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
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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.
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Svein Ole Borgen Anne Moxnes JervellAbstract
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Svein Ole BorgenAbstract
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Alhaji S. Jeng T. K Haraldsen N. Vagstad A. Grønlund S. TveitnesAbstract
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Tore SkrøppaAbstract
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Celine ReboursAbstract
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