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.
2024
Abstract
Income comparisons between farm and non-farm households play a crucial role in many aspects of farm policy. Using household income data from tax returns of all Norwegian taxpayers in the period 2006–2015 we study these income differences. We find that the unconditional mean income is higher for farm households, but with important differences depending on the comparison group considered. We also find that the income difference is reduced when we control for differences in the personal characteristics of the different non-farm comparison sub-groups. This finding implies that income comparison using unconditional means, as frequently done in agricultural policy making, is potentially misleading. We also show that the income effect of personal characteristics is not the same for different comparison sub-groups, as has been assumed in previous studies of income disparities. Differences in personal characteristics, and the income effect of those characteristics, therefore need to be accounted for if income comparisons between farmers and non-farmers are to inform farm support policies.
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Authors
Sanjana De Zoysa Jeewanthi Sirisena Helani Perera Shalinda Fernando Miyuru Gunathilake Upaka RathnayakeAbstract
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Aim Effective management of non-indigenous species requires knowledge of their dispersal factors and founder events. We aim to identify the main environmental drivers favouring dispersal events along the invasion gradient and to characterize the spatial patterns of genetic diversity in feral populations of the non-native pink salmon within its epicentre of invasion in Norway. Location Mainland Norway and North Atlantic Basin. Methods We first conducted SDM using four modelling techniques with varying levels of complexity, which encompassed both regression-based and tree-based machine-learning algorithms, using climatic data from the present to 2050. Then, we used the triple-enzyme restriction-site associated DNA sequencing (3RADseq) approach to genotype over 30,000 high-quality single-nucleotide polymorphisms to elucidate the patterns of genetic diversity and gene flow within the pink salmon putative invasion hotspot. Results We discovered temperature- and precipitation-related variables drove pink salmon distributional shifts across its non-native ranges and that climate-induced favourable areas will remain stable for the next 30 years. In addition, all SDMs identified north-eastern Norway as the epicentre of the pink salmon invasion, and genomic data revealed that there was minimal variation in genetic diversity across the sampled populations at a genome-wide level in this region. While utilizing a specific group of ‘diagnostic’ SNPs, we observed a significant degree of genetic differentiation, ranging from moderate to substantial, and detected four hierarchical genetic clusters concordant with geography. Main Conclusions Our findings suggest that fluctuations in climate extreme events associated with ongoing climate change will likely maintain environmental favourability for the pink salmon outside its ‘native’/introduced ranges. Locally invaded rivers are themselves potential source populations of invaders in the ongoing secondary spread of pink salmon in Northern Norway. Our study shows that SDMs and genomic data can reveal species distribution determinants and provide indicators to aid in post-control measures and potentially inferences about their success.
Authors
Theresa Weigl Jorunn Børve Emily Follett Ingunn Øvsthus Carl Gunnar Fossdal Hanne Larsen Siv Fagertun RembergAbstract
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Joel Abbey David Percival Laura Elina Jaakola Samuel K. AsieduAbstract
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