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.
2017
Authors
Aida Droce Jens Laurids Sørensen Teis Esben Sondergaard Janus Jagd Rasmussen Erik Lysøe Henriette GieseAbstract
Putative proton coupled di-peptide transporters, PTR2s, are found in filamentous fungi in different numbers and their function during fungal development and plant infection is unresolved. In Fusarium graminearum, the cause of head blight in cereals, we identified four putative PTR2 transporters (FgPTR2A-D). The genes did not cluster together in phylogenetic analyses and only FgPTR2A and FgPTR2C were able to complement a PTR2 deficient yeast mutant in uptake of di-peptides. All FgPTR2s are continuously expressed throughout the fungal lifecycle, although at different levels. In silico analyses of existing expression-data show that FgPTR2B is found at higher levels than the others in planta and during sexual development. Deletion mutants of FgPTR2A, FgPTR2C, and FgPTR2D had a higher production of deoxynivalenol (DON) and zearalenone and lower production of fusarielin H than the wild type. Perithecium development was reduced in these mutants but unaffected by deletion of FgPTR2B. Conidia production was reduced in the FgPTR2B mutant and unaffected by deletion of the other PTR2 transporters. Sexual development and secondary metabolite production are known to be linked at the regulatory level and the results suggest that PTR2s are active in nitrogen turnover and thereby influence signal processes.
Abstract
In the present study we applied X-band interferometric SAR (InSAR) data from the TanDEM-X mission, and investigated the relationship between InSAR height above ground and above-ground biomass (AGB) in a forest with very high biomass. We carried out this study in the East Usambara Mountains in Tanzania, with AGB ranging up to N1000 t/ha. Field inventory provided AGB data for 153 plots of 900 m2 in size. An airborne laser scanning (ALS) provided a DTM as well as AGB predictions for larger 8100 m2 cells over the entire study area. Three TanDEM-X acquisitions provided single-pass InSAR data, from which we generated a Digital Surface Models (DSM) and InSAR height by subtracting the ALS DTM. The results showed that proportionality may represent the relationship where AGB increased with 18.4 t/ha per m increase in InSAR height. The accuracy was low with RMSE = 203 t/ha (44%), which was partly attributable to small field plots and partly to a limited sensitivity of InSAR height to variations in basal area and stand density. An identical proportionality model, with less residual noise, was achieved by replacing the small field plots with the 8100 m2 cells having AGB predictions from ALS data.
Abstract
The fungus Neonectria neomacrospora has recently caused an epidemic outbreak in conifer species within the genus Abies in Denmark and Norway. Christmas tree producers in Europe and North America rely, to a large extent, on Abies species. The damage caused by N. neomacrospora, including dead shoot tips, red flagging of branches and potentially dead trees, have therefore caused concern about reduced quality and loss of trees, and thereby of revenue. Field observations of natural infection of 39 taxa, from 32 species, within the genus Abies in the Hørsholm Arboretum, Denmark, were evaluated; significant differences were seen between taxa, that is, species, and between some species and their subspecies. The Greek fir, Abies cephalonica, was the only species without damage. An inoculation experiment on detached twigs with mycelium plugs from a N. neomacrospora culture showed that all species could be infected. The damage observed in the inoculation experiment could explain 30% of the variation in the field observations based on species mean values. The epidemic outbreak and the high number of species susceptible to this fungus indicate that N. neomacrospora requires attention in the cultivation and conservation of Abies species.
Abstract
Many horse stables have mechanical-fan ventilation systems but still try to regulate ventilation manually by closing doors and windows on a cold winter night. The aim of this study was to investigate the variation in air quality in Norwegian horse stables with different ventilation systems on days with low outdoor air temperatures. A total of 19 insulated, mechanically ventilated stables with horses kept inside during the night were included in the study. Almost all fans were operated during the night (n=18), but inlets for fresh air were highly variable in design and management leading to potential for ineffectiveness of ventilation functions. In four of the stables, there were no specific air inlet systems, and in five stables, the exit door was used as the only air inlet. The air exchange rate was sufficient in all the stables with an automated temperature thermostat for ventilation control. Mean level of carbon dioxide (CO2) was 1,800 ppm and in one stable CO2 exceeded 3,000 ppm. Mean inside ammonia (NH3) was 1.3 ppm, and only in one stable the level of NH3 exceeded 5 ppm. The total dust concentration was 0.69 ± 0.19 mg/m3, and in two stables, the dust concentration exceeded 1.0 mg/m3. Total and respirable dust levels were higher in stables with ventilation rate below recommended level. Half of the stables visited had a lower calculated air exchanges rate than recommended, and the majority of the stables regulated the ventilation manually by closing doors and inlets during night. This indicates a general lack of knowledge among the stable managers of climatic demand in horses and how to operate mechanical ventilation. Still, the majority of the stables maintained acceptable air quality, with NH3 and dust levels within recommended levels, although most stables had elevated humidity.
