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Aurore Ponchon, Amandine Gamble, Jérémy Tornos, Karine Delord, Christophe Barbraud, Justin M. J. Travis, Henri Weimerskirch, Thierry Boulinier. (2021). Similar at-sea behaviour but different habitat use between failed and successful breeding albatrosses (Vol. 678).
Abstract: Breeding failure is expected to induce behavioural changes in central place foragers. Indeed, after a failed reproductive attempt, breeding individuals are relieved from having to return to their breeding site for reproductive duties and thus are less constrained than successful breeders in their movements during the remainder of the breeding season. Accordingly, they are expected to adjust their behaviour, travelling longer in distance and/or time to reach foraging grounds. They are also expected to use different foraging areas to decrease local intra-specific competition with successful breeders. We compared the at-sea behaviour and habitat use of successful and failed Indian yellow-nosed albatrosses nesting in Amsterdam Island, Southern Indian Ocean, during 2 chick-rearing seasons. Failed breeders exhibited the same at-sea foraging behaviour, travelling as far and as long as successful breeders. They also spent the same amount of time on their nest between at-sea trips. Nevertheless, habitat models revealed partial spatial segregation of failed breeders, which used specific foraging areas characterized by deeper and colder waters in addition to the areas they shared with successful breeders. Our study shows the importance of combining a range of analytical methods (spatial analysis, behavioural inferences with advanced movement models and habitat models) to infer the at-sea behaviour and habitat use of seabirds. It also stresses the importance of considering individual breeding status when aiming to understand the spatial distribution of individuals, especially when this information may have conservation implications.
Keywords: Behavioural state Breeding failure Foraging behaviour Habitat models Inter-individual variability Procellariiformes Thalassarche carteri
Programme: 109
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Aymeric Fromant, Karine Delord, Charles-André Bost, Yonina H. Eizenberg, Jonathan A. Botha, Yves Cherel, Paco Bustamante, Brett R. Gardner, Maud Brault-Favrou, Arnaud Lec'hvien, John P. Y. Arnould. (2021). Impact of extreme environmental conditions: Foraging behaviour and trophic ecology responses of a diving seabird, the common diving petrel (Vol. 198).
Abstract: The reproductive success of birds is strongly driven by environmental conditions at different time scales. Thus, during periods of low food availability, breeding success is constrained by the ability of adults to adapt their foraging effort and feeding behaviour to maintain regular incubation shifts and chick provisioning. However, while large seabirds can buffer disruptions in prey availability, the ecophysiological constraints of smaller species may limit their behavioural flexibility. By combining information on at-sea movements, foraging habitat, trophic niche, and breeding success, this study evaluated the effects of intense variability in oceanographic conditions on common diving petrels (Pelecanoides urinatrix) at the northern extent of their range in south-eastern Australia during four consecutive breeding seasons. Unusually low breeding success (6 and 0%) was observed during two years with intense heatwave events, which were associated with higher foraging effort (foraging trips twice longer) and a substantial shift in trophic niche (lower blood δ15N values). These findings suggest that common diving petrels in Bass Strait may have reached a critical threshold above which buffering the effects of environmental variability on their reproductive output is not possible. The clear cascading impacts that marine heatwaves have on zooplankton feeders illustrate the profound bottom-up effect induced by such extreme environmental variations, and suggest strong impact on higher-trophic levels. The wide, circumpolar breeding distribution of the common diving petrel, and its high sensitivity to variations in oceanographic conditions, suggest that this species may be a suitable model to study short-term and long-term behavioural responses to the effects of climate change throughout the Southern Ocean.
Keywords: GPS tracking Habitat modelling Inter-annual variation Marine heatwave Stable isotopes
Programme: 109
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Barbero A., Grilli R., Blouzon C., Ahmed S., Thomas J.L., Frey M., Huang Y., Caillon N., Savarino J. (2021). Innovative approach for new estimation of NOx snow-source on the Antarctic Plateau.
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Barbora Chattová, Marc Lebouvier, Vít Syrovátka, Bart Van de Vijver. (2021). Moss-inhabiting diatom communities from Ile Amsterdam (TAAF, southern Indian Ocean) (Vol. 154).
