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Kernaléguen Laëtitia, Arnould John P Y, Guinet Christophe, Cherel Yves, . (2015). Determinants of individual foraging specialization in large marine vertebrates, the Antarctic and subantarctic fur seals.
. The Journal of animal ecology, 84(4), 1081–91.
Abstract: The degree of individual specialization in resource use differs widely among wild populations where individuals range from fully generalized to highly specialized. This interindividual variation has profound implications in many ecological and evolutionary processes. A recent review proposed four main ecological causes of individual specialization: interspecific and intraspecific competition, ecological opportunity and predation. Using the isotopic signature of subsampled whiskers, we investigated to what degree three of these factors (interspecific and intraspecific competition and ecological opportunity) affect the population niche width and the level of individual foraging specialization in two fur seal species, the Antarctic and subantarctic fur seals (Arctocephalus gazella and Arctocephalus tropicalis), over several years. Population niche width was greater when the two seal species bred in allopatry (low interspecific competition) than in sympatry or when seals bred in high-density stabilized colonies (high intraspecific competition). In agreement with the niche variation hypothesis (NVH), higher population niche width was associated with higher interindividual niche variation. However, in contrast to the NVH, all Antarctic females increased their niche width during the interbreeding period when they had potential access to a wider diversity of foraging grounds and associated prey (high ecological opportunities), suggesting they all dispersed to a similar productive area. The degree of individual specialization varied among populations and within the annual cycle. Highest levels of interindividual variation were found in a context of lower interspecific or higher intraspecific competition. Contrasted results were found concerning the effect of ecological opportunity. Depending on seal species, females exhibited either a greater or lower degree of individual specialization during the interbreeding period, reflecting species-specific biological constraints during that period. These results suggest a significant impact of ecological interactions on the population niche width and degree of individual specialization. Such variation at the individual level may be an important factor in the species plasticity with significant consequences on how it may respond to environmental variability.
Programme: 109
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Fay Rémi, Weimerskirch Henri, Delord Karine, Barbraud Christophe, . (2015). Population density and climate shape early-life survival and recruitment in a long-lived pelagic seabird.
. The Journal of animal ecology, 84(5), 1423–33.
Abstract: 1. Our understanding of demographic processes is mainly based on analyses of traits from the adult component of populations. Early-life demographic traits are poorly known mainly for methodological reasons. Yet, survival of juvenile and immature individuals is critical for the recruitment into the population and thus for the whole population dynamic, especially for long-lived species. This bias currently restrains our ability to fully understand population dynamics of long-lived species and life-history theory. 2. The goal of this study was to estimate the early-life demographic parameters of a long-lived species with a long immature period (9-10 years), to test for sex and age effects on these parameters and to identify the environmental factors encountered during the period of immaturity that may influence survival and recruitment. 3. Using capture-mark-recapture multievent models allowing us to deal with uncertain and unobservable individual states, we analysed a long-term data set of wandering albatrosses to estimate both age- and sex-specific early-life survival and recruitment. We investigated environmental factors potentially driving these demographic traits using climatic and fisheries covariates and tested for density dependence. 4. Our study provides for the first time an estimate of annual survival during the first 2 years at sea for an albatross species (0·801 ± 0·014). Both age and sex affected early-life survival and recruitment processes of this long-lived seabird species. Early-life survival and recruitment were highly variable across years although the sensitivity of young birds to environmental variability decreased with age. Early-life survival was negatively associated with sea surface temperature, and recruitment rate was positively related to both Southern Annular Mode and sea surface temperature. We found strong evidence for density-dependent mortality of juveniles. Population size explained 41% of the variation of this parameter over the study period. 5. These results indicate that early-life survival and recruitment were strongly age and sex dependent in a dimorphic long-lived species. In addition, early-life demographic parameters were affected by natal environmental conditions and by environmental conditions faced during the period of immaturity. Finally, our results constitute one of the first demonstrations of density dependence on juvenile survival in seabirds, with major consequences for our understanding of population dynamics in seabirds.
Programme: 109
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Scanff C., Bachelard C., Cazes G., Rosnet E. & Rivolier J. (1997). Psychological Study of a Crew in Long-Term Space Flight Simulation. The international journal of aviation psychology, 7(4), 293–309.
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Andrews JT, Belt ST, Olafsdottir S, Masse G, Vare LL, . (2009). Sea ice and marine climate variability for NW Iceland/Denmark Strait over the last 2000 cal. yr BP
. The Holocene, 19(5), 775–784.
