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.
2016
Sammendrag
The aim of this study was to determine the efficacy of chitosan and methoxysilane in the prevention of surface mold growth on rubberwood. Three different chitosan samples were tested; C1 (Mw 37 kDa), C2 (Mw 5.4 kDa) and C3 (Mw 3.5 kDa). Radial growth inhibition assay of the chitosan samples was investigated at concentrations ranging from 0.063 to 0.5 %w/v against Aspergillus niger BAM 4 and Penicillium decumbens CBS 121928. Chitosan samples C1 and C3 exhibited strong antifungal activity against both molds. Rubberwood samples were either vacuum or dip treated with varying concentrations of chitosan or silane solution. The content of chitosan in wood showed that after the leaching test, chitosan was well retained in both vacuum and dip treated wood. The concentration of silicon in wood showed similar results. The vacuum treated wood samples with chitosan C1 and C3 at 1 %w/v concentration had strong resistance against A. niger BAM 4. However, dip treated rubberwood samples with 2 %w/v chitosan solutions showed lower resistance against A. niger BAM 4. On the other hand, both vacuum and dip treated rubberwood samples with chitosan had no resistance against P. decumbens CBS 121928. The silane treated wood samples showed no resistance to fungal growth.
Forfattere
Johannes Eichhorn Peter Roskams Nenad Potocic Volkmar Timmermann Marco Ferretti Volker Mues Andras Szepesi Dave Durrant Ivan Seletkovic Hans‐Werner Schroeck Seppo Nevalainen Filippo Bussotti Paloma Garcia Sören WulffSammendrag
Det er ikke registrert sammendrag
Forfattere
Bjørn Mejdell Larsen Paul E. AspholmSammendrag
Karpelva hører med blant de vassdragene som fortsatt har en stor bestand av elvemusling, og som i løpet av de siste ti årene også har hatt en økende rekruttering. Holder rekrutteringen seg på dette nivået i årene som kommer vil det også kunne opprettholde bestanden på lang sikt. Slike lokaliteter har høy verneverdi både lokalt og nasjonalt, men også i internasjonal sammenheng er disse av spesiell interesse. I Karpelva finnes det en stor bestand av elvemusling fra utløpet av Evavatnet til utløpet i sjøen (Karpbukt). Sennagrasvatna og elva ovenfor Evavatnet er ikke undersøkt. Med dagens kunn-skap vet vi at elvemusling er begrenset til en ca. 14,6 km lang elvestrekning når vi ikke inkluderer Sennagrasvatna. Det var en gjennomsnittlig tetthet på 2,57 musling pr. m² i 2012-2015. Dette var det samme som i 2005. Det ble beregnet at det til sammen var litt over en million elvemusling i Karpelva. Av disse var om lag en tredel nedgravd i substratet både i 2005 og 2015 slik at den synlige delen av bestanden utgjorde nær 700.000 individ. Selv om estimatet kan være unøyaktig gir det en bekreftelse på at bestanden er stor og potensielt livskraftig. Muslingene i Karpelva vokste dårlig, og årlig tilvekst fra muslingene var fem år til de ble 25 år var bare 2-3 mm. Gjennomsnittlig lengde for fem år gamle muslinger var 4 mm. Den minste muslingen som ble funnet i 2015 var 6 mm, og den var allerede sju år gammel. Ti og 20 år gamle muslinger var henholdsvis 13 og 41 mm lange i gjennomsnitt. Dette betyr at 1,8 og 14,9 % av antall muslinger som ble lengdemålt i 2015 var yngre enn henholdsvis 10 og 20 år. Bestander som har opprettholdt populasjonsstrukturen i lang tid karakteriseres av at noen muslinger skal være yngre enn 10 år, men at minst 20 % av muslingene må være yngre enn 20 år. Andelen muslinger yngre enn 20 år var derfor noe lavere enn ønskelig. Men i 2005 var det ingen muslinger yngre enn 10 år, og andelen muslinger yngre enn 20 år var bare 3,2 %. Det har derfor vært en positiv utvikling i løpet av de siste ti årene. Laks- og ørretunger fra Karpelva som er undersøkt med hensyn til forekomst av muslinglarver på gjellene kan tyde på at laks ikke egner seg som vert for muslinglarvene ovenfor Sennagras-vatna, og at bestanden av elvemusling i øvre del av Karpelva kan karakteriseres som «ørret-musling». Ved utløpet av Sennagrasvatna derimot kan det være en kortere strekning der det finnes både «laksemusling» og «ørretmusling». Lenger ned i vassdraget er laks primærvert, men der er bestanden av ørret så liten at det ikke er avklart hvilken rolle ørret kan ha som vertsfisk. DNA-prøver er bare analysert fra elvemusling samlet inn i nedre del av Karpelva. Muslingene hadde høy genetisk variasjon, og hadde større likhet med andre laksemusling-populasjoner enn med ørretmusling. Observasjonen av at det tilsynelatende er en polarisert infeksjon av musling-larver på enten ørret eller laks i Karpelva gjør det rimelig å legge til grunn dette som et føre-var-prinsipp i det videre forvaltningsarbeidet med elvemusling og dermed sikre gode bestander av ørret i øvre del og laks i nedre del. Karpelva, Finnmark, elvemusling, overvåking, utbredelse, tetthet, lengde, muslinglarver, vertsfisk (laks og ørret), River Karpelva, Finnmark county, freshwater pearl mussel, monitoring, distribution, density, length, mussel larvae, host fish, (Atlantic salmon and brown trout)
