Consumo de macrófitas acuáticas por la Tagua común Fulica armillata (Aves: Rallidae) en un humedal costero del centro norte de Chile

The Red-gartered Coot Fulica armillata, is a common herbivorous water bird in coastal wetlands of the southern Neotropical region. Microhistological analyses of feces collected at the coastal wetland of Punta Teatinos (north central Chile; ~29ºS), show that this coot feeds predominantly on Stuckenia pectinata, the most abundant submerged macrophyte at this area. The foraging behavior of F. armillata is discussed in regard with its ecological role as a primary consumer on coastal wetlands.La Tagua común Fulica armillata, es un ave acuática herbívora común en los humedales costeros del extremo sur de la región del Neotrópico. Análisis microhistológicos de fecas recolectadas en el humedal de Punta Teatinos (centro norte de Chile; ~29ºS) indican que esta tagua consume primariamente a Stuckenia pectinata, la macrófita sumergida más abundante en esta área. Se discute el comportamiento de forrajeo de F. armillata con respecto a su rol ecológico como consumidor primario en humedales costeros

High temporal variability in the occurrence of consumer-resource interactions in ecological networks

Ecological networks are theoretical abstractions that represent ecological communities. These networks are usually defined as static entities, in which the occurrence of a particular interaction between species is considered fixed despite the intrinsic dynamics of ecological systems. However, empirical analysis of the temporal variation of trophic interactions is constrained by the lack of data with high spatial, temporal, and taxonomic resolution. Here, we evaluate the spatiotemporal variability of multiple consumer-resource interactions of large marine networks. The tropic interactions of all of the analyzed networks had low temporal persistence, which was well described by a common exponential decay in the rank-frequency relationship of consumer-resource interactions. This common pattern of low temporal persistence was evident despite the dissimilarities of environmental conditions among sites. Between-site rank correlations of frequency of occurrence of interactions ranged from 0.59 to 0.73. After removing the interactions with <50% frequency, the between-site correlations decreased to values between 0.60 and 0.28, indicating that low-frequency interactions accounted for the apparent similarities between sites. Our results showed that the communities studied were characterized by few persistent interactions and a large number of transient trophic interactions. We suggest that consumer-resource temporal asynchrony in addition to varying local environmental conditions and opportunistic foraging could be among the mechanisms generating the observed rank-frequency relationship of trophic interactions. Therefore, our results question the analysis of ecological communities as static and persistent natural entities and stress the need for strengthening the analysis of temporal variability in ecological networks and long-term studies.Comment: 21 pages, 3 figure

Genetic consequences of cladogenetic vs. anagenetic speciation in endemic plants of oceanic islands

Adaptive radiation is a common mode of speciation among plants endemic to oceanic islands. This pattern is one of cladogenesis, or splitting of the founder population, into diverse lineages in divergent habitats. In contrast, endemic species have also evolved primarily by simple transformations from progenitors in source regions. This is anagenesis, whereby the founding population changes genetically and morphologically over time primarily through mutation and recombination. Gene flow among populations is maintained in a homogeneous environment with no splitting events. Genetic consequences of these modes of speciation have been examined in the Juan Fernández Archipelago, which contains two principal islands of differing geological ages. This article summarizes population genetic results (nearly 4000 analyses) from examination of 15 endemic species, involving 1716 and 1870 individuals in 162 and 163 populations (with amplified fragment length polymorphisms and simple sequence repeats, respectively) in the following genera: Drimys (Winteraceae), Myrceugenia (Myrtaceae), Rhaphithamnus (Verbenaceae), Robinsonia (Asteraceae, Senecioneae) and Erigeron (Asteraceae, Astereae). The results indicate that species originating anagenetically show high levels of genetic variation within the island population and no geographic genetic partitioning. This contrasts with cladogenetic species that show less genetic diversity within and among populations. Species that have been derived anagenetically on the younger island (1–2 Ma) contain less genetic variation than those that have anagenetically speciated on the older island (4 Ma). Genetic distinctness among cladogenetically derived species on the older island is greater than among similarly derived species on the younger island. An important point is that the total genetic variation within each genus analysed is comparable, regardless of whether adaptive divergence occurs

