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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.

2013

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Abstract

Outbreaks of geometrid defoliators in subarctic birch forest in Fennoscandia often occur at high altitude in a distinct zone along the tree line. At the same time, moth larvae may not have an impact on the forest at lower altitude. Directly adjacent outbreak and nonoutbreak areas offer unique opportunities for studying the underlying mechanisms of outbreaks. Within two altitudinal gradients in coastal northern Norway, we investigated whether altitudinal outbreaks might be caused by release from pupal predation by ground-dwelling invertebrates such as harvestmen (Opiliones), spiders (Araneae), rove beetles (Coleoptera: Staphylinidae), carabid beetles (Coleoptera: Carabidae), and other beetles (Coleoptera). We predicted a consistently higher abundance of such generalist predators at low versus high altitudes. Our results did not support this prediction. There was no consistent altitudinal variation in the abundance of predators that could be related to zonal moth outbreaks in the birch forest slopes. In addition, none of the predator groups investigated showed any numerical response to a distinct outbreak of winter moth that took place during the course of the study. Consequently, localised moth outbreaks at the altitudinal tree line in northern Norway cannot be explained by the release from pupal predation by the predator groups examined here.

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Abstract

The calculation of the embedded energy (EE) of twenty barns shows that there is a considerable variation of EE per cow, where the lowest values were one fourth of the highest. Use of timber instead of concrete in walls had most effect to reduce the amount of EE. Cold barns can contribute to reduce the amount of EE, while the amount of EE is higher in free-stall than in tie-stall barns. While for an existing building the amount of EE is nearly fixed, calculating the anticipated amount for a new building can help to reduce energy use in agriculture and thus contribute to a more sustainable production. Incorporating EE in planning new buildings should be of special importance for organic farming, since regulations demand more area per animal than in conventional farming. In addition to building new, renovation, extension as well as recycling of building materials should be considered. Planning new buildings should also include operational energy, as well as working conditions, animal welfare and economic considerations.