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.
2013
Abstract
No abstract has been registered
Authors
Ole Petter Laksforsmo Vindstad Tino Schott Snorre Hagen Jane Uhd Jepsen Lauri Teemu Kapari Rolf Anker ImsAbstract
Two related issues in studies of biological invasions are how quickly the enemy complexes of invasive species become as species-rich and efficient as those of native species and how important enemy release is for the establishment and spread of invaders. We addressed these issues for the geometrid moths Operophtera brumata and Agriopis aurantiaria, who invaded the coastal mountain birch forest of northern Norway by range expansion approximately a century and 15 years ago, respectively. This was done by comparing larval parasitoid species richness and prevalence among the invaders and the native geometrid Epirrita autumnata. We found that E. autumnata and O. brumata both hosted seven parasitoid species groups, whereas A. aurantiaria hosted only one. Several parasitoid groups were shared between two or more of the geometrids. Total larval parasitism rates were similar in all three geometrid species, and comparison with published studies on larval parasitism in Western Europe suggested that O. brumata and A. aurantiaria do not suffer lower parasitism rates in our study region than in their native ranges. Our results indicate that accumulation of larval parasitoids on invasive geometrids in coastal mountain birch forest may reach completion within a few decades to at least a century after the invasion, and that establishment and spread of such invaders is unlikely to be facilitated by release from larval parasitism. Our investigations also uncovered a high degree of spatiotemporal synchrony between the total larval parasitism rates of O. brumata and A. aurantiaria, suggesting that larval parasitism of different geometrid species in the study system is governed by some common external factor
Authors
Tino Schott Lauri Teemu Kapari Snorre Hagen Ole Petter Laksforsmo Vindstad Jane Uhd Jepsen Rolf Anker ImsAbstract
Outbreaks of geometrid defoliators in subarctic birch forest in Fennoscandia often occur at high altitude in a distinct zone along the tree line. At the same time, moth larvae may not have an impact on the forest at lower altitude. Directly adjacent outbreak and nonoutbreak areas offer unique opportunities for studying the underlying mechanisms of outbreaks. Within two altitudinal gradients in coastal northern Norway, we investigated whether altitudinal outbreaks might be caused by release from pupal predation by ground-dwelling invertebrates such as harvestmen (Opiliones), spiders (Araneae), rove beetles (Coleoptera: Staphylinidae), carabid beetles (Coleoptera: Carabidae), and other beetles (Coleoptera). We predicted a consistently higher abundance of such generalist predators at low versus high altitudes. Our results did not support this prediction. There was no consistent altitudinal variation in the abundance of predators that could be related to zonal moth outbreaks in the birch forest slopes. In addition, none of the predator groups investigated showed any numerical response to a distinct outbreak of winter moth that took place during the course of the study. Consequently, localised moth outbreaks at the altitudinal tree line in northern Norway cannot be explained by the release from pupal predation by the predator groups examined here.
Authors
I.N Bolotov A.A Makhrov Yu. V. Bespalaya I.V. Vikhrev O.V. Aksenova Paul Eric Aspholm M. Yu Gofarov A.N: Ostrovskii I. Yu. Popov I. S. Pal'tser M. Rudzite M. Rudzitis I. S. Voroshilova S.E. SokolovaAbstract
No abstract has been registered
Authors
Panu Oulasvirta Paul Eric Aspholm Marko Kangas Bjørn Mejdell Larsen Pirko-Lisa Luhta P. Olofsson J. TaskinenAbstract
No abstract has been registered
Abstract
No abstract has been registered
2012
Authors
Alexander Kopatz Hans Geir Eiken Snorre Hagen Minna Ruokonen Rodrigo Esparza-Salas Julia Schregel Ilpo Kojala Martin Smith Ingvild Wartiainen Paul Eric Aspholm Steinar Wikan Alexander M. Rykov Olga Makarova Natalia Polikarpova Konstantin F. Tirronen Pjotr I. Danilov Jouni AspiAbstract
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.
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
Oddmund Kleven Björn M. Hallström Frank Hailer Axel Janke Snorre Hagen Alexander Kopatz Hans Geir EikenAbstract
No abstract has been registered