Abstract
No abstract has been registered
Abstract
National parks are established to reduce human influence on nature and contribute to species conservation, biodiversity and ecological services. Other states of protection like the UNESCO world heritage sites, for example, are created for maintaining culturally important places or lifestyles. In the Matobo Hills (Zimbabwe) both states of protection are present, a national park and a world heritage site. In addition, the land outside the National Park belongs to two different systems of ownership, namely “common” (i.e. community-owned) and “not-common” (privately or governmentally owned) land. In this paper, we investigated how the state of protection and the ownership affected the land use and land cover. We derived maps using Landsat images from 1989, 1998 and 2014 by supervised classification with Random Forests. To compensate for the lack of ground data we inferred past land use and land cover from recent observations combining photographs, Google Earth images and change detection. We could identify four classes, namely shrub land, forest, patchy vegetation and agricultural area. The Matobo National Park showed a stable composition of land cover during the study period and the main changes were observable in the surroundings. Outside the national park, forest increased by about 7%. The common lands have changed substantially and their agricultural area decreased. We attribute this development to the Fast Track Land Reform, which took place in the early 2000s. Our approach shows that combining information on recent land cover with change detection allows to study the temporal development of protected areas.
Authors
Phyllis G. Weintraub Sonja J. Scheffer Diedrich Visser Graciela Valladares Alberto Soares Correa B. Merle Shepard Aunu Rauf Sean T. Murphy Norma Mujica Charles MacVean Jürgen Kroschel Miriam Kishinevsky Ravindra C. Joshi Nina Johansen Rebecca H. Hallett Hasan S. Civelek Bing Chen Helga Blanco MetzlerAbstract
No abstract has been registered
Authors
Ola FlatenAbstract
No abstract has been registered
Abstract
In the city of Tromsø in northern Norway, invasive Tromsø palm (Norwegian: Tromsøpalme; English: Persian hogweed) is widespread. Although Tromsø palm has negative impacts on biodiversity and contains a phototoxic sap that burns human skin, it is also considered to be a local symbol of Tromsø city and is appreciated by many inhabitants. This study examined private landowners’ characteristics, perceptions, and landowners’ regulation of invasive Tromsø palm on their parcels on Tromsø Island in 2012 (vegetation season: May–September) to provide information concerning which landowner groups could be assisted by official regulation. Eleven key informants and 17 landowners were interviewed. Afterward, Tromsø palm on Tromsø Island was mapped using aerial photos and street-level photos from Google Maps®/Google Street View® and fieldwork verification. This distribution map was superimposed on a property map in a geographic information system to produce a map showing private parcels that contained Tromsø palm and associated neighboring parcels that did not contain Tromsø palm. Questionnaires were mailed to the 441 owners of the selected parcels, and 199 of the returned questionnaires were analyzed. Tromsø palm was more likely to be fully regulated/absent on a parcel that was inhabited (particularly if the owner lived on-site) and less likely to be fully regulated/absent if the parcel was jointly managed by several households. These findings indicate that authorities could focus their management efforts on supporting regulation efforts of those private landowners who own currently uninhabited or rented-out parcels and landowners of parcels jointly managed by several households. Furthermore, those landowners who found regulation measures against the plant on Tromsø Island important tended to have partly or fully regulated Tromsø palm on their plots. This might imply that information campaigns from authorities might encourage more landowners to regulate Tromsø palm.
Authors
Norbert Pirk Mikhail Mastepanov Efrén López-Blanco Louise H. Christensen Hanne H Christiansen Birger Ulf Hansen Magnus Lund Frans-Jan W. Parmentier Kirstine Skov Torben R. ChristensenAbstract
No abstract has been registered