Publikasjoner
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.
2018
Forfattere
Ari Hietala Isabella Børja Hugh Cross Nina Elisabeth Nagy Halvor Solheim Volkmar Timmermann Adam Vivian-SmithSammendrag
European ash (Fraxinus excelsior), a keystone species with wide distribution and habitat range in Europe, is threatened at a continental scale by an invasive alien ascomycete, Hymenoscyphus fraxineus. In its native range of Asia, this fungus is a leaf endophyte with weak parasitic capacity and robust saprobic competence in local ash species that are closely related to European ash. In European ash, H. fraxineus has a similar functional role as in Asia, but the fungus also aggressively kills shoots, resulting in crown dieback and tree death. H. fraxineus is a typical invasive species, as its spread relies on high propagule pressure. While crown dieback of European ash is the most obvious symptom of ash dieback, the annual colonization of ash leaves is a crucial key dependency for the invasiveness of H. fraxineus, since its fruiting bodies are formed on overwintered leaf vein tissues in soil debris. Leaves of European ash host a wide range of indigenous epiphytes, endophytes, facultative parasites and biotrophic fungi, including Hymenoscyphus albidus, a relative of H. fraxineus that competes for the same sporulation niche as the invader. At face value, leaves of European ash are colonized by a large and diverse indigenous mycobiome. In order to understand why this invader became successful in Europe, we discuss and summarize the current knowledge of diversity, seasonal dynamics and traits of H. fraxineus and indigenous fungi associated with leaves of European ash.
Forfattere
Donghai Wu Philippe Ciais Nicolas Viovy Alan K. Knapp Kevin Wilcox Michael Bahn Melinda D. Smith Sara Vicca Simone Fatichi Jakob Zscheischler Yue He Xiangyi Li Akihito Ito Almuth Arneth Anna Harper Anna Ukkola Athanasios Paschalis Benjamin Poulter Changhui Peng Daniel Ricciuto David Reinthaler Guangsheng Chen Hanqin Tian Helene Genet Jiafu Mao Johannes Ingrisch Julia E.S.M. Nabel Julia Pongratz Lena R. Boysen Markus Kautz Michael Schmitt Patrick Meir Qiuan Zhu Roland Hasibeder Sebastian Sippel Shree R.S. Dangal Stephen Sitch Xiaoying Shi Yingping Wang Yiqi Luo Yongwen Liu Shilong PiaoSammendrag
Field measurements of aboveground net primary productivity (ANPP) in temperate grasslands suggest that both positive and negative asymmetric responses to changes in precipitation (P) may occur. Under normal range of precipitation variability, wet years typically result in ANPP gains being larger than ANPP declines in dry years (positive asymmetry), whereas increases in ANPP are lower in magnitude in extreme wet years compared to reductions during extreme drought (negative asymmetry). Whether the current generation of ecosystem models with a coupled carbon– water system in grasslands are capable of simulating these asymmetric ANPP responses is an unresolved question. In this study, we evaluated the simulated responses of temperate grassland primary productivity to scenarios of altered precipitation with 14 ecosystem models at three sites: Shortgrass steppe (SGS), Konza Prairie (KNZ) and Stubai Valley meadow (STU), spanning a rainfall gradient from dry to moist. We found that (1) the spatial slopes derived from modeled primary productivity and precipitation across sites were steeper than the temporal slopes obtained from interannual variations, which was consistent with empirical data; (2) the asymmetry of the responses of modeled primary productivity under normal inter-annual precipitation variability differed among models, and the mean of the model ensemble suggested a negative asymmetry across the three sites, which was contrary to empirical evidence based on filed observations; (3) the mean sensitivity of modeled productivity to rainfall suggested greater negative response with reduced precipitation than positive response to an increased precipitation under extreme conditions at the three sites; and (4) gross primary productivity (GPP), net primary productivity (NPP), aboveground NPP (ANPP) and belowground NPP (BNPP) all showed concave-down nonlinear responses to altered precipitation in all the models, but with different curvatures and mean values. Our results indicated that most models overestimate the negative drought effects and/or underestimate the positive effects of increased precipitation on primary productivity under normal climate conditions, highlighting the need for improving eco-hydrological processes in those models in the future.