Abstract: MD99-2263 is a 46 cm box core collected from Djupall, a trough that cuts across the NW Iceland Shelf and ends above Denmark Strait. We provide a multiproxy record that documents changes in the regional marine climate over the last ~1700 yr. The depth/age model is based on seven calibrated radiocarbon dates on mollusk shells and on 210Pb and 137Cs. Sediment accumulation rates were variable (0.2--0.8 mm/yr) but increased dramatically ~AD 1500. Grain-size, magnetic properties, quantitative mineral composition of the <2 mm sediment fraction, benthic foraminiferal composition, benthic and planktic {Delta}18O ratios, and abundances/fluxes of the sea ice biomarker IP25 were determined. To better compare the various proxies, 12 of the critical climate proxies were co-ordinated into 100-yr/sample time series, which were examined by Principal Component Analysis. The 1st axis explained 49% of the variance and the 2nd axis explained an additional 17%. The variables most strongly associated with the 1st axis were sediment properties (phi mean, clay%) and the sea ice biomarker. Mineralogical indicators of drift ice rafting, such as the presence of quartz and potassium- and sodium-feldspars, coincide with the IP25 biomarker data and show an increase after AD 1200, but high values of quartz and some feldspars also occurred between c. AD 300 and 900 with pronounced minima between AD 900 and 1100. Overall, our data suggest a simple two-fold division in climate conditions over the last 1700 yr, with the major change occurring c. AD 1200. In the last few decades, conditions have reverted towards those experienced prior to AD 1200.
Programme: 452
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Vare L L, Masse G, Belt S T, . (2010). A biomarker-based reconstruction of sea ice conditions for the Barents Sea in recent centuries
. The Holocene, 20(4), 637–643.
Abstract: Variations in sea ice occurrence for the Barents Sea since c. AD 1700 have been determined by analysis of the abundance of the sea ice biomarker IP25 in three marine sediment box cores obtained from locations in the north, southeast and southwest parts of the region. Depth/age models for each core were established using excess 210Pb activity profiles. Comparisons between these depth/age models with those reported previously for the Barents Sea, suggest that the proxy sea ice record may, alternatively, extend back to c. AD 1500--1600. Sedimentation accumulation rates and bulk densities were combined with IP 25 concentrations, resulting in temporal changes to IP25 fluxes, which have been interpreted in terms of sea ice variability. The IP25 sea ice proxy data are also compared with other bulk organic geochemical parameters (total organic carbon and C/N ratios) and with sediment particle size distributions. The data indicate ice-free conditions for the southwest Barents Sea for the past c. 300 yr, consistent with previous reports based on historical sea ice records. In contrast, the combined proxy data from the southeast and north Barents Sea suggest variable spring sea ice occurrence on a c. 10--50 yr timescale, with reduced sea ice over the last c. 40--100 yr. In the early record, an enhanced sea ice occurrence is observed for the southeast Barents Sea during the mid--late nineteenth century, but as early as c. AD 1780 for the northern region. The outcomes of this study are broadly consistent with those obtained from ice edge position determinations derived previously from observational records. The study also demonstrates the potential of using IP25 as a sea ice proxy for longer-term palaeo sea ice determinations (e.g. the Holocene) for the Barents Sea.
Programme: 452
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Van der Putten Nathalie, Verbruggen Cyriel, Björck Svante, de Beaulieu Jacques-Louis, Barrow Chris J, Frenot Yves, . (2012). Is palynology a credible climate proxy in the Subantarctic?
. The Holocene , 22 (10 ), 1113–1121 .
Abstract: Pollen and spore analysis is the most successfully used palaeobotanical discipline for reconstructing Holocene vegetation and climate history throughout the world. Subantarctic islands are very specific areas. They are located in the circum-Antarctic Southern Ocean in latitudes that are under strong influence of the southern westerly winds, and are characterised by a treeless, phanerogam-poor flora. Palynological research on many of these islands has resulted in diverging conclusions about how to infer climate history from pollen data. In this study we compare pollen data with macrofossil data on the one hand, and the palaeoenvironmental history based on a multiproxy record on the other hand, of two peat sequences from two different subantarctic islands, South Georgia and Île de la Possession (Îles Crozet). We conclude that palynology must be used with caution as a proxy for climate change on these islands, especially when no other proxy data are available. The uplandlowland principle, as it has been applied in pollen studies in the South Indian Ocean islands, results in erroneous conclusions about climate change on Île de la Possession. More palaeoclimatic multiproxy and pollen studies, in combination with pollenvegetation relationship studies, can, however, contribute to a more reliable model of how to interpret pollen data in the Subantarctic. We want to stress that our conclusions are only based on Holocene records. Consequently, the question remains if palynology can be used as a palaeoclimatic proxy when climatic changes were more pronounced such as during the last glacialinterglacial transition.
