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Christophe Barbraud - One of the best experts on this subject based on the ideXlab platform.
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Do repeated captures and handling affect phenotype and survival of growing Snow Petrel (Pagodroma Nivea)?
Polar Biology, 2020Co-Authors: Sophie M. Dupont, Christophe Barbraud, Olivier Chastel, Karine Delord, Charline Parenteau, Cécile Ribout, Frédéric AngelierAbstract:In vertebrates, developmental conditions can affect not only fledging success but also the phenotype of the offspring, with potential long-term consequences on adult performance. However, surprisingly the potential impact of anthropogenic disturbance on developing chicks is rarely investigated, notably in Antarctic wildlife. In this study, we specifically investigated the effects of repeated nest visits, capture, and handling on offspring survival and several complementary offspring phenotypic traits in the Snow Petrel ( Pagodroma Nivea ) chicks after thermal emancipation. We did not find any significant effect of our disturbance protocol on the morphology (body size, body mass, body condition), the physiology (breath rate, stress-induced corticosterone levels) and the behaviour (defense behaviour) of developing Snow Petrels. This specific disturbance protocol did not have any significant effect on chick survival, but there was a non-significant trend towards a lower survival for the disturbed group ( p = 0.1006), which showed an especially high mortality during a period of repeated snow storms. To conclude, investigator disturbance seems to have little effect on Snow Petrel chicks after thermal emancipation, but to remain cautious, we recommend to avoid capture and handling of Snow Petrel chicks during or soon after inclement weather.
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Sexual segregation in a highly pagophilic and sexually dimorphic marine predator
bioRxiv, 2019Co-Authors: Christophe Barbraud, Karine Delord, Paco Bustamante, Akiko Kato, Yves CherelAbstract:Sexual segregation is common in many species and has been attributed to intra-specific competition, sex-specific differences in foraging efficiency or in activity budgets and habitat choice. However, very few studies have simultaneously quantified sex-specific foraging strategies, at sea distribution, habitat use, and trophic ecology. Moreover, these studies come from low latitude areas reflecting a lack of evidence for polar species. We investigated sexual segregation in snow petrels Pagodroma Nivea and combined movement, foraging trip efficiency, stable isotope and oceanographic data to test whether sexual segregation results from sex-specific habitat use. Breeding birds foraging in the Dumont d'Urville sea, Antarctica, were tracked during incubation. Some similarities between males and females foraging characteristics did not support the sexual segregation hypothesis. Indeed, space-use sharing and utilization distribution, d13C values and foraging trip performances (trip duration, length, speed and directions, mass gain, proportion mass gain) were similar between males and females.. However, there was support for sexual segregation in foraging characteristics linked to foraging habitats. Females foraged less than males in areas with higher sea ice concentration (SIC >70%) and had lower d15N values in plasma, blood cells and feathers. Foraging efficiency (proportionate daily mass gain while foraging), was greater for females than for males, and was greater for larger females with deeper bills. Females were more efficient than males during short ( 70%) more profitable SIC (males) and low SIC areas (females), probably driven by intraspecific competition. Therefore, male and female snow petrels segregate at small spatial scales mainly determined by habitat (SIC) characteristics.
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Species‐specific foraging strategies and segregation mechanisms of sympatric Antarctic fulmarine petrels throughout the annual cycle
Ibis, 2016Co-Authors: Karine Delord, Christophe Barbraud, Yves Cherel, Patrick Pinet, David Pinaud, Sophie De Grissac, Agnès Lewden, Henri WeimerskirchAbstract:International audienceDetermining the year-round distribution and behaviour of birds is necessary for a betterunderstanding of their ecology and foraging strategies. Petrels form an important componentof the high-latitude seabird assemblages in terms of species and individuals. The distributionand foraging ecology of three sympatric fulmarine petrels (Southern FulmarFulmarus glacialoides, Cape Petrel Daption capense and Snow Petrel Pagodroma Nivea)were studied at Adelie Land, East Antarctica, by combining information from miniaturizedsaltwater immersion geolocators and stable isotopes from feathers. During thebreeding season at a large spatial scale (c. 200 km), the three species overlapped in theirforaging areas located in the vicinity of the colonies but were segregated by their dietand trophic level, as indicated by the different chick d15N values that increased in theorder Cape Petrel < Southern Fulmar < Snow Petrel. During the non-breeding season,the three fulmarines showed species-specific migration strategies along a wide latitudinalgradient. Snow Petrels largely remained in ice-associated Antarctic waters, Southern Fulmarstargeted primarily the sub-Antarctic zone and Cape Petrels migrated further north.Overall, birds spent less time in flight during the non-breeding period than during thebreeding season, with the highest percentage of time spent sitting on the water occurringduring the breeding season and at the beginning of the non-breeding period beforemigration. This activity pattern, together with the d13C values of most feathers, stronglysuggests that moult of the three fulmarine petrels occurred at that time in the very productivehigh Antarctic waters, where birds fed on a combination of crustaceans and fish.The study highlights different segregating mechanisms that allow the coexistence of closelyrelated species, specifically, prey partitioning during the breeding season and spatialsegregation at sea during the non-breeding season
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Contrasting effects of the extent of sea‐ice on the breeding performance of an Antarctic top predator, the Snow Petrel Pagodroma Nivea
Journal of Avian Biology, 2001Co-Authors: Christophe Barbraud, Henri WeimerskirchAbstract:Recent studies have shown that the Antarctic Circumpolar Wave and the related sea-ice cover around the Antarctic continent may have a profound effect on the lower trophic levels of the marine environment. In particular, extensive sea-ice cover enhances the survival of krill. However, the effects of sea-ice cover on top predators remain poorly understood. Using time series from 1973 to 1999, we examine the influence of regional sea-ice extent on a number of indices of breeding performance of an avian predator, the Snow Petrel, in Antarctica. The percentage of breeding pairs was highly variable and there were fewer birds breeding when sea-ice cover was extensive during July. By contrast, overall breeding success and fledgling body condition were improved during years with extensive sea-ice cover during the preceding November and July-September. These results indicate that the same sea-ice conditions may have different effects on the breeding performance of a species. The overall increase in winter sea-ice extent during the last decade appears to have resulted in an overall improvement of the quality of fledglings produced, and thus probably of future recruitment.
