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.
2021
Authors
Ulrike BayrAbstract
Traditional landscape photographs reaching back until the second half of the nineteenth century represent a valuable image source for the study of long-term landscape change. Due to the oblique perspective and the lack of geographical reference, landscape photographs are hardly used for quantitative research. In this study, oblique landscape photographs from the Norwegian landscape monitoring program are georeferenced using the WSL Monoplotting Tool with the aim of evaluating the accuracy of point and polygon features. In addition, the study shows how the resolution of the chosen digital terrain model and other factors affect accuracy. Points mapped on the landscape photograph had a mean displacement of 1.52 m from their location on a corresponding aerial photograph, while mapped areas deviated on average 5.6% in size. The resolution of the DTM, the placement of GCPs and the angle of incidence were identified as relevant factors to achieve accurate geospatial data. An example on forest expansion at the abandoned mountain farm Flysetra in Mid-Norway demonstrates how repeat photography facilitates the georectification process in the absence of reliable ground control points (GCPs) in very old photographs.
Authors
Christophe Pelabon Elena Albertsen Arnaud Le Rouzic Cyril Firmat Geir Hysing Bolstad W. Scott Armbruster Thomas Fredrik HansenAbstract
Although artificial-selection experiments seem well suited to testing our ability to predict evolution, the correspondence between predicted and observed responses is often ambiguous due to the lack of uncertainty estimates. We present equations for assessing prediction error in direct and indirect responses to selection that integrate uncertainty in genetic parameters used for prediction and sampling effects during selection. Using these, we analyzed a selection experiment on floral traits replicated in two taxa of the Dalechampia scandens (Euphorbiaceae) species complex for which G-matrices were obtained from a diallel breeding design. After four episodes of bidirectional selection, direct and indirect responses remained within wide prediction intervals, but appeared different from the predictions. Combined analyses with structural-equation models confirmed that responses were asymmetrical and lower than predicted in both species. We show that genetic drift is likely to be a dominant source of uncertainty in typically-dimensioned selection experiments in plants and a major obstacle to predicting short-term evolutionary trajectories.
Authors
YeonKyeong Lee Payel Bhattacharjee Marcos Viejo Ole Christian Lind Brit Salbu Dag Anders Brede Jorunn Elisabeth OlsenAbstract
No abstract has been registered
Authors
Paul Vargas Jentzsch Christian Sandoval Pauker Paola Zárate Pozo Marco Sinche Serra Gonzalo Jácome Camacho Victor Rueda-Ayala Patricia Garrido Luis Ramos Guerrero Valerian CiobotăAbstract
Essential oils are liquid mixtures of volatile compounds extracted from plants. Their quality is usually controlled via gas chromatography (GC), although with limitations when adulterants are nonvolatile substances. The essential oils of lavender (Lavandula angustifolia Mill.), peppermint (Mentha piperita L.), patchouli (Pogostemon cablin Benth), and their adulterated versions were measured by GC coupled to flame ionization detector (GC-FID) and Raman spectroscopy. Canola oil, a nonvolatile substance, was used as the adulterant. The adulterated essential oils contained 1%, 3%, 5%, 10%, 15%, and 20% (v/v) of canola oil. Chromatograms of the adulterated essential oils containing 20% (v/v) of canola oil showed decrements in peak areas of the essential oil components, compared with peaks of the pure essential oils. The highest decrements were observed for the adulterated essential oil of patchouli. In general, detection of adulterated essential oils by simple visual inspection of the Raman features was difficult, due to slight differences observed in the spectra. Principal Components Analysis (PCA) allowed achieving a good spectral discrimination between pure and adulterated essential oils. These results suggest that Raman spectroscopy can overcome limitations of GC-based methods, thus becoming an interesting alternative and complementary technique for quality control of essential oils.
Authors
Anita SønstebyAbstract
No abstract has been registered
Authors
Inger HansenAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Anna Palmé Birgitte Lund Elina Kiviharju Heli Fitzgerald Hjörtur Thorbjörnsson Jenny Hagenblad Jens Weibull Kjersti Bakkebø Fjellstad Kristina Bjureke Linn Borgen Nilsen Magnus Göransson Maija Häggblom Marko Hyvärinen Mora Aronsson Virva LyytikäinenAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
The decline of the Arctic cryosphere during recent decades has lowered the region’s surface albedo, reducing its ability to reflect solar radiation back to space. It is not clear what role the Antarctic cryosphere plays in this regard, but new remote-sensing-based techniques and datasets have recently opened the possibility to investigate its role. Here, we leverage these to show that the surface albedo reductions from sustained post-2000 losses in Arctic snow and ice cover equate to increasingly positive snow and ice albedo feedback relative to a 1982–1991 baseline period, with a decadal trend of +0.08 ± 0.04 W m–2 decade–1 between 1992 and 2015. During the same period, the expansion of the Antarctic sea-ice pack generated a negative feedback, with a decadal trend of −0.06 ± 0.02 W m–2 decade–1. However, substantial Antarctic sea-ice losses during 2016–2018 completely reversed the trend, increasing the three-year mean combined Arctic and Antarctic snow and ice albedo feedback to +0.26 ± 0.15 W m–2. This reversal highlights the importance of Antarctic sea-ice loss to the global snow and ice albedo feedback. The 1992–2018 mean feedback is equivalent to approximately 10% of anthropogenic CO2 emissions over the same period; the share may rise markedly should 2016–2018 snow and ice conditions become common, although increasing long-wave emissions will probably mediate the impact on the total radiative-energy budget.