Sammendrag
Beta-keratin in poultry feathers is a structural protein that is resistant to degradation due to disulfide and hydrogen bonds. Feather meal can be a valuable feed compound if the digestibility can be increased. The objective of the present study was to analyze the effects of chemical, enzymatic, and pressure-thermic treatments for chicken feathers on solubility, in vitro protein digestibility (IVPD), and amino acid composition of solubilized and residual fractions. Two experiments were conducted. In experiment 1, models for solubility and IVPD were developed including the above factors applying a central composite face-centered design. Addition of sodium hydroxide (NaOH) and sodium sulfite (Na2SO3), and autoclaving time affected solubility and IVPD of the feather hydrolysates, but not addition of keratinolytic enzyme. In experiment 2, 7 combinations of the hydrolysis factors NaOH, Na2SO3, and autoclaving time with a predicted IVPD of 900 g/kg of DM, calculated for the sum of solubilized and residual feather fractions, were included to measure effects on IVPD and amino acid composition in each fraction. The IVPD values were higher for solubilized than residual fractions when treated with NaOH and autoclaving, but no differences were found when treated with Na2SO3 and autoclaving. Losses of cystine were substantial for all treatments, but lower for Na2SO3 than for NaOH. Furthermore, use of lower Na2SO3 concentration and longer autoclaving time reduced losses of cystine. Compared with NaOH treatments, Na2SO3 gave lower losses of threonine, arginine, serine, and tyrosine. With reference to the ideal protein profile for Atlantic salmon (Salmo salar L.), the treatments with 60 or 90 min autoclaving and 0.36 or 0.21% Na2SO3 had the highest chemical scores. The scores were generally higher for amino acids in residual than solubilized fractions, but with 90 min autoclaving and 0.21% Na2SO3 differences were small. In conclusion, hydrolysis of chicken feathers with low concentrations of Na2SO3 combined with autoclaving results in feather meal with high nutritional value for Atlantic salmon; separation of solubilized and residual fractions is not necessary.
Sammendrag
Fusarium head blight and seedling blight, both caused by Fusarium spp. and Microdochium spp., and glume blotch caused by Parastagonospora nodorum, are important diseases in wheat. In Norway, wheat seed lots are routinely analysed for infestation by these pathogens using traditional methods (plating grain on PDA, recording presence or absence of fungal colonies). This method is time consuming, require knowledge within fungal morphology, and do not facilitate identification to species in all cases. Molecular methods such as quantitative PCR (qPCR) could allow detection and quantification of fungal DNA at the species level in a relatively time effective way, particularly since the method allows for automation in different steps such as DNA extraction and pipetting. Whether the latter method is suitable within seed health evaluations will depend on the relationship between the amount of DNA of the different fungal species and field performance, and the purpose of the test (evaluation of planting value, need for seed treatment, survey of fungal species, quality of grain for consumption etc). To compare the two different methods, about 150 spring wheat seed lots from the years 2016-2017 (including two cultivars) were selected for the analysis of different fungi using species-specific qPCR and compared with the results from routine testing on PDA. In the 2016 material (81 samples), a mean seed infestation rate of 26% was observed for Microdochium spp. in the PDA test. The level of Fusarium was lower (mean infestation rate of 5%). A strong relationship was observed between the percentage of seeds infested by Microdochium and the level of Microdochium DNA (sum of DNA from Microdochium majus and Microdochium nivale) quantified by qPCR (R2 of 0.76, p<0.01). The relationship between Fusarium infested seeds and the level of Fusarium DNA (sum of DNA from three species) was moderate (R2 of 0.33, p<0.01). The samples were also analysed for the presence of P. nodorum. Compared to Fusarium and Microdochium, P. nodorum was present at an intermediate level (mean infestation rate of 12%). The relationship between the two different methods was weaker for this fungus (R2 of 0.21, p<0.01) than for Fusarium and Microdochium. The relationship between germination capacity and rating of the three groups of fungi by either method was studied. Preliminary results suggest that of the three fungi, Microdochium was associated with germination capacity in the 2016 material, and that the Microdochium infestation rate on PDA was slightly better correlated to germination capacity than the level of Microdochium DNA. Further results will be presented at the conference, including the association between the relative DNA content of the different Microdochium and Fusarium species and seed germination.
