Ligazóns

Acetylcholinesterase activity in seabirds affected by the Prestige oil spill on the Galician coast (NW Spain)

Enlace mardeaves Alca torda,Fratercula arctica,PUBLICACIÓN CIENTÍFICA,REPOSITORIO,Uria aalge ,,,,
Oropesa, A.L., Pérez-López, M., Hernández, D., García, J.P., Fidalgo, L.E., López-Beceiro, A. & Soler, F., 2007. Acetylcholinesterase activity in seabirds affected by the Prestige oil spill on the Galician coast (NW Spain). Science of the total environment, 372(2), pp.532-538.

In November 2002, the tanker Prestige broke in two and sank at the bottom of the ocean spilling about 70,000 t of fuel oil, which reached the coast of Galicia. It was considered the largest spill in maritime history, greatly affecting marine and related avian species. The spilled fuel oil contained high concentrations of polycyclic aromatic hydrocarbons (PAHs). Many species were affected and were found dead, although ongoing research is still being carried out on the sublethal effects. In this sense, little is known about the action of PAHs on Cholinesterase activity in seabirds. Consequently, the purpose of this study was to provide more information on the neurotoxicity of fuel oil on the seabirds most affected by the Prestige accident: common guillemot, Atlantic puffin and razorbill. On the other hand, data on normal values of acetylcholinesterase (AChE) activity were obtained to supply non-exposed values in seabirds. The oil spill produced a clear inhibitory effect on brain AChE activity in common guillemot (16%, p ≤ 0.01) and razorbill (22%, p ≤ 0.01), but not in Atlantic puffin (4%). Physiological levels of brain AChE, expressed in nmol acetylcholine hydrolysed min− 1 mg− 1 protein were similar in non-exposed common guillemot (388.6 ± 95.0) and Atlantic puffin (474.0 ± 60.7), however, razorbill values were higher (644.6 ± 66.9).

Heavy metal and arsenic content in seabirds affected by the Prestige oil spill on the Galician coast (NW Spain)

Enlace mardeaves Alca torda,Fratercula arctica,PUBLICACIÓN CIENTÍFICA,REPOSITORIO,Uria aalge ,,,
Pérez-López, M., Cid, F., Oropesa, A.L., Fidalgo, L.E., Beceiro, A.L. & Soler, F., 2006. Heavy metal and arsenic content in seabirds affected by the Prestige oil spill on the Galician coast (NW Spain). Science of the total environment, 359(1), pp.209-220.

Seabirds are top consumers in marine foodchains which offer opportunities to detect and assess the toxicological effects of different inorganic elements on the marine ecosystem. In order to provide baseline data concerning trace element levels in seabird species from NW Spain, zinc, copper, arsenic, chromium, lead, cadmium and mercury concentrations were analyzed in liver of three different seabird species (common guillemot, Atlantic puffin and razorbill) affected by the Prestige oil spill in September 2002 on the Galician coast. In general, with the exception of mercury, levels of all the analyzed elements were similar or lower in comparison with those reported for the same species in other Atlantic areas, and did not exceed levels indicative of increased environmental exposure.

Population modelling of European shags (Phalacrocorax aristotelis) at their southern limit: conservation implications

Enlace mardeaves Phalacrocorax aristotelis,PUBLICACIÓN CIENTÍFICA,REPOSITORIO ,,,

Velando, A. and Freire, J., 2002. Population modelling of European shags (Phalacrocorax aristotelis) at their southern limit: conservation implications. Biological Conservation, 107(1), pp.59-69.

The European shag (Phalacrocorax aristotelis) population at Cíes Islands (the most important breeding area in its southern limit) increased rapidly from 1986 to 1992, and afterwards the population suffered a slight decline. This study analyzed population data obtained from ringing recoveries and reproductive monitoring between 1993 and 1997. The reproductive success was highly variable and associated with adverse weather events. Adult survival rate was very low compared with other colonies, probably due to high accidental capture in gill-nets. In recent years, the fishing effort with gill-nets increased in the study area. Sensitivity analysis of parameters showed that the population is more affected by changes in adult survival than in reproductive success. When dynamic simulations were run with an increase in shag mortality of 5% above the present level, population extinction occurred in all simulations. In contrast, when a reduction of mortality of 5% was introduced in the simulations, the population increased in all cases. The main lines of action to study and protect this population should be: (1) ringing schemes to obtain better estimates of survival variability; (2) studies on the interaction of feeding areas and fishing vessels; (3) regulations on gill-netting; and (4) the incorporation of population models as an adaptive management tool to synthesize assessment work and management scenarios.