Programme: 136
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Najat Bhiry, Armelle Decaulne, Myosotis Bourgon-Desroches. (2019). Development of a subarctic peatland linked to slope dynamics at Lac Wiyâshâkimî (Nunavik, Canada) (Vol. 29).
Abstract: A palaeoecological study of a subarctic minerotrophic peatland was undertaken to reconstruct the formation of the site as an archive of slope geomorphological processes. The study peatland is located about 400 m from Caribou slope (unofficial name) on Lepage Island, Lac Wiyâshâkimî, Nunavik (northern Québec, Canada). The site is close to the lakeshore and receives runoff directly from Caribou slope and its catchment. Gravity processes have been active on Caribou slope since the deglaciation of the region at approximately 6000 cal. yr BP. These processes may be differentiated in terms of Holocene stages of intensity. The objective of our study was to detect evidence of gravity processes in the peatland and to note their frequency since its establishment using loss-on-ignition testing, macrofossil analysis and radiocarbon dating. Our results indicate that peat began to accumulate over the sandy-gravelly sediments at around 4900 cal. yr BP. Larix Laricina, Carex aquatilis and Carex rostrata were present at this time until 4660 cal. yr BP, at which point these taxa were replaced by aquatic taxa such as Hippuris vulgaris and Daphnia (aquatic invertebrates). The percentage of mineral sediments (sand) remained high during this period, which could be linked to slope activity. After 4660 cal. yr BP, sandy sediments diminished while episodes of aquatic conditions and sand inflow occurred on at least three occasions (at 4660, 3905 and 3130 cal. yr BP). The increase in water flow and the introduction of more medium to fine sand into the peatland could be linked to slope movements and the long-distance runout of debris flow that we observed in the field. Given these factors, conditions at the study site remained wet from the earliest phases until the present. Unlike the subarctic permafrost peatlands in northern Québec, permafrost did not become established at the study site.
Programme: 1148
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Barbara Delmonte, Holly Winton, Mélanie Baroni, Giovanni Baccolo, Margareta Hansson, Per Andersson, Carlo Baroni, Maria Cristina Salvatore, Luca Lanci, Valter Maggi. (2020). Holocene dust in East Antarctica: Provenance and variability in time and space (Vol. 30).
Abstract: In this paper, we provide a comprehensive overview of the state-of-knowledge of dust flux and variability in time and space in different sectors of East Antarctica during the Holocene. By integrating the literature data with new evidences, we discuss the dust flux and grain-size variability during the current interglacial and its provenance in the innermost part of the East Antarctic plateau as well as in peripheral regions located close to the Transantarctic Mountains. The local importance of aeolian mineral dust aerosol deflated from low-elevation areas of peripheral East Antarctica is also discussed in the light of new data from several coastal, low-elevation sites.
Keywords: East Antarctica ice cores dust dust stratigraphy Holocene provenance
Programme: 1145
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Ishino S., Hattori S., Savarino J., Legrand M., Albalat E., Albarède F., Preunkert S., Jourdain B., Yoshida N. (2020). Homogeneous sulfur isotope signature in East Antarctica and implication for sulfur source shifts through the last glacial-interglacial cycle.
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Annabel Rixen, Sylvie Blangy. (2016). Life after Meadowbank: Exploring gold mine closure scenarios with the residents of Qamini’tuaq (Baker Lake), Nunavut (Vol. 3).
Abstract: Mining development in the Canadian Arctic is commonly portrayed as a source of jobs and development for Northern communities. Yet its broader impacts on community well-being, especially after mine closure, remain understudied. This article presents post-mining scenarios as envisioned by the Inuit community of Qamini'tuaq (Baker Lake), 3 years before the Meadowbank gold mine's anticipated closure. Study participants rated mine closure impacts on the “Well-Being Wheel”, an evaluation tool co-designed with the authors and featuring five axes: Family Life, Jobs, Food Independence, Health and Learning (all closely tied to caribou-based subsistence lifestyles). Participants also explored best-case and worst-case outcomes. All scenarios highlighted far-reaching impacts on diverse aspects of Inuit well-being. A pessimistic scenario signified a sudden surge in unemployment, with stresses on mental health, family life and food security. An optimistic scenario promised new business development, social service support, and the resurgence of caribou herds. We conclude that in Qamini’tuaq, mining has failed to produce lasting “social and economic development” when we consider its holistic impacts on well-being and subsistence lifestyles. Yet participatory scenario construction may foster effective cross-sector collaboration in anticipation of mine closure. We recommend the strengthening of essential social services and local caribou livelihoods as a strategy to improve post-mining outcomes.
Keywords: Caribou livelihoods Future scenarios Inuit well-being Mine closure Participatory action research Remediation
Programme: 1193
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