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norskBlar i tittel Doktorgradsavhandlinger (BFE-fak)
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Challenges for ice-associated top trophic Arctic animals in a changing climate
(Doctoral thesis; Doktorgradsavhandling, 2017-02-17)The Arctic is currently in a rapid state of change, with temperature increases in this region being three times the rate of the global average and sea-ice extent declining rapidly. In 2006, a sudden shift in the sea-ice regime in Svalbard, Norway, occurred with the altered sea-ice conditions persisting to the present day. In order to study the impacts of the environmental changes occurring in the ... -
The challenges of understanding the biogeography of commercially important crustacean species of the Southwestern Indian Ocean — Separating what we know from what we think we know.
(Doctoral thesis; Doktorgradsavhandling, 2020-05-25)Demersal trawl fisheries play an important role in providing income and protein to the people of the Southwestern Indian Ocean (SWIO). These fisheries are very destructive to the habitats in which they operate and have an impact on the associated biodiversity. Three crustacean species, knife prawn (<i>Haliporoides triarthrus</i>), African langoustine (<i>Metanephrops mozambicus</i>) and pink geryon ... -
Changing Business models for Sustainability: Role of drivers and dynamic capabilities in Arctic nature tourism
(Doctoral thesis; Doktorgradsavhandling, 2023-01-31)<p>This thesis investigates nature tourism companies, which strive to incorporate sustainability into their business models and change them to be more resilient. For this purpose, it adopts a dynamic perspective on business models by which companies address corporate sustainability which is understood here as a balance among environmental, social, and economic pillars as well as a sustainable ... -
Characterization of a Cytokinin Response Factor in Arabidopsis thaliana
(Doctoral thesis; Doktorgradsavhandling, 2012-05-15)Acclimation responses to environmental growth conditions in plants involve complex and fine-tuned signalling networks. Environmental signals, biotic and abiotic, are received and mediated, and lead eventually to transcriptional regulation. The plant hormones are vastly involved in these processes as intercellular mediators whereas the reception of such a hormone at the site of action involves ... -
Chondrichthyan fishes in the Arctic Ocean and adjacent seas - do we know our species?
(Doctoral thesis; Doktorgradsavhandling, 2014-10-31)The basal prerequisite for managing species and understanding ecosystems is correct species and population identification. Without knowing the species, we cannot with accuracy detect changes in distribution or abundance due to climate change, fisheries, diseases or any other types of impact. This thesis gives the first complete overview of chondrichthyan fishes (sharks, skates, rays and chimaeras), ... -
Circadian-based processes in the High Arctic: activity, thermoregulation and photoperiodism in the Svalbard ptarmigan (Lagopus muta hyperborea)
(Doctoral thesis; Doktorgradsavhandling, 2021-04-15)<p>This thesis addresses aspects of the circadian and photoperiodic system in a High Arctic bird: the Svalbard ptarmigan (<i>Lagopus muta hyperborea</i>, Sundevall 1845). The most northern resident bird inhabits a unique photic environment; 2/3 of its year it spends either under a night without sunrise (polar night) or under a never setting Sun (polar day). Studies so far suggest a temporal loss of ... -
Climate change impact on high latitude freshwater fish populations
(Doctoral thesis; Doktorgradsavhandling, 2021-11-12)<p>Climate change is one of the greatest threats to animal wildlife in high latitude freshwater ecosystems. Climate warming is rapidly increasing water temperatures in these areas, affecting biological processes of ectotherms such as growth, maturation and reproduction, which in turn trigger population responses. The magnitude of the effects of climate warming will vary depending on the thermal niche ... -
Climate warming impact on the deep demersal fish community East of Greenland
(Doctoral thesis; Doktorgradsavhandling, 2022-04-06)This thesis presents a study of the impact of climate warming on deep demersal fish communities East of Greenland, in a transition zone between Atlantic and Arctic waters. Climate change was expected to affect fish community composition and functional characterization via poleward distributional shifts and changes in abundance. To assess the climate driven effects on fish communities, I used long ... -
Coastal Communities and Employment Systems: Networks and communities in change
(Doctoral thesis; Doktorgradsavhandling, 2013-11-29)Gitt at norske fiskerier har gjennomgått store endringer side 1970-tallet, med utgangspunkt i Jentoft and Wadel (1984), utforsker dette arbeidet det moderne sysselsettingssystemet på kysten, hvordan det har endret seg og hva effekten har vært på kystsamfunn. Studien viser at relasjonene mellom fiskeriene og kystsamfunnene har endret seg. På 1970-talet var sysselsettingssystemet preget av et helhetlig ... -
Conceptualizing fishery systems: A mental models approach
(Doctoral thesis; Doktorgradsavhandling, 2022-04-22)Thinking of fisheries as a system is a relatively new approach in fisheries science and management. As part of my contribution to this perspective, this thesis uses mental models as a new approach to gain insights into how individuals conceptualize fisheries. Mental models are internal representations of the surrounding world (e.g., phenomena, processes, problems) and they are important because these ... -