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contrasting effects of the extent of sea ice on the breeding performance of an antarctic top predator the snow petrel Pagodroma Nivea
Journal of Avian Biology, 2001Co-Authors: Christophe Barbraud, Henri WeimerskirchAbstract:Recent studies have shown that the Antarctic Circumpolar Wave and the related sea-ice cover around the Antarctic continent may have a profound effect on the lower trophic levels of the marine environment. In particular, extensive sea-ice cover enhances the survival of krill. However, the effects of sea-ice cover on top predators remain poorly understood. Using time series from 1973 to 1999, we examine the influence of regional sea-ice extent on a number of indices of breeding performance of an avian predator, the Snow Petrel, in Antarctica. The percentage of breeding pairs was highly variable and there were fewer birds breeding when sea-ice cover was extensive during July. By contrast, overall breeding success and fledgling body condition were improved during years with extensive sea-ice cover during the preceding November and July-September. These results indicate that the same sea-ice conditions may have different effects on the breeding performance of a species. The overall increase in winter sea-ice extent during the last decade appears to have resulted in an overall improvement of the quality of fledglings produced, and thus probably of future recruitment.
Pierre Jouventin - One of the best experts on this subject based on the ideXlab platform.
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morphological and genetic variability of snow petrels Pagodroma Nivea
Ibis, 2008Co-Authors: Pierre Jouventin, Christopherrobin ViotAbstract:Snow Petrels vary greatly in size, the largest birds being over twice as heavy as the smallest. Two morphological types have been distinguished, but the Adelieland population alone shows continuous variation spanning the complete range of the species. There is no evidence of size-related assortative mating. Size variation cannot be attributed to nest site location nor to individual age, nor is the large sexual dimorphism sufficient to account for the situation. The great individual variation in size is accompanied by an important genetic variability as revealed by a starch gel electrophoretic study. Comparisons of wing length data from many localities around the Antarctic Continent suggest a cline, with a peak at the Balleny Islands. Taking into account the extent of size variation at breeding places only, it appears that morphological variability is low at Balleny Islands, where only large form birds are known, and at Antarctic localities inhabited exclusively by small form birds. In contrast, several localities on the continent in the vicinity of Balleny Islands, and especially Adelieland, exhibit a high degree of variability. We propose that during the quaternary glaciations, the Antarctic continent provided no refugia for this species, but, when glaciation ended, Snow Petrels re-established colonies, coming from two refugia, a low latitude one inhabited by small birds Pagodroma Nivea Nivea, and one in higher latitudes characterized by large birds P. n. major. Reproductive isolation broke down, and a hybridization zone was created. The high proportion of polymorphic loci exhibited by the Adelieland population is then attributable to the mixing of two previously isolated genetic pools.
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Ten polymorphic microsatellite markers in the wandering albatross Diomedea exulans
Molecular Ecology Notes, 2005Co-Authors: Marie-pierre Dubois, Philippe Jarne, Pierre JouventinAbstract:We describe 10 new variable dinucleotide microsatellites in the wandering albatross Diomedea exulans , as well as conditions for multiplexing and simultaneous genotyping sets of loci. Their variability was assessed in two and one populations from the Crozet and Kerguelen archipelagos (southern Indian Ocean), respectively. Two to 13 alleles were detected per population, and the mean gene diversity was around 0.4. The low genetic differentiation suggests that these populations constitute a single panmictic unit. Cross-species amplification provided some variability at three and five loci in two other marine birds ( Bulweria bulwerii and Pagodroma Nivea ), but none in Calonectris diomedea .
