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.
2008
Authors
Vidar Selås Ronny Steen Sverre Kobro Terje Lislevand Ingvar StenbergAbstract
In Norway, a positive relationship between spring numbers of lesser spotted woodpecker (Dendrocopos minor) and previous June temperatures has been interpreted as an effect of temperatures on woodpecker survival and reproduction during the breeding season. This article considers the possibility that woodpecker numbers are related to the abundance of the moth Argyresthia goedartella in the current year. Larvae and pupae of A. goedartella are important food for lesser spotted woodpeckers in early spring when few other surface-living invertebrates are available. The occurrence of this moth depends on the flowering of birch (Betula spp.) and alder (Alnus glutinosa), which in turn is influenced by June temperatures in the preceding year. Spring numbers of the lesser spotted woodpecker in two regions of Norway were compared with a trapping index of A. goedartella and weather variables assumed to influence the woodpeckers' breeding success and adult survival. The best multiple regression model included December temperatures and moth indices, supporting the hypothesis of a strong impact of A. goedartella on spring survival. Conservation strategies for the lesser spotted woodpecker should therefore focus not only on minimum areas of deciduous forests with decaying wood, but also on the availability of the moths' host trees, birch and alder.
Authors
Geir Kjølberg Knudsen Maria Bengtsson Sverre Kobro Gunnhild Jaastad Trond Hofsvang Peter WitzgallAbstract
Apple fruit moth Argyresthia conjugella is a specialist seed predator of rowan Sorbus aucuparia. Large-scale synchronous fluctuation of seed production in rowan (i.e. named masting) drives the apple fruit moth to seek alternative host plants such as apple, during years when rowan berries are not available for oviposition. The role of plant volatile compounds in the attraction of gravid apple fruit moth females is studied in a laboratory wind tunnel. Volatiles from rowan branches with green berries stimulate female moths to fly upwind and to land at the odour source. By contrast, females are not attracted to rowan branches without green berries, and they are not attracted to apple, demonstrating that the chemical stimulus from rowan berries is required for attraction. Attraction to synthetic compounds identified from rowan, anethole and 2-phenyl ethanol confirms the role of plant volatiles in host finding. These two compounds, however, show a discrepant behavioural effect in wind tunnel and field tests. Field traps baited with 2-phenyl ethanol capture female moths but anethole does not produce significant captures. Wind tunnel tests produce the opposite results: moths fly upwind towards the anethole lure, whereas 2-phenyl ethanol is not attractive at all. Wind tunnel attraction to 2-phenyl ethanol is achieved by adding odour from a rowan branch without berries, which is not attractive on its own. This finding demonstrates that interaction with the background odour contributes to the behavioural effect of plant volatile stimuli in the field.
Authors
Silja Korhonen-Sande Erlend NybakkAbstract
No abstract has been registered
Authors
Arild Andersen An Tran Thi Thien Einar NordhusAbstract
The present distribution and host plant preferences of the polyphagous pest species Liriomyza sativae, L. huidobrensis, L. trifolii and L. bryoniae within the different provinces of Vietnam is discussed. For each species also the possible further spread within Vietnam is discussed.
Abstract
No abstract has been registered
Abstract
In this project plant and vegetation preferences of two Norwegian dairy cattle breeds with different selection history were studied. The Norwegian dairy breed Blacksided Trønder and Nordland Cattle (STN) has never been selected efficiently for higher milk production. The other breed, however, the Norwegian Red (NR), has mainly been selected for this. Two herds both consisting of STN and NR cows, were studied. To examine the animals\" plant preferences, faeces samples were collected and analysed for plant fragments. Vegetation maps were also used to find possible differences in grazing preferences. Breed differences with regard to recorded plant fragments in the faeces samples were significant for Nardus stricta, a species characteristic for nutrient poor but mostly species rich vegetation types in the studied areas, vegetation types of high importance for the biodiversity especially in one of the areas. STN had the highest share of Nardus stricta. Altogether the results of the study indicate that a higher producing cattle breed might prefer to graze more nutrient rich vegetation areas compared to a lower yielding cattle breed, when grazing less nutrient and base rich - but species rich grasslands.
Abstract
No abstract has been registered
Abstract
The current report is a background for a Pest Risk Assessment (PRA) of the bark beetle species Ips amitinus in the PRA area of Norway, following the International Standards for Phytosanitary Measures ISPM 11 (FAO 2004). The report is based on updated information about distribution, pathogenicity and ecological information, which add to a previous PRA for this species. It is concluded that the risk of establishment is high with the current import and management practices. I. amitinus may potentially cause significant tree damage alone or in interaction with Ips typographus; however, the outcome is very much dependent on scenarios of climate development and population dynamics.
Authors
Wim de Vries Svein Solberg Matthias Dobbertin Hubert Sterba Daniel Laubhann Gert Jan Reinds Gert-Jan Nabuurs Per Gundersen Mark A. SuttonAbstract
Nitrogennedfallet i skog virker gjødslende på skog, og fører derfor til økt karbonbinding. Så selv om nitrogennedfallet er en forurensning, så har det den positive effekt at det bidrar til å motvirke klimaendringene. Spørsmålet er hvor stor denne effekten er. Vi har i vårt EU/Forest Focus-prosjekt ”Assessment of the relative importance of nitrogen deposition, climate change and forest management on the sequestration of carbon at intensive monitoring plots in Europe” estimert denne effekten til å være omkring 30 kg ekstra bundet karbon for hver kg nitrogen som blir avsatt i skog...
Authors
Rastislav Solár Miroslav Mamo Janka Dibdiakova Ladislav Reinprecht Milo Pánek Jozef HudecAbstract
A series of comparable specimens of hornbeam wood were submitted to pre-treatments by white-rot fungi and by alkali, or alkali followed by oxidation agents. The pre-treatments caused weight loss of wood and modified its physical properties and chemical composition.All pre-treatments reduced axial permeability of the test specimens in wet state (w FSP). The pre-treatments of the test specimens by diluted sodium hydroxide, or sodium hydroxide followed by hydrogen peroxide, however increased rate of diffusion in direction parallel to grain. The pre-treatments also made the kinetics of wood/water interactions in its initial phase much higher, especially when the white-rot fungi were used.The chemical pre-treatments of hornbeam wood caused its extreme final swelling, and on the other hand, a careful drying to initial moisture content resulted in its deep collapse. An increased rate of wood/water interactions, higher uptake of water and higher diffusion coefficients of wood pre-treated by alkali may play a positive role in the pulping processes.