Patrick Samantha C., Pinaud David, Weimerskirch Henri, Morand‐Ferron Julie. (2017). Boldness predicts an individual's position along an exploration–exploitation foraging trade‐off (Vol. 86).
Abstract: Abstract Individuals do not have complete information about the environment and therefore they face a trade?off between gathering information (exploration) and gathering resources (exploitation). Studies have shown individual differences in components of this trade?off but how stable these strategies are in a population and the intrinsic drivers of these differences is not well understood. Top marine predators are expected to experience a particularly strong trade?off as many species have large foraging ranges and their prey often have a patchy distribution. This environment leads these species to exhibit pronounced exploration and exploitation phases but differences between individuals are poorly resolved. Personality differences are known to be important in foraging behaviour but also in the trade?off between exploration and exploitation. Here we test whether personality predicts an individual exploration?exploitation strategy using wide ranging wandering albatrosses (Diomedea exulans) as a model system. Using GPS tracking data from 276 wandering albatrosses, we extract foraging parameters indicative of exploration (searching) and exploitation (foraging) and show that foraging effort, time in patch and size of patch are strongly correlated, demonstrating these are indicative of an exploration?exploitation (EE) strategy. Furthermore, we show these are consistent within individuals and appear stable in the population, with no reproductive advantage. The searching and foraging behaviour of bolder birds placed them towards the exploration end of the trade?off, whereas shy birds showed greater exploitation. This result provides a mechanism through which individual foraging strategies may emerge. Age and sex affected components of the trade?off, but not the trade?off itself, suggesting these factors may drive behavioural compensation to maintain resource acquisition and this was supported by the evidence that there were no fitness consequence of any EE trait nor the trade?off itself. These results demonstrate a clear trade?off between information gathering and exploitation of prey patches, and reveals for the first time that boldness may drive these differences. This provides a mechanism through which widely reported links between personality and foraging may emerge.
Keywords: albatrosses area‐restricted search first passage time marginal value theorem personality seabirds
Programme: 109
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Patrick Samantha Clare, Weimerskirch Henri, Aubry Lise. (2017). Reproductive success is driven by local site fidelity despite stronger specialisation by individuals for large‐scale habitat preference (Vol. 86).
Abstract: Summary There is widespread evidence that within populations, specialists and generalists can coexist and this is particularly prevalent in marine ecosystems, where foraging specialisations are evident. While individuals may limit niche overlap by consistently foraging in specific areas, site fidelity may also emerge as an artefact of habitat choice, but both drivers and fitness consequences of site fidelity are poorly understood. Here, we examine an individual metric of site and habitat fidelity, using tracking data collected over 11 years for black?browed albatrosses (Thalassarche melanophris). Fidelity was calculated as the similarity between pairs of foraging zones, quantifying measures for within and between years. Foraging areas were identified using area?restricted search, defined as periods during which birds decrease speed and increase turning. Our results demonstrate that birds were considerably more specialised in the habitat in which they forage than the exact location they use within years, and there was a similar pattern between years. However, despite this, it was site fidelity that explained reproductive success. Within a single year, females which were more faithful to a specific location had higher reproductive success than non?specialists, and between years there was a tendency for both sexes. Our results suggest that black?browed albatrosses are highly faithful in their foraging habitat but it is rather site fidelity that is more clearly associated with reproductive success.
Keywords: black‐browed albatross foraging niche width generalist intra‐individual variability seabirds
Programme: 109
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Pejić Tanja, Tkalčić Hrvoje, Sambridge Malcolm, Cormier Vernon F., Benavente Roberto. (2017). Attenuation tomography of the upper inner core (Vol. 122).
Abstract: Abstract The solidification of the Earth's inner core shapes its texture and rheology, affecting the attenuation and scattering of seismic body waves transmitted through it. Applying attenuation tomography in a Bayesian framework to 398 high?quality PKIKP waveforms, we invert for the apparent Qp for the uppermost 400?km below the inner core boundary at latitudes 45°S to 45°N. We use damping and smoothing for regularization of the inversion, and it seems that the smoothing regularization combined with the discrepancy principle works better for this particular problem of attenuation tomography. The results are consistent with a regional variation in inner core attenuation more complex than hemispherical, suggesting coupling between inner core solidification and the thermal structure of the lowermost mantle.