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The effect of mate choice on speciation in snow petrels
Animal Behaviour, 2001Co-Authors: Pierre Jouventin, Joël BriedAbstract:Although snow petrels, Pagodroma Nivea, show a tendency to assortative mating by size morph, the existence of mixed pairs producing viable young reveals that reproductive isolation between the two size morphs is imperfect. However, the degree of isolation depends on breeding locality. A given area can harbour either (1) only small birds, or (2) only large birds, or (3) small bird colonies close to large bird ones, or (4) mixed pairs, the percentage of which varies from one locality to another. We investigated the mating and nesting patterns that result in mixed pairings and can explain the speciation process considered to be in progress by modern authors. Data from a 34-year demographic study in Terre Adelie, Antarctica, showed that mate and nest fidelity were very high. Nest changes, but not divorces, generally led to higher fecundity. Snow petrels did not seem to choose their mates on the basis of age or experience, and divorcees tended to form new pair bonds with neighbours; nevertheless, there was evidence for active mate fidelity. Pairs involving mates of the same size morph and mixed pairs had similar fecundity. Despite its heterogeneity, the breeding habitat of snow petrels was relatively predictable. Ice repeatedly made some nests unsuitable for breeding. Obtaining a nest that was not frozen was therefore the primary requirement for breeding. Strong competition for nests may explain high fidelity rates and, combined with the absence of reproductive costs in mixed pairs, may have promoted decreased choosiness during mate choice, preventing total reproductive isolation between the two morphs.
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Effect of sea-ice extent on adult survival of an Antarctic top predator: the snow petrel Pagodroma Nivea
Oecologia, 2000Co-Authors: Christophe Barbraud, Henri Weimerskirch, Christophe Guinet, Pierre JouventinAbstract:The snow petrel Pagodroma Nivea is an obligate associate of sea-ice and one of the most abundant seabird species of the Southern Ocean. Time- and sex-specific annual variation in adult survival was estimated using capture-mark-recapture of petrels nesting at Pétrels Island, Terre Adélie, 1981–1997. On the basis of a regression analysis, 44% of the variation was linked inversely to the latitudinal extent of sea-ice during winter (June) in the region offshore of the study colony, where this population is likely to spend the non-breeding season. Monthly sea-surface temperature anomalies tended to influence adult survival but the relationship was not statistically significant. Why sea-ice extent should have such a critical effect on this species is yet to be explained, but the relationship, in the context of environmental warming and the consequent potential loss of Antarctic sea-ice, is an important one for this species.
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effect of sea ice extent on adult survival of an antarctic top predator the snow petrel Pagodroma Nivea
Oecologia, 2000Co-Authors: Christophe Barbraud, Henri Weimerskirch, Christophe Guinet, Pierre JouventinAbstract:The snow petrel Pagodroma Nivea is an obligate associate of sea-ice and one of the most abundant seabird species of the Southern Ocean. Time- and sex-specific annual variation in adult survival was estimated using capture-mark-recapture of petrels nesting at Petrels Island, Terre Adelie, 1981–1997. On the basis of a regression analysis, 44% of the variation was linked inversely to the latitudinal extent of sea-ice during winter (June) in the region offshore of the study colony, where this population is likely to spend the non-breeding season. Monthly sea-surface temperature anomalies tended to influence adult survival but the relationship was not statistically significant. Why sea-ice extent should have such a critical effect on this species is yet to be explained, but the relationship, in the context of environmental warming and the consequent potential loss of Antarctic sea-ice, is an important one for this species.
Henri Weimerskirch - One of the best experts on this subject based on the ideXlab platform.
