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
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Sammendrag
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Sammendrag
Extensive green roofs have become a frequently used option for stormwater retention across manydifferent climates including cold and wet regions. Despite the extensive documentation of green rooftechnology for stormwater management, the knowledge about their function and potential use in wetand cold regions is deficient. Using historic data on daily temperature and precipitation in a green roofwater balance model coupled with the Oudin model of evapotranspiration (ET), we evaluated the effects ofmaximum green roof storage capacities (Smax) and ET on stormwater retention along climatic gradientsin Northern Europe. Large differences in potential annual stormwater retention were found betweenlocations, driven by differences in temperature and precipitation amounts. Highest retention in abso-lute values was found for the wettest locations, while the warmest and driest locations showed highestretention in percentage of annual precipitation (up to 58% compared to 17% for the lower range). Alllocations showed a considerable retention of stormwater during summer, ranging from 52% to 91%. Stor-age capacities accepting drought conditions once every 3.3–3.9 year were found to be about 25 mm inthe cold and wet locations increasing to 40–50 mm in the warmer and drier locations. Correspondingstorage capacities to prevent wilting of non-succulent vegetation was on average a factor of 1.5 larger(not including Sheffield and Malmö). Annual retention increased both with an increase in plant wateruse (specific crop factors, Kc) and with an increase in Smax, but was found to be more sensitive to changesin Kcthan to changes in Smax. Hence, ET was the limiting factor for green roof retention capacity in thecold and wet locations, but relatively large changes in evapotranspiration would be needed to have animpact on retention. The potential to use vegetation with higher water use to better restore the storagecapacity between storm-events in these regions was however limited by the risk of permanent wilting ofnon-succulent vegetation, even on the wettest locations. A considerable increase in roof storage capacityand substrate thickness would be required to reduce this risk; still the increase in stormwater retentionwould be marginal.
Sammendrag
Nitrogen-limited ecosystems are threatened by extensive spread of broom (Cytisus scoparius (L.) Link), a European leguminous shrub that is invasive in several countries. The establishment of invading species may, however, be suppressed by competition from native vegetation. The neighbor impact of the grass Festuca rubra subsp. commutata Gaudin on the performance of C. scoparius was studied in a greenhouse experiment with different arrival order, under low and high nitrogen supply, and with or without inoculation of nitrogen-fixing bacteria. Aboveground biomass of both species was measured after a six-months establishment period, and after a five-months regrowth period. In both periods, presence of F. rubra reduced the performance of C. scoparius as indicated by negative neighbor-effect intensity indices (NIntA). During the establishment period the competitive impact of F. rubra was highest, when planted before C. scoparius, followed by synchronous and late planting. Inoculation with rhizobia and low fertilization decreased the competitive impact of F. rubra. After cutting and regrowth priority effects of F. rubra were still visible. Interaction between the two study species was not affected anymore by inoculation, but strongly by fertilization, with highest competitive impact of F. rubra on C. scoparius under high nitrogen fertilization. In both study periods biomass of C. scoparius was negatively correlated with biomass of F. rubra. Our study provides knowledge about competition processes, which help to improve conservation and restoration measures regarding the spread of C. scoparius. Early sowing of a native grass can help to suppress the invasive species at an early stage. Competitive impact of the grass might be strengthened by high nitrogen availability.
Sammendrag
Grønne tak demper og fordrøyer avrenning etter nedbør og er etablert som et tiltak for lokal overvannsdisponering. I prosjektet Fremtidens Byer, ble det i 2014 etablert forsøkstak med utprøving av ulike tekniske løsninger og vegetasjon i flere norske byer. I denne rapporten følger vi opp utviklingen på disse takene med analyser og vurderinger av vegetasjonen 4 vekstsesonger etter oppstart......
Sammendrag
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Sammendrag
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Sammendrag
Det er ikke registrert sammendrag
Sammendrag
(Forord) Denne veilederen er et resultat av et samarbeidsprosjekt mellom NIBIO og Fylkesmennene i Akershus, Østfold, Buskerud, Vestfold, Hedmark og Nord-Trøndelag. Dette er fylker med mye bakkeplanering, og fylkesmennene deltar derfor også med finansiering. Prosjektet startet med et idemøte med deltakere fra fylkesmenn, veiledningstjenesten, entreprenører og andre statlige etater med interesser innen bakkeplanering...
Forfattere
N.P. Havill J. Elkinton J.C. Andersen Snorre Hagen Hannah J. Broadley G.J. Boettner A. CacconeSammendrag
The European winter moth, Operophtera brumata, is a non-native pest in the Northeastern USA causing defoliation of forest trees and crops such as apples and blueberries. This species is known to hybridize with O. bruceata, the Bruce spanworm, a native species across North America, although it is not known if there are hybrid generations beyond F1. To study winter moth population genetics and hybridization with Bruce spanworm, we developed two sets of genetic markers, single nucleotide polymorphisms (SNPs) and microsatellites, using genomic approaches. Both types of markers were validated using samples from the two species and their hybrids. We identified 1216 SNPs and 24 variable microsatellite loci. From them we developed a subset of 95 species-diagnostic SNPs and ten microsatellite loci that could be used for hybrid identification. We further validated the ten microsatellite loci by screening field collected samples of both species and putative hybrids. In addition to confirming the presence of F1 hybrids reported in previous studies, we found evidence for multi-generation asymmetric hybridization, as suggested by the occurrence of hybrid backcrosses with the winter month, but not with the Bruce spanworm. Laboratory crosses between winter moth females and Bruce spanworm males resulted in a higher proportion of viable eggs than the reciprocal cross, supporting this pattern. We discuss the possible roles of population demographics, sex chromosome genetic incompatibility, and bacterial symbionts as causes of this asymmetrical hybridization and the utility of the developed markers for future studies.