| 1. |
- Balazy, Kaja, et al.
(författare)
-
Molecular tools prove little auks from Svalbard are extremely selective for Calanus glacialis even when exposed to Atlantification
- 2023
-
Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 13
-
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.
|
|
| 2. |
- Wojczulanis-Jakubas, Katarzyna, et al.
(författare)
-
Assortative mating patterns of multiple phenotypic traits in a long-lived seabird
- 2018
-
Ingår i: Ibis. - : WILEY. - 0019-1019 .- 1474-919X. ; 160:2, s. 464-469
-
Tidskriftsartikel (refereegranskat)abstract
- Choosing the right mate is crucial for successful breeding, particularly in monogamous species with long and extensive bi-parental care, and when the breeding pair is presumed to last many seasons. We investigated the degree of assortative mating in the Little Auk Alle alle, a long-lived seabird with long-term pair bonds and bi-parental care for fixed (morphological) and labile (physiological, behavioural) traits. Using randomization tests, we suggest assortative mating with respect to wing length, extent of the white area on the upper eyelid and hormonal stress response (the difference between stress-induced and baseline corticosterone levels). We discuss how the assortative mating patterns that we found in the Little Auk may be adaptive.
|
|
| 3. |
- Wojczulanis-Jakubas, Katarzyna, et al.
(författare)
-
Differential timing and latitudinal variation in sex ratio of Aquatic Warblers during the autumn migration
- 2017
-
Ingår i: Die Naturwissenschaften. - : Springer Science and Business Media LLC. - 1432-1904. ; 104:11-12, s. 101-101
-
Tidskriftsartikel (refereegranskat)abstract
- Differential migration has been extensively reported in spring, but less so in autumn, particularly in relation to sex in monomorphic bird species. Here, we analysed the autumn passage of a monomorphic, globally threatened passerine, the Aquatic Warbler Acrocephalus paludicola throughout Western Europe, with regard to age and sex. We showed that, overall, adults migrated earlier than first-year birds, and males migrated earlier than females during the autumn migration. This may be caused by an overall social dominance of adults over immatures, and differentiated migration strategy of males and females. In addition, we found male-skewed sex proportions, with a tendency to an equalised ratio in more southern stopover sites. This may indicate a male bias in the global population or different migration strategies of the sexes. Differential migration may cause the age and sex classes to be exposed differently to various threats affecting demographic structure of the species.
|
|
