Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2012
Forfattere
Julia Schregel Alexander Kopatz Snorre Hagen Henrik Brøseth Martin Smith Steinar Wikan Ingvild Wartiainen Paul Eric Aspholm Jouni Aspi Jon Swenson O. Makarova Natalia Polikarpova Michael Schneider Per Knappskog Minna Ruokonen Ilpo Kojola Konstantin F. Tirronen Pjotr I. Danilov Hans Geir EikenSammendrag
Noninvasively collected genetic data can be used to analyse large-scale connectivity patterns among populations of large predators without disturbing them, which may contribute to unravel the species’ roles in natural ecosystems and their requirements for long-term survival. The demographic history of brown bears (Ursus arctos) in Northern Europe indicates several extinction and recolonization events, but little is known about present gene flow between populations of the east and west. We used 12 validated microsatellite markers to analyse 1580 hair and faecal samples collected during six consecutive years (2005–2010) in the Pasvik Valley at 70_N on the border of Norway, Finland and Russia. Our results showed an overall high correlation between the annual estimates of population size (Nc), density (D), effective size (Ne) and Ne ⁄Nc ratio. Furthermore, we observed a genetic heterogeneity of _0.8 and high Ne ⁄Nc ratios of _0.6, which suggests gene flow from the east. Thus, we expanded the population genetic study to include Karelia (Russia, Finland), Va¨sterbotten (Sweden) and Troms (Norway) (477 individuals in total) and detected four distinct genetic clusters with low migration rates among the regions. More specifically, we found that differentiation was relatively low from the Pasvik Valley towards the south and east, whereas, in contrast, moderately high pairwise FST values (0.91–0.12) were detected between the east and the west. Our results indicate ongoing limits to gene flow towards the west, and the existence of barriers to migration between eastern and western brown bear populations in Northern Europe.
Sammendrag
Light-emitting diodes (LEDs), high-pressure sodium lamps (HPSLs) and some cladding materials offer possibilities of influencing arthropod integrated pest management in greenhouse crops where light quality, quantity and photoperiod differ from nature. Light intensity, photoperiod and wavelength distribution affect plant functions and quality which, in turn, can be reflected in the performance of herbivores. The attenuation of UV-light in HPSL spectrum and in the natural winter daylight of northern latitudes may make plants more vulnerable to pests, whereas the high ratio of red to far-red of HPSLs may act to compensate for the effects of attenuated UV-levels. High red to far red ratio has been shown to result in increased production of plant phenolics and physical defences such as leaf toughness, which, in turn, can negatively influence the performance of some herbivore guilds on plants. Specific spectra produced by LEDs can influence plant quality and hence herbivore performance, but direct effects on arthropods can be even more pronounced, such as the inability to visually locat host plants in red and blue lights. Other direct effects of artificial light on pests and beneficial organisms include the detrimental effect of UV-C and UV-B on arthropods, diapause prevention by species-specific wavelengths or photoperiods, attraction to yellow-green and polarized light, reduced visibility of host or prey, and changes in take-off behaviour. Other effects include response to light intensity, interactive effects of light quality and photoperiod on fecundity, and species-specific effects of continuous light on the population growth of arthropods and plant-infesting fungi as well as the rhythmic expression of xenobiotic metabolising genes in arthropods. The potential of using the knowledge of photobiology and visual ecology of organisms for plant protection are discussed using whiteflies and fungal diseases of plants as the model species.
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No abstract has been registered
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Forfattere
Anne-Grete Roer Hjelkrem Audun Korsæth Trond Henriksen Ottar Michelsen Anders Hammer StrømmanSammendrag
No abstract has been registered
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Forfattere
Belachew Asalf Tadesse Arne Stensvand David Gadoury Lance Cadle-Davidson Robert C. Seem N.A. Peres Arne TronsmoSammendrag
No abstract has been registered
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No abstract has been registered
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No abstract has been registered