Universidad de Magallanes
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Understanding ground-nesting habitat selection by waterbirds to prioritize invasive predator control on islands
No full textThe introduction of carnivores to islands affects the conservation status of native prey. For two decades, American mink (Neogale vison) has expanded its distribution in the sub-Antarctic archipelago of Austral Patagonia, while preying on nests of solitary ground-nesting birds. Here, upland geese (Chloephaga picta) and flightless steamer ducks (Tachyeres pteneres) are naïve to such predation risk because of the lack of native terrestrial predators. We used nest occupancy models to reveal preferred breeding habitats of those two groundnesting waterbirds to prioritize areas for future mink control programs. We searched for nests along 80 transects on Navarino Island, southernmost Chile, and 11 transects on 10 nearby islets (3 +/- 2.9 ha). Our results showed that islets were essential for breeding in comparison to the main island (5.3 nests/km versus 0.8 nests/km, respectively). The occupancy models revealed that islets were particularly important for flightless steamer ducks, endemic to western Patagonia. As breeding habitat, upland geese preferred medium-dense shrubland, and flightless steamer ducks preferred rocky coastlines. Nest detection was negatively affected by dense vegetation and, in the case of the upland geese, towards the end of the survey. Ten camera traps (n = 385 trap nights) revealed mink presence on all islets, highlighting their capacity to swim in cold water, up to 340 m distance from the main island. We conclude that islets represent breeding refuges for ground-nesting waterbirds and therefore advocate allocating resources for mink control during the warm season on islets. We also provide predictive maps of nesting habitat preference of upland geese and flightless steamer ducks for conservation managers to focus their often scarce human and financial resources on areas critical for breeding. Finally, we argue that detection probability should be an integral part of bird breeding studies, which can be methodologically achieved through targeting transects, not nests, as sample units
Habitat type controls microarthropod community changes across a Magellanic sub-Antarctic elevation gradient
No full textIntroduction Elevation gradients are often used as a proxy for climate change as they allow comparisons of ecological responses over much larger temporal and spatial scales than is possible through experimental manipulations.Methods Here, we tested how microarthropod communities (Collembola and Acari) are affected by climatic differences between sea level and 600 m a.s.l. on Navarino Island, in the Magellanic sub-Antarctic ecoregion of southern Chile (mean annual temperatures of 5.6 vs 3.1 degrees C, respectively). We quantified microarthropod abundance, richness and community trait characteristics in dominant moss (Racomitrium lanuginosum and Polytrichum strictum) and lichen (Usnea trachycarpa, Pseudocyphellaria freycinetii and Stereocaulon alpinum) vegetation growing at both elevations. These moss and lichen genera are characterized by large morphological differences and allow testing of how habitat characteristics affect microarthropod community response across elevation gradients.Results Collembola and Acari community composition differed between the low and high elevation sites. Total abundance levels of Acari were maintained in each habitat across elevation, whereas Collembola richness strongly declined (50%) at high elevation in the moss habitats. Acari community differences across elevation were driven by relative abundance changes whereas the Collembola community lost species at higher elevation. An anticipated decline of smaller eudaphic Collembola at high elevation was only observed in the moss Racomitrium, reflecting potentially lower temperature buffering capacity and shelter options compared to Polytrichum. Lichens mostly supported larger epigeic species irrespective of elevation. There were no consistent patterns linking microarthropod communities with habitat water holding capacity or water loss rates across the studied habitats and elevation.Discussion Habitat type and the genus of moss or lichen were associated with microarthropod community changes across elevation, including examples of declines, increases and no change. These findings highlight that community responses across gradients may not always relate to the generally hypothesized environmental variables (e.g. temperature variability) and that habitat characteristics should be taken into account when using elevation as a proxy for climate change
Biodiversity and relative abundance of benthic invertebrates in the intertidal of Taraba Sound, Magellan Region, Chile