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Species‐specific foraging strategies and segregation mechanisms of sympatric Antarctic fulmarine petrels throughout the annual cycle
Ibis, 2016Co-Authors: Karine Delord, Christophe Barbraud, Yves Cherel, Patrick Pinet, David Pinaud, Sophie De Grissac, Agnès Lewden, Henri WeimerskirchAbstract:International audienceDetermining the year-round distribution and behaviour of birds is necessary for a betterunderstanding of their ecology and foraging strategies. Petrels form an important componentof the high-latitude seabird assemblages in terms of species and individuals. The distributionand foraging ecology of three sympatric fulmarine petrels (Southern FulmarFulmarus glacialoides, Cape Petrel Daption capense and Snow Petrel Pagodroma Nivea)were studied at Adelie Land, East Antarctica, by combining information from miniaturizedsaltwater immersion geolocators and stable isotopes from feathers. During thebreeding season at a large spatial scale (c. 200 km), the three species overlapped in theirforaging areas located in the vicinity of the colonies but were segregated by their dietand trophic level, as indicated by the different chick d15N values that increased in theorder Cape Petrel < Southern Fulmar < Snow Petrel. During the non-breeding season,the three fulmarines showed species-specific migration strategies along a wide latitudinalgradient. Snow Petrels largely remained in ice-associated Antarctic waters, Southern Fulmarstargeted primarily the sub-Antarctic zone and Cape Petrels migrated further north.Overall, birds spent less time in flight during the non-breeding period than during thebreeding season, with the highest percentage of time spent sitting on the water occurringduring the breeding season and at the beginning of the non-breeding period beforemigration. This activity pattern, together with the d13C values of most feathers, stronglysuggests that moult of the three fulmarine petrels occurred at that time in the very productivehigh Antarctic waters, where birds fed on a combination of crustaceans and fish.The study highlights different segregating mechanisms that allow the coexistence of closelyrelated species, specifically, prey partitioning during the breeding season and spatialsegregation at sea during the non-breeding season
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Corticosterone, prolactin and egg neglect behavior in relation to mercury and legacy POPs in a long-lived Antarctic bird
Science of The Total Environment, 2014Co-Authors: Sabrina Tartu, Frédéric Angelier, Henri Weimerskirch, Paco Bustamante, Jan Ove Bustnes, John C. Wingfield, Pierre Labadie, Hélène Budzinski, Olivier ChastelAbstract:Seabirds often have high loads of contaminants. These contaminants have endocrine disrupting properties but their relationships with some endocrine mechanisms are still poorly investigated in free-living organisms. This is the case for the stress response which shifts energy investment away from reproduction and redirects it towards survival. In birds, this stress response is achieved through a release of corticosterone and is also accompanied by a decrease in circulating prolactin, an anterior pituitary hormone widely involved in regulating parental cares. We measured blood concentrations of some legacy persistent organic pollutants (POPs) and mercury (Hg) and examined their relationships with the corticosterone and prolactin responses of known-age (9-46 years old) incubating snow petrels (Pagodroma Nivea) to a standardized capture/handling stress protocol. In this Antarctic seabird, we also investigated whether high contaminant burden correlates with a higher occurrence of egg neglect, a frequently observed behaviour in snow petrels. POPs and Hg were unrelated to age. Stress-induced corticosterone concentrations were positively related to POPs in both sexes, and stress-induced prolactin concentrations were negatively related to Hg in males. Egg-neglect behaviour was not related to POPs burden, but males with higher Hg concentrations were more likely to neglect their egg. This suggests that in birds, relationships between age and contaminants are complex and that even low to moderate concentrations of POPs and Hg are significantly related to hormonal secretion. In this Antarctic species, exposure to legacy POPs and Hg could make individuals more susceptible to environmental stressors such as ongoing disturbances in polar regions.
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Age-Related Mercury Contamination and Relationship with Luteinizing Hormone in a Long-Lived Antarctic Bird
PLOS ONE, 2014Co-Authors: Sabrina Tartu, Henri Weimerskirch, Paco Bustamante, Aurélie Goutte, Yves Cherel, Jan Ove Bustnes, Olivier ChastelAbstract:Seabirds, as long-lived top predators, accumulate contaminants such as mercury (Hg), an established endocrine disruptor. In long lived species hormonal secretion varies with age; therefore, Hg-induced endocrine disruption may be exacerbated in some age classes. Here we investigated relationships between blood total Hg and luteinizing hormone (LH, a key pituitary hormone for the onset of breeding), in pre-laying known-age (11-45 years old) snow petrels (Pagodroma Nivea) from Adelie Land, Antarctica. We predicted that 1) blood Hg would increase with advancing age as a consequence of bio-accumulation; and that 2) increasing blood Hg would be related to decreased concentrations of LH in the most Hg-contaminated individuals. Hg concentrations were higher in females than in males (p 13 C and δ 15 N) suggested that this unexpected pattern could originate from age and sex-related variations in trophic niche, and hence Hg exposure. Regarding LH, our prediction was only supported in young birds (≤ 23 years) where baseline LH was inversely correlated with Hg concentrations (p=0.04). Hg burden did not predict baseline LH or GnRH-induced LH in birds that were more than 23 years old. These results show that age and contaminants may interfere with major endocrine mechanisms and, together with other recent studies, support the view that Hg could be connected to LH secretion and could then impair the fitness of long-lived birds.
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Why do some adult birds skip breeding? A hormonal investigation in a long-lived bird
Biology Letters, 2011Co-Authors: Aurélie Goutte, Henri Weimerskirch, Marion Kriloff, Olivier ChastelAbstract:Skipping reproduction is often observed in long-lived organisms, but proximate mechanisms remain poorly understood. Since young and/or very old snow petrels (Pagodroma Nivea) commonly skip breeding, we tested whether they are physiologically able to breed during the pre-laying stage. To do so, we measured the ability of known-age (11–45 years old) petrels to release luteinizing hormone (LH, a crucial driver for breeding), by injecting exogenous gonadotropin-releasing hormone (GnRH). Although young petrels exhibited low baseline LH levels, they were able to elevate LH levels after a GnRH challenge. Moreover, young and very old petrels showed a stronger decrease in LH levels after the 10 min post-GnRH injection compared with middle-aged petrels. Birds that skipped breeding were as able as breeders to release LH after a GnRH challenge, indicating that they had functional pituitaries. However, the decision to skip reproduction was linked to a strong LH decrease after the 10 min post-GnRH injection. Our result suggests that the youngest and the oldest petrels fail to maintain elevated baseline LH levels, thereby do not initiate reproductive activities. Skipping reproduction in long-lived birds probably results from age-related changes in the dynamics of the hypothalamic–pituitary–gonadal (HPG) axis function.
