Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
1999
Authors
Torstein KvammeAbstract
No abstract has been registered
Authors
Per Holm NygaardAbstract
This thesis deals with effects of acidification, fertilisation and addition of Al on boreal vegetation as studied in different field- and laboratory experiments. The results are discussed in relation to the natural vegetation dynamics and critical loads of S and N for forest soils. Field experiments with artificial acid rain caused damage to bryophytes like Pleurozium schreberi and Dicranum polysetum at pH 2.5 and pH 3.0. The presence of Melampyrum pratense was reduced when treated with pH 2.5 and pH 3.0. For the pH 2.5 treatment, a decreased leaf production and decreased internal Mg concentration of Vaccinium myrtillus leaves were recorded. Treatment with pH 2.5 and 3.0 resulted in decreased base saturation in the O and E horizons, in particular Mg2, which may explain the effects on V. myrtillus. Repeated N-fertiliser additions caused vegetation changes, particularly at higher doses (1500 kg N/ha).An increase in cover of the species Deschampsia flexuosa, Molinia caerulea, Agrostis capillaris, Carex canescens, Rubus idaeus, Epilobum angustifolium and Dryopteris assimilis were found 8 years after the last N-application. Chemical analysis of leaves of V. myrtillus demonstrated an increase in N and a decrease in P concentrations on the fertilised plots compared to controls.The concentration of exchangeable Ca2, Mg2and K in the humus layer were reduced in fertilised plots compared to control plots. No differences in pH(H2O) or exchangeable acidity in the humus layer were found between fertilised plots and control plots. Laboratory experiments with Mg-limited Norway spruce seedlings showed that 80 M Al3 and a constant molar Ca/Al ratio of 0.2 decreased the uptake of Ca2 and Mg2, and reduced root length growth. However, no indication of an ameliorating effect of K on Al were seen, therefore these experiments give no support for including K into the critical load criterion. In the critical load calculation it seems that the molar Ca/Al ratio has been emphasised too much, and in particular that the scientific evidence of the critical chemical value (Ca/Al=1) is not well documented. A lot of the processes going on in the forest ecosystem are oversimplified or even left out in the present calculations. Long-term monitoring of forest vegetation at Karlshaugen, under moderate deposition regime of S and N, showed that other processes than deposition of S and N determine the vegetation dynamics, in particular the development of the dominant canopy species and field layer species seems to be much more important because of their influence on light and nutrients. Reduced frequency and persistence were shown for many field layer species and cryptogames during a 60 years period. A comparison of pH in soilwater from O-layer between 1961 and 1991 showed an increase in median pH of 0.1 pH unit for the area
Authors
C. Walter L.J. Grace S.S. Donaldson J. Moody J.E. Gemmell S. van der Maas Harald Kvaalen Anders LönneborgAbstract
An efficient Biolistic transformation technology was developed to stably transform Picea abies (L.) Karst. Several embryogenic tissue lines were tested for proliferation on standard embryogenesis media. Transient transformation studies with these lines were performed to optimize the parameters for genetic transformation. Selection conditions for transgenic tissue based on the nptII resistance gene in combination with the antibiotic geneticin were defined such that only transgenic P. abies lines were able to develop. Nontransgenic tissue was completely inhibited under these conditions. Stable integration of a uidA reporter gene and a nptII resistance gene into the genome of P. abies was achieved and more than 200 mature embryos were regenerated for every transformation event. Histochemical and fluorometric analysis indicated strong expression of the uidA gene in transgenic material. ELISA studies to detect and quantify the nptII gene product as well as polymerase chain reaction and Southern blotting confirmed the presence and integration of uidA and nptII genes into the P. abies genome. Transgenic P. abies plants from nine independent transformation events were recovered and are currently growing in a greenhouse for genetically modified organisms, awaiting field release.
– Classification of Russia\"s boreal forest in relation to global climate warming
Vladimir Stolbovoi
Authors
Vladimir StolbovoiAbstract
No abstract has been registered
Authors
Alf BakkeAbstract
No abstract has been registered
Authors
Bjørn ØklandAbstract
Information about larval ecology is fundamental in entomological research; however, in many insect species the larval habitat is still unknown. In the present project, Diptera insects were reared from various microhabitats and substrates of coniferous and deciduous forests of southern Norway. The material included 54 species that have not been reared earlier and 213 new species-microhabitat relationships. Many new records were found in dead wood of common tree species, such as Picea abies, Populus tremula and Fraxinus excelsior. Microhabitats associated with the root zone of windfelled trees showed the highest number of new species-microhabitat relationships.
Authors
Gunnar Ogner Kari Anne SølvernesAbstract
The impact of elevated CO2 and increased temperature on the soil of a mini forest ecosystem was investigated in an open-top chamber experiment. The CO2 treatments of the OTCs were ambient, 500 and 700 mmol CO2 mol-1 with an ambient outdoor control. All soils were warmed by natural air flow and radiation to a temperature 2-3 C above a corresponding forest soil site. Overheating was prevented by a cooling system. Silver birch and Norway spruce were planted in undisturbed soil monolithic profiles, with their original understory, in lysimeters and compared to a lysimeter control with understory only. Soil samples were collected in the forest at the end of the experiment and used as reference samples. Increased temperature was found to cause the greatest effect on soil. All data clearly indicated increased breakdown of the soil organic matter with increased temperature. The breakdown of raw humus gave a decrease in concentration of total C, total N, and in the exchangeable plus extractable elements (org.-C, Ca, K, Mg, Mn, t-P and t-S) relative to the original forest reference soil in the range of 18 - 57 %. The exchangeable plus extractable elements (Al, Fe, Si, NH4-N and org.-N) from the raw humus layer increased in concentration relative to original forest soil by 28 - 96 %. The effect of different vegetation on soil quality was less than for the temperature increase. Birch had the strongest effect by decreasing soil acidity and the concentration of exchangeable Al throughout the soil profile relative to spruce. Birch also increased weathering of mineral soil relative to spruce. The effects of CO2 treatment on the soil were clearly smaller than for the temperature and vegetation parameters. Elevated CO2 gave increased concentrations of exchangeable plus extractable Zn, organic C and organic N for the raw humus layer of the understory and spruce vegetation relative to the raw humus of the birch lysimeters. Principal component analysis of the complete data set indicated an effect of elevated CO2 on the humus layer relative to the ambient treatments. This effect was seen most clearly in the lysimeters with understory vegetation.
Authors
M.J. Latkowska Harald Kvaalen M. AppelgrenAbstract
No abstract has been registered
Authors
Sharon FriedmanAbstract
No abstract has been registered
Authors
A. FriesAbstract
No abstract has been registered