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
Abstract
1. Whether plant competition grows stronger or weaker across a soil fertility gradient is an area of great debate in plant ecology. We examined the effects of competition and soil fertility and their interaction on growth rates of the four dominant tree species in the sub-boreal spruce forest of British Columbia. 2. We tested separate soil nutrient and moisture indices and found much stronger support for models that included the nutrient index as a measure of soil fertility. 3. Competition, soil fertility and their interaction affected radial growth rates for all species. 4. Each species supported a different alternate hypothesis for how competitive interactions changed with soil fertility and whether competition intensity was stronger or weaker overall as soil fertility increased depended on the context, specifically, species, neighbourhood composition and type of competition (shading vs. crowding). 5. The four species varied slightly in their growth response to soil fertility. 6. Individual species had some large variations in the shapes of their negative relationships between shading, crowding and tree growth, with one species experiencing no net negative effects of crowding at low soil fertility. 7. Goodness-of-fit was not substantially increased by models including competition–soil fertility interactions for any species. Tree size, soil fertility, shading and crowding predicted most of the variation in tree growth rates in the sub-boreal spruce forest. 8. Synthesis. The intensity of competition among trees across a fertility gradient was species- and context-specific and more complicated than that predicted by any one of the dominant existing theories in plant ecology.
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Authors
Fuad Gasi Silvio Simon Naris Pojskic Mirsad Kurtovic Ivan Pejic Mekjell Meland Clive KaiserAbstract
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Bark beetles cause widespread damages in the coniferous-dominated forests of central Europe and North America. In the future, areas affected by bark beetles may further increase due to climate change. However, the early detection of the bark beetle green attack can guide management decisions to prevent larger damages. For this reason, a field-based bark beetle monitoring program is currently implemented in Germany. The combination of remote sensing and field data may help minimizing the reaction time and reducing costs of monitoring programs covering large forested areas. In this case study, RapidEye and TerraSAR-X data were analyzed separately and in combination to detect bark beetle green attack. The remote sensing data were acquired in May 2009 for a study site in south-west Germany. In order to distinguish healthy areas and areas affected by bark beetle green attack, three statistical approaches were compared: generalized linear models (GLM), maximum entropy (ME) and random forest (RF). The spatial scale (minimum mapping unit) was 78.5 m2. TerraSAR-X data resulted in fair classification accuracy with a cross-validated Cohen’s Kappa Coefficient (kappa) of 0.23. RapidEye data resulted in moderate classification accuracy with a kappa of 0.51. The highest classification accuracy was obtained by combining the TerraSAR-X and RapidEye data, resulting in a kappa of 0.74. The accuracy of ME models was considerably higher than the accuracy of GLM and RF models.
Authors
Randi Seljåsen Kjell gjermund Vogt Elisabeth Olsen Per Lea Lars Arne Høgetveit Torgeir Taje Richard Meadow Gunnar BengtssonAbstract
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Authors
Simon Ballance Stefan Sahlstrøm Per Lea Nina Elisabeth Nagy Petter V. Andersen Tzvetelin Dessev Sarah Hull Maria Vardakou Richard FaulksAbstract
This is a post-peer-review, pre-copyedit version of an article published in [European Journal of Nutrition]. The final authenticated version is available online at: https://doi.org/10.1007/s00394-012-0386-5
Authors
Lampros LamprinakisAbstract
Valio, a well-established "national institution" in Finland, had a rich background based on cooperative tradition and extensive regional spread. In the late 1980s and early 1990s, the company had to undergo a process of change and re-organization in order to address the challenges arising from the EU accession. After years of restructuring and changing in its business model, Valio remains a major player in Finland and one of the most well-known brands in the region. The purpose of this case study is to stimulate a critical evaluation of the processes Valio undertook in order to address the coming challenges. The case is especially suited as a starting point for a broader discussion on organizational change and adaptation. Teaching notes are provided with proposals and questions.