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.
2004
Authors
Arild Andersen Helge Sjursen Trond RafossAbstract
I 1998-2000 ble det biologiske mangfoldet av minerfluer undersøkt i konvensjonelt og økologisk dyrket korn og gras i Sørøst-Norge. Fluene ble fanget med håv i 1x10m store ruter i åkerkanten, 0,5, 5, 15 og 30 m ute i åkeren. Totalt 5822 individer av minst 66 arter ble fanget. Deler av biodiversiteten var høyere i de økologiske feltene. I både konvensjonelle og økologiske felt ble biodiversiteten redusert når en gikk fra åkerkanten og utover i åkeren. In 1998-2000 the species richness and species diversity of Agromyzidae were investigated in conventionally and biologically managed cereal and grass fields in Southeastern Norway.Flies were caught with sweep-net in 1x10 m plots in the boundary, 0.5, 5, 15 and 30 m into the fields. A total of 5822 specimens of at least 66 species were caught. Parts of the biodiversity was shown to be higher in biological fields. In bothconventional and biological fields the biodiversity was reduced when moving from the boundary and into the field.
Authors
Vidar Selås Olav Hogstad Sverre Kobro Trond RafossAbstract
Cyclic outbreaks of forest moth pest species have long remained a puzzle for foresters and ecologists. This paper presents time-series exhibiting a strong negative relationship between sunspot numbers and population indices of autumnal and winter moths, both in a mountain birch forest in central Norway and in a mixed lowland forest in southern Norway. In the latter area, also the population level of a moth species feeding entirely on lichens was negatively related to sunspot numbers. Low sunspot activity leads to a thinner ozone layer and thus higher surface ultraviolet (UV)-B radiation. As winter moth larvae prefer leaves subjected to enhanced UV-B radiation, we suggest that the causal relationship between sunspots and moths is that the metabolic costs of producing UV-B-protective pigments during periods of low sunspot activity reduce trees" and lichens" resistance to herbivores, and thus increase the survival of moth larvae. Higher peak densities of moth cycles in mountain forests could be explained by the general higher UV-B radiation at higher altitudes.
Authors
Svein Ole BorgenAbstract
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Authors
Tore SkrøppaAbstract
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Authors
Tonje Økland Vegar Bakkestuen Rune Halvorsen Økland Odd EilertsenAbstract
Question: Does the understorey vegetation of Norwegian boreal forests change in relation to broad-scale, long-term changes? Location: Norway. Methods: Permanently marked 1-m2 vegetation plots from 17 monitoring reference areas in forests dominated by Picea abies (11 areas, 620 plots) and Betula spp. (six areas, 300 plots) were analysed twice, at the start in 1988-1997 and 5 yr later (1993-2002). Species subplot frequency data were analysed separately for each area by univariate and multivariate statistical methods; 5-yr changes in single species abundances, species number per plot and species composition were tested. Results: Two distinct patterns of change were found: Abundance of several vascular plant species decreased in SE Norwegian Picea forests, most noticeably of species with a preference for richer soils, such as Oxalis acetosella. Abundance of many bryophyte species as well as bryophyte species number per plot increased in forests of both types over most of Norway. Conclusions: The pattern of vascular plant changes is probably a time-delayed response of long-lived, mainly clonal, populations to acidified soils resulting from deposition of long-distance airborne pollutants. The pattern bryophyte changes, with reference to the close link between climatic conditions for growth and abundance changes for Hylocomium splendens established in previous demographic studies, is related to climatic conditions favourable for bryophyte growth. We conclude that many forest understorey plants are sensitive indicators of environmental change, and that the concept used for intensive monitoring of Norwegian forests enables early detection of changes in vegetation brought about by broadscale, regional, impact factors.
Abstract
Head-space sampling (HS) has been combined with enantioselective gas chromatography (GC) for the analysis of chiral and non-chiral monoterpenes present in the cortical tissues of five different Norway spruce clones. (1S)-()--Pinene, (1S,5S)-()sabinene, (1S)-()--pinene, and (4S)-()limonene dominated over (1R)-()--pinene, (1R,5R)-()-sabinene, (1R)-()--pinene, and (4R)-()-limonene.Results showed a large variation in the enantiomeric composition of cortical tissues between different clones. The development of HSGC greatly increased the speed of precise analyses of chiral monoterpenes in small samples and therefore offer excellent opportunities in studies on the ecophysiological and chemotaxomic roles of these chiral components
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Authors
Stig Lande Morten Eikenes Mats WestinAbstract
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