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.
2010
Sammendrag
Semi-natural grasslands and their species and populations are declining rapidly throughout Europe, bringing about a need for successful vegetation recreation methods. To maintain biodiversity and ecological services of semi-natural grasslands, we need more knowledge on the relative performance of different recreation methods. In a replicated experiment in western Norway, we evaluated two hay transfer methods (hard or light raking of local hay), sowing of local seeds and natural regeneration for recreating semi-natural grassland in a road verge. We compared treated trial plots with their respective donor plots (where hay and seeds were harvested) for three successive years by evaluating vegetation cover, species richness and species transfer rates, and vegetation dynamics analysed by Bray-Curtis compositional dissimilarity (BC) and GNMDS (Global Non-Metric Multidimensional Scaling) ordination. Vegetation cover at the trial site exceeded that of donor sites in three years. Transfer rates of common species were high for seed sowing and both hay transfer procedures. Species composition in trial plots for all three treatments became significantly more similar to donor plots, but was still relatively dissimilar after three years. Natural regeneration showed a different temporal pattern and also had a higher successional rate. The species composition of the other treatments followed the same trajectory toward the donor sites as revealed by GNMDS. We found relatively small differences between the two hay transfer methods and seed sowing. Transfer of local hay therefore appears to be a successful method of establishing local species when recreating semi-natural grasslands, and is generally cheaper than using commercial local seed mixtures.
Forfattere
Christian Sonne Jan Ove Bustnes Dorte Herzke Veerle Jaspers Adrian Covaci Duncan Halley Truls Moum Igor Eulaers Marcel Eens Rolf A. Ims Sveinn Are Hanssen Kjell E Erikstad Trond Johnsen Lisbeth Schnug Frank F. Rigét Asger Lundorff JensenSammendrag
Organohalogen contaminants (OHCs) may affect various physiological parameters in birds including blood chemistry. We therefore examined blood plasma clinical-chemical parameters and OHCs in golden eagle, white-tailed eagle and goshawk chicks from Northern Norway. Correlation analyses on pooled data showed that alkaline phosphatase (ALKP), glucose and creatinine were significantly negatively correlated to various OHCs (all: p<0.05; r: -0.43 to -0.55; n=23), while alanine aminotransferase (ALAT), total protein, cholesterol, uric acid, total bilirubin, ratios protein:creatinine and uric acid:creatinine were significantly positively correlated to various OHCs (all: p<0.05; r: 0.43-0.96). Based on these relationships, we suggest that the OHC concentrations found in certain raptor chicks of Northern Scandinavia may impact blood plasma biochemistry in a way that indicates impacts on liver, kidney, bone, endocrinology and metabolism. In order to elaborate further on these relationships and mechanisms, we recommend that a larger study should take place in the near future.
Sammendrag
Scots pine (Pinus sylvestris) and especially its heartwood is one of the most common construction materials for general outer use e.g. windows or facades in northern Europe. It is considered being use class 3 and is according to EN 350-2 \"not treatable\". Reports from industry and researchers indicate that the heartwood treatability is not uniform. It is still unclear what causes these differences. To increase its durability by means of impregnation would be a contribution to extend the use of both a natural and native material. The understanding of a potential pattern analog to latitudinal/longitudinal origin or other forest or wood properties could help to improve the impregnation by better material selection. Scots pine samples from 25 different sites in 6 countries in northern Europe have been collected throughout autumn and winter 2009/2010. A circle of varying size containing approximately 30 trees was set up in a representative site of each stand. All diameters were measured and arranged in three classes. Three trees of each class were chosen randomly. Only the middle and upper diameter classes were used for studying heartwood permeability. The small diameter class had insufficient heartwood width to be processed. Samples of 20 x 20 x 50 mm were cut and conditioned in a climate chamber. The samples were impregnated with a water-soluble monomer furfuryl alcohol solution in a standard pressure/vacuum process. Results showed a generally low permeability but a few samples had an unexpected high ration of filling. Further on, the samples with the highest and lowest treatability will undergo anatomical and chemical tests to explain these properties.
