441 research outputs found
Imminent extinction of the guanay cormorant on the Atlantic South American coast: A conservation concern?
No full textGuanay cormorants Phalacrocorax bougainvilli are distributed mostly on the Pacific coast of Peru and northern Chile. A small population of around 50 pairs was described on the Patagonian Atlantic coast in the late 1960s. Further records have revealed a progressive decrease of this population. During 1999 we looked for guanay cormorants at those Atlantic colonies where the species was recorded in the past. Only four individuals were detected in one colony (Punta Lobería), and all of them were mated with king cormorants P. albiventer. In addition, we recorded hybrids between guanay and king cormorants mated with pure king cormorants P. atriceps. Causes of the population decline are unknown. Since guanay cormorants inhabiting the Atlantic coast could be a genetically differentiated population, we emphasize the need for molecular studies. If genetic polymorphism is detected, the capture of remnant individuals in order to constitute a genetic stock should be considered.Fil: Bertellotti, Néstor Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Donazar, José A.. Estación Biológica de Doñana; EspañaFil: Blanco, Guillermo. Consejo Superior de Investigaciones Científicas; EspañaFil: Forero, Manuela G.. Consejo Superior de Investigaciones Científicas; Españ
Diet of bottlenose dolphins (Tursiops truncatus) from the Gulf of Cadiz: Insights from stomach content and stable isotope analyses [Dataset]
No full textThe ecological role of species can vary among populations depending on local and regional differences in diet. This is particularly true for top predators such as the bottlenose dolphin (Tursiops truncatus), which exhibits a highly varied diet throughout its distribution range. Local dietary assessments are therefore critical to fully understand the role of this species within marine ecosystems, as well as its interaction with important ecosystem services such as fisheries. Here, we combined stomach content analyses (SCA) and stable isotope analyses (SIA) to describe bottlenose dolphins diet in the Gulf of Cadiz (North Atlantic Ocean). Prey items identified using SCA included European conger (Conger conger) and European hake (Merluccius merluccius) as the most important ingested prey. However, mass-balance isotopic mixing model (MixSIAR), using δ13C and δ15N, indicated that the assimilated diet consisted mainly on Sparidae species (e.g. seabream, Diplodus annularis and D. bellottii, rubberlip grunt, Plectorhinchus mediterraneus, and common pandora, Pagellus erythrinus) and a mixture of other species including European hake, mackerels (Scomber colias, S. japonicus and S. scombrus), European conger, red bandfish (Cepola macrophthalma) and European pilchard (Sardina pilchardus). These contrasting results highlight differences in the temporal and taxonomic resolution of each approach, but also point to potential differences between ingested (SCA) and assimilated (SIA) diets. Both approaches provide different insights, e.g. determination of consumed fish biomass for the management of fish stocks (SCA) or identification of important assimilated prey species to the consumer (SIA).The study was funded by Fundación Loro Parque, CEPSA (Compañía Española de Petroleos S.A.), EcoCet Project [CGL2011-25543] J.G. and R.dS. were funded by the Spanish Ministry of Economy and Competitiveness through the Severo Ochoa Programme for Centres of Excellence in R+D+I [SEV-2012-0262]. A.M. and L.N. were partly supported by the Portuguese Foundation for Science and Technology [SFRH/BPD/64889/2009 and SFRH/BD/51416/2011]. Project ECOBOGUE-P11RNM7467 was funded by “Consejería de Economía, Innovación y Ciencia – Junta de Andalucía.Peer reviewe
OFFSPRING SEX RATIO IS RELATED WITH LAYING DATE AND HATCHING SEQUENCE IN THE MAGELLANIC PENGUIN SPHENISCUS MAGELLANICUS
No full textWe analyzed the variation in the secondary sex ratio of Magellanic Penguin Spheniscus magellanicus breeding in six colonies on the Patagonian coast of Argentina. We tested the effects of laying date and hatching sequence on the probability of producing sons and daughters. The global secondary sex ratio did not differ from equality, and there were no differences among the colonies. However, regardless of the colony, laying date, and hatching sequence, there was a significant effect on the proportion of males and females reared. Pairs that were laid early in the breeding season were more likely to raise a male. In addition, offspring that hatched first were more likely to be male than those that hatched second. Our results are consistent with the adaptive importance of producing males, likely the costliest sex, early in the breeding season or early in the brood when food resources are still abundant
High trophic overlap within the seabird community of Argentinean Patagonia: a multiscale approach
