó a ocultarlo. Como escribió Roland Huntford, su único miedo era que se supiera lo que escondía su corazón”.
Enfermedad frecuente
El doctor Fernando Sarnago, presidente de la Sección de Cardiopatías Congénitas de la Sociedad Española de Cardiología explica por correo electrónico que la CIA “es la cardiopatía congénita más frecuente del adulto. Es un defecto de la correcta separación entre las dos aurículas del corazón, debido a que el tabique no se forma completamente y queda un agujero de tamaño variable”.
“Este agujero hace que se comuniquen el lado izquierdo y el derecho del corazón. Y, dado que la presión de sangre es mayor en el lado izquierdo, al menos inicialmente produce un paso de sangre hacia el lado derecho del corazón y hacia los pulmones, con la consiguiente sobrecarga de trabajo para ese corazón derecho”, añade Sarnago.
El cardiólogo recuerda que, inicialmente, la CIA es muy bien tolerada, “pero con el paso del tiempo esa sobrecarga habitualmente daña el corazón derecho y la circulación pulmonar: produce fundamentalmente retención de líquidos y sensación de ahogo con disminución de la capacidad de esfuerzo. Todos estos síntomas están englobados dentro del concepto médico de insuficiencia cardíaca. Además, el paciente sufre arritmias y taquicardias que inicialmente son paroxísticas [crisis violentas] y posteriormente pueden cronificarse.
Un globo inflándose cerca del Discovery. Foto de Ernest Shackleton.
Un globo inflándose cerca del Discovery. Foto de Ernest Shackleton. (Ernest Shackleton - Otras Fuentes)

E l frío favorece la aparición
La esperanza de vida en los defectos de tamaño grande no tratados suele ser entre los 40 y los 50 años, lo que cuadra con la edad de muerte del explorador. Y, como recuerda Sarnago, “las situaciones de esfuerzo físico intenso brusco y el frío intenso -con la broncoconstricción que produce- pueden favorecer la aparición de una arritmia paroxística: al acelerar bruscamente el corazón, puede conducir a la sensación de falta de aire intensa, el mareo o incluso la pérdida de conocimiento transitorias. Todo ello mejora claramente al desaparecer la taquicardia”.
“No había manera de tratar la CIA en tiempos de Shackleton. Hoy es diferente: es relativamente sencillo hacer un diagnóstico”, apunta Calder. Sarnago explica que, hace 100 años, la única forma de diagnóstico era a través de la exploración física, los síntomas y la radiología de tórax.
“El tratamiento en aquella época era únicamente paliativo para alguno de los síntomas. Y es cierto que se aconsejaba evitar el esfuerzo físico intenso y las temperaturas extremas. El tratamiento quirúrgico corrector no se comenzó a realizar hasta la década de los 50 y consiste en la sutura del defecto o la colocación de un parche que tape el agujero. Desde hace unos años, para la gran mayoría de las CIA, puede colocarse un parche o tapón mediante un cateterismo, evitando la cirugía abierta”.
Los autores del artículo señalan que puede haber gente que considere que Shackleton era un irresponsable al comandar expediciones antárticas si sabía que estaba enfermo. “Pero, parafraseando al doctor Samuel Johnson, pocas veces hay escasez de personas prudentes, mientras que las grandes cosas las hacen aquellos que están dispuestos a tomar riesgos. Poca gente puede negar que el liderazgo de Shackleton fue crucial hace 100 años para que todos sus compañeros sobrevivieran. Y permanece como inspiración y ejemplo para las próximas generaciones”.
La vanguardia