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Age and the timing of breeding in a long-lived bird: a role for stress hormones?
Functional Ecology, 2010Co-Authors: Aurélie Goutte, Henri Weimerskirch, Élodie Antoine, Olivier ChastelAbstract:Summary 1. Young birds often reproduce later in the season than older ones, with poorer breeding success, but the proximate mechanisms involved in such a pattern remain poorly studied, especially in long-lived species. One possible mechanism is the endocrine stress response which is accompanied by the release of corticosterone. Elevated corticosterone levels can trigger physiological and behavioural responses that may delay or even suppress reproduction. 2. We tested the hypothesis that the delayed timing of breeding of young birds may be related to a greater susceptibility to stress compared with older ones during the pre-laying period of the breeding season. For this purpose, known-age (7–44 years old) pre-laying snow petrels, Pagodroma Nivea, were monitored for baseline and acute stress-induced corticosterone levels. We examined whether baseline and stress-induced corticosterone levels were related to age, and whether they could influence the decision to breed and egg-laying date. 3. Young snow petrels were more likely to skip the breeding season and to breed later than middle-aged birds. In addition, the oldest birds bred later than middle-aged ones, suggesting a possible senescence on laying dates. Baseline corticosterone levels were independent of age but young and very old birds were more sensitive to stress than middle-aged ones. However, there was no effect of stress-induced corticosterone levels on breeding decision and egg-laying date. Elevated baseline corticosterone levels during the pre-laying period were associated with a higher probability of skipping breeding in females and a delayed timing of egg-laying in both sexes. 4. These results suggest that the greater susceptibility of young breeders to stress was not the functional mechanism explaining their delayed timing of breeding. Baseline corticosterone levels, although independent of age, appear to be a more likely mediator of breeding decision and egg-laying date. In long-lived birds, the relationship between age and timing of breeding may be rather indirect, as other age-related factors such as breeding experience or foraging skills may have a deeper impact on baseline corticosterone than age per se.
Olivier Chastel - One of the best experts on this subject based on the ideXlab platform.
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Do repeated captures and handling affect phenotype and survival of growing Snow Petrel (Pagodroma Nivea)?
Polar Biology, 2020Co-Authors: Sophie M. Dupont, Christophe Barbraud, Olivier Chastel, Karine Delord, Charline Parenteau, Cécile Ribout, Frédéric AngelierAbstract:In vertebrates, developmental conditions can affect not only fledging success but also the phenotype of the offspring, with potential long-term consequences on adult performance. However, surprisingly the potential impact of anthropogenic disturbance on developing chicks is rarely investigated, notably in Antarctic wildlife. In this study, we specifically investigated the effects of repeated nest visits, capture, and handling on offspring survival and several complementary offspring phenotypic traits in the Snow Petrel ( Pagodroma Nivea ) chicks after thermal emancipation. We did not find any significant effect of our disturbance protocol on the morphology (body size, body mass, body condition), the physiology (breath rate, stress-induced corticosterone levels) and the behaviour (defense behaviour) of developing Snow Petrels. This specific disturbance protocol did not have any significant effect on chick survival, but there was a non-significant trend towards a lower survival for the disturbed group ( p = 0.1006), which showed an especially high mortality during a period of repeated snow storms. To conclude, investigator disturbance seems to have little effect on Snow Petrel chicks after thermal emancipation, but to remain cautious, we recommend to avoid capture and handling of Snow Petrel chicks during or soon after inclement weather.
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Does short-term fasting lead to stressed-out parents? A study of incubation commitment and the hormonal stress responses and recoveries in snow petrels
Hormones and Behavior, 2014Co-Authors: Frédéric Angelier, Charline Parenteau, John C. Wingfield, Marie Pellé, Olivier ChastelAbstract:Abstract The hormonal stress response is flexible and can be modulated by individuals according to its costs and benefits. Therefore, it is predicted that parents in poor body condition should modify their hormonal stress response, and thus, redirect energy allocation processes from parental care to self-maintenance when stressors occur. To test this prediction, most studies on free-living vertebrates have only focused on the stress response while the stress recovery – how quickly hormonal levels return to baseline values – has been neglected. Moreover, most studies have only focused on corticosterone – the primary mediator of allostasis – without paying attention to prolactin despite its major role in mediating parental behaviors. Here, we examined the effect of a short-term fasting event on the corticosterone and prolactin stress responses and recoveries, and we subsequently explored their relationships with parental decision in the snow petrel ( Pagodroma Nivea ). By comparing the hormonal profiles of fasting and non-fasting snow petrels, we showed that parents modulate their corticosterone (but not prolactin) stress response according to their energetic status. We also described for the first time the hormonal stress recoveries in wild birds and found that they did not differ between fasting and non-fasting birds. Importantly, egg neglect was negatively correlated with circulating prolactin but not corticosterone levels in this species, demonstrating therefore a complex link between body condition, parental behavior and circulating corticosterone and prolactin levels. We suggest that both corticosterone and prolactin play a major role in the way parents adjust to stressors. This multiple signaling may allow parents to fine-tune their response to stressors, and especially, to activate specific allostasis-related mechanisms in a timely manner.