Keywords: attenuation inner core tomography
Programme: 133
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Péron Guillaume, Gaillard Jean‐Michel, Barbraud Christophe, Bonenfant Christophe, Charmantier Anne, Choquet Rémi, Coulson Tim, Grosbois Vladimir, Loison Anne, Marzolin Gilbert, Owen‐Smith Norman, Pardo Déborah, Plard Floriane, Pradel Roger, Toïgo Carole, Gimenez Olivier. (2016). Evidence of reduced individual heterogeneity in adult survival of long‐lived species (Vol. 70).
Abstract: The canalization hypothesis postulates that the rate at which trait variation generates variation in the average individual fitness in a population determines how buffered traits are against environmental and genetic factors. The ranking of a species on the slow?fast continuum ? the covariation among life?history traits describing species?specific life cycles along a gradient going from a long life, slow maturity, and low annual reproductive output, to a short life, fast maturity, and high annual reproductive output ? strongly correlates with the relative fitness impact of a given amount of variation in adult survival. Under the canalization hypothesis, long?lived species are thus expected to display less individual heterogeneity in survival at the onset of adulthood, when reproductive values peak, than short?lived species. We tested this life?history prediction by analysing long?term time series of individual?based data in nine species of birds and mammals using capture?recapture models. We found that individual heterogeneity in survival was higher in species with short?generation time (< 3 years) than in species with long generation time (> 4 years). Our findings provide the first piece of empirical evidence for the canalization hypothesis at the individual level from the wild.
Keywords: Capture‐recapture comparative analyses individual differences life‐history evolution mixture models random‐effect models vertebrates
Programme: 109
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Pitout F., Marchaudon A., Blelly P.‐L., Bai X., Forme F., Buchert S. C., Lorentzen D. A. (2015). Swarm and ESR observations of the ionospheric response to a field‐aligned current system in the high‐latitude midnight sector (Vol. 42).
Abstract: Abstract We present a conjunction between the Swarm fleet and the European Incoherent Scatter Svalbard Radar (ESR) on 9 January 2014. The Swarm orbit in the early phase of the mission gives us the unique opportunity of sequencing the temporal evolution of the observed field?aligned current system in the nightside, near magnetic local midnight. These field?aligned currents are seen to move poleward through the radar field of view and to affect the observed ionosphere. The upward field?aligned current (FAC) is responsible, at least in part, for the heating of the ionospheric electrons. It is less clear whether the downward FAC cools the ionosphere. We use the TRANSCAR model of the ionosphere to quantify the thermoelectric effect that comes into play. Finally, we compare the plasma parameters measured by the Langmuir probe on board Swarm and the ESR and conclude on an agreement within the errors.
Keywords: field‐aligned currents ionosphere
Programme: 312
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Sauser Christophe, Delord Karine, Barbraud Christophe. (2018). Increased sea ice concentration worsens fledging condition and juvenile survival in a pagophilic seabird, the snow petrel (Vol. 14).
Abstract: Polar sea ice is changing rapidly, threatening many taxa in the Arctic and the Antarctic. Little is known about the effects of sea ice on early life-history traits of sea ice specialist species, although juvenile stages are a critical component of population dynamics and recruitment. We examined how annual variation in sea ice concentration (SIC) affects juvenile survival and body condition at fledging in the snow petrel Pagodroma nivea using long-term datasets encompassing 22 years for body condition and 37 years for juvenile survival. We show that SIC and southern annular mode (SAM), the principal mode of variability of the atmospheric circulation in the Southern Hemisphere, have strong nonlinear effects on juvenile survival and body condition. Below ca 20–30% SIC, body condition remained stable, but decreased almost linearly for higher SIC. Juvenile survival was negatively related to SIC and to SAM during the chick rearing period. We suggest that the base of the sea ice food web would be directly affected by sea ice conditions, thus acting locally on the abundance and structure of prey communities.
Programme: 109
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Stier Antoine, Romestaing Caroline, Schull Quentin, Lefol Emilie, Robin Jean‐Patrice, Roussel Damien, Bize Pierre, Davey Matthew. (2017). How to measure mitochondrial function in birds using red blood cells: a case study in the king penguin and perspectives in ecology and evolution (Vol. 8). Bachelor's thesis, , .