Abstract: Background and aims – Despite the ongoing taxonomical revision of the entire (sub)-Antarctic diatom flora, our knowledge on the ecology and community associations of moss-inhabiting diatoms is still rather limited. In the present study, our research aim was to survey the diversity together with the environmental factors structuring the epiphytic moss diatom communities on Ile Amsterdam (TAAF), a small volcanic island in the southern Indian Ocean.Material and methods – A morphology-based dataset and (physico)chemical measurements were used for the ecological and biogeographical analysis of moss-inhabiting diatom flora from Ile Amsterdam. In total, 148 moss samples were examined using light microscopy.Key results – The analysis revealed the presence of 125 diatom taxa belonging to 38 genera. The uniqueness of the Ile Amsterdam diatom flora is mainly reflected by the species composition of the dominant genera Pinnularia, Nitzschia, Humidophila, and Luticola, with a large number of unknown and often new species. This highly specific diatom flora, together with differences in the habitats sampled and the isolated position of the island, resulted in very low similarity values between Ile Amsterdam and the other islands of the Southern Ocean. From a biogeographical point of view, 40% of the taxa have a typical cosmopolitan distribution, whereas 22% of all observed species can be considered endemic to Ile Amsterdam, with another 17% species showing a restricted sub-Antarctic distribution. The NMDS analysis, based on a cluster dendrogram, divides the samples into six main groups. For each group, indicator species were determined. Both environmental data and diatom distributions indicate that apart from elevation, specific conductance, pH, and moisture are the major factors determining the structure of moss-inhabiting diatom communities on Ile Amsterdam.Conclusion – The isolated geographic position and unique climatological and geological features of the island shaped the presence of a unique diatom flora, characterised by many endemic species. The results of the study are of prime importance for further (palaeo-)ecological and biogeographical research.
Keywords: Bacillariophyta diatoms ecology Ile Amsterdam mosses southern Indian Ocean sub-Antarctic region
Programme: 136
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Benjamin Merkel, Sébastien Descamps, Nigel G. Yoccoz, David Grémillet, Francis Daunt, Kjell E. Erikstad, Aleksey V. Ezhov, Mike P. Harris, Maria Gavrilo, Svein-Håkon Lorentsen, Tone K. Reiertsen, Harald Steen, Geir H. Systad, Þorkell Lindberg Þórarinsson, Sarah Wanless, Hallvard Strøm. (2021). Individual migration strategy fidelity but no habitat specialization in two congeneric seabirds (Vol. 48).
Abstract: Aim In migratory species, individuals often use fixed and individual-specific migration strategies, which we term individual migration strategy fidelity (IMSF). Our goal was to test if guillemots have flexible or fixed individual migration strategies (i.e. IMSF), if this behaviour is consistent across large parts of the genus’ range and if they were philopatric to geographical sites or a habitat feature. Location North Atlantic. Taxon Uria spp. Methods We quantified consistent individual differences in inter-annual spatial distribution and habitat occupied throughout the non-breeding period using a large geolocator tracking dataset of 729 adult seabirds breeding at 13 colonies across the Northeast Atlantic and repeatedly tracked up to 7 years over a 9-year period. Additionally, we used a similarity index to calculate relative fidelity to either geographical sites or habitats and linear mixed-effects models to assess persistence of spatial site fidelity over multiple years. Results Both guillemot species exhibited IMSF across a large part of the genus’ range which persisted over multiple years. Individuals of both species and almost all colonies showed fidelity to geographical sites and not to specific habitats. Main conclusions Guillemots show IMSF that is best explained by site familiarity (fidelity to specific sites) rather than habitat specialization (fidelity to specific habitats). In the context of rapidly changing environments, favourable habitats may permanently shift locations and hence species displaying IMSF driven by site familiarity—such as the genus Uria—may not be able to adjust their migration strategies sufficiently fast to sustain individual fitness and ensure population persistence.
