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Lesur Vincent, Rother Martin, Wardinski Ingo, Schachtschneider Reyko, Hamoudi Mohamed, Chambodut Aude, . (2015). Parent magnetic field models for the IGRF-12GFZ-candidates
. Earth, Planets and Space, 67(1), 87.
Abstract: We propose candidate models for IGRF-12. These models were derived from parent models built from 10 months of Swarm satellite data and 1.5 years of magnetic observatory data. Using the same parameterisation, a magnetic field model was built from a slightly extended satellite data set. As a result of discrepancies between magnetic field intensity measured by the absolute scalar instrument and that calculated from the vector instrument, we re-calibrated the satellite data. For the calibration, we assumed that the discrepancies resulted from a small perturbing magnetic field carried by the satellite, with a strength and orientation dependent on the Sun’s position relative to the satellite. Scalar and vector data were reconciled using only a limited number of calibration parameters. The data selection process, followed by the joint modelling of the magnetic field and Euler angles, leads to accurate models of the main field and its secular variation around 2014.0. The obtained secular variation model is compared with models based on CHAMP satellite data. The comparison suggests that pulses of magnetic field acceleration that were observed on short time scales average-out over a decade.
Programme: 139
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Renault David, Chevrier Muriel, Laparie Mathieu, Vernon Philippe, Lebouvier Marc, . (2015). Characterization of the habitats colonized by the alien ground beetle Merizodus soledadinus at the Kerguelen islands
. Revue d'écologie, 70(12), 28–32.
Abstract: In the present work, we conducted a field-based study to identify the type of habitats colonized by the alien ground beetle Merizodus soledadinus at the Kerguelen Islands, southern Indian Ocean, and to delineate the spatial dynamics of this species. We used periodic trapping at several coastal habitats on Ile Haute (one of the islands from the Kerguelen archipelago), together with opportunistic active searches at other locations on this subantarctic archipelago. A total of 1081 sites were visited. Our data showed that adult M. soledadinus were mostly found near the tide drift line (372/540 obs., i.e., 69 %) in various habitats, including (1) in the foreshore under timber, (2) beneath stones in coastal areas near penguin colonies, and (3) in herbfields and meadows. It was previously assumed that the habitat distribution of this species was restricted to the herbfields of coastal areas, with our inland observations showing that M. soledadinus (265/541 obs., i.e. 49 %) occupied areas (1) in the vicinity of cushion-carpets, (2) along rivers and ponds beneath stones or mammal carrion, and (3) in fell-fields that contained plant patches (Azorella selago, Colobanthus kerguelensis, or Lycopodium magellanicum and/or bryophytes). Our study is expected to facilitate the implementation of biosecurity measures to mitigate accidental introduction of M. soledadinus to pristine areas that it has not yet colonized.
Programme: 136
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DUHAMEL Guy, HAUTECOEUR Mélyne, DETTAI Agnès, CAUSSE Romain, PRUVOST Patrice, BUSSON Frédéric, COULOUX Arnaud, KOUBBI Philippe, WILLIAMS Richard, OZOUF-COSTAZ Catherine, NOWARA Gabrielle, . (2010). Liparids from the Eastern sector of Southern Ocean and first information from molecular studies
. Cybium, 34(4), 319–343.
Abstract: Deux campagnes réalisées dans le secteur oriental de l'océan Austral (POKER 2006 au large des îles Kerguelen et CEAMARC 2008 au large de la Terre Adélie et de la Terre George V) et couvrant complètement ces zones, ont permis d'obtenir une intéressante et abondante collection de liparidés (deux genres, 13 espèces, 90 spécimens). Les spécimens ont été étudiés avec des approches modernes en systématique, à la fois morpho-anatomiques et à partir de séquences géniques (Barcoding, COI). En dehors de compléments utiles pour la description des espèces, souvent connues d'exemplaires uniques, la distribution géographique et les habitats potentiels bathymétriques et locaux sont précisés. Les arbres résultants des études moléculaires, incluant pour la première fois des spécimens d'origines géographiques différentes, tendent à démontrer, d'une part, la non monophylie de deux genres (Liparis et Careproctus) et, d'autre part, que la plupart des clades comprennent des espèces des deux hémisphères. Le jeu de données désormais disponible sera utile pour des études ultérieures menées sur cette importante famille bien représentée dans les mers polaires.
