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
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Sammendrag
Today the spruce bark beetle Ips typographus is always univoltine in Northern Europe including Norway and completes development from egg to adult between May and August. Further south in Europe, development is bivoltine with the completion of two generations in most years. A temperature-driven developmental model suggests that by 2070-2100 the voltinism of I. typographus will change dramatically in Norway. If summers become only 2.5°C warmer than today bivoltinism can be expected every single year in the major spruce growing areas in S-Norway. This is likely to have dramatic effects on forestry since two generations per year will give two, instead of one, attack periods each summer. In addition to increasing the number of attacked trees the effect of the attacks may also be more severe, as Norway spruce is more susceptible to beetle attacks later in the summer. However, climate change will probably also change the phenology of Norway spruce and thus its susceptibility to attack by I. typographus and its phytopathogenic fungal associates. We are currently modelling how tree resistance varies with temperature and tree phenology in order to provide more well-founded advice to forest managers on the interaction between bark beetles and tree in a future climate.
Forfattere
Tatsiana Espevig Michelle DaCosta Trygve S. Aamlid Anne Marte Tronsmo Bruce B. Clarke Bingru HuangSammendrag
Cold acclimation plays a decisive role in turfgrass winter survival. This study was performed in collaboration with Rutgers University and University of Massachusetts (USA) to examine changes in carbohydrate levels in crown tissues during the first and second phases of cold acclimation in velvet bentgrass (Agrostis canina L.) and creeping bentgrass (A. stolonifera L.), and their association with freezing tolerance.. Four treatments representing different phases of cold acclimation were compared: (i) nonacclimated plants maintained at 18 °C/12 °C (day/night); (ii) plants acclimated at 2 °C for 2 wk and 250 μmol m-2 s-1 for 12 h photoperiod ; (iii) as treatment (ii) but for 4 wk; and (iv) as treatment (iii) plus additional sub-zero acclimation in the dark at -2 °C for 2 wk. Velvet bentgrass and creeping bentgrass showed no difference in lethal temperatures for 50% of the test population (LT50) as estimated by whole plant survival. Acclimation at 2 °C for 2 and 4 weeks resulted in accumulation of sucrose and fructans, and significantly lowered LT50 as compared with nonacclimated plants. Subzero acclimation resulted in less fructans, no difference in sucrose, and higher concentration of reducing sugars, but LT50 was not lower than after acclimation at 2 °C for 4 weeks.
Forfattere
Ellen Mosleth Færgestad Anette Moldestad Bernt Hoel Arne Oddvar Skjelvåg Anne Kjersti UhlenSammendrag
Det er ikke registrert sammendrag
Forfattere
Lone Ross GobakkenSammendrag
An evident change in climate the last decades has been recorded, and combined effects of increased CO2, elevated temperature and altered precipitation regimes have been observed to represent a change to the fundamental drivers within ecosystems. Growth of moulds, both in nature and on man-made constructions and objects, will most likely increase due to changes in the climate. The survival, the reproduction, the dispersal and the geographic distribution of moulds are decided by both direct and indirect effects of climate change. Not only the moulds, but also their hosts and substrates, possible competitors and enemies will be affected by climate change. It is essential to understand the interactions between the members in these ecosystems to be able to control and predict future development of moulds. The effect of introducing new building directives, environmental friendly materials and products which are meant to oblige the demand for more climate friendly buildings and houses, is an aspect that may generate unexpected and unintended mould growth on man-made constructions and objects. Future research should focus on the interaction between the moulds, the hosts, the substrates and the climatic factors, and what implications future changes in building directives and housing policy will have on mould growth.
Sammendrag
Protected Landscapes (PLs) are increasingly used in Norway to conserve cultural (human modified) landscapes. In many cases the maintenance of agricultural activities in PLs is required to preserve landscape character. Whilst research exists on land conservation policies in general, the particular effects of PL on management and adjustment of the farms involved have not received attention in the literature. We present results from a questionnaire sent to owners of agricultural land within PLs in Norway. Whilst landowners were divided upon the effects of PLs on farm management, the economic situation of the farm was little affected. Furthermore, changes in farm management after the establishment of a PL did not seem to have been driven by the establishment of the PLs per se. Most importantly, farm management changes were related to potential options to develop the farm and its land. A statistical model showed that PL-farms did not differ significantly from farms outside PL in the development of their land use or animal husbandry. Our findings thus indicate that the establishment of PL played a minor role as a driving force of changes in farm management and farm income.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
We monitored the effects of the drought stress on 20-year old clones of Norway spruce (Picea abies) by using a range of instrumental methods. On two experimental plots (Hoxmark, Norway, 59°40\"14`N, 10°47\"36`E) the drought was induced in a period between May and October 2009 by removing the throughfall using the rain shelters and trenching. We collected data on soil moisture, stem and branch sap flow, xylem diameter, anatomical and calorimetric analysis of the needles, fine root biomass and dynamics and resistance to pathogens. Standard meteorological data were collected locally throughout the whole period. Here we present the preliminary analysis of sap flow and xylem diameter in a period 1-17 august 2009. The sap flow was measured on stems in the breast height by using the method of stem tissue heat balance (THB, EMS Brno). The values were measured once in 2 minutes and saved as the average of 10 minutes. The fluctuations in xylem diameter was monitored by using the automatic dendrometers DR26 (EMS Brno). We evaluated both diurnal and seasonal dynamics. Preliminary results show a significant difference in shape of diurnal curves of transpiration as well as different time lag among the sap flow and the potential evapo-transpiration. Also the differences in diurnal dynamics of the stem circumference suggested different xylem water potential in stressed and control trees. In the drought-stressed trees the diurnal fluctuation in stem diameter was about 4 times higher and the total stem increment one third lower, com-pared to the control trees.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Anette Moldestad Ellen Mosleth Færgestad Bernt Hoel Anne Kjersti UhlenSammendrag
Det er ikke registrert sammendrag