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.
2023
Abstract
Questions During the winter of 2014, an intense drought combined with sub-zero temperatures resulted in a massive Calluna dieback in Norwegian heathlands. We studied the initial vegetation recovery under two management approaches: natural recovery and prescribed burning. We hypothesized that natural recovery will be slower in more drought-affected sites, whereas burning will facilitate post-fire recovery in all sites by effectively removing dead and damaged heath. Both natural recovery and post-fire succession will be slower in the north. Location Calluna heath in seven sites spanning an approx. 600-km latitudinal gradient along the coast of Norway (60.22–65.69° N). Methods After a natural drought, 10 permanent plots per site were either burnt or left for natural recovery. Vegetation data were recorded annually in 2016 (pre-fire) and 2017–2019 (post-fire) reflecting a factorial repeated-measures design (n = 280). The data were analyzed using mixed-effects models. Results Two years after the drought, we observed high but variable Calluna damage and mortality. Over the four years of study, damaged Calluna recovered, whereas dead Calluna showed little recovery. Both the extent of the damage and mortality, as well as the rate of natural recovery, are only weakly related to site climate or environmental factors. Fire efficiently removed dead and damaged Calluna and facilitated post-fire successional dynamics and recovery in a majority of sites. Conclusions Extreme winter drought resulted in substantial and often persistent damage and dieback on Calluna along the latitudinal gradient. In sites with high mortality, prescribed burning removed the dead biomass and, in some cases, facilitated vegetation recovery. Traditional heathland management, which uses burning to facilitate all-year grazing by Old Norse sheep in Atlantic coastal heathlands, can be an efficient tool to mitigate dieback events and more generally to increase resistance to and resilience after extreme drought events in the future.
Abstract
The benefits of individual vessel quota (IVQ) management in terms of improved harvest strategy and profitability are well recognized, but there is less focus on how different components of a quota portfolio can influence decisions underlying the effort allocation and profit-maximizing behaviour of fishers. Variations in the components of the quota portfolio may create economic incentives that alter the optimal harvest strategy and profitability. Thus, we study the potential impact of different components of quota portfolio on the intra-annual harvest strategy and profitability in two segments of the Norwegian bottom trawl fleet. By developing a vessel-based spatio-temporal bioeconomic framework, we demonstrate and compare adopted harvest strategies and accrued profits for small and large trawl vessels under three scenarios regarding restrictive quotas in codfish fishery. Our analysis confirms that alternations in the components of the quota portfolio influence the spatio-temporal dynamics of the fishing effort for small and large trawl vessels in different ways, probably due to the differences in vessel-specific characteristics. We also demonstrate that the differences in profit between small and large vessels in part depend on the overall size of the quota portfolio. The economies of scale in the trawl industry are being eroded as the shares of higher-priced species in the quota portfolio decreases. The benefits of economies of scale cannot be reaped as trawlers respond to the reduction in profit by redirecting effort from offshore areas of the Arctic to nearshore waters or staying ashore. Likewise, having small quotas of high-priced species reduces the effectiveness of the IVQ system in meeting management objectives, and could in some cases undermine sustainability outcomes. Our results also demonstrate that both the intensity with which fishers react to the fluctuations in market price levels and fishers’ perceptions of location attractiveness are influenced by the components of the quota portfolio.
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Authors
Mario Guajardo Rasmus Bang Bjørn Gunnar Hansen Jon Kristian Sommerseth Ola Flaten Leif Jarle AsheimAbstract
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Authors
Mathias Amundsen Anne Linn Hykkerud Niina Kelanne Sanni Tuominen Gesine Schmidt Oskar Laaksonen Baoru Yang Inger Martinussen Laura Jaakola Kjersti AabyAbstract
Wild lingonberries are a traditional source of food in the Nordic countries and an important contributor to economic activity of non-wood forest products in the region. Lingonberries are a rich source of bioactive compounds and can be a valuable contributor to a healthy diet. However, there are few studies available on how the bioactive compounds in lingonberries develop as they ripen. In this investigation, we examined the content of 27 phenolic compounds, three sugars, four organic acids, and 71 volatile organic compounds at five ripening stages. The study showed that, while the highest content of phenolic compounds was found early in the development, the organoleptic quality of the fruits improved as they ripened. From the first to the last stage of development, anthocyanins went from being nearly absent to 100 mg/100 g fw, and there was an increased content of sugars from 2.7 to 7.2 g/100 g fw, whereas the content of organic acids decreased from 4.9 to 2.7 g/100 g fw, and there were several changes in the profile of volatiles. The contents of flavonols, cinnamic acid derivatives, flavan-3-ols, and the total concentration of phenolic compounds were significantly lower in the fully ripe berries compared to berries in the early green stage. In addition to the changes occurring due to ripening, there was observed variation in the profile of both phenolic compounds and volatiles, depending on the growth location of the berries. The present data are useful for the assessment of harvest time to obtain the desired quality of lingonberries.
