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.
1998
Authors
Albert Tietema Bridget A. Emmett Per Gundersen O. Janne Kjønaas Chris J. KoopmansAbstract
As part of four European ecosystem manipulation experiments in coniferous forests, field-scale 15N tracer experiments have been carried out. The experiments involved a year-long addition of 15NH4 and/or 15NO3- to throughfall at experimental plots with different N inputs. The fate of this applied 15N in the important ecosystems pools (trees, ground vegetation, forest floor and mineral soil), as well as in drainage was measured. About 10-30% of added 15N was taken up by the trees and 10-15% was retained in the mineral soil. Both retention efficiencies were found to be constant with N input. The part of 15N retained in the organic layer was relatively high (20-45% of applied) at low N inputs (0-30 kg N ha-1 yr-1) but low (10-20%) at high N inputs (30-80 kg N ha-1 yr-1). An inverse relationship between N input and the loss of 15N in drainage was found: drainage losses increased as a function of N input. These results suggest that increased N inputs exceed the capacity of the microbial population to retain throughfall-N in the organic layer, with the result that N leaching increases.
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Authors
Reiner H. Giesler Arne Olav Stuanes U.S. Lundström O. Janne Kjønaas Filip MoldanAbstract
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Authors
M.J. Latkowska Harald Kvaalen M. AppelgrenAbstract
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Authors
Fred Midtgaard B.A. Rukke Anne Sverdrup-ThygesonAbstract
Habitat use of Bolitophagus reticulatus (L.) (Coleoptera: Tenebrionidae), living in the basidiocarps of Fomes fomentarius (L.) Kickx, was investigated in three forest areas in south-eastern Norway: a continuous, coniferous forest, an agricultural area with mostly deciduous forest islands in a matrix of cultivated land a homogeneous, old deciduous forest stand. B. reticulatus was almost exclusively found inside dead basidiocarps. The size of the basidiocarp was the most important variable for predicting the probability of B. reticulatus presence in the basidiocarps from all three study areas. Drier basidiocarps had a higher probability of beetle presence than the wetter ones. Basidiocarps situated above the ground level had a higher probability of beetle presence than those close to or on the ground level.In the first study area, the presence of Cisidae was found to reduce the probability of B. reticulatus presence perhaps as a result of competition. The disappearance of beetles from previously inhabited basidiocarps seemed to be due to depletion of resources.
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Authors
Tore VikAbstract
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Authors
Harald Kvaalen Halvor SolheimAbstract
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