Papers by Meritxell Genovart
Publicación online disponible en: http://www.icm.csic.es/scimar/index.php [EN] The impact of yell... more Publicación online disponible en: http://www.icm.csic.es/scimar/index.php [EN] The impact of yellow-legged gulls on Audouin´s gulls was studied by means of observations from a blind, at the Ebro Delta, the Chafarinas Islands and the Columbretes Islands colonies, during different stages of Audouin´s Gulls breeding cycle. The rates of predation (upon eggs and chicks) and kleptoparasitism (aerial and on courtship and chick-feeding regurgitates) were recorded to evaluate this impact. Kleptoparasitism and predation rates recorded at the three colonies may be considered low when compared with similar studies dealing with other gull species. It seems that interactions did not represent a threat to the population dynamics of Audouin´s Gulls in any of the three colonies. The highest rates of aerial kleptoparasitism, courtship feeding and chick mortality were recorded at the Columbretes Islands, and the lowest at the Ebro Delta. The ratio of the number of yellow-legged gulls to the number of ...
Small spatial scale Egg size Stable isotopes Trophic segregation Body size Breeding performance a
1. Large-scale seasonal climatic indices, such as the North Atlantic Oscillation (NAO) index or t... more 1. Large-scale seasonal climatic indices, such as the North Atlantic Oscillation (NAO) index or the Southern Oscillation Index (SOI), account for major variations in weather and climate around the world and may influence population dynamics in many organisms. However, assessing the extent of climate impacts on species and their life-history traits requires reliable quantitative statistical approaches. 2. We used a new analytical tool in mark-recapture, the multi-event modelling, to simultaneously assess the influence of climatic variation on multiple demographic parameters (i.e. adult survival, transient probability, reproductive skipping and nest dispersal) at two Mediterranean colonies of the Cory's shearwater Calonectris diomedea, a trans-equatorial migratory long-lived seabird. We also analysed the impact of climate in the breeding success at the two colonies. 3. We found a clear temporal variation of survival for Cory's shearwaters, strongly associated to the large-scale SOI especially in one of the colonies (up to 66% of variance explained). Atlantic hurricane season is modulated by the SOI and coincides with shearwater migration to their wintering areas, directly affecting survival probabilities. However, the SOI was a better predictor of survival probabilities than the frequency of hurricanes; thus, we cannot discard an indirect additive effect of SOI via food availability. Accordingly, the proportion of transients was also correlated with SOI values, indicating higher costs of first reproduction (resulting in either mortality or permanent dispersal) when bad environmental conditions occurred during winter before reproduction. 4. Breeding success was also affected by climatic factors, the NAO explaining c. 41% of variance, probably as a result of its effect in the timing of peak abundance of squid and small pelagics, the main prey for shearwaters. No climatic effect was found either on reproductive skipping or on nest dispersal.
Biblioteca de la Universidad Complutense de Madrid, Base de datos de artículos de revistas, ...
El objetivo de este trabajo ha sido elaborar un diagnóstico de conservación para una especie en p... more El objetivo de este trabajo ha sido elaborar un diagnóstico de conservación para una especie en peligro de extinción, la pardela Balear (Puffinus mauretanicus) en el marco del Parque Nacional de Cabrera. Para completar conocimientos se ha dispuesto de datos históricos y de muestras de otras colonias con las que indirectamente se pueden valorar problemas comunes de conservación de la especie, pues las colonias del Parque son pequeñas y más sensibles pues a los efectos de la investigación. Hemos indagado sobre los siguientes aspectos: a) ecología de poblaciones, b) ecología trófica, c) hábitat oceanográfico y d) concentración de contaminantes (mercurio).
«Identidad y estuctura genetica de la pardela balear» Figura 4. Red haplotípica calculada por Máx... more «Identidad y estuctura genetica de la pardela balear» Figura 4. Red haplotípica calculada por Máxima Parsimonia. El tamaño de los círculos es proporcional a la frecuencia de cada haplotipo, y la sección coloreada es proporcional al porcentaje de individuos de cada colonia que presenta dicho haplotipo. Figure 4. Haplotypic MP network. Sizes and colors are proportional to abundance on each population.
Dispersal is critically linked to the demographic and evolutionary trajectories of populations, b... more Dispersal is critically linked to the demographic and evolutionary trajectories of populations, but in most seabird species it may be difficult to estimate. Using molecular tools, we explored population structure and the spatial dispersal pattern of a highly pelagic but philopatric seabird, the Cory's shearwater Calonectris diomedea. Microsatellite fragments were analysed from samples collected across almost the entire breeding range of the species. To help disentangle the taxonomic status of the two subspecies described, the Atlantic form C. d. borealis and the Mediterranean form C. d. diomedea, we analysed genetic divergence between subspecies and quantified both historical and recent migration rates between the Mediterranean and Atlantic basins. We also searched for evidence of isolation by distance (IBD) and addressed spatial patterns of gene flow. We found a low genetic structure in the Mediterranean basin. Conversely, strong genetic differentiation appeared in the Atlantic basin. Even if the species was mostly philopatric (97%), results suggest recent dispersal between basins, especially from the Atlantic to the Mediterranean (aprox. 10% of migrants/generation across the last two generations). Long-term gene flow analyses also suggested an historical exchange between basins (about 70 breeders/generation). Spatial analysis of genetic variation indicates that distance is not the main factor in shaping genetic structure in this species. Given our results we recommend gathering more data before concluded whether these taxa should be treated as two species or subspecies.
