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.
2017
Sammendrag
Stand dynamics and the gap initiation prior to gap formation are not well- understood because of its long- term nature and the scarcity of late- successional stands. Reconstruction of such disturbance is normally based on historical records and den-droecological methods. We investigated gap initiation and formation at the fine- scale stand level in the old- growth reserve of Karlshaugen in Norway. Given its long- term conservation history, and thorough mapping in permanent marked plots with spatially referenced trees, it provides an opportunity to present stand development before, during, and after gap formation. Late- successional decline in biomass was recorded after more than 50 years of close to steady state. Gaps in the canopy were mainly cre-ated by large old trees that had been killed by spruce bark beetles. Snapping by wind was the main reason for treefall. Long- term dominance of Norway spruce excluded downy birch and Scots pine from the stand. Comparisons of the forest floor soil prop-erties between the gap and nongap area showed significantly higher concentrations of plant available Ca within the gap area. Plant root simulator (PRS™) probes showed significantly higher supply rates for Ca and Mg, but significantly lower K for the gap compared to the nongap area. Soil water from the gap area had significantly higher C:N ratios compared to the nongap area. Fine- scale variation with increasing distance to logs indicated that CWD is important for leaking of DOC and Ca. Our long- term study from Karlshaugen documents gap dynamics after more than 50 years of steady state and a multiscale disturbance regime in an old- growth forest. The observed dis-turbance dynamic caused higher aboveground and belowground heterogeneity in plots, coarse woody debris, and nutrients. Our study of the nutrient levels of the forest floor suggest that natural gaps of old- growth forest provide a long- lasting biogeo-chemical feedback system particularly with respect to Ca and probably also N. Norway spruce trees near the gap edge responded with high plasticity to reduced competition, showing the importance of the edge zone as hot spots for establishing heterogeneity, but also the potential for carbon sequestration in old- growth forest.
Sammendrag
Organisms that modify the environment (niche constructors) are likely candidates to mediate the effects of climate warming. Here we assess tundra plant community changes along a temperature gradient and how these are modified in the presence of the common allelopathic dwarf shrub Empetrum nigrum and the large herbivore Rangifer tarandus. We developed a structural equation model based on data from a field-based study of 1450 tundra plant communities across Northern Fennoscandia, covering a temperature gradient of 3.5 °C, contrasting Rangifer densities, a range of Empetrum abundances in addition to gradients in topography and bedrock. We found temperature to be a significant positive predictor of Empetrum, herbaceous and woody plant abundances. However, the effect of temperature as predictor for herbaceous plant abundance was significantly reduced in communities with Empetrum present. For woody plant abundance Empetrum was a stronger predictor than temperature. In comparison, we found Rangifer density to have marginal or no effect on either herbaceous or woody plant abundance. These findings were not modified by either topography or bedrock. Results from this study indicate that herbaceous plant responses to climate warming are currently reduced in communities where Empetrum is present, whereas the abundance of Empetrum and other woody plants is promoted. Results also indicate that any future Empetrum encroachment is likely to drive tundra communities towards slower process rates and lower biodiversity. As such our results substantiate the importance of understanding the dynamics of niche constructor species and include them in predictive models of climate change.
Sammendrag
Several studies focus on the effects of climate variability on female and male gender relations as perceived through various biophysical and socio-economic aspects. More emphasis is given on the impacts of extreme weather events on rural communities of less developed regions. The results are often interpreted in a qualitative manner through policy measures that may reduce gender inequalities. However, the interpretation of the qualitative results to more crisp and measurable outputs is often not attained while the validation of the findings is rarely ensured. The current study suggests a gender-differentiated impact framework based on qualitative and quantitative components for the assessment of climate variability effects on rural communities in South India. Fifteen villages mostly practicing rice farming in Andhra Pradesh and Telangana states were selected as representative drought-prone case studies. The study results advocate that the qualitative outcomes were validated from the quantitative approach but for a few cases which could be attributed to methodological and case-specific differentiations. Policy recommendations are made on common gender trainings in water-resistant crops and livestock activities for the alleviation of drought impact and abatement of gender inequalities. Also, entrepreneurship workshops for women could enhance gender balance and diverse family income from the current sole dependence on farming revenues. Regional climate adaptation programs could be better implemented when the specific features and capacities of local communities are taken into consideration.
