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
Tatsiana EspevigSammendrag
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Sammendrag
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Sammendrag
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Sammendrag
Det er ikke registrert sammendrag
Sammendrag
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Forfattere
Lars T. Havstad Trygve S. Aamlid Ove Hetland Åge Susort Anne Steensohn Elise Krey Pedersen Eli Unn DahlSammendrag
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Sammendrag
Det ble sommeren 2017 gjennomført et kartleggingsprogram for å undersøke om importert plantemateriale av jordbær kunne være infisert av virus. Det ble tatt ut stikkprøver i jordbærfeltene hos utvalgte bærprodusenter som hadde baser sin produksjon på importerte planter, til sammen 150 prøver. Disse prøvene ble testet for fire bladlusoverførte virus som er relativt vanlige i Europa, men ikke i Norden: jordbær-nervebåndvirus (strawberry vein banding virus), jordbær-mildmosaikkvirus (strawberry mottle virus), jordbær-bladgulningvirus (strawberry mild yellow edge virus) og jordbærbladkrøllevirus (strawberry crinkle virus). Det ble påvist virus i prøver fra tre lokaliteter: strawberry crinkle virus ble funnet på tre steder, mens strawberry mild yellow edge virus ble funnet på ett sted i en prøve som hadde dobbeltinfeksjon med strawberry mild yellow edge virus og strawberry crinkle virus. Prøvene hadde ikke synlige symptomer.
Sammendrag
This study addresses changes in visual appearance of unpainted wood materials exposed outdoors. Specimens of Norway spruce (Picea abies) Scots pine (Pinus sylvestris), aspen (Populus tremula), acetylated Radiata pine (Pinus radiata) and DMDHEU-modified Scots pine sapwood were exposed facing south in Ås, Norway for 60 weeks. During this period, surface mould growth development and wasp attack were assessed visually. Development in lightness (L*) and the uniformity of the weather grey colour were assessed by image analysis. The mould rating of the tested wood materials developed in varying speed, but all specimens had reached the maximum rating after 42 weeks. Our results indicate that most specimens continued to darken after the specimens had reached maximum mould rating, and that evaluation of L* can provide additional information about the surface mould growth. Furthermore, our results indicate that most materials developed a less uniform appearance than what was initially, except from DMDHEU which obtained a more uniform appearance as a consequence of the weathering. This study also shows that wasp attack can give a lighter appearance of the wood by chewing off the top weathered layer. Different wood substrates were attacked in varying degree. Aspen was the substrate most severely attacked by wasps while the acetylated wood was not attacked at all during the 60 weeks of exposure.
Forfattere
Frans-Jan W. Parmentier Daniel Rasse Magnus Lund Jarle W. Bjerke Bert G. Drake Simon Weldon Hans Tømmervik Georg Heinrich HansenSammendrag
Extreme winter events that damage vegetation are considered an important climatic cause of arctic browning—a reversal of the greening trend of the region—and possibly reduce the carbon uptake of northern ecosystems. Confirmation of a reduction in CO2 uptake due to winter damage, however, remains elusive due to a lack of flux measurements from affected ecosystems. In this study, we report eddy covariance fluxes of CO2 from a peatland in northern Norway and show that vegetation CO2 uptake was delayed and reduced in the summer of 2014 following an extreme winter event earlier that year. Strong frost in the absence of a protective snow cover—its combined intensity unprecedented in the local climate record—caused severe dieback of the dwarf shrub species Calluna vulgaris and Empetrum nigrum. Similar vegetation damage was reported at the time along ~1000 km of coastal Norway, showing the widespread impact of this event. Our results indicate that gross primary production (GPP) exhibited a delayed response to temperature following snowmelt. From snowmelt up to the peak of summer, this reduced carbon uptake by 14 (0–24) g C m−2 (~12% of GPP in that period)—similar to the effect of interannual variations in summer weather. Concurrently, remotely-sensed NDVI dropped to the lowest level in more than a decade. However, bulk photosynthesis was eventually stimulated by the warm and sunny summer, raising total GPP. Species other than the vulnerable shrubs were probably resilient to the extreme winter event. The warm summer also increased ecosystem respiration, which limited net carbon uptake. This study shows that damage from a single extreme winter event can have an ecosystem-wide impact on CO2 uptake, and highlights the importance of including winter-induced shrub damage in terrestrial ecosystem models to accurately predict trends in vegetation productivity and carbon sequestration in the Arctic and sub-Arctic.
Sammendrag
Det er ikke registrert sammendrag