Empirical evidence is growing that the offspring sex ratio in birds can be biased in relation to ... more Empirical evidence is growing that the offspring sex ratio in birds can be biased in relation to the body condition of parents during breeding. The sex ratio bias may come about because (1) the actual production of the two sexes may be skewed and/or (2) there may be a sex bias in early nestling mortality contingent on parental condition. By manipulating parental condition and giving them a control brood to rear, thereby eliminating effects operating via the eggs, we examined the extent to which parental condition influences the post-hatching survival of male and female lesser black-backed gulls, Larus fuscus. We found that the pre-fledging survival of male chicks was strongly reduced in all-male broods reared by parents in poor condition. Pre-fledging survival of female chicks was, however, unaffected by parental condition or brood sex composition. Thus, independently of any production biases, sex differences in nestling mortality alone can bias the offspring sex ratio at fledging in relation to the prevailing rearing conditions. In other studies on gulls we have, however, also shown that females in poor condition at laying preferentially produce female eggs. Clearly a bias in fledging sex ratio can occur within the same species due to a combination of differential production and differential post-laying mortality; the latter can involve a differential effect of poor egg quality on male and female offspring, differential effects of brood sex composition on their survival and a difference in the capacity of parents to rear males and females. All of these processes need to be taken into account in attempting to understand offspring sex ratios.
sex ratios in a dimorphic raptor, Montagus Harrier Circus pygargus. Zoological Studies 47(1): 11-... more sex ratios in a dimorphic raptor, Montagus Harrier Circus pygargus. Zoological Studies 47(1): 11-16. We ana- lyzed sex ratios of 809 fledglings from 285 broods of Montagus Harrier (Circus pygargus) in a population locat- ed in Castellon (on the northeastern Iberian Peninsula) in the period 1996-2005. Montagus Harrier females are about 15% larger than males, and according to Fishers theory,
Ecology Letters, 2013
Human activities are the main current driver of global change. From hunter-gatherers through to N... more Human activities are the main current driver of global change. From hunter-gatherers through to Neolithic societies -and particularly in contemporary industrialized countries -humans have (voluntarily or involuntarily) provided other animals with food, often with a high spatio-temporal predictability. Nowadays, as much as 30-40% of all food produced in Earth is wasted. We argue here that predictable anthropogenic food subsidies (PAFS) provided historically by humans to animals has shaped many communities and ecosystems as we see them nowadays. PAFS improve individual fitness triggering population increases of opportunistic species, which may affect communities, food webs and ecosystems by altering processes such as competition,
Oecologia, 2015
survival and growth patterns varied over space and time, and evidence of size-dependent survival ... more survival and growth patterns varied over space and time, and evidence of size-dependent survival was found in all but the smallest stream. At this stream, the probability of reaching larger sizes was lower compared to the other wider and deeper streams. Water temperature variables performed better in the modelling of the highest-altitude population, explaining over a 99 % of the variability in maturation transitions and survival of large fish. The relationships between body size, temperature and fitness components found in this study highlight the utility of multi-state approaches to investigate small-scale demographic processes in heterogeneous environments, and to provide reliable ecological knowledge for management purposes.
PLoS ONE, 2013
Dispersal is critically linked to the demographic and evolutionary trajectories of populations, b... more Dispersal is critically linked to the demographic and evolutionary trajectories of populations, but in most seabird species it may be difficult to estimate. Using molecular tools, we explored population structure and the spatial dispersal pattern of a highly pelagic but philopatric seabird, the Cory's shearwater Calonectris diomedea. Microsatellite fragments were analysed from samples collected across almost the entire breeding range of the species. To help disentangle the taxonomic status of the two subspecies described, the Atlantic form C. d. borealis and the Mediterranean form C. d. diomedea, we analysed genetic divergence between subspecies and quantified both historical and recent migration rates between the Mediterranean and Atlantic basins. We also searched for evidence of isolation by distance (IBD) and addressed spatial patterns of gene flow. We found a low genetic structure in the Mediterranean basin. Conversely, strong genetic differentiation appeared in the Atlantic basin. Even if the species was mostly philopatric (97%), results suggest recent dispersal between basins, especially from the Atlantic to the Mediterranean (aprox. 10% of migrants/generation across the last two generations). Long-term gene flow analyses also suggested an historical exchange between basins (about 70 breeders/generation). Spatial analysis of genetic variation indicates that distance is not the main factor in shaping genetic structure in this species. Given our results we recommend gathering more data before concluded whether these taxa should be treated as two species or subspecies.
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Papers by Meritxell Genovart