Hvordan forebygge og håndtere episoder med skadelige alger og maneter i oppdrettsnæringen

Prosjektleder: Trine DaleDette er hovedrapport for prosjektet «Hvordan forebygge og håndtere episoder med skadelige alger og maneter i oppdrettsnæringen» finansiert av Fiskeri og havbruksnæringens forskningsfinansiering. Hovedmålet i prosjektet har vært å sammenstille eksisterende kunnskap, erfaringer og teknologiske løsninger som er i bruk for å forebygge og håndtere episoder med skadelige alger og maneter og basert på dette utforme og formidle anbefalinger og om mulig beste praksis i ulike situasjoner. Det er utviklet en prototype av et verktøy som på en enkel og lettfattelig måte fremstiller anbefalinger og beste praksis samt kunnskapen som danner bakgrunn for disse.Fiskeri og havbruksnæringens forskningsfinansiering.publishedVersio

Biogeografía marina de Chile continental Marine biogeography of continental Chile

Por casi un siglo, varios autores han analizado los patrones de distribución de la fauna y flora marina del Pacífico de Sudamérica y de la costa de Chile en particular, con el propósito de establecer el número de las unidades biogeográficas presentes. Si bien los patrones generales actuales son relativamente bien conocidos, la mayoría de los estudios se ha enfocado en las discontinuidades distribucionales y en propuestas de clasificación más que en los factores y procesos dinámicos que han formado las unidades espaciales identificadas. Aun en el caso de las clasificaciones, las conclusiones publicadas se basan principalmente en el análisis de uno o pocos grupos seleccionados, y presentan diferencias importantes en los criterios de selección de los grupos, el número de especies involucrado y la metodología usada. Por otra parte, las discrepancias entre estudios específicos tienden a obscurecer un fenómeno relevante y de mayor escala como es la dinámica de las biotas, uno de los aspectos biogeográficos menos conocidos en Chile. En tal contexto, este trabajo presenta una revisión de literatura sobre la biogeografía marina de Chile y sus aspectos asociados, con los siguientes objetivos: (a) resumir las características oceanográficas, climáticas y geomorfológicas de la costa continental de Chile; (b) discutir 27 clasificaciones biogeográficas publicadas para la costa chilena, analizando los criterios y procedimientos usados por los autores, sus conclusiones principales, y la concordancia entre los estudios; (c) evaluar los procesos dispersivos y vicariantes asociados a los desplazamientos y modificaciones de las biotas de la región, en función de los antecedentes disponibles sobre las condiciones existentes y los principales eventos ocurridos durante los períodos Terciario y Cuaternario; y (d) proponer un escenario de cambio biogeográfico basado en determinantes históricas y su influencia en la formación, carácter y dinámica de distribución de biotas en la costa chilena, con énfasis en la identificación y naturaleza biogeográfica de las principales unidades espaciales. A partir de la información anterior, se propone una hipótesis de clasificación biogeográfica al nivel de biotas, no necesariamente concordante con estudios previos al nivel de fauna o flora. Esta clasificación identifica tres unidades espaciales mayores: un área sur que incluye a una biota austral (Provincia Magallánica), un área norte que incluye una biota templada-cálida (Provincia Peruana), y un área Intermedia extensa (no transicional) que incluye componentes mixtos de biota sin carácter ni rango biogeográfico definido. Se discute además la diferente naturaleza de dos zonas transicionales situadas en los límites del área Intermedia, una transición de contacto hacia el norte y una transición inducida hacia el sur, que se habrían generado por migraciones de biota y eventos glacio-tectónicos respectivamente<br>For almost a century, a number of authors have analyzed the distribution patterns of the marine fauna and flora in the South American Pacific and particularly along the coast of Chile, with the purpose of determining the number of existing biogeographical units. Although the general, present day patterns are relatively well known, most studies have focused on distributional breaks and classification proposals rather than on the factors and dynamic processes that formed the identified spatial units. Even in the case of biogeographical classifications, published conclusions are based mainly on the analysis of one or few selected groups, exhibiting important differences in their criteria for selecting groups, the number of species involved, and their methodology. On the other hand, diverging conclusions among particular studies tend to obscure the more relevant, large-scale phenomenon of biota dynamics, one of the less known biogeographic aspects in Chile. Within that context, this paper presents a literature review on the marine biogeography of Chile and related subjects, with the following objectives: (a) to summarize the oceanographic, climatic and geomorphologic characteristics of the Chilean continental coast; (b) to discuss 27 biogeographic classifications published for the Chilean coast, analyzing both the procedures and criteria used by their authors, along with their main conclusions and agreements; (c) to assess the vicariant and dispersal processes associated with the displacement and modification of the regional biotas, regarding the available antecedentes on the prevailing conditions and main events during the Tertiary and Quaternary periods; and (d) to propose a scenario of biogeographic change based on historical determinants and their influence on the formation, character, and dynamics of biotas along the Chilean coast, emphasizing the identification and biogeographic nature of the main spatial units. From the preceding information, I propose a hypothesis of biogeographic classification for the level of biotas, not necessarily coincident with prior studies at lower levels such as flora or fauna. This classification identifies three major spatial units: a southern area which comprises an austral biota (Magellan Province), a northern area which comprises a warm-temperate biota (Peruvian Province), and a non transitional, Intermediate Area including mixed components of biota and exhibiting a poor biogeographic definition of both its character and hierarchical rank. I also discuss the different nature of two transitional zones located at the boundaries of the Intermediate Area, a southward induced transition and a northward contact transition, likely produced by the migration of biotas and glacial-tectonic events, respectivel