No full textThe Taraba Sound is situated north of the Strait of Magellan within the Chilean fjord and channel system. In this inlet, samples were collected at three beach levels (supralittoral, mesolittoral and infralittoral) along four transects perpendicular to the coastline. A total of 2,754 specimens were collected and identified, representing seven phyla and 24 operational taxonomic units (OTUs). The dominant components across the four beaches were bivalves and crustaceans, with Choromytilus chorus and Paramoera cf. fissicauda contributing significantly to zone similarity. Beaches 2 and 4, located adjacent to river mouths, had lower salinity and consequently lower species richness, abundance, diversity and evenness, particularly in the supra- and mesolittoral zones where freshwater influence is more pronounced. Our study represents the first comprehensive characterisation of intertidal benthic invertebrate biodiversity in the region. Its findings provide valuable baseline data for future research, especially considering the anticipated increase in aquaculture concession applications and the establishment of offshore sea farming centres in the region
The global relevance of locally grounded ethnobiology
No full textWhile ethnobiology is a discipline that focuses on the local, it has an outstanding, but not yet fully realized potential to address global issues. Part of this unrealized potential is that universalistic approaches often do not fully recognize culturally grounded perspectives and there are multiple challenges with scaling up place-based research. However, scalability is paramount to ensure that the intimate and context-specific diversity of human-environmental relationships and understandings are recognized in global-scale planning and policy development. Here, we identify four pathways to enable the scalability of place-based ethnobiological research from the ground up: local-to-global dialogues, aggregation of published data, multi-sited studies, and geospatial analyses. We also discuss some major challenges and consideration to encourage continuous reflexivity in these endeavours and to ensure that scalability does not contribute to unnecessarily decontextualizing, co-opting, or overwriting the epistemologies of Indigenous Peoples and local communities. As ethnobiology navigates multiple scales of time and space and seeks to increase its breadth, this study shows that the use of deliberately global approaches, when carefully nested within rich field-based and ecological and ethnographically grounded data, can contribute to: (1) upscaling case-specific insights to unveil global patterns and dynamics in the biocultural contexts of Indigenous Peoples and local communities; (2) bringing ethnobiological knowledge into resolutions that can influence global environmental research and policy agendas; and (3) enriching ethnobiology's field-based ethos with a deliberate global analytical focus
Breaking the Law: Is It Correct to Use the Converse Bergmann Rule in Ceroglossus chilensis? An Overview Using Geometric Morphometrics
No full textThe converse Bergmann's rule is a pattern of body size variation observed in many ectothermic organisms that contradicts the classic Bergmann's rule and suggests that individuals inhabiting warmer climates tend to exhibit larger body sizes compared to those inhabiting colder environments. Due to the thermoregulatory nature of Bergmann's rule, its application among ectotherms might prove to be more complicated, given that these organisms obtain heat by absorbing it from their habitat. The existence of this inverse pattern therefore challenges the prevailing notion that larger body size is universally advantageous in colder climates. Ceroglossus chilensis is a native Chilean beetle that has the largest latitudinal range of any species in the genus, from 34.3 degrees S to 47.8 degrees S. Within Chile, it continuously inhabits regions extending from Maule to Aysen, thriving on both native and non-native forest species. Beyond their remarkable color variation, populations of C. chilensis show minimal morphological disparity, noticeable only through advanced morphological techniques (geometric morphometrics). Based on both (1) the "temperature-size rule", which suggests that body size decreases with increasing temperature, and (2) the reduced resource availability in high-latitude environments that may lead to smaller body sizes, we predict that C. chilensis populations will follow the converse Bergmann's rule. Our results show a clear converse pattern to the normal Bergmann rule, where smaller centroid sizes were found to be measured in the specimens inhabiting the southern areas of Chile. Understanding the prevalence of the converse Bergmann's rule for ectotherm animals and how often this rule is broken is of utmost importance to understand the underlying mechanisms allowing organisms to adapt to different environments and the selective pressures they face
Averaging Functions on Triangular Fuzzy Numbers and an Application in Graphs
No full textAdmissible orders on fuzzy numbers are total orders, which refine a basic and well-known partial order on fuzzy numbers. In this work, we define an admissible order on triangular fuzzy numbers (i.e., TFN 's) and study some fundamental properties with its arithmetic and their relation with this admissible order. We also propose a new hyperstructure for ordered vector spaces and, in particular, consider the case of TFN . In addition, we also introduce the concepts of averaging functions on TFN , with emphasis on ordered weighted averaging functions on TFN equipped with an admissible order. Finally, the problem of joining central vertices is presented with an illustrative example where the previous concept is used
