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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.

2017

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Abstract

Methods: In 2009, we resurveyed three plant sociological studies up to 85 years after the first surveys. Vegetation data were recorded from 1m2 non-permanently marked plots, and soil pH was measured. We applied restricted permutation tests to evaluate whether observed changes in vegetation (species richness, occurrence frequency, coverage) and in soil pH were significant and independent of plant community type. We compared species co-occurrences over time to study changes in species composition and to identify the species most likely causing these changes. Results: Total number of species and average number of species per plot has not changed and are 75 and 9, respectively. Occurrence frequency changed significantly for 34% of the 64 species tested (11 species increased, 11 decreased). Species cover decreased significantly for 27% of the species and increased for one species. Observed changes in frequency and cover are not significantly related with species’ functional groups or species affiliated with moist or dry habitats. Polygonum viviparum, Saxifraga cernua and Alopecurus borealis have changed most in co-occurring with other species. Soil pH increased significantly from 6.4 to 6.8. Conclusions: Our results suggest that the strong climatic warming in the High Arctic over the past decades has contributed to significant changes in the vegetation studied on Svalbard over the past 85 years. Internal community re-structuring and the overall stability in species richness may be explained by time-delayed responses of well-established communities, and/or by a limited size of the species pool in the area.

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Abstract

Life Cycle Assessment (LCA) is a widely used tool to assess environmental sustainability of products. The LCA should optimally cover the most important environmental impact categories such as climate change, eutrophication and biodiversity. However, impacts on biodiversity are seldom included in LCAs due to methodological limitations and lack of appropriate characterization factors. When assessing organic agricultural products the omission of biodiversity in LCA is problematic, because organic systems are characterized by higher species richness at field level compared to the conventional systems. Thus, there is a need for characterization factors to estimate land use impacts on biodiversity in life cycle assessment that are able to distinguish between organic and conventional agricultural land use that can be used to supplement and validate the few currently suggested characterization factors. Based on a unique dataset derived from field recording of plant species diversity in farmland across six European countries, the present study provides new midpoint occupation Characterization Factors (CF) expressing the Potentially Disappeared Fraction (PDF) to estimate land use impacts on biodiversity in the ‘Temperate Broadleaf and Mixed Forest’ biome in Europe. The method is based on calculation of plant species on randomly selected test sites in the biome and enables the calculation of characterization factors that are sensitive to particular types of management. While species richness differs between countries, the calculated CFs are able to distinguish between different land use types (pastures (monocotyledons or mixed), arable land and hedges) and management practices (organic or conventional production systems) across countries. The new occupation CFs can be used to supplement or validate the few current CF's and can be applied in LCAs of agricultural products to assess land use impacts on species richness in the ‘Temperate Broadleaf and Mixed Forest’ biome.

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Abstract

Soft rot and blackleg of potato caused by pectinolytic bacteria lead to severe economic losses in potato production worldwide. To investigate the species composition of bacteria causing soft rot and black leg of potato in Norway and Poland, bacteria were isolated from potato tubers and stems. Forty-one Norwegian strains and 42 Polish strains that formed cavities on pectate medium were selected for potato tuber maceration assays and sequencing of three housekeeping genes (dnaX, icdA and mdh) for species identification and phylogenetic analysis. The distribution of the species causing soft rot and blackleg in Norway and Poland differed: we have demonstrated that mainly P. atrosepticum and P. c. subsp. carotovorum are the causal agents of soft rot and blackleg of potatoes in Norway, while P. wasabiae was identified as one of the most important soft rot pathogens in Poland. In contrast to the other European countries, D. solani seem not to be a major pathogen of potato in Norway and Poland. The Norwegian and Polish P. c. subsp. carotovorum and P. wasabiae strains did not cluster with type strains of the respective species in the phylogenetic analysis, which underlines the taxonomic complexity of the genus Pectobacterium. No correlation between the country of origin and clustering of the strains was observed. All strains tested in this study were able to macerate potato tissue. The ability to macerate potato tissue was significantly greater for the P. c. subsp. carotovorum and Dickeya spp., compared to P. atrosepticum and P. wasabiae.

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Abstract

We examine the effects of adding an independent food attribute on consumers’ willingness to pay (WTP) estimates for both cue and independent food attributes. In three separate choice experiments, a cue attribute present along the entire sequence of choices had independent food attributes enucleated and made explicit from the cue at later stages. Logit models were estimated using (i) a complete panel approach; (ii) error components and (iii) utility in WTP-space. Results suggest that the way a subject processes food attributes depends not only on the design dimensions but also on food attributes’ functional roles. When complexity of designs increases, models that account for different sources of heterogeneity have better fit to the data.

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Abstract

As China's industrialization and urbanization have grown rapidly in recent years, China's CO2 emissions rose from 3405.1799 Mt to 10,249.4630 Mt from 2000 to 2013, and it has reached the highest levels in the word since 2006. Chinese government has emphasized the importance of reducing carbon emissions and set the target of reducing carbon intensity to 60e65% of 2005 levels by 2030. Investigating the convergence of carbon intensity can identify the convergence rate, which is helpful in guiding allocations of carbon intensity reduction. The Yangtze River Delta is one of the key carbon emission regions in China, with higher urbanization levels and larger carbon emissions; thus, we employed prefecture-level panel data derived from grid data between 2000 and 2010 to examine whether the convergence of carbon intensity exists across prefecture-level cities in the Yangtze River Delta. Spatial panel data models were utilized to investigate b-convergence of carbon intensity. The results indicated that carbon intensity showed divergence during 2002e2004 and s-convergence over other periods (2000e2002 and 2004 e2010). Carbon intensity exhibited stochastic convergence, indicating that the shocks to carbon intensity relative to the average level of carbon intensity are only transitory. There was a spatial spillover effect and b-convergence of carbon intensity, suggesting that prefecture-level cities with higher carbon intensity would decrease rapidly in the Yangtze River Delta. Our results highlight the importance of considering the present state of carbon intensity, spatial factors, and socioeconomic factors such as industrial structure and economic levels during allocation planning for reducing carbon intensity.