Sammendrag
Scots pine (Pinus sylvestris) sapwood is per definition (EN-350-2) easy to treat. Combination with its good availability on the European markets, it is a construction and building material in demand. However, partially large differences in penetration are reported from industry and research. To keep a reliable product quality, impregnation processes aligned to the material most difficult to treat. Hence, it is crucial to know about the factors inhibiting the fluid flow into the material. Scots pine samples from a wide geographic distribution, 25 different sites in 6 different countries, have been collected and impregnated with an aqueous monomer furfuryl alcohol solution. From each of the respective sites logs of 1.3 meter in length were collected from nine trees belonging to three different breast height diameter classes. Three trees from each dominance class were chosen randomly. The log was drawn from the felled stem in a height of 1.2 meters with exact marked north/south exposition. Sapwood slabs orientated in the heaven directions, underwent a drying procedure at 40°C for 48 h and small clear samples of 20 x 20 x 50 mm were prepared. A large variation of the ratio of filling was found for the material tested. Diameter as well as sample origin seem to influence the materials permeability.
Sammendrag
Vokterhunder benyttes i dag i flere land som forebyggende tiltak mot rovviltskader. Tiltaket har generelt vist en sterk tapsreduserende effekt. De fleste bruksmåter i utlandet er basert på at vokterhunden sosialiseres på sau i tidlig valpealder. Hunden vil dermed oppfatte sauene som sine flokkmedlemmer som den vil forsvarer mot rovvilt. Et effektivt forsvar forutsetter imidlertid at sauene går i flokk. Det norske saueholdet er karakterisert ved at sauene beiter spredt på store utmarksarealer. For at bruk av vokterhund skal kunne bli et effektivt tiltak i Norge, må derfor sauene samles, enten ved gjeting eller ved bruk av inngjerdede beiter. Alternativt kan man finne nye måter å bruke vokterhund på som er bedre tilpasset det tradisjonelle norske saueholdet. Av de sju ulike bruksmåter for vokterhund som er beskrevet, anbefales to metoder under norske forhold: vokterhunder på patrulje og vokterhunder på inngjerdet beite. Den første metoden krever ikke at sauene går i flokk og er dermed tilpasset det norske beitebruket. Den sistnevnte metoden krever en omlegging av beitedrifta, men har imidlertid vist seg å ha bedre tapsforebyggende effekt. Den forebyggende effekt er diskutert opp mot tiltakets kostnader og ulemper, som arbeidsinnsats, reduserte slaktevekter, gjerdehold og et utvidet innmarksbruk. Ulike bruksmåter krever ulik styrke av sosialisering mellom hund og sau. En beskrivelse over sosialiseringsopplegget i forhold til bruksmåte er gitt. I tillegg gir veilederen også nyttige tips om rasevalg, valg av valp og dressur.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Heleen de Wit Toril Eldhuset Jan MulderSammendrag
Dissolved aluminium (Al) in soils, mobilized by acid deposition, is considered a threat to forest health through hampering root growth and nutrient uptake. Since the end of the 1980s dissolved Al in forest soil water plays a key role in the assessment of critical loads of acid deposition. So far, most evidence for toxicity of dissolved Al in forest soil water is based on nutrient solution studies and pot experiments. Here, we present results from one of the few in situ ecosystem-scale forest manipulation experiments to study the effect of Al on mature forest trees. A plotwise addition of dilute AlCl3 was conducted during seven years in an even-aged spruce forest (Picea abies) in an area in Norway with low acid deposition. Soil solution concentrations of Al were increased to potentially toxic levels (up to 500 mu mol L-1) and base cation (Ca + Mg + K) to inorganic Al ratios in the soil solution in the root zone were mostly below 1 in the Al-addition treatments. In the control treatment (only water addition) Al concentrations did not exceed 15 mu mol L-1 and base cation to inorganic Al ratios were above 1. The toxic effects of Al on fine root growth and plant growth found in hydroponic studies and pot trials are not confirmed by this field manipulation. However, magnesium (Mg) contents in needles decreased significantly and persistently in plots with elevated Al concentrations, whereas the needle Ca content did not respond. The depletion of the Mg content in needles is suggested to be due to antagonistic effects of high Al concentrations at the root surface, consistent with observed reductions in Mg to Al ratio of inner bark. This study clearly supports a role for Al in critical load functions for forests as dissolved Al causes a decrease in uptake of Mg. However, other signs of reduced forest vitality were not observed. Soil base cation status may need to be included in risk evaluations of forest health under acid deposition. (C) 2010 Elsevier B.V. All rights reserved.
