Geographic variations in shell growth rates of the mussel Diplodon chilensis from temperate lakes of Chile: Implications for biodiversity conservation

AbstractThe Chilean lake district includes diverse lentic ecosystems along ca. 700km of the country (36°–43°S), including the “Nahuelbutan lakes”, “Araucanian lakes” and “Chiloe lakes”. This area is recognized as an important “hot spot” of benthic freshwater biodiversity in Southern South America. In Chilean temperate lakes, increased nutrient loads of P and N caused eutrophication, particularly in the Nahuelbutan Lakes. The freshwater Hyriidae mussel Diplodon chilensis (Gray, 1828) which is one of the most abundant species in Chilean temperate lakes, is known to be very susceptible to eutrophication. This species presents a clear reduction in its geographic ranges and is considered to be a threatened species in many Chilean lakes. In this study, we used a correlative approach to determine how eutrophication-driven changes in the food supply and in geographical parameters of different Chilean lakes affected the shell growth rates of D. chilensis. The results obtained from sclerochronological analyses of the mussel shells suggest an association with a group of environmental variables, including geographical types (negative), such as latitude and altitude, and limnological types (positive), especially phosphorous and turbidity. However, the D. chilensis populations under extreme conditions of turbidity in eutrophic and hypertrophic lakes are extinct or nearly so. The high positive correlation of the mean D. chilensis growth rates with orthophosphate (R=0.76; P<0.05), in relation to dissolved inorganic nitrogen, suggests that P is the major limiting factor of the primary productivity in Chilean temperate lakes. We discuss some implications of our results in terms of the conservation of biodiversity in temperate lake ecosystems at different taxonomic levels

Freshwater Invertebrates of Southwestern South America: Diversity, Biogeography, and Threats

This chapter reviews the current state of knowledge of invertebrates of rivers, lakes, and wetlands in western South America, from southern Peru to the Strait of Magellan in southern Chile. A characterization of the diverse groups of insects, mollusk crustaceans, and other smaller groups is presented, and a biogeographic analysis of them is made with emphasis on their main forcing factors, ecology, and threats in the Anthropocene. This fauna presents Gondwanic characteristics, with clear North–South latitudinal patterns, covering from the Desert of Atacama in the North, one of the most arid deserts of the world, to the rainy and cold regions of the southern end of South America. The central zone of this territory includes one of the global biodiversity “hot spots,” which currently presents serious threats associated with changes in habitat, introduction of invasive species, climate change, and overexploitation of aquatic resources

Macroinvertebrates and Fishes as Bioindicators of Stream Water Pollution

Freshwater ecosystems worldwide have been progressively deteriorated during the past decades due to an increasing human pressure that has lead to a decrease in aquatic biodiversity. Among the human activities of high impact on freshwater ecosystems is the land-use change, principally from native forests to agriculture. To evaluate the impacts of human activities on water quality, a traditional approach has considered the use of single physical-chemical parameters. However, this approach may be insufficient to fully assess the impact of these human activities on freshwaters. Therefore, there is a need for alternative tools such as the indices of biotic integrity that may provide a complement to traditional approaches. In the literature, there are several examples of biotic indicators that have shown promising results in evaluating water quality including the use of macroinvertebrates and fish diets. Here, we provide a review of the indicators of biotic integrity that included fish assemblages as well as macroinvertebrates as bioindicators. We identify pros and cons of using aquatic communities as indicators of water quality. Finally, we develop a procedure that combines fish and macroinvertebrate assemblages as bioindicators and discuss their effectiveness using illustrative examples from streams under several agricultural uses in the Mediterranean region of Chile

Diversità e singolarità dei patrimonio naturale e culturale del Cile

Análisis del patrimonio cultural y natural (expresado en el paisaje) de Chile, destacando la diversidad y singularidad del patrimonio y su relación con las distintas zonas geografícas del paí

Efecto del reemplazo de la vegetación nativa de ribera sobre la comunidad de macroinvertebrados bentónicos en arroyos de climas templados, Chile central

