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
Authors
Oddmund Kleven Björn M. Hallström Frank Hailer Axel Janke Snorre Hagen Alexander Kopatz Hans Geir EikenAbstract
No abstract has been registered
Authors
Paul Eric AspholmAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Paul Eric AspholmAbstract
No abstract has been registered
Authors
I.N Bolotov Yu. V. Bespalaya A.A Makhrov Paul Eric Aspholm A.S Aksenov M. Yu Gofarov G.A. Dvoryankin O.V. Usacheva I.V. Vikhrev S.E. Sokolova A.A. Pashinin A. DavydovAbstract
No abstract has been registered
Authors
Rune Andreassen Julia Schregel Alexander Kopatz Camilla Tobiassen Per Knappskog Snorre Hagen Oddmund Kleven Michael Schneider Ilpo Kojola Jouni Aspi Alexander M. Rykov Konstantin F. Tirronen Pjotr I. Danilov Hans Geir EikenAbstract
No abstract has been registered
Authors
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 EikenAbstract
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.
2011
Authors
Ole Petter Laksforsmo Vindstad Snorre Hagen Jane Uhd Jepsen Lauri Teemu Kapari Tino Schott Rolf Anker ImsAbstract
Population cycles of the winter moth (Operophtera brumata) in sub-arctic coastal birch forests show high spatiotemporal variation in amplitude. Peak larval densities range from levels causing little foliage damage to outbreaks causing spatially extensive defoliation. Moreover, outbreaks typically occur at or near the altitudinal treeline. It has been hypothesized that spatiotemporal variation in O. brumata cycle amplitude results from climate-induced variation in the degree of phenological matching between trophic levels, possibly between moth larvae and parasitoids. The likelihood of mismatching phenologies between larvae and parasitoids is expected to depend on how specialized parasitoids are, both as individual species and as a guild, to attacking specific larval developmental stages (i.e. instars). To investigate the larval instar-specificity of parasitoids, we studied the timing of parasitoid attacks relative to larval phenology. We employed an observational study design, with sequential sampling over the larval period, along an altitudinal gradient harbouring a pronounced treeline outbreak of O. brumata. Within the larval parasitoid guild, containing seven species groups, the timing of attack by different groups followed a successional sequence throughout the moth’s larval period and each group attacked 1–2 instars. Such phenological diversity within parasitoid guilds may lower the likelihood of climate-induced trophic mismatches between victim populations and many/all of their enemies. Parasitism rates declined with increasing altitude for most parasitoid groups and for the parasitoid guild as a whole. However, the observed spatiotemporal parasitism patterns provided no clear evidence for or against altitudinal mismatch between larval and parasitoid phenology.
Authors
Alexander Kopatz Hans Geir Eiken Paul Eric Aspholm Camilla Tobiassen Beate Banken Bakke Julia Schregel Tuomo Ollila Olga Makarova Natalia Polikarpova Vladimir Chizhov Snorre HagenAbstract
No abstract has been registered