Forfattere
Manuel J. Steinbauer John-Arvid Grytnes Gerald Jurasinski Aino Kulonen Jonathan Lenoir Harald Pauli Christian Rixen Manuela Winkler Manfred Bardy-Durchhalter Elena Barni Anne D. Bjorkman Frank T. Breiner Sarah Burg Patryk Czortek Melissa A. Dawes Anna Delimat Stefan Dullinger Brigitta Erschbamer Vivian Astrup Felde Olatz Fernández-Arberas Kjetil Farsund Fossheim Daniel Gómez-García Damien Georges Erlend T. Grindrud Sylvia Haider Siri Vatsø Haugum Hanne Henriksen Maria J. Herreros Bogdan Jaroszewicz Francesca Orinda Holl Jaroszynska Robert Kanka Jutta Kapfer Kari Klanderud Ingolf Kühn Andrea Lamprecht Magali Matteodo Umberto Morra di Cella Signe Normand Arvid Odland Siri Lie Olsen Sara Palacio Martina Petey Veronika Piscová Blazena Sedlakova Klaus Steinbauer Veronika Stöckli Jens-Christian Svenning Guido Teppa Jean-Paul Theurillat Pascal Vittoz Sarah J. Woodin Niklaus E. Zimmermann Sonja WipfSammendrag
Globally accelerating trends in societal development and human environmental impacts since the mid-twentieth century1–7 are known as the Great Acceleration and have been discussed as a key indicator of the onset of the Anthropocene epoch6 . While reports on ecological responses (for example, changes in species range or local extinctions) to the Great Acceleration are multiplying8,9 , it is unknown whether such biotic responses are undergoing a similar acceleration over time. This knowledge gap stems from the limited availability of time series data on biodiversity changes across large temporal and geographical extents. Here we use a dataset of repeated plant surveys from 302 mountain summits across Europe, spanning 145 years of observation, to assess the temporal trajectory of mountain biodiversity changes as a globally coherent imprint of the Anthropocene. We find a continent-wide acceleration in the rate of increase in plant species richness, with five times as much species enrichment between 2007 and 2016 as fifty years ago, between 1957 and 1966. This acceleration is strikingly synchronized with accelerated global warming and is not linked to alternative global change drivers. The accelerating increases in species richness on mountain summits across this broad spatial extent demonstrate that acceleration in climate-induced biotic change is occurring even in remote places on Earth, with potentially far-ranging consequences not only for biodiversity, but also for ecosystem functioning and services.
Forfattere
Wei He Weimin Ju Christopher R. Schwalm Sebastian Sippel Xiaocui Wu Qiaoning He Lian Song Chunhua Zhang Jing Li Stephen Sitch Nicolas Viovy Pierre Friedlingstein Atul K. JainSammendrag
Recently, severe droughts that occurred in North America are likely to have impacted its terrestrial carbon sink. However, process‐based understanding of how meteorological conditions prior to the onset of drought, for instance warm or cold springs, affect drought‐induced carbon cycle effects remains scarce. Here we assess and compare the response of terrestrial carbon fluxes to summer droughts in 2011 and 2012 characterized by contrasting spring conditions. The analysis is based on a comprehensive ensemble of carbon cycle models, including FLUXCOM, TRENDY v5, SiBCASA, CarbonTracker Europe, and CarbonTracker, and emerging Earth observations. In 2011, large reductions of net ecosystem production (NEP; −0.24 ± 0.17 Pg C/year) are due to decreased gross primary production (−0.17 ± 0.18 Pg C/year) and slightly increased ecosystem respiration (+0.07 ± 0.17 Pg C/year). Conversely, in 2012, NEP reductions (−0.17 ± 0.25 Pg C/year) are attributed to a larger increase of ecosystem respiration (+0.48 ± 0.27 Pg C/year) than gross primary production (+0.31 ± 0.29 Pg C/year), induced predominantly by an extra warmer spring prior to summer drought. Two temperate ecoregions crops/agriculture and the grass/shrubs contribute largest to these reductions and also dominate the interannual variations of NEP during 2007–2014. Moreover, the warming spring compensated largely the negative carbon anomaly due to summer drought, consistent with earlier studies; however, the compensation occurred only in some specific ecoregions. Overall, our analysis offers a refined view on recent carbon cycle variability and extremes in North America. It corroborates earlier results but also highlights differences with respect to ecoregion‐specific carbon cycle responses to drought and heat.