Keywords: guillemots light-level geolocation murres Uria aalge Uria lomvia
Programme: 388
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Benjamin Merkel, Sébastien Descamps, Nigel G. Yoccoz, David Grémillet, Per Fauchald, Jóhannis Danielsen, Francis Daunt, Kjell Einar Erikstad, Aleksey V. Ezhov, Mike P. Harris, Maria Gavrilo, Svein-Håkon Lorentsen, Tone K. Reiertsen, Geir H. Systad, Thorkell Lindberg Thórarinsson, Sarah Wanless, Hallvard Strøm. (2021). Strong migratory connectivity across meta-populations of sympatric North Atlantic seabirds (Vol. SEA).
Abstract: Identifying drivers of population trends in migratory species is difficult, as they can face many stressors while moving through different areas and environments during the annual cycle. To understand the potential of migrants to adjust to perturbations, it is critical to study the connection of different areas used by different populations during the annual cycle (i.e. migratory connectivity). Using a large-scale tracking data set of 662 individual seabirds from 2 sympatric auk meta-populations (common guillemots Uria aalge and Brünnich’s guillemots U. lomvia) breeding in 12 colonies throughout the Northeast Atlantic, we estimated migratory connectivity in seasonal space use as well as occupied environmental niches. We found strong migratory connectivity, within and between species. This was apparent through a combination of seasonal space use and occupied environmental niches. Brünnich’s guillemot populations grouped into 2 and common guillemot populations into 5 previously undescribed spatiotemporal clusters. Common guillemot populations clustered in accordance with the variable population trends exhibited by the species, while Brünnich’s guillemot populations are declining everywhere where known within the study area. Individuals from different breeding populations in both species were clustered in their space and environmental use, utilising only a fraction of the potential species-wide range. Further, space use varied among seasons, emphasising the variable constraints faced by both species during the different stages of their annual cycle. Our study highlights that considering spatiotemporal dynamics, not only in space but also in occupied environmental niches, improves our understanding of migratory connectivity and thus population vulnerability in the context of global change.
Keywords: Environmental niche Inter-population mixing Large-scale spatiotemporal dynamics Light-level geolocation Murres Population spread Seasonality
Programme: 388
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Benjamin Pohl, Thomas Saucède, Vincent Favier, Julien Pergaud, Deborah Verfaillie, Jean-Pierre Féral, Ylber Krasniqi, Yves Richard. (2021). Recent Climate Variability around the Kerguelen Islands (Southern Ocean) Seen through Weather Regimes (Vol. 60). Bachelor's thesis, , .
Abstract: Daily Weather Regimes Are Defined Around The Kerguelen Islands (Southern Ocean) On The Basis Of Daily 500-hpa Geopotential Height Anomalies Derived From The Era5 Ensemble Reanalysis Over The Period 1979–2018. Ten Regimes Are Retained As Significant. Their Occurrences Are Highly Consistent Across Reanalysis Ensemble Members. Regimes Show Weak Seasonality And Nonsignificant Long-term Trends In Their Occurrences. Their Sequences Are Usually Short (1–3 Days), With Extreme Persistence Values Above 10 Days. Seasonal Regime Frequency Is Mostly Driven By The Phase Of The Southern Annular Mode Over Antarctica, Midlatitude Dynamics Over The Southern Ocean Such As The Pacific–south American Mode, And, To A Lesser Extent, Tropical Variability, With Significant But Weaker Relationships With El Niño–southern Oscillation. At The Local Scale Over The Kerguelen Islands, Regimes Have A Strong Influence On Measured Atmospheric And Oceanic Variables, Including Minimum And Maximum Air Temperature, Mostly Driven By Horizontal Advections, Seawater Temperature Recorded 5 M Below The Surface, Wind Speed, And Sea Level Pressure. Relationships Are Weaker For Precipitation Amounts. Regimes Also Modify Regional Contrasts Between Observational Sites In Kerguelen, Highlighting Strong Exposure Contrasts. The Regimes Allow Us To Improve Our Understanding Of Weather And Climate Variability And Interactions In This Region; They Will Be Used In Future Work To Assess Past And Projected Long-term Circulation Changes In The Southern Midlatitudes.
