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
Christer MagnussonAbstract
No abstract has been registered
Authors
Arne Sæbø Robert Popek Barbara Nawrot Hans Martin Hanslin Helena Gawronska Stanislaw W GawronskiAbstract
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Authors
Gisela Lüscher Michaela Arndorfer Katalin Balázs K.G. Bernhardt M. Bogers R.G.H. Bunce J.-P. Choisis Peter Dennis Wenche E. Dramstad Sebastian Eiter Gunnar Engan Wendy Fjellstad T. Frank Jürgen Friedel Ilse Geijzendorffer P. Gillingham Felix Herzog K.-J. Hülsbergen Philippe Jeanneret G. Jerkovich Rob Jongman Maximilian Kainz M.L. Oschatz Susanne Papaja-Hülsbergen Philippe Pointereau Jean-Pierre Sarthou M.K. Schneider Norman Siebrecht Sebastian WolfrumAbstract
No abstract has been registered
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Andreas TreuAbstract
No abstract has been registered
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John Marshall Bryden Mildred E. WarnerAbstract
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Authors
Kyrre Linné Kausrud Bjørn Økland Olav Skarpaas Jean-Claude Grégoire Nadir Erbilgin Nils Christian StensethAbstract
In recent decades we have seen rapid and co-occurring changes in landscape structure, species distributions and even climate as consequences of human activity. Such changes affect the dynamics of the interaction between major forest pest species, such as bark beetles (Coleoptera: Curculionidae, Scolytinae), and their host trees. Normally breeding mostly in broken or severely stressed spruce; at high population densities some bark beetle species can colonise and kill healthy trees on scales ranging from single trees in a stand to multi-annual landscape-wide outbreaks. In Eurasia, the largest outbreaks are caused by the spruce bark beetle, Ips typographus (Linnaeus), which is common and shares a wide distribution with its main host, Norway spruce (Picea abies Karst.). A large literature is now available, from which this review aims to synthesize research relevant for the population dynamics of I. typographus and co-occurring species under changing conditions. We find that spruce bark beetle population dynamics tend to be metastable, but that mixed-species and age-heterogeneous forests with good site-matching tend to be less susceptible to large-scale outbreaks. While large accumulations of logs should be removed and/or debarked before the next swarming period, intensive removal of all coarse dead wood may be counterproductive, as it reduces the diversity of predators that in some areas may play a role in keeping I. typographus populations below the outbreak threshold, and sanitary logging frequently causes edge effects and root damage, reducing the resistance of remaining trees. It is very hard to predict the outcome of interspecific interactions due to invading beetle species or I. typographus establishing outside its current range, as they can be of varying sign and strength and may fluctuate depending on environmental factors and population phase. Most research indicates that beetle outbreaks will increase in frequency and magnitude as temperature, wind speed and precipitation variability increases, and that mitigating forestry practices should be adopted as soon as possible considering the time lags involved.
Abstract
No abstract has been registered
Authors
Jørn Henrik Sønstebø Mari Mette TollefsrudAbstract
Background: The conifer tree Abies lasiocarpa, is native to North America with a distribution range from Alaska in the north to Arizona and New Mexico in the south. The southern populations partly belong to the variety A. lasiocarpa var. arizonica, which has a distinct morphology. A. lasiocarpa is an important species for Christmas tree production in Norway and there is an increasing demand for seeds from proveniences known to produce high quality Christmas trees. Currently, seeds are imported from natural stands in the US and Canada or collected from plantations in Norway with unknown origin, but which are known to produce high quality trees. To increase the harvest potential of seeds in A. lasiocarpa both in natural stands and in seed production stands in Norway, it is important to know the population genetic structure in North America and identify the origin of the current seed producing trees in Norway. Population genetic structures will be used to identify new potential seed collection areas in North America.Main objectives: Investigate population genetic structure across the distribution range of A. lasiocarpa. Characterize genetic diversity in north American provenances and seed bearing stands in Norway. Assign Norwegian provenances to north American provenances in order to identify their origin and new potential seed collection zones.
Abstract
The ascomycete fungus Hymenoscyphus pseudoalbidus (anamorph Chalara fraxinea) is responsible for ash dieback currently expanding over large parts of Europe. Our objective was to investigate the genetic structure of H. pseudoalbidus and to examine its relationship to the species H. albidus, known as a saprotroph. The study comprised 181 isolates of H. pseudoalbidus collected within the diseased area, 17 H. albidus isolates from six apothecia, collected outside the diseased area in Norway, and nine apothecia of H. pseudoalbidus collected in Sweden. By analysis of microsatellite markers developed for this study, combined with AP-PCR using the M13 primer, we demonstrated sexual heterothally in H. pseudoalbidus, detected high gene flow and low geographic structure of the H. pseudoalbidus population and found indications of a founder effect. Also, substantial genetic differences were detected between the two species of fungi; only four of seven microsatellite markers developed for H. pseudoalbidus were amplified for H. albidus, and no alleles were shared among the species. Furthermore, AP-PCR banding patterns were distinctly different for the two species. We conclude that even though the two fungi have a similar habitat and are morphologically virtually identical, they do not share a recent common ancestor.