Keywords: Barcoding, Distribution, Liparidae, Southern Ocean,
Programme: 1124
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Cotte Cédric, Delord Karine, Péron Clara, Bost Charles-André, Duhamel Guy, Pruvost P, Gasco N, Martin A, Weimerskirch Henri, . (2011). Interactions between seabirds and fisheries in the French EEZs: implications for conservation and management
. Société d'Ichtyologie.
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Rocañín-Arjó, Ares; Rodríguez-Botigué, Laura; Esteban, Esther; Theves, Catherine; Evdokimova, Larissa E.; Fedorova, Sardana A.; Gibert, Morgane; Crubezy, Eric; Moral, Pedro. (2013). Close genetic relationships in vast territories: autosomal and X chromosome Alu diversity in Yakuts from Siberia
. Anthropologischer Anzeiger, 70(3), 309–317.
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Convey Peter, Lebouvier Marc, . (2009). Environmental change and human impacts on terrestrial ecosystems of the sub-Antarctic islands between their discovery and the mid-twentieth century
. PAPERS AND PROCEEDINGS OF THE ROYAL SOCIETY OF TASMANIA, 143, 33–44.
Abstract: Sub-Antarctic islands share many similarities in their history of human interaction and impacts before the mid-twentieth century. Large impacts on land were associated with marine exploitation industries of sealing and whaling. Their onshore activities involved considerable construction and pollution in many accessible landing bays, inevitably destroying large areas of coastal terrestrial habitat. Considerable transfer of nutrients to terrestrial environments will have been associated with scavengers utilising large carrion supplies. Attempted establishment of agricultural industries, particularly the introduction of grazing mammals, took place on several islands and, although rarely proving economically viable, often resulted in the long-term creation of feral populations. These were accompanied by introductions of other alien vertebrates, plants and invertebrates to most sub-Antarctic islands, although precise records of introduction events, or subsequent biological studies in this period, largely do not exist. Thus, exploitation industries in this region inevitably led to considerable alterations and impacts to terrestrial ecosystems almost from the outset of human contact with the islands. In the absence of baseline ecological and biodiversity studies, the true magnitude of many of these impacts is difficult to assess, although their legacy continues to the present day. Indeed, the almost complete removal of fur seals may have allowed coastal vegetation to become more extensive and lush than hitherto, paradoxically now regarded as “typical” and threatened by recovery of seal populations.
Keywords: Ecology and Environment,
Programme: 136
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Frédéric Angelier, Olivier Chastel, Adam Z. Lendvai, Charline Parenteau, Henri Weimerskirch, John C. Wingfield. (2020). When do older birds better resist stress? A study of the corticosterone stress response in snow petrels (Vol. 16). Bachelor's thesis, Royal Society, .
Abstract: Life-history theory predicts that, to optimize their fitness, individuals should increase their reproductive effort as their residual reproductive value decreases. Accordingly, several studies have shown that individuals downregulate their glucocorticoid stress response (a proxy of reproductive investment in vertebrates) as they age, and as the subsequent reproductive value decreases. However, and surprisingly, results appear inconsistent, suggesting that the environmental context or the individual state may affect the relationship between age and reproductive effort. Here, we tested for the first time this hypothesis, and more specifically, whether this attenuation of the corticosterone stress response with advancing age depends on the energetic status of individuals. We compared the influence of age on the corticosterone stress response between fasting and non-fasting breeding snow petrels (Pagodroma nivea), an extremely long-lived bird. As expected, we found that the corticosterone stress response was attenuated in old petrels, but only when they were not fasting. Interestingly, this pattern was not apparent in fasting petrels, suggesting that old birds downregulate their corticosterone stress response and increase their parental investment only when they are in good body condition. At the ultimate level, old individuals may maintain a strong corticosterone stress response when fasting because the survival costs of increased stress resistance and parental effort might then outweigh their reproductive benefits.