The glacial geomorphology of the Cordillera Darwin Icefield, Tierra del Fuego, southernmost South America
No full textThe Cordillera Darwin Icefield (CDI) has experienced widespread retreat since the Little Ice Age (LIA, similar to 1870 AD). Prior to this, information on outlet glacier dynamics is limited as there are few terrestrial observations and little mapped deglacial evidence, limiting our understanding of CDI dynamics on Holocene centennial to millennial timescales. Here we present a glacial geomorphological map of terrestrial landforms and features for the CDI and surrounding areas of the Tierra del Fuego archipelago. We digitized more than 8,000 glacial landforms and features covering an area of similar to 13,300 km(2) from a combination of digital elevation models (DEMs) and high-resolution satellite and aerial imagery (<3 m), supported by multitemporal field mapping. This work provides a detailed geomorphological assessment for the area, summarized in a single map, that identifies three main glacial landsystem types of the Patagonian-Fuegian landscape: (i) upland glacier, (ii) lowland land-terminating, and (iii) glaciomarine fjord. The resulting map forms the basis for future chronological campaigns
Percepción de los tutores sobre la sensibilidad auditiva de niños y niñas de 3 a 6 años diagnosticados con trastornos del espectro autista de la escuela Santa Laura de Punta Arenas
No full textLa hiperacusia corresponde a la intolerancia a ruidos o sonidos, que a otras personas o en otras circunstancias no resultan molestos. Este síntoma es observado habitualmente por la población en general y puede verse con mayor frecuencia frente a situaciones de estrés físico o psicológico. Un grupo que sufre altos niveles de estrés es aquel perteneciente al trastorno del espectro autista. Para evaluar la hiperacusia se requiere de instrumentos clínicos que cuantifiquen la tolerancia, no obstante,existen encuestas que pueden ayudar a entregar una imagen perceptiva de este fenómeno, como es el cuestionario de hiperacusia de Khalfa. Objetivo es analizar la percepción de los tutores sobre la sensibilidad auditiva en niños y niñas de 3 a 6 años diagnosticados conTEA de la escuela Santa Laura de Punta Arenas a través de la aplicación de cuestionario de sensibilidad auditiva de Khalfa (2002).MATERIALES Y MÉTODOS. El enfoque de investigación es el cuantitativo y descriptivo, midiendo la percepción de los tutores enrelación conla sensibilidad auditiva en niños con TEA.RESULTADOS.Los tutores perciben molestias frente a los sonidos fuertes en actividades de mayor carga de estrés, sin embargo,no requieren insumos de protección ante estas situaciones.CONCLUSIONES. Gran parte de los niños con trastornos de espectro autistade la escuela Santa Laura no presentan dificultades ante sonidos de la vida cotidiana, no resultando estos molestos para ellos, sin embargo, se observa molestia a sonidos fuertes frente a situaciones de mayor carga de estrés como son fiestas y actividades sociales, resultando en conductas de alejamiento y baja tolerancia a los ruidos
Early mutational signatures and transmissibility of SARS-CoV-2 Gamma and Lambda variants in Chile
No full textGenomic surveillance (GS) programmes were crucial in identifying and quantifying the mutating patterns of SARS-CoV-2 during the COVID-19 pandemic. In this work, we develop a Bayesian framework to quantify the relative transmissibility of different variants tailored for regions with limited GS. We use it to study the relative transmissibility of SARS-CoV-2 variants in Chile. Among the 3443 SARS-CoV-2 genomes collected between January and June 2021, where sampling was designed to be representative, the Gamma (P.1), Lambda (C.37), Alpha (B.1.1.7), B.1.1.348, and B.1.1 lineages were predominant. We found that Lambda and Gamma variants' reproduction numbers were 5% (95% CI: [1%, 14%]) and 16% (95% CI: [11%, 21%]) larger than Alpha's, respectively. Besides, we observed a systematic mutation enrichment in the Spike gene for all circulating variants, which strongly correlated with variants' transmissibility during the studied period (r = 0.93, p-value = 0.025). We also characterised the mutational signatures of local samples and their evolution over time and with the progress of vaccination, comparing them with those of samples collected in other regions worldwide. Altogether, our work provides a reliable method for quantifying variant transmissibility under subsampling and emphasises the importance of continuous genomic surveillance
Environmental plastics in the context of UV radiation, climate change, and the Montreal Protocol
No full textThere are close links between solar UV radiation, climate change, and plastic pollution. UV-driven weathering is a key process leading to the degradation of plastics in the environment but also the formation of potentially harmful plastic fragments such as micro- and nanoplastic particles. Estimates of the environmental persistence of plastic pollution, and the formation of fragments, will need to take in account plastic dispersal around the globe, as well as projected UV radiation levels and climate change factors.imag