Authors
Mathias Amundsen Laura Jaakola Kjersti Aaby Inger Martinussen N. Kelanne S. Tuominen O. Laaksonen B. Yang Anne Linn HykkerudAbstract
Lingonberries (Vaccinium vitis-idaea L.) from two locations, northern (69°N, 18°E) and southern (59°N, 10°E) Norway, were grown under controlled conditions in a phytotron at two temperatures (9 and 15 °C) to study the effects of the ripening temperature and origin on the chemical composition of the berries. The concentrations of phenolic compounds, sugars, and organic acids as well as the profile of volatile organic compounds (VOCs) were determined using chromatographic and mass spectrometric methods. Five anthocyanins, eleven flavonols, eight cinnamic acid derivatives, three flavan-3-ols, three sugars, three organic acids, and 77 VOCs were identified, of which 40 VOCs had not previously been reported in lingonberries. Berries from both locations, were found to have higher contents of anthocyanins and cinnamic acid derivatives when ripened at lower temperature (9 °C), compared to the higher temperature (15 °C). Lingonberries of northern origin had a different VOC profile and higher contents of anthocyanins and organic acids than berries originating from the south. Lingonberries from the northern location also had higher proportions of cyanidin-3-O-glucoside and cyanidin-3-O-arabinoside than lingonberries from the southern location. The results show that the composition of lingonberries is influenced by both the environment and the origin of the plants, with phenolic compounds mainly influenced by the growth temperature and VOCs mainly influenced by plant origin.
Authors
Mathias Amundsen Kjersti Aaby Laura Jaakola Gesine Schmidt Inger Martinussen Anne Linn HykkerudAbstract
Lingonberries (Vaccinium vitis-idaea L.) have received much positive attention due to their exotic taste and high phenolic content. These small red fruits grow across Norway, a country with large variations in abiotic and biotic growth conditions. The large variations in abiotic and biotic growth conditions have potential to influence quality and availability of lingonberries. A three-year study (2019-2021) with 64 field plots across Norway have therefore been set up, with the aim of studying the effect of climate and growth conditions on lingonberries. Here, anthocyanin content in berries from the first growth season is presented. Eight locations across Norway (58 to 69°N) with supposed high production potential of lingonberries were selected. Within each location, eight stands (250 m2) with different biotic conditions were chosen. Berries from each sector were lyophilised and extracted with 70% methanol. Phenolic compounds were analysed by HPLC-DAD-MSn, with quantification of anthocyanin at 520 nm and MS used for identification. The three major anthocyanins in Norwegian lingonberries were cyanidin-3-galactoside (69-90%), -arabinoside (6-23%) and -glucoside (2-10%). Additionally, small quantities of three other cyanidin glycosides were preliminarily identified. The total content of anthocyanins in lingonberries ranged from approximately 320 to 790 mg 100 g‑1 dw. There appears to be a variation in anthocyanin concentration linked to latitude. However, as the variation was as large within the stands of each location as they were between the locations, different growth factors would also play key parts in synthesis of anthocyanins in lingonberries. Results from analysis of berries collected in 2020 and 2021 are necessary to have the basis to draw a conclusion on how biotic and abiotic factors influence anthocyanin content of lingonberries.
Authors
Mathias Amundsen Laura Elina Jaakola Kjersti Aaby Gesine Schmidt Inger Martinussen Anne Linn HykkerudAbstract
Lingonberry is an evergreen dwarf shrub abundant in the area of Nordic countries and a food traditionally regarded as a staple of Nordic diets. There is however limited commercial harvest of these readily available berries. The objective of this doctoral thesis is to investigate how the composition Norwegian lingonberries vary and is affected by abiotic and biotic growth conditions. The thesis consists of four papers of which three studies were conducted in controlled conditions investigating the effects of ripening, light conditions, and temperature during ripening on the composition of the targeted compounds in lingonberries. The fourth paper of the thesis investigates the variation in composition of wild Norwegian lingonberries and how different environmental factors influence this composition. In lingonberries, in total 29 phenolic compounds, sucrose, glucose and fructose as well as 4 organic acids and 77 volatile organic compounds were detected.. In the controlled studies time of harvest significantly influenced the quality of the lingonberries. Spectral light composition with supplemental blue wavelengths increased the content of anthocyanins, and slightly influenced the ratio of sugars to organic acids. There was only a limited effect of light intensity on the content of anthocyanins in lingonberries. Berries grown at lower temperatures had a higher content of anthocyanins and organic acids, whereas the other phenolic compounds were not significantly influenced. Latitude and temperature had the most significant effect on the content of anthocyanins in lingonberries. While light conditions only slightly influence berry quality, factors such as amount of precipitation during ripening, the density of deciduous trees, and altitude also significantly influenced berry quality. Precipitation influenced the content of organic acids in the field study. The result from this study further strengthens the evidence that lingonberries are a rich source for dietary polyphenols, and that berry quality increases with later harvest times. High quality lingonberries can be found across the country with large variation within local areas. The combination of field experiments and controlled experiments showed that weather conditions during ripening, latitude and density of deciduous trees all influence berry quality.
Abstract
No abstract has been registered