Weak large‐scale population genetic structure in a philopatric seabird, the European Shag Phalacrocorax aristotelis

Enlace mardeaves Phalacrocorax aristotelis,PUBLICACIÓN CIENTÍFICA,REPOSITORIO ,,
Barlow, E.J., Daunt, F., Wanless, S., Alvarez, D., Reid, J.M. and Cavers, S., 2011. Weak large‐scale population genetic structure in a philopatric seabird, the European Shag Phalacrocorax aristotelis. Ibis, 153(4), pp.768-778.
Quantifying population genetic structure is fundamental to testing hypotheses regarding gene flow, population divergence and dynamics across large spatial scales. In species with highly mobile life-history stages, where it is unclear whether such movements translate into effective dispersal among discrete philopatric breeding populations, this approach can be particularly effective. We used seven nuclear microsatellite loci and mitochondrial DNA (ND2) markers to quantify population genetic structure and variation across 20 populations (447 individuals) of one such species, the European Shag, spanning a large geographical range. Despite high breeding philopatry, rare cross-sea movements and recognized subspecies, population genetic structure was weak across both microsatellites and mitochondrial markers. Furthermore, although isolation-by-distance was detected, microsatellite variation provided no evidence that open sea formed a complete barrier to effective dispersal. These data suggest that occasional long-distance, cross-sea movements translate into gene flow across a large spatial scale. Historical factors may also have shaped contemporary genetic structure: cluster analyses of microsatellite data identified three groups, comprising colonies at southern, mid- and northern latitudes, and similar structure was observed at mitochondrial loci. Only one private mitochondrial haplotype was found among subspecies, suggesting that this current taxonomic subdivision may not be mirrored by genetic isolation.

Multilocus population analysis of Gavia immer (Aves: Gaviidae) mtDNA reveals low genetic diversity and lack of differentiation across the species breeding range

Enlace mardeaves Gavia immer,PUBLICACIÓN CIENTÍFICA,REPOSITORIO ,,,

Bartolomé, C., Maside, X., Camphuysen, K.C., Heubeck, M. & Bao, R., 2011. Multilocus population analysis of Gavia immer (Aves: Gaviidae) mtDNA reveals low genetic diversity and lack of differentiation across the species breeding range. Organisms Diversity & Evolution, 11(4), pp.307-316.

We analyzed the patterns of nucleotide sequence variation at three mitochondrial DNA loci, the noncoding mitochondrial control region and two genes (cytochrome b and cytochrome oxidase I) of Gavia immer in the largest collection of wintering individuals from Southern Europe to date. The sample consisted of 33 birds, oiled during the 2002/2003 Prestige tanker spill and washed ashore on the Galician coast (NW Iberian Peninsula). The aims of the study were to investigate the levels of standing genetic variation in the species, and to identify the geographic origin of these wintering birds. To do this, all available sequences of these loci, mostly from North American specimens collected from both the Atlantic and Pacific coasts, were retrieved from GenBank and included in the analysis. Overall, only 14 genetic variants were detected in the nearly 2 Kb surveyed, which reflects very low levels of nucleotide site diversity in this species. Interestingly, all variants were found at very low frequencies, and there was no indication of any clear subdivision in the G. immer population. This genetic profile is consistent with G. immer being a single panmictic population of small effective population size as compared with other seabirds. These circumstances preclude identification of the breeding regions of these wintering birds relying solely on genetic data. In the light of these results, possible causes, and the genetic and ecological consequences, of this demographic scenario are discussed.

The yellow-legged gull, Larus michahellis, an occasional predator of Timon lepidus in the Atlantic Islands National Park (Galicia, NW Spain)

Enlace mardeaves Larus michahellis,PUBLICACIÓN CIENTÍFICA,REPOSITORIO ,,

Piorno, V., Fernández-Bouzas, J.A. & Velo-Antón, G. The yellow-legged gull, Larus michahellis, an occasional predator of Timon lepidus in the Atlantic Islands National Park (Galicia, NW Spain). Bol. Asoc. Herpetol. Esp. 27(1). (2016).

El lagarto ocelado (Timon lepidus) mantiene poblaciones de gran interés en varias islas, tanto por su estatus de conservación como por las particulares interacciones ecológicas que en ellas se desarrollan. En el caso del Parque Nacional de las Islas Atlánticas de Galicia, esta especie convive con una importante colonia de cría de gaviota patiamarilla (Larus michahellis). Desde el año 2009 hasta 2015 hemos detectado en este Parque Nacional siete casos de consumo de T. lepidus por L. michahellis. Se trata de una conducta nunca antes documentada y de reciente aparición, que podría estar relacionada con los efectos que el cierre de vertederos y la reducción de los descartes pesqueros están teniendo en esta especie de gaviota. El carácter ocasional de esta depredación no hace esperar efectos apreciables en estas poblaciones insulares de lagarto ocelado.