Forfattere
Kimm J.E. van Hulzen Claus J. Scholz Barbara Franke Stephan Ripke Marieke Klein Andrew McQuillin Edmund J.S. Sonuga-Barke John R. Kelsoe Mikael Landén Ole Andreassen Klaus-Peter Lesch Heike Weber Stephen Faraone Alejandro Arias-Vasquez Andreas Reif Søren Dalsgaard Srdjan Djurovic Omar Gustafsson Morten Mattingsdal Ingrid Melle Gunnar Morken Johannes SchumacherSammendrag
Det er ikke registrert sammendrag
Forfattere
Kenan Kanlic Belma Kalamujic Naris Pojskic Jasmin Grahic Fuad Gasi Åsmund Asdal Mekjell MelandSammendrag
In order to investigate the genetic structure and differentiation among north and south European apple germplasm, 141 apple accessions maintained in ex situ collections in Norway and 110 traditional and international apple accessions from Bosnia and Herzegovina (B&H) were analyzed using 8 microsatellite markers. Bayesian analyses, based on the microsatellite data, grouped most of the accessions into two major clusters. The first cluster consisted mainly of traditional and international B&H accessions, as well as Norwegian accessions derived mostly from foreign or formal breeding programs (‘James Grieve’, ‘Katja’, ‘Summerred’, ‘Bramleys Seedling’, ‘Elstar’, ‘Katinka’, ‘Belle de Boskoop’, ‘Jacques Lebel’, etc.). The second cluster consisted almost exclusively of traditional Norwegian accessions. Further analyses divided each cluster into two sub-clusters. Cluster 1.1 included Norwegian accessions derived from foreign or commercial breeding programs, international cultivars and B&H accessions introduced from Europe and North America during the rule of Austria-Hungarian Empire. Cluster 1.2 included traditional B&H accessions introduced during the reign of Ottoman Empire. Cluster 2.1 and 2.2 consisted mainly of traditional apple accession from Norway. The results obtained indicate a clear genetic structure and differentiation among north and south European apple germplasm, presumably due to climate adaptation and selection.
Sammendrag
The number of effective breeders (Nb) and effective population size (Ne) are population parameters reflective of evolutionary potential, susceptibility to stochasticity, and viability. We have estimated these parameters using the linkage disequilibrium-based approach with LDNE through the latest phase of population recovery of the brown bears (Ursus arctos) in Finland (1993–2010; N = 621). This phase of the recovery was recently documented to be associated with major changes in genetic composition. In particular, differentiation between the northern and the southern genetic cluster declined rapidly within 1.5 generations. Based on this, we have studied effects of the changing genetic structure on Nb and Ne, by comparing estimates for whole Finland with the estimates for the two genetic clusters. We expected a potentially strong relationship between estimate sizes and genetic differentiation, which should disappear as the population recovers and clusters merge. Consistent with this, our estimates for whole Finland were lower than the sum of the estimates of the two genetic clusters and both approaches produced similar estimates in the end. Notably, we also found that admixed genotypes strongly increased the estimates. In all analyses, our estimates for Ne were larger than Nb and likely reflective for brown bears of the larger region of Finland and northwestern Russia. Conclusively, we find that neglecting genetic substructure may lead to a massive underestimation of Nb and Ne. Our results also suggest the need for further empirical analysis focusing on individuals with admixed genotypes and their potential high influence on Nb and Ne.
Sammendrag
De norske askeskogene er en nordlig utløper av større askeskoger i Europa som spredte seg nordover etter siste istid. Vi har undersøkt genetisk variasjon i ask (Fraxinus excelsior) og funnet at asken i Norge fulgte en østlig innvandringsvei fra overvintringsområder i SørøstEuropa. Mens den genetiske variasjonen i stor grad ble opprettholdt gjennom Europa, gikk svært mye av den genetiske variasjonen tapt nordover langs kysten av Norge, hvor vi også finner de største genetiske forskjellene mellom askepopulasjonene. Kunnskap om askens genetiske variasjon er verdifull for forvaltningen med tanke på framtidig restaurering og bevaring av genetiske ressurser nå som asken er truet av askeskuddsjuke.
Sammendrag
Et forsøk med sommer- og vintereik fra 14 populasjoner fra Borre i nord til Mandal i sør, i tillegg til tre danske frøkilder, ble etablert på Kaldvell, Aust-Agder, i 2001. De samme materialene ble plantet på fem forsøkslokaliteter i Danmark. Etter 15 år var 68 % av trærne i forsøket på Kaldvell fortsatt i live, med en variasjon fra 55 til 81 % i overlevelse mellom populasjonene. Middelhøyden på feltet var da 4,5 m. Det var klare forskjeller i høyde mellom populasjonene med en variasjon fra 3,5 til 5,7 m. Det var også forskjeller mellom populasjoner for andel trær som hadde sannsynlighet for god tømmerkvalitet med tilnærmet rett stamme de første tre meter fra bakken. Andel trær i de ulike populasjonene som hadde rett stammeform varierte fra 5 til 23 %. På to felt i Danmark ble det gjort registrering av tidspunkt for knoppskyting på våren, og det var variasjon mellom populasjoner også for denne egenskapen. Trær fra populasjoner med sein knoppskyting i Danmark hadde dårligst stammeform på Kaldvell. På feltene i Danmark var det også forskjeller mellom populasjoner for de samme egenskapene. For noen av disse var det samsvar med resultatene fra Kaldvell, men ikke for alle. Forsøket inneholder trær fra både vinter- og sommereik. Trærne fra populasjoner med betydelig andel sommereik har i dette forsøket både dårligst overlevelse og laveste høyder. Forsøket viser at det er betydelige forskjeller i mange egenskaper på trær fra forskjellige populasjoner av eik. Dersom en ønsker å etablere plantefelt av eik med god overlevelse og vekst og rette stammer, er det derfor viktig å ha kunnskap om vekst og kvalitetsegenskaper til trærne fra populasjonene eikenøttene kommer fra.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag