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
Sammendrag
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Forfattere
Sam Steyaert Shane Frank Stefano Puliti Rudy Badia Mie P. Arnberg Jack Beardsley Asle Økelsrud Rakel BlaalidSammendrag
Cadaver decomposition islands around animal carcasses can facilitate establishment of various plant life. Facultative scavengers have great potential for endozoochory, and often aggregate around carcasses. Hence, they may disperse plant seeds that they ingest across the landscape towards cadaver decomposition islands. Here, we demonstrate this novel mechanism along a gradient of wild tundra reindeer carcasses. First, we show that the spatial distribution of scavenger faeces (birds and foxes) was concentrated around carcasses. Second, faeces of the predominant scavengers (corvids) commonly contained viable seeds of crowberry, a keystone species of the alpine tundra with predominantly vegetative reproduction. We suggest that cadaver decomposition islands function as endpoints for directed endozoochory by scavengers. Such a mechanism could be especially beneficial for species that rely on small-scale disturbances in soil and vegetation, such as several Nordic berry-producing species with cryptic generative reproduction.
Sammendrag
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Forfattere
Francesca Giannetti Gherardo Chirici Terje Gobakken Erik Næsset Davide Travaglini Stefano PulitiSammendrag
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Sammendrag
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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.
Sammendrag
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Foredrag – Snutebillen – en utfordring for foryngelsen
Inger Sundheim Fløistad, Kjersti Holt Hanssen
Sammendrag
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Sammendrag
Several studies have shown the positive effect of nitrogen fertilization on conifer growth. In young Norway spruce (Picea abies) stands, an additional effect of including a mixture of other nutrients has often, but not always, been found. We studied effects of repeated fertilization in 28 stands with young Norway spruce in central Norway. The treatments consisted of plots without nutrient addition (Control), fertilization with 150 kg N ha−1 (150 N), and fertilization with 150 kg N plus addition of P, K, Mg, B, Mn and Cu (150 N + mix), repeated three times with approximately eight years interval. There was a clear positive effect on volume increment of the 150 N and 150 N + mix treatments compared to Control, and the effect was significantly higher for 150 N + mix than for 150 N. Fertilization had a stronger effect in the first fertilization period than in the second, while the third period was intermediate. The effect of 150 N + mix was strongest at plots > 300 m a.s.l. However, this correlation may be due to geological conditions rather than elevation. Further studies are needed to find out under which edaphic conditions a nutrient mixture will increase growth substantially in young spruce stands.
Sammendrag
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