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.
2020
Forfattere
Bert van der Veen Jenny Mattisson Barbara Zimmermann John Odden Jens PerssonSammendrag
Food-caching animals can gain nutritional advantages by buffering seasonality in food availability, especially during times of scarcity. The wolverine (Gulo gulo) is a facultative predator that occupies environments of low productivity. As an adaptation to fluctuating Food availability, wolverines cache perishable food in snow, boulders, and bogs for short- and long-term storage. We studied caching behavior of 38 GPS-collared wolverines in four study areas in Scandinavia. By investigating clusters of GPS locations, we identified a total of 303 food caches from 17 male and 21 female wolverines.Wolverines cached food all year around, from both scavenging and predation events, and spaced their caches widely within their home range.Wolverines cached food items on average 1.1 km from the food source andmade between 1 and 6 caches per source.Wolverines cached closer to the source when scavenging carcasses killed by other large carnivores; this might be a strategy to optimize food gain when under pressure of interspecific competition.When caching, wolverines selected for steep and rugged terrain in unproductive habitat types or in forest, indicating a preference for less-exposed sites that can provide cold storage and/or protection against pilferage. The observed year-round investment in caching by Wolverines underlines the importance of food predictability for survival and reproductive success in this species. Increasing temperatures as a consequence of climate change may provide newchallenges for wolverines by negatively affecting the preservation of cached food and by increasing competition from pilferers that benefit from awarmer climate. It is however still not fully understood which consequences this may have for the demography and behavior of the wolverine.
Forfattere
Valborg KvakkestadSammendrag
Det er ikke registrert sammendrag
Sammendrag
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Forfattere
Inger HansenSammendrag
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Forfattere
Ingrid TengeSammendrag
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Forfattere
Ingrid TengeSammendrag
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Sammendrag
Reinsdyr som beiter på innmarka kan i noen geografiske områder være årsak til en betydelig konflikt mellom reindriftsutøvere og landbruksnæringa. Uenigheten dreier seg i stor grad om hvem som har ansvaret og hvem som skal betale for tapt avling. Men hvor stor skade gjør reinsdyra egentlig på avlingsnivået?
Forfattere
Anne Linn HykkerudSammendrag
Det er ikke registrert sammendrag
Sammendrag
Adjustable crop load primarily involves bud manipulation, and usually switches from vegetative to reproductive buds. While this switch is not fully understood, it is still controlled by the ratio of hormones, which promote or inhibit bud formation. To determine the reasons for biennial bearing, the effect of apple rootstock, scion cultivar, crop load, as well as metabolic changes of endogenous phytohormones [zeatin, jasmonic acid, indole-3 acetic acid (IAA), abscisic acid (ABA), and gibberellins 1, 3, and 7 (GAs)], and soluble sugars (glucose, fructose, and sorbitol) were evaluated, and their connections with return bloom and yield of apple tree buds were analyzed. Cultivars “Ligol” and “Auksis” were tested on five rootstocks contrasting in induced vigor: semi-dwarfing M.26; dwarfing M.9, B.396, and P 67; and super-dwarfing P 22. Crop load levels were adjusted before flowering, leaving 75, 113, and 150 fruits per tree. Principal component analysis (PCA) scatter plot of the metabolic response of phytohormones and sugars indicated that the effect of the semi-dwarfing M.26 rootstock was significantly different from that of the dwarfing M.9 and P 67, as well as the super-dwarfing P 22 rootstocks in both varieties. The most intensive crop load (150 fruits per tree) produced a significantly different response compared to less intensive crop loads (113 and 75) in both varieties. In contrast to soluble sugar accumulation, increased crop load resulted in an increased accumulation of phytohormones, except for ABA. Dwarfing rootstocks M.9, B.396, and P 67, as well as super-dwarf P 22 produced an altered accumulation of promoter phytohormones, while the more vigorous semi-dwarfing M.26 rootstock induced a higher content of glucose and inhibitory phytohormones, by increasing content of IAA, ABA, and GAs. The most significant decrease in return bloom resulted from the highest crop load in “Auksis” grafted on M.9 and P 22 rootstocks. Average difference in flower number between crop loads of 75 and 150 fruits per tree in “Ligol” was 68%, while this difference reached ~ 90% for P 22, and ~ 75% for M.9 and M.26 rootstocks. Return bloom was dependent on the previous year’s crop load, cultivar, and rootstock.
Forfattere
Anita SønstebySammendrag
Det er ikke registrert sammendrag