The Experts below are selected from a list of 66 Experts worldwide ranked by ideXlab platform
Benno Luthi - One of the best experts on this subject based on the ideXlab platform.
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post fledging dispersal of king penguins aptenodytes patagonicus from two breeding sites in the south atlantic
PLOS ONE, 2014Co-Authors: Klemens Putz, P N Trathan, Julieta Pedrana, Martin A Collins, Sally Poncet, Benno LuthiAbstract:Most studies concerning the foraging ecology of marine vertebrates are limited to breeding adults, although other life history stages might comprise half the total population. For penguins, little is known about juvenile dispersal, a period when individuals may be susceptible to increased mortality given their naive foraging behaviour. Therefore, we used satellite telemetry to study king penguin fledglings (n = 18) from two sites in the Southwest Atlantic in December 2007. The two sites differed with respect to climate and proximity to the Antarctic Polar Front (APF), a key Oceanographic Feature generally thought to be important for king penguin foraging success. Accordingly, birds from both sites foraged predominantly in the vicinity of the APF. Eight king penguins were tracked for periods greater than 120 days; seven of these (three from the Falkland Islands and four from South Georgia) migrated into the Pacific. Only one bird from the Falkland Islands moved into the Indian Ocean, visiting the northern limit of the winter pack-ice. Three others from the Falkland Islands migrated to the eastern coast of Tierra del Fuego before travelling south. Derived tracking parameters describing their migratory behaviour showed no significant differences between sites. Nevertheless, generalized linear habitat modelling revealed that juveniles from the Falkland Islands spent more time in comparatively shallow waters with low sea surface temperature, sea surface height and chlorophyll variability. Birds from South Georgia spent more time in deeper waters with low sea surface temperature and sea surface height, but high concentrations of chlorophyll. Our results indicate that inexperienced king penguins, irrespective of the location of their natal site in relation to the position of the APF, develop their foraging skills progressively over time, including specific adaptations to the environment around their prospective breeding site.
Klemens Putz - One of the best experts on this subject based on the ideXlab platform.
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post fledging dispersal of king penguins aptenodytes patagonicus from two breeding sites in the south atlantic
PLOS ONE, 2014Co-Authors: Klemens Putz, P N Trathan, Julieta Pedrana, Martin A Collins, Sally Poncet, Benno LuthiAbstract:Most studies concerning the foraging ecology of marine vertebrates are limited to breeding adults, although other life history stages might comprise half the total population. For penguins, little is known about juvenile dispersal, a period when individuals may be susceptible to increased mortality given their naive foraging behaviour. Therefore, we used satellite telemetry to study king penguin fledglings (n = 18) from two sites in the Southwest Atlantic in December 2007. The two sites differed with respect to climate and proximity to the Antarctic Polar Front (APF), a key Oceanographic Feature generally thought to be important for king penguin foraging success. Accordingly, birds from both sites foraged predominantly in the vicinity of the APF. Eight king penguins were tracked for periods greater than 120 days; seven of these (three from the Falkland Islands and four from South Georgia) migrated into the Pacific. Only one bird from the Falkland Islands moved into the Indian Ocean, visiting the northern limit of the winter pack-ice. Three others from the Falkland Islands migrated to the eastern coast of Tierra del Fuego before travelling south. Derived tracking parameters describing their migratory behaviour showed no significant differences between sites. Nevertheless, generalized linear habitat modelling revealed that juveniles from the Falkland Islands spent more time in comparatively shallow waters with low sea surface temperature, sea surface height and chlorophyll variability. Birds from South Georgia spent more time in deeper waters with low sea surface temperature and sea surface height, but high concentrations of chlorophyll. Our results indicate that inexperienced king penguins, irrespective of the location of their natal site in relation to the position of the APF, develop their foraging skills progressively over time, including specific adaptations to the environment around their prospective breeding site.
Dann Peter - One of the best experts on this subject based on the ideXlab platform.
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Data from: Non-equilibrium conditions explain spatial variability in genetic structuring of little penguin (Eudyptula minor)
2015Co-Authors: Burridge, Christopher P., Peucker, Amanda J., Valautham, Sureen Kumar, Styan, Craig A., Dann PeterAbstract:Factors responsible for spatial structuring of population genetic variation are varied, and in many instances there may be no obvious explanations for genetic structuring observed, or those invoked may reflect spurious correlations. A study of little penguins (Eudyptula minor) in southeast Australia documented low spatial structuring of genetic variation with the exception of colonies at the western limit of sampling, and this distinction was attributed to an intervening Oceanographic Feature (Bonney Upwelling), differences in breeding phenology, or sea level change. Here, we conducted sampling across the entire Australian range, employing additional markers (12 microsatellites and mitochondrial DNA, 697 individuals, 17 colonies). The zone of elevated genetic structuring previously observed actually represents the eastern half of a genetic cline, within which structuring exists over much shorter spatial scales than elsewhere. Colonies separated by as little as 27 km in the zone are genetically distinguishable, while outside the zone, homogeneity cannot be rejected at scales of up to 1400 km. Given a lack of additional physical or environmental barriers to gene flow, the zone of elevated genetic structuring may reflect secondary contact of lineages (with or without selection against interbreeding), or recent colonization and expansion from this region. This study highlights the importance of sampling scale to reveal the cause of genetic structuring
P Dann - One of the best experts on this subject based on the ideXlab platform.