Las colonias de aves marinas de la costa Occidental de Galicia. Características, censo y evolución de sus poblaciones

Enlace mardeaves Larus fuscus,Larus michahellis,Phalacrocorax aristotelis,PUBLICACIÓN CIENTÍFICA,REPOSITORIO,Rissa tridactyla,Uria aalge ,,,

Bárcena, F. & Souza, J.A. Las colonias de aves marinas de la costa Occidental de Galicia. Características, censo y evolución de sus poblaciones. Ecología 1. (1987). ISSN 0214-0896

 

Procesos de colonización y agregación social en la pardela cenicienta (Calonectris diomedea) en Galicia

Enlace mardeaves Calonectris diomedea,INFORME,REPOSITORIO ,,,,,,,

Munilla, I., Velando, A., & Genovart, M. Procesos de colonización y agregación social en la pardela cenicienta (Calonectris diomedea) en Galicia. En: Proyectos de Investigación en Parques Nacionales 2010-2013. 371-391. Organismo Autónomo de Parques Nacionales. (2015).

La pardela cenicienta (Calonectris diomedea) colonizó el Parque Nacional de las Islas Atlánticas de Galicia en 2007 y actualmente se encuentra en las islas Monteagudo y Sur del archipiélago de las Cíes. La estima de la población es de 22 sitios aparentemente ocupados, la mayor parte de ellos (19 sitios) en Tropezas (Monteagudo). Además Galicia cuenta con otras dos colonias, también de fundación reciente, en Sisargas (17 sitios) y Coelleira (22 sitios). Para el conjunto de Galicia se observó una tendencia creciente del número de sitios aparentemente ocupados, del número de parejas reproductoras y del número de pollos entre 2009 y 2013, si bien la proporción de sitios ocupados por parejas reproductoras a lo largo de estos años en las tres localidades fue muy variable. La comparación con datos morfométricos de las subespecies mediterránea (C.d.diomedea) y atlántica (C.d.borealis) indica que la mayoría de las aves de Galicia se asemejan a borealis; no obstante, la proporción de individuos intermedios es considerable y algunos se clasificarían como diomedea. Este resultado es coherente con los datos genéticos y con la escucha de reclamos de diomedea en las colonias gallegas. Existe un dimorfismo sexual marcado que varía en función de la colonia. La heterocigosidad media de las pardelas del Parque Nacional, medida en 10 microsatélites nucleares polimórficos fue de 0,43 ± 0,25, semejante a la del resto de colonias gallegas y a la de otras de la especie. En general, ninguno de los 5 índices de diversidad genética empleados muestra indicios de que la diversidad genética de las colonias gallegas sea inferior a la de las colonias históricas y numerosas. Los valores de los índices de fijación (FST) entre pares de poblaciones muestran que las diferencias genéticas entre las colonias gallegas son pequeñas aunque en el par Sisargas-Coelleira son significativas. La comparación con otras colonias atlánticas (Berlengas, Azores, Canarias, Selvagens y Desertas) y mediterráneas (Menorca, Mallorca, Alborán y Túnez) muestra que las colonias gallegas se diferencian genéticamente de Selvagens, Desertas y de todas las colonias mediterráneas excepto Túnez. Los métodos de análisis Bayesianos mostraron que las pardelas gallegas se agrupaban claramente con los individuos atlánticos, si bien algunas presentaron una traza mediterránea. Mediante el análisis químico de las plumas que recubren la glándula uropigial se cuantificaron 27 compuestos, cuatro de ellos aparecieron siempre y otros 8 están presentes en más de la mitad de los individuos muestreados. Existen cuatro terpenos que, cuando están presentes, presentan unas abundancias muy superiores al resto. Cinco compuestos son responsables de las diferencias encontradas entre las tres colonias de Galicia en cuanto a la composición química de las secreciones uropigiales y, además, cada colonia cuenta con ciertos compuestos característicos. Los resultados de la parte más aplicada del proyecto han demostrado que mediante la emisión de estímulos acústicos se puede conseguir que las pardelas cenicientas ocupen estructuras artificiales apropiadas para la cría. Nuestra experiencia sugiere que es posible propiciar la formación de colonias de pardela cenicienta mediante el uso combinado de estímulos de agregación social y estructuras de anidamiento artificiales y apoya el empleo de vallados interiores como una medida eficaz en la gestión de especies vulnerables amenazadas por carnívoros terrestres en islas.