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Corticosterone, prolactin and egg neglect behavior in relation to mercury and legacy POPs in a long-lived Antarctic bird
Science of The Total Environment, 2014Co-Authors: Sabrina Tartu, Frédéric Angelier, Henri Weimerskirch, Paco Bustamante, Jan Ove Bustnes, John C. Wingfield, Pierre Labadie, Hélène Budzinski, Olivier ChastelAbstract:Seabirds often have high loads of contaminants. These contaminants have endocrine disrupting properties but their relationships with some endocrine mechanisms are still poorly investigated in free-living organisms. This is the case for the stress response which shifts energy investment away from reproduction and redirects it towards survival. In birds, this stress response is achieved through a release of corticosterone and is also accompanied by a decrease in circulating prolactin, an anterior pituitary hormone widely involved in regulating parental cares. We measured blood concentrations of some legacy persistent organic pollutants (POPs) and mercury (Hg) and examined their relationships with the corticosterone and prolactin responses of known-age (9-46 years old) incubating snow petrels (Pagodroma Nivea) to a standardized capture/handling stress protocol. In this Antarctic seabird, we also investigated whether high contaminant burden correlates with a higher occurrence of egg neglect, a frequently observed behaviour in snow petrels. POPs and Hg were unrelated to age. Stress-induced corticosterone concentrations were positively related to POPs in both sexes, and stress-induced prolactin concentrations were negatively related to Hg in males. Egg-neglect behaviour was not related to POPs burden, but males with higher Hg concentrations were more likely to neglect their egg. This suggests that in birds, relationships between age and contaminants are complex and that even low to moderate concentrations of POPs and Hg are significantly related to hormonal secretion. In this Antarctic species, exposure to legacy POPs and Hg could make individuals more susceptible to environmental stressors such as ongoing disturbances in polar regions.
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Age-Related Mercury Contamination and Relationship with Luteinizing Hormone in a Long-Lived Antarctic Bird
PLOS ONE, 2014Co-Authors: Sabrina Tartu, Henri Weimerskirch, Paco Bustamante, Aurélie Goutte, Yves Cherel, Jan Ove Bustnes, Olivier ChastelAbstract:Seabirds, as long-lived top predators, accumulate contaminants such as mercury (Hg), an established endocrine disruptor. In long lived species hormonal secretion varies with age; therefore, Hg-induced endocrine disruption may be exacerbated in some age classes. Here we investigated relationships between blood total Hg and luteinizing hormone (LH, a key pituitary hormone for the onset of breeding), in pre-laying known-age (11-45 years old) snow petrels (Pagodroma Nivea) from Adelie Land, Antarctica. We predicted that 1) blood Hg would increase with advancing age as a consequence of bio-accumulation; and that 2) increasing blood Hg would be related to decreased concentrations of LH in the most Hg-contaminated individuals. Hg concentrations were higher in females than in males (p 13 C and δ 15 N) suggested that this unexpected pattern could originate from age and sex-related variations in trophic niche, and hence Hg exposure. Regarding LH, our prediction was only supported in young birds (≤ 23 years) where baseline LH was inversely correlated with Hg concentrations (p=0.04). Hg burden did not predict baseline LH or GnRH-induced LH in birds that were more than 23 years old. These results show that age and contaminants may interfere with major endocrine mechanisms and, together with other recent studies, support the view that Hg could be connected to LH secretion and could then impair the fitness of long-lived birds.
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Why do some adult birds skip breeding? A hormonal investigation in a long-lived bird
Biology Letters, 2011Co-Authors: Aurélie Goutte, Henri Weimerskirch, Marion Kriloff, Olivier ChastelAbstract:Skipping reproduction is often observed in long-lived organisms, but proximate mechanisms remain poorly understood. Since young and/or very old snow petrels (Pagodroma Nivea) commonly skip breeding, we tested whether they are physiologically able to breed during the pre-laying stage. To do so, we measured the ability of known-age (11–45 years old) petrels to release luteinizing hormone (LH, a crucial driver for breeding), by injecting exogenous gonadotropin-releasing hormone (GnRH). Although young petrels exhibited low baseline LH levels, they were able to elevate LH levels after a GnRH challenge. Moreover, young and very old petrels showed a stronger decrease in LH levels after the 10 min post-GnRH injection compared with middle-aged petrels. Birds that skipped breeding were as able as breeders to release LH after a GnRH challenge, indicating that they had functional pituitaries. However, the decision to skip reproduction was linked to a strong LH decrease after the 10 min post-GnRH injection. Our result suggests that the youngest and the oldest petrels fail to maintain elevated baseline LH levels, thereby do not initiate reproductive activities. Skipping reproduction in long-lived birds probably results from age-related changes in the dynamics of the hypothalamic–pituitary–gonadal (HPG) axis function.