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Nonequilibrium Conditions Explain Spatial Variability in Genetic Structuring of Little Penguin (Eudyptula minor).
J Hered, 2015Co-Authors: P DannAbstract:Factors responsible for spatial structuring of population genetic variation are varied, and in many instances there may be no obvious explanations for genetic structuring observed, or those invoked may reflect spurious correlations. A study of little penguins (Eudyptula minor) in southeast Australia documented low spatial structuring of genetic variation with the exception of colonies at the western limit of sampling, and this distinction was attributed to an intervening Oceanographic Feature (Bonney Upwelling), differences in breeding phenology, or sea level change. Here, we conducted sampling across the entire Australian range, employing additional markers (12 microsatellites and mitochondrial DNA, 697 individuals, 17 colonies). The zone of elevated genetic structuring previously observed actually represents the eastern half of a genetic cline, within which structuring exists over much shorter spatial scales than elsewhere. Colonies separated by as little as 27 km in the zone are genetically distinguishable, while outside the zone, homogeneity cannot be rejected at scales of up to 1400 km. Given a lack of additional physical or environmental barriers to gene flow, the zone of elevated genetic structuring may reflect secondary contact of lineages (with or without selection against interbreeding), or recent colonization and expansion from this region. This study highlights the importance of sampling scale to reveal the cause of genetic structuring.
Congdon, Bradley C. - One of the best experts on this subject based on the ideXlab platform.
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Oceanographic drivers of near-colony seabird foraging site use in tropical marine systems
'Inter-Research Science Center', 2018Co-Authors: Mcduie Fiona, Weeks, Scarla J., Congdon, Bradley C.Abstract:Wedge-tailed shearwaters of Australia’s southern Great Barrier Reef (GBR), obtain food for their chicks on short-trips adjacent to the breeding colony. GPS tracking (Feb-Apr 2013-14) indicated that most trips were of one-day duration (70-85%) and that all were within 300km of the colony. Oceanographic characteristics of foraging and non-foraging areas were compared to identify mechanisms linked to prey availability. Foraging generally occurred adjacent to the Capricorn shelf, where the largest Oceanographic Feature in the region, the Capricorn Eddy, creates increased frontal activity and upwellings. Shearwaters consistently revisited four bathymetrically and topographically distinct foraging zones influenced by this mesoscale eddy. In 2013, strong sea-surface temperature (SST) fronts associated with relatively intense eddy activity influenced foraging activity in all foraging zones. In 2014 the dominant Oceanographic factors influencing foraging were SST and [Chlorophyll a] or their anomalies, with these influences varying among zones; thus suggesting a weakened effect of the eddy and elevated importance of fine-scale phenomena such as localised upwellings. Foraging in the coastal foraging zone was also significantly influenced by terrestrial inputs. At these times birds foraged in association with freshwater flood plumes and higher [chlorophyll a]. The Oceanographic mechanisms underlying prey availability to shearwaters in this system are tightly linked to variations in climatic conditions. Consequently, predictions associated with climate change such as increased ENSO frequency or severity, are likely to seriously diminish the profitability of identified foraging locations and the reproductive output from impacted colonies. Currently, most identified foraging areas are without specific management or protection status
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Oceanographic drivers of near-colony seabird foraging site use in tropical marine systems
'Inter-Research Science Center', 2018Co-Authors: Mcduie Fiona, Weeks, Scarla J., Congdon, Bradley C.Abstract:Wedge-tailed shearwaters of Australia’s southern Great Barrier Reef (GBR), obtain food for their chicks on short trips adjacent to the breeding colony. GPS tracking (from February to April in 2013 and 2014) indicated that most trips were of 1 d duration (70 to 85%) and that all were within 300 km of the colony. Oceanographic characteristics of foraging and non-foraging areas were compared to identify mechanisms driving prey availability. Foraging generally occurred adjacent to the Capricorn Shelf, where the largest Oceanographic Feature in the region, the Capricorn Eddy, creates increased frontal activity and upwellings. Shearwaters consistently revisited 4 bathymetrically and topographically distinct foraging zones influenced by this mesoscale eddy. In 2013, strong sea surface temperature (SST) fronts associated with relatively intense eddy activity influenced foraging activity in all foraging zones. In 2014 the dominant Oceanographic factors influencing foraging were SST and chlorophyll a concentration ([chl a]) or their anomalies. However, these influences varied among zones, suggesting a weakened effect of the eddy and elevated importance of fine-scale phenomena such as localised upwellings. Foraging in the coastal foraging zone was also significantly influenced by terrestrial inputs: specifically, birds foraged in association with freshwater flood plumes with higher [chl a]. The Oceanographic mechanisms underlying prey availability to shearwaters in this system are tightly linked to variations in climatic conditions. Consequently, predicted changes associated with climate change, such as increased frequency or severity of El Niño events, are likely to seriously diminish the profitability of identified foraging locations and the reproductive output of impacted colonies. Currently, most identified foraging areas are without specific management or protection status