Polar Research (E-Journal)
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On the polar edge: the status of the northern gannet (Morus bassanus) in the Barents Sea in 2015-16
No full textDuring its population recovery in the North Atlantic in the early 1900s, the northern gannet (Morus bassanus) established its first colony in Norway at Runde in 1946. Since the 1960s, gannets have established (and later abandoned) several small colonies in the north of the country. These colonies have been regularly monitored, and in 2015–16 ca. 3300 apparently occupied nests (AON) were counted in seven colonies in northern Norway. Two colonies that existed in 2008 had been abandoned and four new ones established. Two of the latter were again abandoned before 2015. In 1995, one pair established a colony at Kharlov on the Kola Peninsula, Russia, where numbers increased to 200–250 AON in 2016. The newest and world’s northernmost colony was established at Bjørnøya (Bear Island) in 2011, extending the species’ breeding range well into the Arctic. These recent establishments are thought to be associated with a warming of the Barents Sea and the northward spread of common prey of the gannet such as herring and mackerel. This paper documents recent establishments, growths and abandonments of colonies at the gannet’s northern limit of distribution
Cratering behaviour and faecal C:N ratio in relation to seasonal snowpack characteristics in a High-Arctic ungulate
No full textSnow and ice determine winter forage availability for Arctic herbivores. Winter precipitation is anticipated to increase, and icing following warm spells and rain-on-snow (ROS) are likely to become more frequent. While this may reduce herbivore survival, fecundity and population growth, we can also expect behavioural and dietary responses. Here, we tested predictions from optimal foraging theory on how changing snowpack conditions influence choice of feeding craters and diet quality in a large generalist herbivore, the wild Svalbard reindeer. Snow and ice conditions over winter 2012/13 (a ‘normal’ winter with little ROS and icing) were measured in reindeer feeding craters, in paired controls one metre away and in fixed control sites. On average, feeding craters had less snow and integrated ram hardness (IRH, the force needed to reach the ground), but not less ice, than nearby controls. However, on this fine spatial scale, reindeer tended to select for microhabitat with worse snowpack conditions up to a certain level of snow (ca. 10 cm), ice (0.5 cm) and IRH (250 kg cm) in the nearby controls, reflecting the trade-off between selection for forage abundance versus accessibility in a sparsely vegetated environment. In this lichen-free system, faecal C:N ratios increased during winter as forage accessibility was increasingly restricted by snow, possibly indicating a reduction in diet quality due to changes in diet composition. Our study suggests that snowpack depth and hardness largely determine Svalbard reindeer feeding behaviour and diet quality during the course of a winter season
Volcanic passive continental margin beneath Maitri station in central DML, East Antarctica: constraints from crustal shear velocity through receiver function modelling
No full textDronning Maud Land (DML) in East Antarctica is considered to be a key area for the reconstruction of the Gondwana supercontinent. We investigate the crustal shear wave velocity (Vs) model beneath the Maitri station, situated in the central DML of East Antarctica, through receiver function modelling. The analysis shows an average crustal thickness of 38.50 ± 0.5 km and a Vp/Vs ratio of 1.784 ± 0.002. The obtained Vs structure suggests that the topmost ca. 2.5 km of the crust contains ice and sediments with low Vs (1.5–2.0 km/s). This layer is underlain by a thick (ca. 12.5 km) layer of Vs = 2.25–2.6 km/s, suggestive of an extrusive igneous rock (rhyolite) at this depth range. Between 16 and 28 km depth, the Vs increases from 2.9 to 3.4 km/s. In the lower crust, a 7 km thick layer of Vs = 3.9 km/s is followed by 6 km thick underplated layer (Vs = 4.1 km/s) at the crust–mantle boundary. The uppermost mantle Vs is ca. 4.3 km/s. With the observation of underplated material in the lowermost crust, extrusive volcanic rocks in the upper crust, seaward dipping reflectors in the surrounding and a general paucity of seismicity, we believe the crust beneath the Maitri station represents a volcanic passive continental margin. We also believe that after its origin in the Precambrian and during its subsequent evolution it might have been affected by the post-Precambrian tectono-thermal event(s) responsible for the Gondwana supercontinent break-up
Estimating little auk (Alle alle) breeding density and chick-feeding rate using video surveillance
No full textHigh Arctic ecosystems are under change and need to be monitored. We studied little auks (Alle alle), the most abundant seabird in the North Atlantic, in their main breeding area in the North Water Polynya region of High-Arctic north-west Greenland. We developed a method for estimating breeding density and chick-feeding rate based on video surveillance. As the nests of little auks are secluded between rocks and cannot be directly observed, the method rests on detailed recording of feeding events, when parent birds arrive from the sea with filled gular pouches and disappear into the scree to feed their chicks, supplemented with recording of fledging and pre-fledging behaviour of chicks outside the nesting holes. We installed video cameras in two study plots during the late chick-rearing and fledging periods 2 – 11 August 2012 and 5 – 12 August 2013, and the method proved useful for estimating the density of active nests immediately prior to fledging (which corresponds roughly to productivity of fledglings/m2). The densities of active nests for the two plots in 2012 and 2013 ranged between 1.06 and 1.63 nests/m2, and an average of 9.1 feeds/chick/day (n = 8 pairs, 3 × 24 h, 219 feedings) was recorded for this late stage of the chick-rearing period. Our video surveillance method has advantages over the mark–resight methods and other techniques used to monitor little auk colonies
The Arctic guide: wildlife of the Far North