No full text1. Food web interactions in animal communities can be investigated through the measurement of stable isotopes (e.g. δ15N, δ13C). We used this approach in a community of 14 species of seabirds breeding on the Argentinean Patagonian coast. Tissue samples were collected from nestling and adult seabirds, as well as prey, during three consecutive breeding seasons in 28 breeding colonies. 2. Relative to those in other temperate and polar regions, this seabird community showed a high degree of overlap in trophic level (TL) among species (93% of species within a TL range of 0·7) and also a comparatively high mean trophic level (4·1). 3. Relative positions of seabirds in relation to prey suggest that most species feed on pelagic fish and to a lesser extent on invertebrates. Stable isotope values of specialist feeders, Olrolg’s (Larus atlanticus) and dolphin gulls (Leucophaeus scoresbii), which were previously assumed to feed mainly on crabs and sea lion excrement, respectively, suggested a broader diet than expected. 4. Based on stable isotope values of individuals, groups of phylogenetically related species generally showed a high degree of overlap within each group. 5. Given the degree of isotope overlap in this species-rich community, coexistence could be interpreted as a consequence of superabundance of food or species diversification in morphology and foraging strategies. The short range of trophic level makes these seabirds vulnerable to the reduction of fish stocks due either to commercial fishing or stochastic fluctuations.Fil: Forero, Manuela G.. Instituto Mediterráneo de Estudios Avanzados; España. Estación Biológica de Doñana; EspañaFil: Bortolotti, Gary R.. University Of Saskatchewan; CanadáFil: Hobson, Keith A.. University Of Saskatchewan; CanadáFil: Donazar, Jose A.. Estación Biológica de Doñana; EspañaFil: Bertellotti, Néstor Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Blanco, Guillermo. Instituto de Investigación en Recursos Cinegéticos; Españ
Spin networks and sturmian orbitals: Orthogonal complete polynomial sets in molecular quantum mechanics
No full textAn outline is given of current advances on some basic ingredients of applied quantum mechanics, that were previously developed along different lines and are now being compacted within a unifying framework. Specifically, (i) complete orthogonal expansion basis sets for the atomic and molecular orbitals of quantum chemistry are classified within angular momentum theory, presently incorporated in and generalized as spin network theory; (ii) spin-networks and the underlying theory of hypergeometrical polynomials are presented within a graphical approach; (iii) the combinatorial significance of the graphical approach is given a projective geometry foundation; (iv) emergence and role of hidden (Regge's) symmetries are revealed and discussed in a variety of contexts
Author correction: Genome-wide association study identifies susceptibility loci for B-cell childhood acute lymphoblastic leukemia
No full text\ua9 2019, The Author(s). The original version of this Article contained an error in the spelling of a member of the PRACTICAL Consortium, Manuela Gago-Dominguez, which was incorrectly given as Manuela Gago Dominguez. This has now been corrected in both the PDF and HTML versions of the Article. Furthermore, in the original HTML version of this Article, the order of authors within the author list was incorrect. The PRACTICAL consortium was incorrectly listed after Richard S. Houlston and should have been listed after Nora Pashayan. This error has been corrected in the HTML version of the Article; the PDF version was correct at the time of publication
Food resource utilisation by the Magellanic penguin evaluated through stable-isotope analysis: Segregation by sex and age and influence on offspring quality
No full textWe used stable-isotope analysis (SIA) to evaluate sources of variation in the diet of and prey selection by Magellanic penguins Spheniscus magellanicus breeding on the Argentinean Patagonia coast. Our aim was to determine potential sources of variation in diet, focusing mainly on sex and age, although geographic and temporal effects were also taken into account. In addition, we evaluated how prey selection affects offspring quality. We measured stable nitrogen (δ15N) and carbon (δ13C) isotope values in whole blood of chicks (n = 98), yearlings (n = 15) and adults (n = 143) in 9 different breeding colonies during 2 consecutive breeding seasons (1999 and 2000). We also measured stable isotope values in representative prey consumed by this species. Stable nitrogen and carbon isotope values in blood for penguins varied from 17.8 to 20.0‰ and from -18.1 to -14.8‰, respectively. Both colony and season had a significant effect on the 2 isotope signatures. Adult males had higher blood δ15N and δ13C values than females. Age significantly affected both δ15N and δ13C values, with chicks showing the highest and yearlings the lowest δ15N values. Chicks showed lower δ13C values than yearlings and adults. Mean prey δ15N values ranged from 13.6‰ in squid to 18.0‰ in octopus. As anchovy, the main prey consumed by the species in the study area, did not differ from other fish species (hake) in its δ15N value, we used it to represent a fish dietary alternative. Using a 2-source (anchovy and squid) isotopic mixing model, we determined that the mean proportion of anchovy in the diet was 49% for yearlings, 76% for chicks, and 69% and 67% for adult males and females, respectively. Sex and age differences in diet, as revealed by stable isotopes, may be the consequence of individual morphology (sexual size dimorphism) and reproductive constraints imposed by chick development since growing young require more nutritive prey than adults and yearlings. This reasoning would also explain the significant and positive correlation found between proportion of anchovy in the diet and body condition of chicks.Fil: Forero, Manuela G.. Consejo Superior de Investigaciones Científicas. Instituto Mediterráneo de Estudios Avanzados; EspañaFil: Hobson, Keith A.. Canadian Wildlife Service; Canadá. University of Saskatchewan; CanadáFil: Bortolotti, Gary R.. University of Saskatchewan; CanadáFil: Donázar, Jose A.. Consejo Superior de Investigaciones Científicas; EspañaFil: Bertellotti, Néstor Marcelo. Consejo Superior de Investigaciones Científicas; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Blanco, G.. Instituto de Investigación en Recursas Cinegéticos; Españ
El empleo de isótopos estables de nitrógeno y carbono para estudiar la ecología de las aves marinas: aplicaciones a la comunidad de aves marinas del mediterráneo
