| 1. |
- Balazy, Kaja, et al.
(författare)
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Molecular tools prove little auks from Svalbard are extremely selective for Calanus glacialis even when exposed to Atlantification
- 2023
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Two Calanus species, C. glacialis and C. finmarchicus, due to different life strategies and environmental preferences act as an ecological indicators of Arctic Atlantification. Their high lipid content makes them important food source for higher trophic levels of Arctic ecosystems including the most abundant Northern Hemisphere's seabird, the little auk (Alle alle). Recent studies indicate a critical need for the use of molecular methods to reliably identify these two sympatric Calanus species. We performed genetic and morphology-based identification of 2600 Calanus individuals collected in little auks foraging grounds and diet in summer seasons 2019-2021 in regions of Svalbard with varying levels of Atlantification. Genetic identification proved that 40% of Calanus individuals were wrongly classified as C. finmarchicus according to morphology-based identification in both types of samples. The diet of little auks consisted almost entirely of C. glacialis even in more Atlantified regions. Due to the substantial bias in morphology-based identification, we expect that the scale of the northern expansion of boreal C. finmarchicus may have been largely overestimated and that higher costs for birds exposed to Atlantification could be mostly driven by a decrease in the size of C. glacialis rather than by shift from C. glacialis to C. finmarchicus.
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| 2. |
- Bertrand, Philip, et al.
(författare)
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Feeding at the front line : interannual variation in the use of glacier fronts by foraging black-legged kittiwakes
- 2021
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Ingår i: Marine Ecology Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 677, s. 197-208
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Tidskriftsartikel (refereegranskat)abstract
- Tidewater glacier fronts can represent important foraging areas for Arctic predators. Their ecological importance is likely to change in a warmer Arctic. Their profitability and use by consumers are expected to vary in time, but the underlying mechanisms driving such variation remain poorly known. The subglacial plume, originating from meltwater discharge, is responsible for the entrainment and transport of zooplankton to the surface, making them more readily available for surface-feeding seabirds. Both discharge and zooplankton abundance are known to fluctuate in time and are thus expected to modulate the foraging profitability of glacier fronts. This study tested the predictions that annual use of glacier fronts by black-legged kittiwakes Rissa tridactyla is positively related to the average glacier discharge and prey biomass in the fjord. To do this, we combined a multiyear dataset of environmental drivers and GPS tracks of birds in Kongsfjorden, Svalbard. Our results confirmed the interannual variation in the use of glacier fronts by kittiwakes; however, contrary to our predictions, these variations were negatively correlated to both glacier discharge and zooplankton abundance. These apparent negative relationships likely reflect non-linear effects and complex interactions between local and regional environmental factors that affect the relative profitability of glacier fronts as foraging areas. Despite their high spatial predictability, glacier fronts may not offer consistent foraging opportunities for marine predators over time.
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| 3. |
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| 4. |
- Kersten, Oliver, et al.
(författare)
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Complex population structure of the Atlantic puffin revealed by whole genome analyses
- 2021
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642.
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Tidskriftsartikel (refereegranskat)abstract
- The factors underlying gene flow and genomic population structure in vagile seabirds arenotoriously difficult to understand due to their complex ecology with diverse dispersal barriers and extensive periods at sea. Yet, such understanding is vital for conservation management of seabirds that are globally declining at alarming rates. Here, we elucidate thepopulation structure of the Atlantic puffin (Fratercula arctica) by assembling its referencegenome and analyzing genome-wide resequencing data of 72 individuals from 12 colonies.We identify four large, genetically distinct clusters, observe isolation-by-distance betweencolonies within these clusters, and obtain evidence for a secondary contact zone. Theseobservations disagree with the current taxonomy, and show that a complex set of contemporary biotic factors impede gene flow over different spatial scales. Our results highlightthe power of whole genome data to reveal unexpected population structure in vagile marineseabirds and its value for seabird taxonomy, evolution and conservation
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| 5. |
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| 6. |
- Patterson, Allison, et al.
(författare)
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Foraging range scales with colony size in high-latitude seabirds
- 2022
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 32:17, s. 3800-3807
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Tidskriftsartikel (refereegranskat)abstract
- Density-dependent prey depletion around breeding colonies has long been considered an important factor controlling the population dynamics of colonial animals.1, 2, 3, 4 Ashmole proposed that as seabird colony size increases, intraspecific competition leads to declines in reproductive success, as breeding adults must spend more time and energy to find prey farther from the colony.1 Seabird colony size often varies over several orders of magnitude within the same species and can include millions of individuals per colony.5,6 As such, colony size likely plays an important role in determining the individual behavior of its members and how the colony interacts with the surrounding environment.6 Using tracking data from murres (Uria spp.), the world’s most densely breeding seabirds, we show that the distribution of foraging-trip distances scales to colony size0.33 during the chick-rearing stage, consistent with Ashmole’s halo theory.1,2 This pattern occurred across colonies varying in size over three orders of magnitude and distributed throughout the North Atlantic region. The strong relationship between colony size and foraging range means that the foraging areas of some colonial species can be estimated from colony sizes, which is more practical to measure over a large geographic scale. Two-thirds of the North Atlantic murre population breed at the 16 largest colonies; by extrapolating the predicted foraging ranges to sites without tracking data, we show that only two of these large colonies have significant coverage as marine protected areas. Our results are an important example of how theoretical models, in this case, Ashmole’s version of central-place-foraging theory, can be applied to inform conservation and management in colonial breeding species.
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