Viser treff 254-273 av 362

    • Plant-Soil Feedback: Alpine Grassland Plants in Home and Away soil 

      Priyadarshi, Ribha (Master thesis; Mastergradsoppgave, 2021-12-16)
      For the grassland, plant soil feedback (PSF) has been the focus of much recent research to understand plant species dynamics. Experimental methods are very important in the plant soil feedback (PSF) analysis, and it has been observed that various PSF experimental approaches yield in different feedback values. More field type experiments are required to understand the role of PSFs in plant communities ...
    • Plastic occurrence in six different species of Arctic seabirds - Harmonizing methods and closing knowledge gaps on plastic occurrence and polymer identity 

      Benjaminsen, Stine Charlotte (Master thesis; Mastergradsoppgave, 2021-05-18)
      The once pristine Arctic is now facing negative alterations with a rapidly changing climate, increasing human activity, and plastic pollution. Seabirds are intrinsic to the marine ecosystems, and in recent years, plastic ingestion by seabirds has been of increasing concern because of the potential negative impact on individual and population levels. The aim of this study was to investigate the plastic ...
    • Populasjonsstruktur og morfologi hos kongsnegl Buccinum undatum L. på to lokaliteter i Balsfjorden, Nord-Norge 

      Juliussen, Helene Ovedie (Master thesis; Mastergradsoppgave, 2007-11-16)
      To lokaliteter i Balsfjorden, Nord-Norge ble sammenlignet med hensyn på fangstmengde, populasjonsstruktur og morfologi til kongsnegl (Buccinum undatum). Til innsamling ble det benyttet walisiske snegleteiner som var egnet med fisk/sild og haneskjell i kombinasjon eller kun fisk/sild. Fangst foregikk månedlig fra mars til og med juni 2004, på 15, 30 og 45 m dyp. Fangsttiden var på 1 døgn. Antall og ...
    • Populasjonsstruktur, kjønnsmodning og variasjon i fekunditet hos kongekrabbe (Paralithodes camtschaticus) i Porsangerfjorden, Finnmark : et litteratur- og feltbasert studium 

      Lindberg, Ken Ståle J. (Master thesis; Mastergradsoppgave, 2012-11-22)
      Russiske forskere introduserte kongekrabben, Paralithodes camtschaticus, til Barentshavet på 1960 og 1970-tallet for å gi lokale fiskere en ny art å høste av. Det var antatt at spredning til norske farvann var lite sannsynlig. Artens etablering ble en suksess sett fra russisk side. Kongekrabben har nå spredt seg over hele kysten av Finnmark fylke, og Porsangerfjorden er den siste av fjordene ...
    • Population dynamics, diet and trophic positioning of three small demersal fish species within Porsangerfjord, Norway 

      Källgren, Emma Katarina (Master thesis; Mastergradsoppgave, 2012-11-15)
      In today’s society, one often stumbles over the quote “you are what you eat”. Diet is closely related to fish size and physical conditions, so in order to understand the food web one must first understand the population dynamics of the fish. Three demersal species in the northern hemisphere are; Artediellus atlanticus, Myoxocephalus scorpius and Leptagonus decagonus. The study was undertaken in ...
    • Potential effects of two stressors on morphological traits of Northern Goshawk (Accipiter gentilis) nestlings 

      Schnug, Lisbeth (Master thesis; Mastergradsoppgave, 2009-01)
      Anthropogenic and natural stressors can affect ecosystems negatively and it is therefore important to have a clear understanding of the responses of organisms to stressors. The Northern Goshawk (Accipiter gentilis) is a common raptor species of the boreal forest ecosystem and its location at the top of its food chain makes it a special target for two important stressors; endoparasitism and environmental ...
    • Predation on artificial ground nests in a subarctic ecosystem 

      Klausen, Kristin Brekke (Master thesis; Mastergradsoppgave, 2008-05-15)
      Studies of gallinaceous bird species stress the importance of high nest losses as a factor influencing life histories and populations. Accordingly knowledge of the mechanisms affecting nest losses is essential for understanding the population dynamics. The aim of this one year study was to estimate predation rates on artificial ground nests in ptarmigan habitats, along a landscape gradient which ...
    • Predator aversion in resident generalist birds. A ghost of evolutionary past? 

      Hotvedt, Ådne (Master thesis; Mastergradsoppgave, 2018-05-14)
      Predator aversion is an important adaptation that can significantly lower the mortality rate among prey animals, but avoiding a predator requires knowing and recognizing them. The predator aversion of Common gulls and Mallard ducks at Prestvannet Lake, Tromsø, Northern Norway was tested in an experiment by placing differing objects resembling snakes next to bread during the summer and autumn of 2017. ...
    • Predictive state-space modelling of lemming population outbreaks on the Fennoscandian tundra: Are determinants of spatial variation in outbreak amplitude temporally consistent? 