No full textThe Arctic guide: wildlife of the Far North is an ambitious and superbly illustrated volume by Sharon Chester, the illustrator, photographer, author and cruise-ship natural history lecturer who has earlier given us Antarctic birds and seals (1993) and A wildlife guide to Chile (2008), among other publications. Following informative introductory sections describin
Foreword to Supplement 1: research on a polar species—the Arctic fox
No full textThe Arctic fox has a circumpolar distribution and is intensively studied because it is adapted to extreme environments and influences the ecology of many other species. We introduce here a collection of 12 articles on Arctic fox biology and management. After summarizing the main biological features of the species, we explore the peer-reviewed literature dealing with the Arctic fox through a bibliometric network analysis which identifies clusters of papers sharing a high similarity of cited literature. We visualize with a word cloud analysis 10 clusters comprising 97% of 755 articles published by 1742 authors from 1996–2015. Behavioural and ecological questions, including conservation science, dominate this recent literature. The collection of papers published in the supplement offers an excellent representation of current research dealing with Arctic fox biology and management
Academia in Svalbard: an increasingly important role for research and education as tools for Norwegian policy
No full textSvalbard, a High-Arctic archipelago over which Norway practises sovereignty in accordance with the terms of the Svalbard Treaty, has become an increasingly important area for Arctic research and higher education. There are four more or less permanent settlements with substantial research infrastructure, and a few manned observatories for special purposes. Several Norwegian and foreign research institutions have established stations and installations in the archipelago. With coal mining activity scaling down because of economic difficulties and lack of political support for subsidies, Norwegian policy will prioritize research and higher education as a way of maintaining Norwegian settlements in Svalbard. I give an overview of the institutions, organizations and facilities for research and higher education in Svalbard, and discuss the increasingly important role of research and education in Norwegian Svalbard policy
Patterns of fungal–algal symbiont association in Usnea aurantiaco-atra reveal the succession of lichen–moss communities in Fildes Peninsula, Antarctica
No full textUsnea aurantiaco-atra is the most widespread flora in Fildes Peninsula. There are two growth types of U. aurantiaco-atra: the erect form on rocks and the prostrate form associated with mosses. Phylogenetic analysis showed that individuals of the two growth forms share genotypes. Moreover, haploid disequilibrium testing indicated no significant genetic difference for the two growth forms when fungal and algal internal transcribed spacer rDNA were treated as two alleles of one lichen individual. The two growth forms of U. aurantiaco-atra appear to reflect different stages of lichen–moss community succession. A mode is proposed for demonstrating the occurrence of this succession
Snowmobile impact on diurnal behaviour in the Arctic fox
No full textAs tourism increases globally, studies have documented impacts on wildlife from anthropogenic disturbances. In this observational experiment we aimed to investigate if snowmobile traffic affected the diurnal activity of Arctic fox in High Arctic Svalbard. We conducted the study in two areas in Svalbard, one control area with low snowmobile traffic and one experimental area with high snowmobile traffic. In each area 10 camera-traps, baited with reindeer carcasses, were positioned and programmed to take photographs every five minutes. The proportion of photographs with foxes was higher during the night than during the day, and the difference between night and day was larger in the area with more snowmobile traffic. By using data obtained according to a similar study design in two Arctic Russian sites, Yamal and Nenetsky, with little human activity and low snowmobile traffic, we were able to compare Arctic fox activity patterns in Svalbard on a larger scale. Our results indicate that snowmobile traffic had an impact on the diurnal activity of the Arctic fox in Svalbard, while there were no obvious diurnal activity patterns among Russian foxes. Even the area with low snowmobile traffic in Svalbard showed increased use of the reindeer carcasses during the night compared to one of the Russian sites, where foxes used carcasses equally during day and night. Such knowledge is of importance in designing cautious management practices
Magnetotelluric signatures of the complex tertiary fold–thrust belt and extensional fault architecture beneath Brøggerhalvøya, Svalbard
No full textMagnetotelluric (MT) data were recently collected on Brøggerhalvøya, Svalbard, in a 0.003– 1000 s period range along a curved WNW–ESE profile. The collected data manifested strong three-dimensional (3D) effects. We modelled the full impedance tensor with tipper and bathymetry included in 3D, and benchmarked the result with determinant data two-dimensional (2D) inversion. The final inversion results indicated striking similarity with known surface bedrock geology and well reflected the tectonic history of the region. The most convincing contribution of the MT data is perhaps the elegantly imaged interplay between repeated basement-involved fold–thrust belt structures and successive down-dropped strata along steeply dipping oblique-normal faults (e.g., the Scheteligfjellet Fault) that created a horst/ridge and graben/depression system. Peculiarly, the MT result suggests that the Paleocene–Eocene fold–thrust belt structures dominate the shallow crustal level, while later normal faults in the area can be traced deeper into the pre-Devonian basement formations strongly affecting fluid and heat migration towards the surface. Near the sub-vertical Scheteligfjellet Fault, the MT model indicates aquifers within the upraised horsts of the pre- Devonian system at 2–5 km depth, sandwiched between the down-faulted resistive (ca. 500–3000 Ωm) Carboniferous and Permian successions. The section west of the Ny-Ålesund settlement has signatures of lateral and subvertical cap-rock sealings, surrounding a steep and deep-seated major fault and aquifer systems. This section of the peninsula therefore requires closer investigation to evaluate the deep geothermal resource prospect