Forfattere
Atle Wibe Anna-Karin Borg-Karlson Jerry Cross Lene SigsgaardSammendrag
One of the major pests on cultivated strawberry in northern part of Europe is the strawberry blossom weevil, Anthonomus rubi. The weevils deposit eggs in the flower buds before it sever the buds from their stalks. This may lead to a direct loss of crop of more than 50%. To develop effective plant protection method against A. rubi funnel traps baited with the sex aggregation pheromone and plant volatiles were used for trapping weevils in the fields. The sex pheromone blend used in the study was a mixture of Grandlure I, Grandlure II and Lavendulol (ratio 1:4:1). Plant volatiles emitted by the strawberry plants were collected using SPME and identified by GC/MS. These chemical analyses identified several compounds present in different quantities. The sex pheromone blend and selected plant volatiles were tested in fields either separately or in different mixtures. The field trials were carried out during a three year period where the last year aimed to optimise the mixture used in the previous years by adding more test compounds and testing the most potent compound at different concentrations. To improve insect catch rates modified traps were also tested. The study sites were in Norway, Denmark and in the UK. General high catch rates were achieved at three different study sites in Norway due to high weevil density. The results from these fields, supported by the results from the fields with lower catch rates, were in accordance with each other. The main finding was that traps baited with some identified plant volatile compounds and the sex pheromone blend increased the catch rates compared to traps bated with single a plant compound or the sex pheromone blend alone. The results show also that the concentration of the plant volatiles relative to the pheromone concentration is important for attracting weevils to the traps. This study has shown that it is important to bait insect traps with both sex aggregation pheromones and plant volatiles at the correct level to achieve significant catch rates of A. rubi. Hopefully, the results will generate knowledge important for developing new plant protection method for strawberry without using insecticides.
Forfattere
Trygve S. Aamlid Bjørn Molteberg Lars Nesheim Trond Olav Pettersen Frank Enger Lasse Weiseth Åge Susort Jan TangsveenSammendrag
Norske fotballbaner har tradisjonelt blitt etablert med engrapp (Poa pratensis) som viktigste grasart, enten ved direkte såing eller legging av ferdiggras. Den største ulempen med engrapp er at den spirer og etablerer seg seint, noe som gjør at tunrapp (Poa annua) ofte kommer inn i etableringsfasen. Ved resåing har det derfor vært vanlig å bruke (flerårig) raigras (Lolium perenne), som etablerer seg raskere og er vel så slitesterkt, men mindre vinterherdig enn engrapp. Ved gjentatt resåing vil raigras utgjøre en større og større del av plantebestandet, og spørsmålet er derfor om vi kan spare penger ved å direkteså raigras allerede ved første gangs etablering av nye baner. Formålet med dette prosjektet er (1) å undersøke hvilken av etableringsmetodene "Ferdiggras av engrapp" eller "Direktesåing av raigras" som gir best banekvalitet ved nyetablering av fotballbaner i ulike landsdeler; og (2) å dokumentere tilslag, dekningsprosent og slitestyrke etter resåing med frøblandinger bestående av raigras eller forspirt engrapp enten like etter sesongavslutning om høsten (oktober), før sesongstart om våren (april) eller i fotballferien (månedsskiftet juni/juli). Fra og med 2009 har vi på en av lokalitetene også lagt til et delmål (3), nemlig å studere hvordan fotballbaner med ei grasmatte av engrapp eller raigras reagerer på ulike klippehøyde. Forsøk ble anlagt på Bioforsk Landvik (Grimstad), Apelsvoll (Østre Toten) og Kvithamar (Stjørdal) i juni 2008. Forsøksopplysinger og resultater fra etableringsåret er gitt i Bioforsk Rapport 4(24). Våren 2009 var raigraset på Kvithamar dødt, sannsynligvis på grunn av 2-3 måneders isdekke, og denne delen av forsøket måtte derfor reetableres. På Apelsvoll og Landvik var henholdsvis 73 og 9 % av raigraset