Sammendrag
Aphids in cereals are an important problem in Europe. Entomopathogenic fungi in the Phylum Entomophthoromycota are among their natural enemies. Under certain conditions, they can cause epizootic events and control pest aphid populations. This epizootic development is affected by many abiotic and biotic factors such as aphid species and their host plant (including weeds within the crop), fungal species and isolates, and temperature. Studies from Denmark, UK, Slovakia and suggest that the genus Pandora is the most prevalent fungal pathogen of the English grain aphid (Sitobion avenae). Which fungal species that is the most prevalent in populations of the other important aphid species in cereals in Europe, the Bird cherry-oat aphid (Rhopalosiphum padi), is less clear. We chose, however, to use Pandora to assess the biological control potential of Entomophthoromycota against aphids in cereals and to produce data that might be used in a pest-warning model incorporating the effect of this natural enemy. This was done by conducting laboratory studies on the virulence of two Pandora isolates (collected in the same field) on R. padi and Myzus persicae at three temperatures (12, 15 and 18◦C). M. persicae is a polyphagous aphid that may be present on weeds. It can be an alternative host for Pandora and hence might also affect the epidemic development of Pandora in aphids that are cereal pests. Our preliminary results show that R. padi is more resistant to the tested Pandora isolates than M. persicae. The two Pandora isolates had different virulence in the two aphid species tested. The temperature did not influence the virulence.
Sammendrag
The status of cereal cultivation in Iceland, northern Norway, Faroe Islands, Orkney and Newfoundland has been studied in a project supported by the Northern Periphery and Arctic Programme (NPA). In Orkney, Iceland and northern Norway cereal cultivation is well established while the Faroe Islands are re-establishing, and Newfoundland is starting, cultivation. The project transfers knowledge between the regions and aims to increase the value of cereal products, indicate new innovative products and increase cultivation of cereals. In this report, the cereal value chain is described to inspire companies and initiators to identify new opportunities and create new jobs. Total cereal grain production in the five regions was about 38,000 tons in 2014 while imports were about 146,000 tons, just for Iceland, Orkney and Newfoundland. The population of the region is about 1.4 million and the annual number of visitors is above 2 million. Considerable amounts of cereal-based products are consumed in the regions. These include many different foods (bakery products, breakfast cereals, snacks, flour, porridges etc.) and beverages (e.g. beer and whisky) and offer many opportunities for using local cereals. Recent trends in the cereal food market are very conducive to the development of new products and greater local production within the project regions. Interest in local food and drinks is increasing and food producers need to respond to increasing demand from visitors. In all of the regions, barley is the most important cereal grown. Barley contains several health-enhancing nutritional components including β-glucan and antioxidants and, with growing awareness of the need for healthy eating, there is increased interest in it as a raw material for the food industry. Barley is also used for the production of malt which is a key ingredient for the production of beer and whisky. The number of microbreweries has grown and they are now found in remote regions. For breweries to distinguish themselves from competitors, product differentiation is becoming increasingly important and an attractive way of doing this is to use local ingredients (barley, malt and herbs). However, in order to utilise local barley for beverage production, it will usually be necessary to develop a local capacity for malting.
