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NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.

2024

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Livestock summer grazing in mountains and forests in Norway is generally considered beneficial to biodiversity. In this study we investigated if this is the case for cattle in boreal production forest. We collected biodiversity data on field layer vegetation, floral resources and flower-visiting insects in young spruce plantations that were planted 2–10 years ago. We picked young spruce plantations inside and outside well-established cattle grazing areas. On each plantation, we sampled fenced and unfenced plots (20 * 20 m each). This study design allowed us to investigate long-term effects of cattle grazing as well as short-term effects of excluding cervids only and short-term effects of excluding cervids and cattle. Long-term cattle grazing reduced the abundance of woody plants and reduced the abundance of flowers. Excluding cervids for two summers led to reduced height of woody plants (shrubs and heather) and to increased flower abundance. In contrast, excluding cervids and cattle for two summers led to increased height of graminoids, herbs and woody plants, to higher abundance of graminoids, higher flower abundance and higher abundance of flower-visiting insects. In conclusion, cattle affected the studied system in different ways and to a larger extent than native cervids. Our study shows that we must be careful when inferring results from cattle grazing studies on grasslands to forest ecosystems. As this study documents a negative effect of cattle on floral resources and flower-visiting insects, and we currently are facing a global pollination crisis, a careful consideration of the current practice of cattle grazing in boreal forest might be needed.

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Rising organic charge in northern freshwaters is attributed to increasing levels of dissolved natural organic matter (DNOM) and changes in water chemistry. Organic charge concentration may be determined through charge balance calculations (Org.−) or modelled (OAN−) using the Oliver and Hruška conceptual models, which are based on the density of weak acid functional sites (SD) present in DNOM. The charge density (CD) is governed by SD as well as protonation and complexation reactions on the functional groups. These models use SD as a key parameter to empirically fit the model to Org.−. Utilizing extensive water chemistry datasets, this study shows that spatial and temporal differences in SD and CD are influenced by variations in the humic-to-fulvic ratio of DNOM, organic aluminum (Al) complexation, and the mole fraction of CD to SD, which is governed by acidity. The median SD values obtained for 44 long-term monitored acid-sensitive lakes were 11.1 and 13.9 µEq/mg C for the Oliver and Hruška models, respectively. Over 34 years of monitoring, the CD increased by 70%, likely due to rising pH and declining Al complexation with DNOM. Present-day median SD values for the Oliver and Hruška models in 16 low-order streams are 13.8 and 15.8 µEq/mg C, respectively, and 10.8 and 12.5 µEq/mg C, respectively, in 10 high-order rivers.

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The sustainable production of perennial grasses in Northern Norway is at risk due to the ongoing climate change. The predicted increase in temperatures and variable weather patterns are further expected to create challenges for winter survival of timothy (Phleum pratense L.). Knowledge about the molecular mechanisms underlying freezing tolerance is crucial for developing robust cultivars. The current study is aimed at identifying genes involved in freezing stress response of timothy and studying gene expression differentiation due to field selection in contrasting environments using RNAseq. Four timothy cultivars were field tested for three years in Tromsø and Vesterålen, in Northern Norway. The surviving material from the field tests, along with plants raised from the original seed lots, were subjected to freezing tests. LT50 values varied across cultivars and materials. Many genes coding for transcription factors and proteins known to play an important role in freezing tolerance, like dehydrins, c-repeat binding factors, and late embryogenesis abundant proteins were upregulated with decreasing temperatures. Moreover, genes associated with glycolysis/gluconeogenesis, TCA cycle, glutathione metabolism, proteasome pathways and genes encoding autophagy-related proteins, plasma membrane-associated proteins, sugar and amino acid transporters had elevated expression in field survivors compared to plants raised from the original material. The lower freezing stress tolerance of field survivors despite the elevated expression of several stress-responsive genes might be due to a combination of selection in the field and the age effect. Furthermore, differences in freezing stress response between northern and southern adapted cultivars and surviving material from two field trial locations are discussed.

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Energy and imported trout egg subsidies hold a pivotal role for Iranian trout farms. They aim to decrease production costs, yet their impact on the profit efficiency of farms remains dubious. The first objective of this paper is to assess how the current subsidy scheme affects the profit efficiency of hatchery and propagation trout farms in Mazandaran, Iran. We examine several subsidy reform scenarios to enhance profit efficiency as a second objective. Standard profit efficiency (SPE) is used to acquire the efficiency of the trout farms using data envelopment analysis. Results show that the majority of farms are inefficient and highly dependent on subsidies. Comparing farms with high efficiency against those with low efficiency as a third aim of research highlights the importance of farms holding a propagation license, engaging in vertical integration, achieving adult trout production surpassing 81 t, and maintaining a fish total feed consumption to trout production ratio below 0.74. Findings from reformation scenarios reveal 1) redirecting the current subsidy towards purchasing the extruder machines for fish feed production, 2) transferring funds to subsidize electricity based on the farm's electricity consumption, and 3) opting for the production of genetically modified eggs gives higher SPE. Reformation can also reduce the burden on public funds and dependency on importation.