angrepet av snømugg, men graset vokste denne skaden av seg i løpet av 1-2 måneder. Engrapp hadde praktisk talt ingen vinterskade på noen av forsøksstedene. Resåing i eksisterende plantedekke ble foretatt etter lufting, men før dressing. På Kvithamar kunne det ikke observeres spirende planter uansett resåingstid. På Apelsvoll og Landvik var det lite eller ikke noe tilslag etter resåing av engrapp, men bruktbart tilslag etter resåing av raigras, særlig som sommeren. Årsaker til dette kan være høy jordtemperatur, redusert konkurranse fra eksisterende plantedekke på grunn av daglige maksimumstemperaturer > 25 ºC, og rikelig med naturlig nedbør i dagene etter såing. På Landvik var andelen raigras i engrapp ved vekstavslutning i 2009 henholdsvis 3, 4 og 10 % etter resåing høsten 2008, våren 2009 og sommeren 2009. Sammenlikna med ordinær klipping med rotorklipper (30-35 mm) to ganger i uka førte klipping med sylinderklipper (15 mm) på de samme dagene til mer åpne flekker / bar jord i feltet på Landvik. Virkningen var størst ut over høsten, da det ble kjørt kraftig slitasje. I motsetning til hva vi hadde forventet ble det ikke påvist mer tunrapp eller dårligere rotutvikling etter en sesong med lav klipping. Spilleoverflaten på de direktesådde raigrasrutene var jamt over hardere og hadde større skjærfasthet (motstandsevne mot skliing) enn spilleoverflaten på engrapprutene. Feltene ble regelmessig utsatt for komprimering / slitasje fra en to-tromla slitasjemaskin med påmonterte fotballknotter og marktrykk som en voksen fotballspiller, og ferdiggraset fungerte da som en beskyttende støtpute som hindret overflaten fra å bli for hard. Til tross for mer filt hadde engrapprutene bedre infiltrasjonskapasitet enn de hardere raigrasrutene på Landvik og Kvithamar. På Apelsvoll var forholdet motsatt, sannsynligvis på grunn av mer dressing i forhold til veksthastighet og lavere innhold av organisk materiale i topplaget. Prosjektet fortsetter til og med vekstsesongen 2011. Så langt ser til ut til at nyetablering av fotball-baner med 100 % raigras ikke kan anbefales i Trøndelag, og sannsynligvis heller ikke i innlandsstrøk på Østlandet, selv om et legges opp til regelmessig resåing. Ved resåing av raigras i eksisterende plante-dekke ser det ut til at såing om sommeren gir bedre tilslag enn såing seint om høsten eller tidlig om våren. Resåping av engrapp i eksisterende plantedekke ser ut til å være bortkasta penger, iallfall på kort sikt.
Sammendrag
In European forests, standing stocks are currently higher than ever during the last decades, in part due to reduced logging or the abandonment of agricultural land. However, data from intensive monitoring plots reveal an increased growth even without direct human intervention.We used a set of 363 plots from 16 European countries to investigate the influence of environmental factors on forest growth: nitrogen, sulphur and acid deposition, temperature, precipitation and drought, for Norway spruce, Scots pine, common beech and European as well as sessile oak.We used existing information on site productivity, stand age and stand density to estimate expected growth. Relative tree growth, i.e., the ratio between actual growth within a five-year period and expected growth, was then related to environmental factors in a stepwise multiple regression.The results consistently indicate a fertilizing effect from nitrogen deposition, with roughly one percent increase in site productivity per kg of nitrogen deposition per ha and year, or 20 kg C fixation per kg N deposition. This was most pronounced for plots having soil C/N ratios above 25. We also found a positive albeit less clear relationship between relative growth and summer temperatures.From the study, we cannot conclude on any detrimental effects on growth from sulphur and acid deposition or from drought periods. A very recent study from the U.S., comprising 4800 plots and 24 tree species, confirms our results. However, we also show that the magnitude of N deposition effects on global forest C balance is currently a highly controversial matter, and comment on this debate. http://www.cef-cfr.ca/uploads/Colloque/Programme10_5.pdf