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.
1996
Authors
Sondre SkatterAbstract
No abstract has been registered
Authors
Bjørn ØklandAbstract
The relationship between the mycetophilid fauna and a set of environmental variables was studied in spruce forests of southeastern Norway. At the stand level, the continuous presence of wood in all decay stages combined with a tree cover appeared to be a major factor for increasing the species richness of mycetophilids. However, the spatial representation of suitable stands in the landscape seems to be particularly important, since the % area of oldgrowth in the surrounding 100 km showed the strongest influence on both species richness and abundance within individual species. The present findings indicate that conservation of a species-rich mycetophilid fauna requires networks of stands within dispersal distances. A reserve network in southern Norway should give special priority to little disturbed forests in the more remote sub-montane areas, since they appear to be very species-rich, and since their strong populations may provide a long-term viability of many mycetophilid species.
Authors
Gro HylenAbstract
No abstract has been registered
Authors
Tonje ØklandAbstract
No abstract has been registered
Authors
Tonje ØklandAbstract
Vegetational and environmental monitoring of boreal spruce forest was initiated in 1988, as a part of the programme “Contrywide Monitoring of Forest Health” at the Norwegian Institute of Land Inventory (NIJOS). As a basis for monitoring, relationships between trees, understory vegetation and environmental conditions (vertical relationships) were analysed for each of ten reference areas. The reference areas were selected to span regional gradients, in climatic conditions and deposition of airborne pollutants, in old-growth, so-called “bilberry-dominated”, “small-fern” and “low-herb”, also paludified, spruce forests south of the Polar Circle. Fifty 1-m2 meso sample plots, randomly chosen within ten 50-m2 macro sample plots in each reference area, were subjected to vegetation analysis, using frequency in subplots as species abundance measure. Environmental (including soil chemical) and tree parameters were recorded for meso as well as macro sample plots. The main vegetational gradients were found by parallel use of DCA and LNMDS ordination methods and subjected to environmental interpretation, mainly by means of non-parametric correlation analyses. DCA and LNMDS in most cases revealed the same main gradients in vegetation, but outliers were more frequent in LNMDS ordinations, due to higher vulnerability of this method to plots with deviating number of species. A complex-gradient in nutrient conditions, with pH and the concentration of nitrogen as the most constantly contributing variables, but with considerable between-area variation with respect to important cations, was evident in nine reference areas. Soil moisture varied along the second vegetational gradient in most areas. In the three most humid reference areas, the Ca concentration was related to variation in soil moisture and gradients from below to between trees, while unrelated or inversely related to the same vegetational gradient as pH. Species abundances were plotted on plot positions in DCA ordinations in order to summarize the species´ responses to environmental variation in each area. Variation in vegetation in the total data set (500 meso sample plots) was partitioned onto two sets of explantory variables (environmental and climatic/geographical) by use of CCA, in order to find the relative importance of environmental and climatic/geographical variation. The fraction of variation exclusively explained by environmental variables was about 17%, while only 5% of the variation was explained exclusively by climatic variables. The variation shared by both sets of variables was about 8%. The main vegetational gradients and environmental/climatic/geographical complex-gradients in the total data set were found by DCA and subsequent interpretation of axes. The main complex-gradients found by separate analyses of data from each reference area, were reflected along the DCA axes in total ordinations, but differences between areas with respect to positions along both environmental and climatic/geographical gradients were also evident. Meso plot occurrences of selected species were plotted in a DCA ordination of the total data set, with variation exclusively due to climatic/geographical variables removed, in order to express regional similarities and differences in the species´ responses to the environment. The different patterns of species´ distributions in the DCA ordination were discussed in the light of their use as indicators of specified environmental conditions.
Abstract
The diversity in different groups of obligate saproxylic beetles was related to ecological variables at three levels of spatial scale in mature spruce-dominated forest. The variables were connected to: decaying woodwood-inhabiting fungilevel of disturbancelandscape ecologyvegetational structure. Several strong relationships were found at medium (1 km2) and large scales (4 km2), while only weak relationships were found at a small scale (0.16 ha; 1ha=104m2). This may be explained by the local variations in habitat parameters and the high mobilities of many beetle species. Factors connected to decaying wood and wood-inhabiting fungi were clearly the most important factors at all scale levels. In particular, the variables diversity of dead tree parts, number of dead trees of large diameter and number of polypore fungi species increased the species richness of many groups and increased the abundance of many species. Eight species were not recorded below a certain density of decaying wood per 1 or 4 km2. Former extensive cutting was a negative factor at large scale, probably because of decreasing recolonization with increasing distance to source habitats. Thinning reduced the diversity of species associated with birch. The development of guidelines favouring the diversity of saproxylic beetles are discussed below
Abstract
No abstract has been registered
1995
Authors
Halvor SolheimAbstract
No abstract has been registered
Authors
Øyvind HoveidAbstract
No abstract has been registered
Authors
Anders LönneborgAbstract
No abstract has been registered