Sammendrag
We investigate a set of long-term (several decades) time series for the runoff at river gauges at daily resolution. They are monitored by the Agencia Nacional de Aguas, and time series provided by the Operador Nacional do Sistema Elétrico, Brazil. A total of 150 time series was obtained, with an average length of 73 years. Both long-term trends as well as the influence of extreme events on the dynamical behaviour are analyzed. We use Horizontal Visibility Graphs (HVGs) to determine the individual temporal networks for the time series, and extract their degree distributions. Statistical and information-theoretic properties of these distributions are calculated: robust estimators of skewness and kurtosis, the maximum degree occurring in the time series, the Shannon entropy, permutation complexity and Fisher Information. For the latter, we also compare the information measures obtained from the degree distributions to those using the original time series directly, to investigate the impact of graph construction on the dynamical properties as reflected in these measures. Focus is on one hand on universal properties of the HVG, common to all runoff series, and on site-specific aspects on the other. We show that a specific pretreatment of the time series conventional in hydrology, the elimination of seasonality by a separate z-transformation for each calendar day, is highly detrimental to the nonlinear behaviour. It changes long-term correlations and the overall dynamic towards more random behaviour. Analysis based on the transformed data easily leads to spurious results, and bear a high risk of misinterpretation.
Sammendrag
Effects of controlled atmosphere (CA) conditions on physiological disorders and fungal fruit decay on apple ‘Aroma’ were investigated. Fruit from three growing seasons were stored at 1% or 2% O2 (both at 2% CO2) at either 1°C or 3°C in small research units; controls were kept in the same ventilated rooms at the two temperatures (ambient air). The fruit were removed from storage after four or six months and assessed for fruit decay immediately afterwards and after two weeks at 20°C. Fruit quality parameters were recorded at the end of storage. On a three-year average, fruit stored in CA was less ripe at the end of storage. After both four and six months storage, CA reduced total decay (physiological disorders and fungal decay) by on average 70% and 45%, respectively, compared to storage in ambient air. Senescent breakdown was lower after CA storage for four months, but not after six months and not after simulated shelf life. Soft scald was lower when stored in CA both after cold storage at 1°C and simulated shelf life. After storage at 3°C there was lower incidence of soft scald when stored in CA after four months, but not after six months. For fungal fruit decay in general, there was no effect of low oxygen, however, 2% O2 gave slightly less bitter rot (Colletotrichum acutatum) than 1% O2 and significantly less than ambient air after simulated shelf life. Averaged over all oxygen levels, 1°C gave significantly less bitter rot than 3°C. It may be concluded that use of CA for storage of ‘Aroma’ is a good way of reducing development of physiological disorders. However, development of bitter rot seemed to be more influenced by temperature and storage time than by low O2.
Forfattere
Reidun Pommeresche Anne-Kristin Løes Torfinn TorpSammendrag
The density and diversity of springtails (Collembola) in the upper soil layer (0–3.8 cm) were studied in a perennial grass-clover ley in NW Norway during April–June 2012. The study was part of a field experiment comparing yields and soil characteristics after application of non-digested slurry (NS) versus anaerobically digested slurry (DS) from dairy cows. In total for three sampling dates, 39 species of springtails were identified. In the Control plots receiving no manure, the density level was around 30 000 individuals (ind.) m−2 throughout the whole season. Three days after slurry application (40 t ha−1), the density of springtails had dropped significantly; from 55 214 to 7410 ind. m−2 in the NS treatment and from 41 914 to 10 260 ind. m−2 in the DS treatment. After 7 weeks the densities had increased again to 54% and 38% of the initial levels in NS and DS treatments, respectively. The springtails were divided into two ecological groups based on morphology and colour. The epigeic group comprised surface-dwelling species with eye organs and pigmentation. The endogeic group comprised soil-dwelling species lacking eye organs and pigmentation, and generally with shorter extremities than those found in the epigeic group. The negative effect of manure application on density was more severe and long-lasting in the epigeic than in the endogeic group. This effect was similar for both manure types. One species (Parisotoma notabilis) comprised 50% of the epigeic population, while three Mesaphorura spp. and Stanaphorura lubbocki comprised half the endogeic population. In general, the community structure, described by the relative abundance of each species, was more affected by manure application in the epigeic than in the endogeic group. Hence, slurry application seemed to affect surface-dwelling species more negatively than soil- dwelling species, even within the small sampling depth used here. The density of endogeic species seemed to recover faster than the density of the epigeic species. A simplified classification of epigeic and endogeic springtails, based on the presence or absence of pigmentation and eyes, may be useful in studies of soil springtails where identification of the actual species is not the primary purpose.