The organic matter from riparian vegetation is determined by the structure and complexity of streams. It presents a higher energetic input to streams as well as important source of food for macroinvertebrates in head streams. In spite of its importance, riparian landscape has been rapidly degraded by human activity, this affects structure and composition of the aquatic community. The present study was made in Central Chile (Biobio Region) which has intensive forest activity with exotic species. Small streams were selected (&lt; 3 order), because they are very particularly sensitive to changes in land use. The sites were grouped identified according to native forest land cover larger than 20% (group 1) and smaller than 20% (group 2). Significant differences (p?&lt; 0.05) in Plecoptera abundance (p&lt;0.05) were found between the two groups. Differences in trophic groups were significant for shredders and predators increased and gathering-collectors decreased their abundance, with native cover smaller than 20%. This showed the dependent on allochthonous material. The vegetation cover and community parameters correlations showed that Diversity (H?) increased with higher percentage of watershed covered by native vegetation and exotic species mix. Results suggest that a buffer conservation area of native riparian vegetation is necessary in streams and rivers in order to maintain the structure and diversity of macroinvertebrates and health of these ecosystems.El aporte de materia orgánica desde la vegetación ribereña es determinante en la estructura y complejidad de los sistemas fluviales; es identificado como el mayor aporte energético en ríos y una fuente importante de alimento para macroinvertebrados en arroyos de cabecera. No obstante, el paisaje ribereño ha sido altamente degradado por actividades humanas, lo que ha afectado la estructura y composición de las comunidades acuáticas. El presente estudio se desarrolló en Chile central (región del Biobío) donde se concentra una intensa actividad forestal con especies exóticas. Se seleccionaron ríos de bajo orden (&lt; 3), por su sensibilidad al cambio de uso del suelo, los cuales fueron clasificados de acuerdo a la cobertura de bosque nativo como mayor al 20% (grupo 1) y menor al 20% (grupo 2). La comparación de los macroinvertebrados según esta clasificación mostró una abundancia significativamente menor (p&lt; 0.05) de Plecoptera en sitios con menos vegetación nativa. Al comparar los grupos tróficos funcionales, hubo diferencias significativas (p?&lt;0.05) para los fragmentadores y los depredadores quienes disminuyeron su abundancia, mientras que los detritívoros aumentaron, lo que demuestra su dependencia del aporte alóctono. Las correlaciones entre el porcentaje de cobertura vegetal y los parámetros comunitarios de macroinvertebrados destacó la correlación entre la Diversidad (H?) y la mezcla de bosque nativo y especies exóticas (r =0.91). Los resultados sugieren la necesidad de conservar un área amortiguadora con vegetación ribereña nativa en arroyos y ríos, que permita mantener la estructura y diversidad de las comunidades y con ello, el estado de salud de estos ecosistemas

Contraction amplitude is a relevant predictor of bolus transit during sitting viscous solution swallows in healthy individuals : preliminary results of a multicenter study using high resolution impedance manometry (HRIM)

Q1Q1https://orcid.org/0000-0002-9219-4548https://orcid.org/0000-0003-1222-0636https://orcid.org/0000-0002-4523-7947Revista Internacional - Indexad

Phylogeography of the Patagonian otter Lontra provocax: adaptive divergence to marine habitat or signature of southern glacial refugia?

<p>Abstract</p> <p>Background</p> <p>A number of studies have described the extension of ice cover in western Patagonia during the Last Glacial Maximum, providing evidence of a complete cover of terrestrial habitat from 41°S to 56°S and two main refugia, one in south-eastern Tierra del Fuego and the other north of the Chiloé Island. However, recent evidence of high genetic diversity in Patagonian river species suggests the existence of aquatic refugia in this region. Here, we further test this hypothesis based on phylogeographic inferences from a semi-aquatic species that is a top predator of river and marine fauna, the huillín or Southern river otter (<it>Lontra provocax</it>).</p> <p>Results</p> <p>We examined mtDNA sequences of the control region, ND5 and Cytochrome-b (2151 bp in total) in 75 samples of <it>L. provocax </it>from 21 locations in river and marine habitats. Phylogenetic analysis illustrates two main divergent clades for <it>L. provocax </it>in continental freshwater habitat. A highly diverse clade was represented by haplotypes from the marine habitat of the Southern Fjords and Channels (SFC) region (43°38' to 53°08'S), whereas only one of these haplotypes was paraphyletic and associated with northern river haplotypes.</p> <p>Conclusions</p> <p>Our data support the hypothesis of the persistence of <it>L. provocax </it>in western Patagonia, south of the ice sheet limit, during last glacial maximum (41°S latitude). This limit also corresponds to a strong environmental change, which might have spurred <it>L. provocax </it>differentiation between the two environments.</p

The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase&nbsp;1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation&nbsp;disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age&nbsp; 6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score&nbsp; 652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc&nbsp;= 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N&nbsp;= 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in&nbsp;Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in&nbsp;Asia&nbsp;and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701