Consideration set size and choice in fish consumption : the influence of attitude, knowledge, convenience, and category presentation
(Doctoral thesis; Doktorgradsavhandling, 2010-06-11)<i>Purpose</i> – Three main objectives are defined in this thesis: 1) To determine the extent to which the nature of a consideration set affects consumer choice; 2) To investigate how consumer attitudes, knowledge, and convenience motivations affect the formation of a consideration set; and 3) To investigate how category presentation moderates the relationship between convenience motivations and ... -
Consumers’ Value Perceptions of Seafood
(Doctoral thesis; Doktorgradsavhandling, 2022-04-08)Consumers’ perception of seafood products plays a critical role in determining their consumption behaviour. As a great quantity of seafood is produced by aquaculture, specifically farmed fish, consumers’ perception of farmed fish is crucial. In recent years, consumers in developing and emerging countries have increased their concern about seafood safety. This thesis investigates consumers’ ... -
A contribution to the economics of multispecies harvesting with special attention to the Barents Sea fisheries
(Doctoral thesis; Doktorgradsavhandling, 1990)This is a thesis on the utilization of renewable resources with species interactions, within the field of natural resource economics. It comprises theoretical analysis as well as empirical application of the theory to the fisheries of the Barents Sea and adjacent areas. -
Converting sub-Arctic birch forests to spruce plantations : responses of predators and prey
(Doctoral thesis; Doktorgradsavhandling, 2010-04-20)In northern Norway large areas of sub-Arctic coastal birch forests have gradually been replaced by non-native spruce plantations during the last century. Spruce planting changes the forest floor vegetation and soil conditions, increase the amount of artificial edges and alter the forest landscape mosaics. Such tree species conversions are likely to reduce or increase suitable wildlife habitat, alter ... -
Cyclically outbreaking geometrid moths in sub-arctic mountain birch forest: the organization and impacts of their interactions with animal communities
(Doctoral thesis; Doktorgradsavhandling, 2015-01-09)In sub-arctic mountain birch forest in northern Fennoscandia, the 2 geometrid moth species Epirrita autumnata (autumnal moth) and Operophtera brumata (winter moth) show high-amplitude population cycles with regular 10-year periodicity. During some population peaks, moth populations attain outbreak densities and cause region-wide defoliation and mortality of mountain birch. The severity and duration ... -
Decadal changes in distribution, abundance and feeding ecology of baleen whales in Icelandic and adjacent waters. A consequence of climate change?
(Doctoral thesis; Doktorgradsavhandling, 2016-01-15)Five species of baleen whales are regularly encountered at their feeding grounds in Icelandic waters during summer. Systematic monitoring of distribution and abundance of cetaceans in Icelandic and adjacent waters was initiated in 1987 as a part of the North Atlantic Sightings Surveys (NASS). In this thesis, the objecive is to summarize the results of these surveys in relation to changes in the ... -
Dendroclimatology on Scots pine (Pinus sylvestris L.) in northern Norway
(Doctoral thesis; Doktorgradsavhandling, 2000-03-17)A total of ten tree-ring chronologies of Scots pine, Pinus sylvestris L., was constructed between the Vesterålen archipelago and the Finnmarksvidda in order to investigate the regional variability of radial growth and climate response of pine. The longest tree-ring chronology, located in Forfjorddalen in Vesterålen, was highly significant back to AD 1354. The study area was divided into three ... -
Determinants and effects of moth population dynamics in altitudinal gradients in northern Fennoscandia
(Doctoral thesis; Doktorgradsavhandling, 2013-05-21)The aim of this PhD-project has been to increase our knowledge of trophic interactions along altitudinal gradients in a system of sympatric, cyclically outbreaking geometrid moth species in sub-arctic, coastal birch forest in northern Norway. The project resulted in four scientific publications; two sub-studies focused on the causal effect of natural enemies on the observed complex spatio-temporal ... -
Diversity along a speciation continuum : ecology and morphology of northern European whitefish (Coregonus lavaretus)
(Doctoral thesis; Doktorgradsavhandling, 2012-08-24)How new species are formed is still a major question in evolutionary biology. In ecological speciation, natural selection drives the evolution of slight distinctions between individuals into extensive differences between species. In this thesis, early stages of an ecologically driven speciation process are addressed using ecological and morphological data from a large number of European whitefish ... -
Diversity of marine wood-inhabiting fungi in North Norway
(Doctoral thesis; Doktorgradsavhandling, 2014-05-27)Marine fungi in arctic waters have rarely been studied. The main aim of this thesis was to explore the diversity of driftwood inhabiting fungal communities in the cold waters of North Norway. In order to gain as comprehensive view as possible, different methodological approaches were applied on the same study substrates, and the recovered fungal communities were analysed for taxonomic, phylogenetic ...