Sammendrag
Purpose: Due to environmental concerns, efforts are made to replace the use of peat in horticultural growth media by organic wastes. Four growth media were prepared with the purpose of achieving adequate physical and chemical properties for plant production. Materials and methods: Growth media prepared from mixtures of coir (C) and paper sludge (P), respectively, with two biogas digestates from food waste (D1 and D2), were tested. These mixtures, 20% D1 or D2 + 80% C or P (v/v), were evaluated as growth media for tomato (Solanum lycopersicum L.) and lettuce (Lactuca sativa L.). Results and conclusion: The growth media were all physically stable during the growing period, provided all the macronutrients and most of the micronutrients necessary for plant growth, adequate pH conditions, as well as an adequate electrical conductivity. The mixture of D2 and P produced the highest biomass compared to a mineral fertilised peat (control), with a biomass production of 76% of the control for lettuce and 54% for tomato. Causes for the biomass reduction relative to the control may be related to ammonium toxicity effects, and/or limited plant-available water. The digestates, particularly D1, seemed also to have a phytotoxic effect on the germination.
Sammendrag
The research literature on food selection by large herbivores is extensive. Still, we are generally lacking in our knowledge of the influence of potentially interacting chemical contents of the food. We made a qualitative review of a systematic literature search of studies that empirically link chemical contents of food to the food selection by northern cervids (genera Alces, Capreolus, Cervus, Dama, Odocoileus, Rangifer). We found that although the majority of the 98 relevant studies measuring any given food constituent (energy, protein, fiber, minerals, plant secondary metabolites) provided support for it acting as a driver of food selection (in either a negative or positive way), there was little support for the traditional hypotheses of maximization or limitation of any single constituent. Rather, because of the animals’ need to acquire an appropriate intake of several constituents at the same time, our review highlights how new empirical stud- ies need to focus on several food constituents in synchrony: (1) Study designs should capture sufficient variation in the content of food constituents in order to tease apart their many co-variations; and (2) insights about nutritional drivers may be lost if one uses only composite currencies such as crude energy, crude fiber, ash, or tannins, which may mask contrasting selection patterns of the lumped constituents. Season had an apparent influence on the selection of some food constituents, particularly various fiber frac- tions. In contrast, our review revealed a lack of evidence that cervids more strongly select for protein in summer than they do in winter. Our overall conclusion of the review is that interacting chemical contents of food make the nutritional value of a given food type into a varying entity. To better elucidate this varia- tion, we need new technologies that non-invasively capture nutrient intake of free-ranging animals, across seasons.
Forfattere
Heidi Udnes Aamot Ingeborg Klingen Simon Edwards May Bente Brurberg Toril Eklo Hege Særvold Steen Jafar Razzaghian Elisa Gauslaa Ingerd Skow HofgaardSammendrag
The plant pathogenic fungus Fusarium langsethiae produces the highly potent mycotoxins HT-2 and T-2. Since these toxins are frequently detected at high levels in oat grain lots, they pose a considerable risk for food and feed safety in Norway, as well as in other north European countries. To reduce the risk of HT-2/T- 2-contaminated grain lots to enter the food and feed chain, it is important to identify factors that influence F. langsethiae infection and mycotoxin development in oats. However, the epidemiology of F. langsethiae is unclear. A three-year survey was performed to reveal more of the life cycle of F. langsethiae and its interactions with oats, other Fusarium species, as well as insects, mites and weeds. We searched for inoculum sources by quantifying the amount of F. langsethiae DNA in crop residues, weeds, and soil sampled from a selection of oat-fields. To be able to define the onset of infection, we analysed the amount of F. langsethiae DNA in oat plant material sampled at selected growth stages (between booting and maturation), as well as the amount of F. langsethiae DNA and HT-2 and T-2 toxins in the mature grain. We also studied the presence of possible insect- and mite vectors sampled at the selected growth stages using Berlese funnel traps. The different types of materials were also analysed for the presence F. graminearum DNA, the most important deoxynivalenol producer observed in Norwegian cereals, and which presence has shown a striking lack of correlation with the presence of F. langsethiae in oat. Results show that F. langsethiae DNA may occur in the oat plant already before heading and flowering. Some F. langsethiae DNA was observed in crop residues and weeds, though at relatively low levels. No Fusarium DNA was detected in soil samples. Of the arthropods that were associated with the collected oat plants, aphids and thrips species were dominating. Further details will be given at the meeting.
Sammendrag
Det er ikke registrert sammendrag