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Introduction: Plantations located outside the species distribution area represent natural experiments to assess tree tolerance to climate variability. Climate change amplifies warming-related drought stress but also leads to more climate extremes. Methods: We studied plantations of the European larch (Larix decidua), a conifer native to central and eastern Europe, in northern Spain. We used climate, drought and tree-ring data from four larch plantations including wet (Valgañón, site V; Santurde, site S), intermediate (Ribavellosa, site R) and dry (Santa Marina, site M) sites. We aimed to benchmark the larch tolerance to climate and drought stress by analysing the relationships between radial growth increment (hereafter growth), climate data (temperature, precipitation, radiation) and a drought index. Results: Basal area increment (BAI) was the lowest in the driest site M (5.2 cm2 yr-1; period 1988–2022), followed by site R (7.5 cm2 yr-1), with the youngest and oldest and trees being planted in M (35 years) and R (150 years) sites. BAI peaked in the wettest sites (V; 10.4 cm2 yr-1; S, 10.8 cm2 yr-1). We detected a sharp BAI reduction (30% of the regional mean) in 2001 when springto-summer conditions were very dry. In the wettest V and S sites, larch growth positively responded to current March and June-July radiation, but negatively to March precipitation. In the R site, high April precipitation enhanced growth. In the driest M site, warm conditions in the late prior winter and current spring improved growth, but warm-sunny conditions in July and dry-sunny conditions in August reduced it. Larch growth positively responded to spring-summer wet conditions considering short (1-6 months) and long (9-24 months) time scales in dry (site M) and wet-intermediate (sites S and R) sites, respectively. Discussion: Larch growth is vulnerable to drought stress in dry slow-growing plantations, but also to extreme spring wet-cloudy events followed by dry-hot conditions in wet fast-growing plantations.

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Purpose of Review In this review, we synthesise current knowledge on trade-offs among traits in key fitness dimensions and identify major research gaps with the intention of laying the groundwork for a rapid advance in tree breeding for multiple objectives as a key contribution to the sustainability of planted forests in the future. Recent Findings Trade-offs among growth, reproduction, defence, stress tolerance and product quality predicted theoretically have been reported experimentally in many breeding programmes. Among these trade-offs, the genetic linkage between resistance against biotic threats and growth (or other relevant traits) is particularly critical for the current and future management of forest genetic resources. Maintaining tree growth and wood quality in the novel environments of the future requires the assessment of genetic correlations of target traits with phenology, closely linked to survival to temperature extremes. Improving our current knowledge on the genetic trade-offs of drought tolerance as a breeding objective in forest trees obligates a more precise definition of both the specific traits and the experimental conditions. Published evidence suggests that common target traits in breeding programmes may trade-off with reproductive success and fire-adaptation, and the simultaneous improvement of growth and wood quality traits still remains as a constraint in traditional tree breeding. Summary Changing environments combined with pests and diseases are challenging plantation forestry worldwide, which implies an urgent need to develop new improvement strategies to build the resilience of forestry for our future environments. It is essential to have a better understanding of how traits interact, especially those important for production, climate and biotic threat resilience, but much of the information is still missing. Since many key trade-offs are affected by the environment, we need new studies under novel environments to forecast levels of multi-trait integration in breeding populations.

