Dariusz Jakubas

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Yeasts are a distinctive group of microfungi, but compared to other microorganisms, their ecological function and biodiversity are poorly known. This is especially so where polar ecosystems are concerned. With climate changes and increasing pollution levels in the Arctic, it can be anticipated that there will be an increase in the prevalence and diversity(More)
The presence of piscivorous vertebrates at fish farms often ignites conflicts over fish resources managed by humans. This study investigates the factors affecting the presence of conflict vertebrates at fish ponds. A telephone survey in western Poland in 2012–2013 examined 104 fish ponds. Six species were most often observed at fish farms: European otter(More)
Glucocorticoids participate in the control of whole body homoeostasis and an organism’s response to stress. Corticosterone, which is the principal glucocorticoid in birds, has been shown to increase in response to different energetic demands and perturbations that individuals have to cope with. In this study, a non-invasive method to examine the(More)
During the chick-rearing period, little auks Alle alle adopt a bimodal foraging strategy, alternating long trips with several short ones. It has been postulated that they reach more remote areas during long feeding trips than during short ones. However, the range of their foraging flights has never actually been measured. The aims of this study were to find(More)
The migration strategies of birds may vary strongly between species and also between age and/or sex groups. We studied the autumn migration and body condition of molecularly sexed Reed Warblers Acrocephalus scirpaceus and Sedge Warblers Acrocephalus schoenobaenus (211 and 208 ind., respectively) at a stopover site on Lake Druzno, Northern Poland, in 2008.(More)
Variation in body size among subpopulations of the same species may reflect phenotypic or genetic responses to environmental gradients or geographical distance. Here, we examine geographical variation in the body size of the dovekie (Alle alle), the most numerous high-Arctic seabird. Locations of dovekie breeding sites are largely restricted to the(More)
We examined behavioural and hormonal stress responses in a small seabird (little auk, Alle alle), which exhibits a transition from biparental to male-only care towards the end of the nesting period, in order to understand the mechanisms underlying this parental strategy. We hypothesized that the male staying with the chick should be less sensitive to(More)
In a number of species with biparental care, the parents of one sex desert the mate and brood before the chick is independent. The reasons for this desertion are poorly understood. In the study reported here we investigated whether sex-specific changes in body mass corrected for size (in short body mass) and the stress-related heterophil to lymphocyte ratio(More)
Long-lived birds often face a dilemma between self-maintenance and reproduction. In order to maximize fitness, some seabird parents alternate short trips to collect food for offspring with long trips for self-feeding (bimodal foraging strategy). In this study, we examined whether temporal and spatial variation in the quality of foraging grounds affect(More)
In seabirds, variation in breeding phenology and success is often induced by macro- and mesoscale fluctuations in oceanographic conditions, which is recordable at the regional or colony scale. Variation in breeding parameters may also exist at the microscale—among discrete breeding aggregations and subcolonies. The aim of this study was to compare breeding(More)