Frédérique Olivier - One of the best experts on this subject based on the ideXlab platform.
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nest selection by snow petrels Pagodroma Nivea in east antarctica validating predictive habitat selection models at the continental scale
Ecological Modelling, 2008Co-Authors: Frédérique Olivier, Simon WotherspoonAbstract:Abstract Little is known on the factors controlling distribution and abundance of snow petrels in Antarctica. Studying habitat selection through modeling may provide useful information on the relationships between this species and its environment, especially relevant in a climate change context, where habitat availability may change. Validating the predictive capability of habitat selection models with independent data is a vital step in assessing the performance of such models and their potential for predicting species’ distribution in poorly documented areas. From the results of ground surveys conducted in the Casey region (2002–2003, Wilkes Land, East Antarctica), habitat selection models based on a dataset of 4000 nests were created to predict the nesting distribution of snow petrels as a function of topography and substrate. In this study, the Casey models were tested at Mawson, 3800 km away from Casey. The location and characteristics of approximately 7700 snow petrel nests were collected during ground surveys (Summer 2004–2005). Using GIS, predictive maps of nest distribution were produced for the Mawson region with the models derived from the Casey datasets and predictions were compared to the observed data. Models performance was assessed using classification matrixes and Receiver operating characteristic (ROC) curves. Overall correct classification rates for the Casey models varied from 57% to 90%. However, two geomorphologically different sub-regions (coastal islands and inland mountains) were clearly distinguished in terms of habitat selection by Casey model predictions but also by the specific variations in coefficients of terms in new models, derived from the Mawson data sets. Observed variations in the snow petrel aggregations were found to be related to local habitat availability. We discuss the applicability of various types of models (GLM, CT) and investigate the effect of scale on the prediction of snow petrel habitats. While the Casey models created with data collected at the nest scale did not perform well at Mawson due to regional variations in nest micro-characteristics, the predictive performance of models created with data compiled at a coarser scale (habitat units) was satisfactory. Substrate type was the most robust predictor of nest presence between Casey and Mawson. This study demonstrate that it is possible to predict at the large scale the presence of snow petrel nests based on simple predictors such as topography and substrate, which can be obtained from aerial photography. Such methodologies have valuable applications in the management and conservation of this top predator and associated resources and may be applied to other Antarctic, Sub-Antarctic and lower latitudes species and in a variety of habitats.
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Modelling habitat selection using presence-only data : Case study of a colonial hollow nesting bird, the snow petrel
Ecological Modelling, 2006Co-Authors: Frédérique Olivier, Simon WotherspoonAbstract:Little is known on distribution and abundance of snow petrels (Pagodroma Nivea) in Antarctica. Studying habitat selection through modelling may provide useful information on the relationships between this species and its environment, especially on potential effects of climate change as modifications of nest sites availability and/or quality may arise in the long term. Based on surveys of the Windmill Islands during summer 2002–2003, several types of habitat suitability models were tested to relate the location of 4000 snow petrel nests with a set of environmental predictors describing rock substrate and topography, which proved useful predictors to identify favourable habitat for snow petrels. GAMs were used in the exploratory phase of the analyses, guiding the parametrization of GLMs, complemented by CT models. All three models rely on randomly generated pseudo-absence points. Their predictive performance was compared to that of a fundamentally different model using presence-only data, ENFA. Based on environmental envelopes, ENFA proved slightly less accurate than GLMs, given the available input data. However, ENFA predictions provide a useful starting point to categorize habitat suitability prior to the application of other modelling techniques. All models were ameliorated by the addition of predictors accounting for the spatial clustering of nests, but are of limited use to predict nest distribution in new areas. Clustering was caused by both coloniality and the underlying spatial structure of the substrate, which constrained nest densities through the distribution of available nest sites. Models fitted only with environmental predictors were refined when random points were separated from nest aggregations with a buffer scaled to the average size of colonies (identified with a simulation). Buffering was redundant for the models including neighbour information. Overall, when fitting models with presence-only data points, improvements are obtained when accounting for the spatial clustering of the species. Given the highly specific nesting requirements of snow petrels, the observed nest clustering may be more constrained by the availability of suitable nests sites rather than driven by conspecific attraction, which emphasizes the importance of microhabitat quality in the habitat selection process.