Programme: 109
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SaucèdeThomas, . (2008). Ecological diversity of Antarctic echinoids.
. Reports on polar and marine research.
Abstract: In: The expedition ANTARKTIS-XXIII/8 of the research vessel “Polarstern” in 2006/2007: ANT-XXIII/8; 23 November 2006-30 January 2007 Cape Town-Punta Arenas (J Gutt, edit.). Berichte zur Polar- und Meeresforschung = Reports on polar and marine research, 569.
Programme: 1124
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Cook Timothée R, Kato Akiko, Tanaka Hideji, Ropert-Coudert Yan, Bost Charles-André, . (2010). Buoyancy under Control: Underwater Locomotor Performance in a Deep Diving Seabird Suggests Respiratory Strategies for Reducing Foraging Effort
. PLoS ONE, 5(3), e9839–.
Abstract: Background
Because they have air stored in many body compartments, diving seabirds are expected to exhibit efficient behavioural strategies for reducing costs related to buoyancy control. We study the underwater locomotor activity of a deep-diving species from the Cormorant family (Kerguelen shag) and report locomotor adjustments to the change of buoyancy with depth.
Methodology/Principal Findings
Using accelerometers, we show that during both the descent and ascent phases of dives, shags modelled their acceleration and stroking activity on the natural variation of buoyancy with depth. For example, during the descent phase, birds increased swim speed with depth. But in parallel, and with a decay constant similar to the one in the equation explaining the decrease of buoyancy with depth, they decreased foot-stroke frequency exponentially, a behaviour that enables birds to reduce oxygen consumption. During ascent, birds also reduced locomotor cost by ascending passively. We considered the depth at which they started gliding as a proxy to their depth of neutral buoyancy. This depth increased with maximum dive depth. As an explanation for this, we propose that shags adjust their buoyancy to depth by varying the amount of respiratory air they dive with.
Conclusions/Significance
Calculations based on known values of stored body oxygen volumes and on deep-diving metabolic rates in avian divers suggest that the variations of volume of respiratory oxygen associated with a respiration mediated buoyancy control only influence aerobic dive duration moderately. Therefore, we propose that an advantage in cormorants – as in other families of diving seabirds – of respiratory air volume adjustment upon diving could be related less to increasing time of submergence, through an increased volume of body oxygen stores, than to reducing the locomotor costs of buoyancy control.
Programme: 394
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Sato Katsufumi, Sakamoto Kentaro Q, Watanuki Yutaka, Takahashi Akinori, Katsumata Nobuhiro, Bost Charles-André, Weimerskirch Henri,. (2009). Scaling of Soaring Seabirds and Implications for Flight Abilities of Giant Pterosaurs. PLoS ONE, 4(4), 6.
Abstract: The flight ability of animals is restricted by the scaling effects imposed by physical and physiological factors. In comparisons of the power available from muscle and the mechanical power required to fly, it is predicted that the margin between the powers should decrease with body size and that flying animals have a maximum body size. However, predicting the absolute value of this upper limit has proven difficult because wing morphology and flight styles varies among species. Albatrosses and petrels have long, narrow, aerodynamically efficient wings and are considered soaring birds. Here, using animal-borne accelerometers, we show that soaring seabirds have two modes of flapping frequencies under natural conditions: vigorous flapping during takeoff and sporadic flapping during cruising flight. In these species, high and low flapping frequencies were found to scale with body mass (mass 0.30 and mass 0.18) in a manner similar to the predictions from biomechanical flight models (mass 1/3 and mass 1/6). These scaling relationships predicted that the maximum limits on the body size of soaring animals are a body mass of 41 kg and a wingspan of 5.1 m. Albatross-like animals larger than the limit will not be able to flap fast enough to stay aloft under unfavourable wind conditions. Our result therefore casts doubt on the flying ability of large, extinct pterosaurs. The largest extant soarer, the wandering albatross, weighs about 12 kg, which might be a pragmatic limit to maintain a safety margin for sustainable flight and to survive in a variable environment.
Programme: 109;394
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