      Kleiven, Eivind Flittie (Master thesis; Mastergradsoppgave, 2015-11-13)
      Lemmings are famous for their spectacular population cycles that causes waves of biomass through the arctic tundra. Both climate variability and the interaction with the sympatric grey-sided vole have been shown to effect lemming outbreaks. However little is known about the transferability of these effects between peaks. I analyzed the spatial variability using snap-trapping data from two ...
    • Prey selection of the Red King Crab (Paralithodes camtschaticus) preying on lumpfish eggs (Cyclopterus lumpus), sea urchins (Strongylocentrotus droebachiensis) and scallops (Chlamys islandica) 

      Michelsen, Helena Kling (Master thesis; Mastergradsoppgave, 2011-05-16)
      The red king crab, Paralithodes camtchaticus, is a new generalist predator in the Barents Sea and may have negative effects upon the commercially fished lumpfish eggs (Cyclopterus lumpus), sea urchins (Strongylocentrotus droebachiensis) and scallops (Chlamys islandica). Generalist predators consume an array of prey types, but have been shown to select certain prey over others. To obtain knowledge ...
    • Progression in humpback whale song structure and complexity on a subarctic feeding ground in Northern Norway 

      Martin, Saskia C. (Master thesis; Mastergradsoppgave, 2021-08-16)
      Male humpback whales (Megaptera novaeangliae) sing structurally complex songs traditionally associated with low latitude breeding grounds. This vocal behaviour is increasingly reported outside these areas. All singers in a given population sing the same version of a song that is constantly evolving with modifications on different levels within the song structure. This study provides the first detailed ...
    • Pseudocalanus in Svalbard waters : identification and distribution patterns of two sibling copepod species 

      Gudmundsdottir, Ragnhildur (Master thesis; Mastergradsoppgave, 2008-11-05)
      Marine copepods of the genus Pseudocalanus (Calanoida) are common in Svalbard waters as well as throughout the northern hemisphere. They contribute considerably to plankton biomass in addition to Calanus spp. and play an important role in the marine food web as a link between planktivores, such as fish larvae, and microalgae. Pseudocalanus consists of several sibling species, and two of them, ...
    • The quick and the slow: Competitive ability of two silica-rich grasses influenced by large and small herbivores 

      Lægreid, Eiliv Jenssen (Master thesis; Mastergradsoppgave, 2013-05)
      Silicate-rich grasses often dominate in heavily grazed areas, presumably because high amounts of silica deter herbivores. Activity of large herbivores and small rodent herbivores increase competitive ability of silicate-rich grasses, possibly through apparent competition. Both types of herbivores often co-exist in grassland ecosystems. Their potential additive effect on competitive ability of ...
    • Rapid microbial responses to temperature changes in Arctic anoxic peat soil 

      Bjørdal, Yngvild (Master thesis; Mastergradsoppgave, 2021-05-18)
      Arctic peatlands act as important sources and sinks of carbon. Microbial decomposition takes place in these soils, producing the greenhouse gasses carbon dioxide and methane as end-products. A variety of aerobic and anaerobic microbial pathways are involved in the decomposition of organic material in peat soil. In anoxic soil layers, methane and carbon dioxide is often produced through syntropic ...
    • Recolonization and succession of a subtidal hard-bottom epibenthic community in Smeerenburgfjorden, NW Svalbard. 

      Keck, Amalia (Master thesis; Mastergradsoppgave, 2018-05-15)
      Rapid changes to the physical environment of Arctic marine systems in recent years impact the structure and function of benthic ecosystems. Exploring the resilience of these systems to perturbations requires a solid understanding of key ecological processes and must be conducted over appropriate time scales due to the slow growth and recruitment of many Arctic benthic organisms. This study addresses ...
    • Recovery potential of Arctic wetland tundra on Svalbard. Long-term impacts of grazing by barnacle geese (Branta leucopsis) within the context of climate change 

      Paquin, Karolina (Master thesis; Mastergradsoppgave, 2014-05-19)
      The substantial increase of the migratory Svalbard population of Barnacle geese Branta leucopsis during the past 50 years has been attributed to a warming climate, changes in agricultural land use, and conservation measures. The geese are likely to continue to forage and reproduce in Arctic wetlands in increasing numbers. This project revisited the experimental plots from an earlier experiment ...
    • Recreational fisheries target declining populations of brown trout (Salmo trutta L.) in Northern Norway as revealed by a genome wide array of SNP markers 

      Schmidt, Simon Nordblad (Master thesis; Mastergradsoppgave, 2019-11-15)
      Marine recreational and commercial exploitation of salmonids often target a mixed stock consisting of genetically distinct and independent populations with varying abundances, life histories, standing genetic variation, and conservation status. In this study we use SNP markers to investigate the genetic population structure of juvenile brown trout (Salmo trutta L.) from five distinct watercourses ...
    • Reindeer diseases associated with supplementary feeding in Norway and Sweden - A questionnaire-based survey 

      Josteinsdottir, Alfa Bachmann (Master thesis; Mastergradsoppgave, 2021-11-15)
      Climatic and anthropogenic factors are increasingly affecting reindeer husbandry in Norway and Sweden. The potential health risks associated with a warming climate, and the necessity to avoid starvation by providing supplementary feed to semi-domesticated reindeer, need to be explored and identified. A questionnaire-based survey among reindeer herders was conducted, containing questions about the ...
    • Reindeer grazing history effects on plant recruitment and life history traits from the germinable seed bank 

      Tevendale, Victoria González (Master thesis; Mastergradsoppgave, 2006-03-27)
      Seed banks represent a source from which new vegetation may quickly arise if the existing stand is disturbed. It is increasingly discussed that reindeer grazing modifies the seed banks in northern ecosystems. However no large-scale studies have been carried out to support this hypothesis. Because reindeer could constitute a selective pressure on vegetation recruitment, the present study investigated ...
    • Relation between habitat characteristics and abundance, diet and condition of 0-group cod in two northern Norwegian fjords 

      Heggland, Kristin Nymark (Master thesis; Mastergradsoppgave, 2013-05)
      There is a correlation between the vegetation coverage and the abundance of 0-group cod. The highest abundance was found between 50 – 70 %, which is consistent with previous studied and imply that there is a nonlinear relationship between vegetation coverage and abundance of 0-group cod. There was found a difference in diet between the three habitats, with the intertidal zones of Balsfjord and ...