No full textPublicación online disponible en: http://www.icm.csic.es/scimar/index.php[EN] The application of the stable isotope technique to ecological studies is becoming increasingly widespread. In the case of seabirds, stable isotopes of nitrogen and carbon have been mainly used as dietary tracers. This approach relieson the fact that food web isotopic signatures are reflected in the tissues of the consumer. In addition to the study of trophic ecology, stable isotopes have been used to track the movement of seabirds across isotopic gradients, as individuals moving between isotopically distinct foodwebs can carry with them information on the location of previous feeding areas. Studies applying the stable isotope methodology to the study of seabird ecology show a clear evolution from broad and descriptive approaches to detailed and individual-based analyses. The purpose of this article is to show the different fields of application of stable isotopes to the study of the seabird ecology. Finally, we illustrate the utility of this technique by considering the particularities of the Mediterranean seabird community, suggesting different ecological questions and conservation problems that could be addressed by using the stable isotope approach in this community.[ES] La aplicación de la medición de isótopos estables
a los estudios ecológicos es cada vez más frecuente. En el caso de las aves marinas, los isótopos estables de nitrógeno
y carbono han sido empleados principalmente como indicadores del régimen alimenticio. Este enfoque se basa en el hecho
de que las concentraciones isotópicas de las cadenas tróficas se reflejan en los tejidos del consumidor. Además de para el
estudio de la ecología trófica, los isótopos estables se han utilizado para estudiar el movimiento de las aves marinas a través
de gradientes isotópicos, ya que los individuos que se mueven entre cadenas tróficas isotópicamente distintas pueden
llevar con ellos información sobre la ubicación de áreas de alimentación anteriores. Los estudios que aplican la metodología
de los isótopos estables al conocimiento de la ecología de las aves marinas muestran una clara evolución, desde los enfoques
amplios y descriptivos, a los análisis detallados y basados en los individuos. El objetivo de este trabajo es mostrar los
diferentes campos de aplicación de los isótopos estables en el estudio de la ecología de las aves marinas. Finalmente, ilustramos
la utilidad de esta técnica considerando las particularidades de la comunidad de aves marinas del mar mediterráneo,
sugiriendo diferentes cuestiones ecológicas y problemas de conservación que se podrían abordar empleando la técnica de
los isótopos estables en esta comunidad.During the writing M.G. Forero was supported
by a post-doctoral scholarship from the
Memorial Isabel López Foundation, University of
Saskatchewan (Canada) and by a contract from the
Ramón y Cajal Programme of the Ministerio de
Ciencia y Tecnología of Spain.Peer reviewe
Changes in diet and trophic position of a top predator 10 years after a mass mortality of a key prey
No full textAbstract
Chiaradia, A., Forero, M. G., Hobson, K. A., and Cullen, J. M. 2010. Changes in diet and trophic position of a top predator 10 years after a mass mortality of a key prey. – ICES Journal of Marine Science, 67: 1710–1720. After the disappearance of primary prey, seabirds exhibit gradually decreased breeding performance, and eventually the population size drops. Results are presented of an investigation into the diet of little penguins (Eudyptula minor) at Phillip Island, Australia, during a period when their key prey, pilchard (Sardinops sagax), declined dramatically. Data from stomach flushing (1982–2006) were used, supported by stable isotope (δ15N, δ13C) analyses of blood samples (2003, 2004, and 2006). The effect of the pilchard mortality on penguin diet was immediate, the birds shifting to a diet almost devoid of pilchard, and this was followed by 2 years of low breeding success, with considerably fewer penguins coming ashore. During periods when pilchard was not part of the diet, penguins consumed prey of a higher trophic level, e.g. higher values of δ15N. Variability in penguin blood δ15N coincided with years of low prey diversity. The disappearance of pilchard resulted in a decrease in prey diversity and led penguins to “fish up” the foodweb, possibly because of the simplified trophic structure. After 1998, however, breeding success re-attained average levels and the numbers of penguins coming ashore increased, probably because of increased abundance of prey other than pilchard after a 3-year period of food scarcity. Although little penguins apparently compensated over time, a less-flexible diet could make them ultimately vulnerable to further changes in their foodweb.</jats:p
Author Correction:Large-scale transcriptome-wide association study identifies new prostate cancer risk regions (Nature Communications, (2018), 9, 1, (4079), 10.1038/s41467-018-06302-1)
No full textThe original version of this Article contained an error in the spelling of a member of the PRACTICAL Consortium, Manuela Gago-Dominguez, which was incorrectly given as Manuela Gago Dominguez. This has now been corrected in both the PDF and HTML versions of the Article. Furthermore, In the original HTML version of this Article, the order of authors within the author list was incorrect. The consortium PRACTICAL consortium was incorrectly listed after Bogdan Pasaniuc and should have been listed after Kathryn L. Penney. This error has been corrected in the HTML version of the Article; the PDF version was correct at the time of publication.</p
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