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nesting habitat preferences of snow petrels Pagodroma Nivea and wilson s storm petrels oceanites oceanicus in east antarctica a modelling approach to predict species distribution
2006Co-Authors: Frédérique OlivierAbstract:Although snow petrels are ubiquitous around the Antarctic, population estimates of this “not so charismatic” top predator are generally limited. Such information is highly valuable for the monitoring and management of Antarctic and Southern Ocean ecosystems, especially in a climate change context. There is a need to complement long–term temporal demographic information obtained at a limited number of monitoring sites with spatial distribution data. Systematic surveys of snow petrels and Wilson’s storm petrels were undertaken at Casey (2002-2003) and Mawson (2004-2005) in order to provide better regional population estimates and test the performance of predictive distribution models based on topographic and substrate variables for refining such estimates. As habitat selection modelling is rarely used in Antarctic regions, methodological developments focus on dealing with the peculiarities of a semi-colonial hollow-nesting species, testing habitat selection modelling approaches and comparing the output of four types of models (Generalized Linear and Generalized Additive Models, Classification Trees and Ecological Niche Factor Analysis) across a range of scales. Snow petrel nest distribution was directly related to the nature of the rock substrate and to major topographic/geomorphological parameters such as hill slope and the direction of the prevailing winds. Model performance varied with the scale at which models were implemented, suggesting that nest selection processes happen predominantly at the habitat unit and individual nest scales. Further study at the nest scale highlighted that the influence of biotic related parameters such as conspecific attraction (modelled as autocorrelation due to coloniality) may be of lesser influence than selection based on individual nest quality. An alternative modelling method, ENFA, which creates environmental envelopes for the niche of the species with presence data only was identified as valuable for Antarctic data sets, which often lack comprehensive records of species absence. The validation of the models created at Casey with nest data collected in the Mawson region returned satisfactory prediction rates in two different habitat types, coastal islands and inland mountains, suggesting that it may be possible to predict snow petrel distribution across East Antarctica using remotely sensed information on topography and geomorphology, for example high-resolution aerial photography to guide in the design of and complement ground surveys. Similar modelling procedures applied to Wilson’s storm petrels produced more mitigated results and selection for this species appeared to be based principally on nest microhabitat characteristics. However, modelling provided useful information on the large-scale habitat preferences and ecological requirements of both species.
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Variations of snow petrel breeding success in relation to sea-ice extent: detecting local response to large-scale processes?
Polar Biology, 2005Co-Authors: Frédérique Olivier, Jan A. Van Franeker, Jeroen C. S. Creuwels, Eric J. WoehlerAbstract:Demographic parameters were estimated for snow petrels Pagodroma Nivea nesting at the study colony of Reeve Hill near Casey station, Antarctica between 1984 and 2003. Average breeding success for the colony varied from 18.2% to 76.5%. Breeding effort, hatching and fledging success were subject to a high interannual variability. We examined the influence of regional sea-ice extent on the breeding performance of snow petrels at Reeve Hill. Fewer birds were breeding when sea-ice had been extensive during April–May. Overall breeding success and fledging success were improved during years with extensive sea-ice cover in winter. Successful breeding effort and breeding success were depressed when there was extensive sea-ice cover during January–February. Sea surface temperatures also correlated to snow petrel breeding performance parameters. Previous work showed that large-scale climatic events (ENSO, Antarctic circumpolar wave) and the related sea-ice cover around the Antarctic might affect the lower trophic levels of the marine environment and consequently food availability for snow petrels. A comparison with the long-term study conducted at Ile des Pétrels (Terre Adélie) suggests that despite similarities in the underlying biological processes that control snow petrel breeding performance, the nature of the correlation of large-scale environmental factors with breeding performance differs substantially between the two colonies, probably because of the confounding effects of other environmental factors acting at a local scale (local weather, nest quality), which also affect bird body condition.
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Variations of snow petrel breeding success in relation to sea-ice extent: detecting local response to large-scale processes?
Polar Biology, 2005Co-Authors: Frédérique Olivier, Jan A. Van Franeker, Jeroen C. S. Creuwels, Eric J. WoehlerAbstract:Demographic parameters were estimated for snow petrels Pagodroma Nivea nesting at the study colony of Reeve Hill near Casey station, Antarctica between 1984 and 2003. Average breeding success for the colony varied from 18.2% to 76.5%. Breeding effort, hatching and fledging success were subject to a high interannual variability. We examined the influence of regional sea-ice extent on the breeding performance of snow petrels at Reeve Hill. Fewer birds were breeding when sea-ice had been extensive during April–May. Overall breeding success and fledging success were improved during years with extensive sea-ice cover in winter. Successful breeding effort and breeding success were depressed when there was extensive sea-ice cover during January–February. Sea surface temperatures also correlated to snow petrel breeding performance parameters. Previous work showed that large-scale climatic events (ENSO, Antarctic circumpolar wave) and the related sea-ice cover around the Antarctic might affect the lower trophic levels of the marine environment and consequently food availability for snow petrels. A comparison with the long-term study conducted at Ile des Petrels (Terre Adelie) suggests that despite similarities in the underlying biological processes that control snow petrel breeding performance, the nature of the correlation of large-scale environmental factors with breeding performance differs substantially between the two colonies, probably because of the confounding effects of other environmental factors acting at a local scale (local weather, nest quality), which also affect bird body condition.
