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.
2013
Forfattere
Marianne Evju Vegar Bakkestuen Hans Blom Tor Erik Brandrud Harald Bratli Bjørn Nordén Odd Egil Stabbetorp Anne Sverdrup-Thygeson Frode ØdegaardSammendrag
Mange truete arter i Norge forekommer fåtallig, klumpvis i bestemte naturtyper (hotspot-habitater) og i bestemte deler av landet (hotspot-regioner). Gjennom å kartlegge og overvåke hotspot-habitater, kan vi effektivt få bedre kunnskap om status og trender for mange truete og rødlistete arter.
Sammendrag
North European epiphytic lichens are often genetically impoverished compared with their North American counterparts. This has been hypothesized to impede sexual reproduction due to reduced chances of finding compatible mating type partners. We compared genetic variation and reproductive mode in two threatened Scandinavian lichens, Evernia divaricata and Usnea longissima, with more viable populations in North America to see (i) if these species also show genetical depletion in northern Europe and (ii) if the occurrence of sexual propagules (ascospores in apothecia) is more prevalent in genetically diverse populations. Genetic variation of the fungal component was assessed by sequencing two nuclear rDNA gene regions (ITS and IGS) in 1005 and 1477 thalli, collected from 92 and 160 localities of E. divaricata and U. longissima, respectively. Scandinavian populations of both species were almost devoid of genetic variation compared with much higher genetic diversity in North America.We found no support for the proposed relationship between genetic diversity and fertility. Fertile thalli were found in several genetically invariable populations. Fertility increased with population size and regional abundance in E. divaricata, but not in U. longissima. In Scandinavia, E. divaricata was more fertile than previously recorded, whereas all sampled populations of U. longissima were sterile and possibly clonal.
Forfattere
Fride Høistad Schei Hans Blom Ivar Gjerde John Arvid Grytnes Einar Heegaard Magne SætersdalSammendrag
Retention of selected trees in clear-felling areas has become an important conservation measure in managed forests. Trees with large size or high age are usually preferred as retention trees. In this paper we investigated whether a single large or several small trees should be left in clear-felling areas to serve as life boats and future habitat for epiphytic species. The focal species were 25 Lobarion epiphytic lichens hosted by aspen (Populus tremula). We analyzed the relationships between: (1) proportion of trees colonized and tree size, (2) number of lichen thalli (lichen bodies) and aspen area, and (3) number of lichen species and aspen area, for 38 forest sites. Mixed effect models and rarefaction analyzes showed that large and small host trees had the same proportion of trees colonized, the same number of thalli, and the same species richness for the same area of aspen bark. This indicates that larger aspens do not have qualities, beyond size, that make them more suitable for Lobarion lichens than smaller sized aspen trees. None of the species, not even the red-listed, showed any tendencies of being dependent on larger aspens, and our results therefore did not support a strategy of retaining only large and old trees for conservation of epiphytic Lobarion lichens. Additionally, young aspens have a longer expected persistence than old aspens. However, old retention trees might be important for other species groups. We therefore recommend a conservational strategy of retaining a mixed selection of small/young and large/old aspens.
Forfattere
Jørund RolstadSammendrag
Environmentalists tell us that we’re loosing species at an increasing rate, and if we are to stop the cascading extinctions by 2020 (which we have agreed upon in international conventions) we need to take immediate action. Making sure we’re not loosing any ’native’ species may seem a daunting task, especially if we look at insects, spiders, fungi, and other tiny creatures that live in dead wood. For thousands of these saproxylic species the wood and timber that we are harvesting make up the bread and butter of their everyday life. The competition is fierce, and it doesn’t get any better when we remove most of the wood that otherwise would have become their future homes. What shall we do?
Sammendrag
Forskere er bekymret for flere typer hengelav. Lite genetisk variasjon kan få konsekvenser for skogens helse.
Sammendrag
Mjuktjafs og huldrestry er hengelav som er svært følsomme for hogst og luftforurensning. Liten genetisk variasjon og ukjønnet formering gjør imidlertid disse rødlistede vokterne av skogens helsetilstand mer utsatt enn tidligere antatt.
Intervju – Skovens sundhedsvogtere svækkes af hugst og forurening
Lars Sandved Dalen, Jørund Rolstad
Sammendrag
To arter af hængelav, en skæglav og en slåenlav, er meget følsomme over for hugst og luftforurening. Svag genetisk variation og ukønnet formering gør de rødlistede vogtere af skovens sundhedstilstand mere udsatte end troet.
2012
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Fire is the most important ecological factor governing boreal forest stand dynamics. In low- to moderate-severity fires, the post-fire growth of the surviving trees varies according to fire frequency, intensity and site factors. Little is known about the growth responses of Scots pine (Pinus sylvestris L.) following fires in boreal forests. We quantified changes in tree growth in the years following 61 historical forest fires (between 1210 and 1866) in tree-ring series collected from fire-scarred Scots pine trees, snags and stumps in Trillemarka nature reserve in south-central Norway. Basal area increment 10 years pre-, 5 years post-, and 11-20 years post-fire were calculated for 439 fire scars in 225 wood samples. We found a slight temporary growth reduction 5 years post-fire followed by a marked growth increase 11-20 years post-fire. Beyond 20 years post-fire, the long-term tree growth declined steadily up to approximately 120 years. Our results indicate that recurring fires maintained high tree growth in remnant Scots pines, most probably due to a reduction in tree density and thus decreased competition.