Forfattere
Sebastian Sippel Holger Lange Miguel D. Mahecha Michael Hauhs Paul Bodesheim Thomas W. Kaminski Fabian Gans Osvaldo A. RossoSammendrag
Data analysis and model-data comparisons in the environmental sciences require diagnostic measures that quantify time series dynamics and structure, and are robust to noise in observational data. This paper investigates the temporal dynamics of environmental time series using measures quantifying their information content and complexity. The measures are used to classify natural processes on one hand, and to compare models with observations on the other. The present analysis focuses on the global carbon cycle as an area of research in which model-data integration and comparisons are key to improving our understanding of natural phenomena. We investigate the dynamics of observed and simulated time series of Gross Primary Productivity (GPP), a key variable in terrestrial ecosystems that quantifies ecosystem carbon uptake. However, the dynamics, patterns and magnitudes of GPP time series, both observed and simulated, vary substantially on different temporal and spatial scales. We demonstrate here that information content and complexity, or Information Theory Quantifiers (ITQ) for short, serve as robust and efficient data-analytical and model benchmarking tools for evaluating the temporal structure and dynamical properties of simulated or observed time series at various spatial scales. At continental scale, we compare GPP time series simulated with two models and an observations-based product. This analysis reveals qualitative differences between model evaluation based on ITQ compared to traditional model performance metrics, indicating that good model performance in terms of absolute or relative error does not imply that the dynamics of the observations is captured well. Furthermore, we show, using an ensemble of site-scale measurements obtained from the FLUXNET archive in the Mediterranean, that model-data or model-model mismatches as indicated by ITQ can be attributed to and interpreted as differences in the temporal structure of the respective ecological time series. At global scale, our understanding of C fluxes relies on the use of consistently applied land models. Here, we use ITQ to evaluate model structure: The measures are largely insensitive to climatic scenarios, land use and atmospheric gas concentrations used to drive them, but clearly separate the structure of 13 different land models taken from the CMIP5 archive and an observations-based product. In conclusion, diagnostic measures of this kind provide dataanalytical tools that distinguish different types of natural processes based solely on their dynamics, and are thus highly suitable for environmental science applications such as model structural diagnostics.
Forfattere
Sanford D. Eigenbrode A. Nicholas E. Birch Summer Lindzey Richard Meadow William E. SnyderSammendrag
1. Push-pull or stimulo-deterrent cropping systems combine a trap crop or other attractant or arrestant stimulus distant from the crop and a deterrent or repellent near or within the target crop, to divert pests, reducing their populations on the target crop. Although the concept is decades old, there are few successful applications in pest management. 2. In this article, we address this shortcoming by offering a mechanistic conceptual framework of push-pull systems, based on the cues, sensory modalities, pest behaviours and spatial ranges over which they can occur during host selection and that can influence pest distribution. 3. We review published work on push-pull systems in the light of this framework, finding that the literature tends to focus on longer-range stimulo-deterrence strategies rather than the full range of cues involved and modalities that can come into play, with imperfect understanding of cues involved in most systems. 4. The imbalance in research emphasis and incomplete understanding of push-pull mechanisms suggest opportunities to improve and broaden the palette of potential push-pull technologies. 5. The framework also helps clarify other aspects important for achieving success with push-pull methods, including the role of synergy, deployment geometry, intraspecific variability and the wider arthropod community in these systems. 6. Synthesis and applications. A conceptual and mechanistic framework is provided for the development of push-pull or stimulo-deterrent pest management approaches. This framework informs a proposed research agenda for designing push-pull technologies. That agenda involves including all cues and modalities, exploiting synergies, tuning deployment geometry in accordance with these factors. It also considers pest and crop dynamics and the arthropod community of the system. The framework can benefit managers by helping them to consider more fully the behaviour of the target pests when creating crop and non-crop geometries to achieve push-pull benefits. Research-based push-pull systems will be better implemented and modified by producers if they understand how insects respond to sources of push and pull in the system, allowing effective monitoring and fine-tuning to increase effectiveness of this specialized component of integrated pest management.