Abstract: Summary Mitochondria are the powerhouse of animal cells. They produce through oxidative phosphorylation more than 90% of the cellular energy (ATP) required for organism's growth, reproduction, and maintenance. Hence, information on mitochondrial function is expected to bring important insights in animal ecology and evolution. Unfortunately, the invasiveness of the procedures required to measure mitochondrial function (e.g. sampling of liver or muscles) has limited its study in wild vertebrate populations so far. Here, we capitalize on the fact that bird red blood cells (RBCs) possess functional mitochondria to describe a minimally invasive approach to study mitochondrial function, using blood samples. In the king penguin, we present a protocol, using a high?resolution respirometry system and specific agonists and antagonists enabling the assessment of mitochondrial function in RBCs. We evaluated the inter?assay repeatability of our measures of mitochondrial function, and tested the influence of sample storage and bird handling time on these measures. We also compared measures of mitochondrial function in RBCs and in the pectoral muscle obtained from the same individuals. Mitochondria from RBCs showed the expected responses to mitochondrial agonists and antagonists, and therefore the protocol presented allows computing effective measures of mitochondrial function. The different measures of RBC mitochondrial function were significantly repeatable, were not affected by the handling time of the bird prior to blood sampling (i.e. stress response), and only minimally affected by the storage time of the sample at 4 °C up to 24 h. Most notably, we showed that mitochondrial parameters measured in RBCs moderately correlated to those measured in the pectoral muscle. This study sheds light on the use of RBCs in birds as a valuable and minimally invasive source of information on mitochondrial function. This approach opens new opportunities to study mitochondrial function in free?living animals and could bring knowledge gains in ecology and evolution. Fish, amphibians and reptiles also possess mitochondria in their RBCs, and the approach presented here could also be applicable to these taxa.
Keywords: erythrocyte high‐resolution respirometry metabolism mitochondria non‐invasive methodology
Programme: 119,131
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Thiebot Jean‐Baptiste, Delord Karine, Barbraud Christophe, Marteau Cédric, Weimerskirch Henri. (2016). 167 individuals versus millions of hooks: bycatch mitigation in longline fisheries underlies conservation of Amsterdam albatrosses (Vol. 26).
Abstract: Abstract 1. Industrial fisheries represent one of the most serious threats worldwide to seabird conservation. Death of birds in fishing operations (i.e. bycatch) has especially adverse effects on populations of albatrosses, which have extremely low fecundity. 2. The single population worldwide of Amsterdam albatross (Diomedea amsterdamensis) comprises only 167 individuals and risks considerable decline over the mid?term from additional mortality levels potentially induced by fisheries. The priority actions listed in the current conservation plan for this species included characterizing the longline fisheries operating within its range, dynamically analysing the overlap between albatrosses and these fisheries, and providing fisheries management authorities with potential impact estimates of longline fisheries on the Amsterdam albatross. 3. During all life?cycle stages and year quarters the birds overlapped extensively with fishing effort in the southern Indian and Atlantic oceans. Fishing effort, and consequently overlap score (calculated as the product of fishing effort and time spent by the birds in a spatial unit) was highest in July?September (45% of the hooks annually deployed). Just three fleets (Taiwanese, Japanese and Spanish) contributed to >98% of the overlap scores for each stage (72% from the Taiwanese fleet alone, on average). Daily overlap scores were higher for the non?breeding versus the breeding stages (3?fold factor on average). 4. Based on previous bycatch rates for other albatross species, this study estimated that longline fisheries currently have the potential to remove ~2?16 individuals (i.e. ~5%) each year from the total Amsterdam albatross population, depending on whether bycatch mitigation measures were or were not systematically employed during the fishing operations. 5. Recent bycatch mitigation measures may be instrumental in the conservation of the Amsterdam albatross. This study suggests three further key recommendations: (1) to focus conservation efforts on the austral winter; (2) to require all operating vessels to report ring recoveries; and (3) to allocate special regulation of fishing operations in the areas of peak bycatch risk for the Amsterdam albatrosses. Copyright ? 2015 John Wiley & Sons, Ltd.
Keywords: birds distribution endangered species fishing island ocean tracking
Programme: 109
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Tixier Paul, Gasco Nicolas, Duhamel Guy, Guinet Christophe. (2016). Depredation of Patagonian toothfish (Dissostichus eleginoides) by two sympatrically occurring killer whale (Orcinus orca) ecotypes: Insights on the behavior of the rarely observed type D killer whales (Vol. 32).
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V. Donato, N. Pouvreau, L. Testut, T. Donal, A. Coulomb, J-P. Barriot, G. Wöppelmann. (2017). National Report of France to the XVth GLOSS Group of Experts Meeting, (15th meeting), 9-10 July 2017, New-York.
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