Programme: 688,1044,1048
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Benjamin Pohl, Vincent Favier, Jonathan Wille, Danielle G Udy, Tessa R Vance, Julien Pergaud, Niels Dutrievoz, Juliette Blanchet, Christoph Kittel, Charles Amory, Gerhard Krinner, Francis Codron. (2021). Relationship Between Weather Regimes and Atmospheric Rivers in East Antarctica (Vol. 126).
Abstract: Here, we define weather regimes in the East Antarctica—Southern Ocean sector based on daily anomalies of 700 hPa geopotential height derived from ERA5 reanalysis during 1979–2018. Most regimes and their preferred transitions depict synoptic-scale disturbances propagating eastwards off the Antarctic coastline. While regime sequences are generally short, their interannual variability is strongly driven by the polarity of the Southern Annular Mode (SAM). Regime occurrences are then intersected with atmospheric rivers (ARs) detected over the same region and period. ARs are equiprobable throughout the year, but clearly concentrate during regimes associated with a strong atmospheric ridges/blockings on the eastern part of the domain, which act to channel meridional advection of heat and moisture from the lower latitudes towards Antarctica. Both regimes and ARs significantly shape climate variability in Antarctica. Regimes favorable to AR occurrences are associated with anomalously warm and humid conditions in coastal Antarctica and, to a lesser extent, the hinterland parts of the Antarctic plateau. These anomalies are strongly enhanced during AR events, with warmer anomalies and dramatically amplified snowfall amounts. Large-scale conditions favoring AR development are finally explored. They show weak dependency to the SAM, but particularly strong atmospheric ridges/blockings over the Southern Ocean appear as the most favorable pattern, in which ARs can be embedded, and to which they contribute.
Keywords: atmospheric rivers East Antarctica snowfall amounts temperature anomalies weather regimes
Programme: 411
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Buscetti, M. (2021). Influence of geomagnetic storms on seismometers.
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C. Albert, V. S. Bråthen, S. Descamps, T. Anker-Nilssen, A. Cherenkov, S. Christensen-Dalsgaard, J. Danielsen, K. E. Erikstad, M. Gavrilo, S. A. Hanssen, H. H. Helgason, J. E. Jónsson, Y. Kolbeinsson, Y. Krasnov, M. Langset, E. Lorentzen, B. Olsen, T. K. Reiertsen, H. Strøm, G. H. Systad, G. Tertitski, P. M. Thompson, T. L. Thórarinsson, P. Bustamante, B. Moe, J. Fort. (2021). Inter-annual variation in winter distribution affects individual seabird contamination with mercury (Vol. 676).
Abstract: Migratory seabirds are exposed to various pollutants throughout their annual cycle. Among them, mercury (Hg) is of particular concern given its large impact on animal health. Recent studies suggest that winter is a critical period for seabirds when contamination by Hg can be higher than at other times of year. However, individuals within and between species can have different migration strategies and winter distributions that could affect their exposure. Here, we combined multi-year individual tracking data and Hg measurements from 6 Arctic seabird species. We investigated whether inter-annual variations in individual winter contamination with Hg was related to seabird fidelity to a wintering site over years. First, our results show that Hg concentrations above the toxicity threshold (i.e. 5 µg g-1 dry weight in feathers) were observed in variable proportions according to species (from 2% of northern fulmars to 37% of Brünnich’s guillemots). Second, individuals with high fidelity to a wintering ground had more similar Hg concentrations among years compared to individuals with low fidelity, suggesting an effect of their migratory strategy on Hg contamination. Further, we found that the directional change in wintering areas among years influenced seabird Hg contamination, highlighting an additional effect of seabirds’ winter distribution. More specifically, individuals migrating to the northwest direction of a previous wintering ground tended to be more contaminated compared to those moving to eastern directions. These results confirm spatial differences in Hg concentration throughout the North Atlantic-Arctic and an east-west gradient increase in Hg concentrations. Verifying this trend will require more large-scale ecotoxicological studies at smaller spatial resolution.
Keywords: Biologging Feathers Migration North Atlantic-Arctic Pollutant
Programme: 388
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