Educación Científica y Evolutiva en Chile: Problemas Funcionales y Confictos entre Enseñar y Aprender Science and Evolution Education in Chile: Functional Problems and Conficts between Teaching and Learning

En Chile, la educación media (secundaria) y universitaria de pregrado, y la conexión entre ellas, son los puntos más sensibles de la educación científca en biología y evolución, que estuvo seriamente deprimida hacia fnes del siglo XX. No obstante, hoy enfrentamos un escenario de transición favorable donde convergen tres factores capaces de potenciar la alfabetización biológica en sentido amplio: un nuevo currículum secundario que incluye un fuerte componente biológico, con énfasis en evolución y ecología; una reactivación de la formación pedagógica a nivel universitario; y un desarrollo científco creciente en el área de biología evolutiva. Sin embargo, estos factores aún están conectados débilmente, y su mejor articulación podría contribuir a mejorar signifcativamente la retroalimentación entre los componentes del sistema educativo, y a resolver algunos confictos dialécticos entre enseñar y aprender que se generan en diferentes niveles jerárquicos del mismo sistema. El reforzamiento de la interdisciplinaridad entre biología y pedagogía en la formación de nuevos profesores sería un factor clave, ya que el profesor secundario parece ser la piedra angular del sistema educativo, además de jugar un rol crucial en la formación inicial de los futuros científcos.<br>In Chile, high school (secondary) and university undergraduate levels, and their connection, are the most sensitive points of science education in biology and evolution, which was seriously depressed at the end of the 20th century. Nonetheless, we face today a favourable transitional scenario where three converging factors are able to foster science literacy in a wide sense: a new high school curriculum including a strong biological component, with emphasis on evolution and ecology; a reactivation of university formation of secondary pedagogues; and a growing scientifc development in the feld of evolutionary biology. However, these factors are still weakly connected, and strengthening their articulation might improve signifcantly the feedback between all components of the Chilean educational system, helping to solve some dialectic conficts between teaching and learning that originate at different hierarchical levels of the same system. The reinforcement of interdisciplinarity between biology and pedagogy in the process of formation of new teachers would be a key factor, because the high school teacher turns to be the cornerstone of the educational system, in addition playing a crucial role in the initial formation of the future scientists