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CONTEXT Researchers have identified numerous strategies to improve economic performance and reduce greenhouse gas (GHG) emission intensity in combined milk and beef production on dairy farms. However, there remains a need to better understand how the effectiveness of these strategies varies under different operational conditions. OBJECTIVE This study aims to examine how the economic and GHG emission intensity mitigation effectiveness of increased milk yield, extended longevity of dairy cows, reduced age at first calving, and intensified beef production from bulls depend on operational conditions in dual purpose cattle systems. METHOD We present a quantitative framework to (1) economically optimize production at farm level under various constraints and (2) calculate corresponding GHG emissions. The framework is tailored for Norwegian dual-purpose cattle systems and used to assess the economic and GHG emission intensity mitigation effects of incremental adjustments in relevant decisions. RESULTS AND CONCLUSIONS The results show that increased milk yield, extended productive life of dairy cows, reduced age at first calving, and lower slaughter age of bulls can lead to economic and climatic win-wins in terms of higher gross margins and reduced emissions per kg of protein produced. However, they may also result in lose-win and win-lose outcomes depending on the operational conditions. All four measures free up roughage production capacity, which, if used to maintain/increase milk and/or beef production, typically results in economic gains. However, if e.g., the available milk quota or space prevent this, economic losses may occur. The climate impact also depends on how the freed-up capacity is used: if it boosts production, the effects vary based on the scale and type of increase and the farm's initial setup, while unused capacity leads to reduced emission intensity. Conflicts typically arise when: 1) the extra capacity increases less climate-friendly production, raising emission intensity despite economic gains, or 2) extra capacity cannot be used, causing economic losses despite climate benefits. Our results also show that what can be labeled a win in climate terms, and to what extent, depends on the selected target metric(s). SIGNIFICANCE Governments and societies strive to balance food production with environmental goals. In this context, it is essential to identify farm-level economic and climatic win-win and lose-win scenarios, not only for farmers but also for policymakers and the broader society. This study could inform decision-making and policy development, potentially enhancing economic and climatic performance in combined milk and meat production.

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Future agricultural practices necessitate green alternatives to replace hazardous insecticides while distinguishing between pests and beneficial insects. Chitosan, as a biological macromolecule derived from chitin, is biodegradable and exhibits low toxicity to non-target organisms, making it a sustainable alternative to synthetic pesticides. This review identifies chitosan-derivatives for insecticidal activity and highlights its efficacy including genotoxicity, defense mechanism, and disruption of insect's exoskeleton at different concentrations against several insect pests. Similarly, synergistic effects of chitosan in combination with natural extracts, essential oils, and plant-derived compounds, enhances insecticidal action against various pests was evaluated. The chitosan-based insecticide formulations (CHIF) in the form of emulsions, microcapsules, and nanoparticles showed efficient insecticide action on the targeted pests with less environmental impact. The current challenges associated with the field-trial application were also recognized, by optimizing potent CHIF-formulation parameters, scaling-up process, and regulatory hurdles addressed alongside potential solutions. These findings will provide insight into achieving the EU mission of reducing chemical pesticides by 50 %.

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Ascospores discharged at rainfall and dispersed by wind can provide long-distance spread of the European canker fungus, Neonectria ditissima. Ascospores are produced by perithecia which are the sexual reproductive stage. Diffuse knowledge exists on the seasonal pattern of perithecium formation under different climatic conditions. Therefore, the development of perithecia was observed for several successive seasons at five sites in three Northern European countries. In Norway and Finland, ripe perithecia were commonly recorded throughout the year, and on individual cankers continuously for up to 28 months. In contrast, asexual reproductive structures (sporodochia) were confined to the growing season in both countries. In Northern Germany an average of 51% of cankers developed ripe perithecia by late winter, and perithecial senescence ensued in late spring. On average, ripe perithecia were present on cankers for 22 weeks. In contrast, sporodochia were observed all year round. The timing of perithecium maturation correlated with the number of days with > 2 mm rainfall in July–September. The presence of mature perithecia and sporodochia for different lengths of time in different countries has implications for regional disease management strategies.

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Lys ringråte, forårsaket av bakterien Clavibacter sepedonicus (Cms, tidligere Clavibacter michiganensis subspecies sepedonicus), er en farlig bakteriesjukdom på potet. Kraftige angrep kan gi betydelig avlingsreduksjon. Lys ringråte har vært offisielt kjent i Norge siden 1964. I de fire siste årene (perioden 2019-2022) ble lys ringråte påvist i fire av 1383 analyserte prøver (ca. 0,3 %) som hovedsakelig representerte mat- og industripotet men også 50 settepotetpartier i 2019. Tiltak er iverksatt for å utrydde infeksjonen ved funn. Mørk ringråte er en karantenesykdom på potet og angriper også andre planter i søtvierfamilien. Den er forårsaket av bakterien Ralstonia solanacearum. Angrep av mørk ringråte fører til at potetplantens ledningsvev blir ødelagt og tilstoppet slik at riset visner, og senere blir det en brunfarget, ringformet råte i knollene. Skadegjøreren har ikke blitt påvist i Norge. Det er hvert år betydelig import av mat- og industripotet til Norge fra land hvor sykdommen forekommer. Det ble i 2023 mottatt 291 potetprøver for testing. Det ble ikke påvist hverken lys eller mørk ringråte i noen av prøvene. Resultatene fra 2023 viser at status for lys ringråte i Norge iht. ISPM 8 er å anse som: present, not widely distributed and under official control. Resultatene fra 2023 viser at status for mørk ringråte i Norge iht. ISPM 8 er å anse som: absent, pest not recorded.