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.
2005
Authors
D. Tønnesen Tor Myking Ingvald Røsberg Nicholas Clarke Brit Lisa Skjelkvåle Øyvind Kaste Thorbjørn LarssenAbstract
Impact assessment for a proposed LNG plant has been carried out for three potential locations in northwest Russia. The impact from the plant is small, and the critical loads for terrestrial ecosystems and aquatic ecosystems will not be exceeded at any of the 3 locations.
Authors
Michel VerheulAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Bjørn ØklandAbstract
Ips typographus is considered the most destructive of the bark beetles in the coniferous forests of the Palaearctic region. At low population densities this species breeds in fresh windfalls or dying trees of Norway spruce. At high densities, in contrast, the beetles may show tree-killing outbreaks at regional scales. Spatio-temporal analyses based on pheromone trap data indicated that large windfall events may be a major instigator and synchronizer of beetle outbreaks in areas subjected to regionalized weather systems. The general dominance of lag 1 density dependence of the time series indicated that the beetle populations are constrained by intraspecific competition for breeding substrates. The time series sequence before the large windfelling of 1987 was however declining without significant density dependence. We suggest this to be a transition period, reflecting a drop in carrying capacity due to depletion of susceptible trees during the preceding outbreak period (1970s) and a drop in beetle number to below the density required to kill trees. A variety of organisms exhibit episodes of explosive population growth, triggered by disturbance events. A new general model is constructed to capture the coupling of disturbance events with resource accumulation / depletion. The model is refined and parameterized using the dynamics of the Ips typographus in Scandinavia as a model system. The waiting times between outbreaks of simulated time series were generally longer and more variable than the outbreak lengths, which agree well with the historical records in the last 250 years. Spectral analysis and logspline density plots of waiting times suggest that the transition from aperiodic to periodic population dynamics should be regarded as a continuum.
Abstract
No abstract has been registered
Authors
Dagang Tang Thorjørn Larssen Min Shao Xiaoshan Zhang Lei Duan Wang Yanhui Shang He Zhao Dawei Renjun Xiang Jinsong Xiao Jiahai Luo Wenche Aas Rolf David Vogt Hans Martin Seip Espen Lydersen Odd Eilertsen Haijing Liu Jixi Gao Tonje Økland Svein Solberg Valter Angell Jan MulderAbstract
No abstract has been registered
Authors
Bernt-Håvard Øyen Per Holm NygaardAbstract
Most countries in Europe have experienced loss of natural forest cover as land has been cleared for farming and other uses. Lack of timber and firewood resources over the last 350 years has been a driving force behind most afforestation work. This paper discusses the history and some major trends and drivers in the afforestation process in Western Norway.
Authors
Alhaji Jeng Roshan M. Bajracharya Subodh Sharma Bishal K. SitaulaAbstract
No abstract has been registered
Authors
Karl Hilding Thunes R.F. Billings Lawrence R. KirkendallAbstract
De pågående masseangrep av Dendroctonus spp. startet mer eller mindre synkront i alle sentralamerikanske land sent i 1998 og tidlig i 1999; epidemien har hittil ødelagt flere hundre tusen hektar furuskog i Mexico, Belize, Guatemala, Honduras og Nicaragua, og i et mindre omfang El Salvador. Til tross for at landene er små, er naboer og har den samme insektfienden er samarbeid over landegrensene omtrent fraværende. Hele skadebildet og omfanget er også en direkte trusselmot det sterkt truete furu-eik økosystemet i regionen. Et felles regime for forvaltning av furuskogene og deres skadegjørere bør bli utviklet for fremtiden, men koordinert aksjon for å stoppe billene blir forhindret av forskjeller i styrke, kapasitetog mandat hos de forvaltende institusjoner i hvert land. Likevel, omfanget og alvoret i den pågående epidemien har resultert i flere bilaterale og regionale initiativer, og lagt grunnen for formelle, langvarige regionale samarbeidsprogrammer i forvaltningen av denne viktige biologiske ressursen.
Abstract
No abstract has been registered