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.
2016
Abstract
Accessibility is a central issue for human activity, particularly in mountain areas. We investigate changes in physical accessibility in a Western Norwegian mountain area during the past 40–60 years and identify driving forces of changes. Changes in accessibility were measured as changes in travel time between permanently and seasonally inhabited farmsteads. Additionally, travel time from new access points in the mountains was calculated. C.75% of the investigated access routes to seasonal farmsteads have remained unchanged due to continued use or maintenance work, or been slightly improved due to development of paths into roads. In addition, new access routes have emerged as a result of road construction. Regrowth of paths due to abandonment of seasonal farming has reduced accessibility. Changes in accessibility have led to a concentration of activities in more easily accessibly parts of the study area. Documented changes in accessibility result from a complex interaction of driving forces that initiate or influence change. Important drivers interacting with road construction and abandonment of seasonal farming can be categorized as socio-economic, political and technological. However, the importance of culturally rooted commitment of local people or a small number of enthusiasts must not be underestimated.
Abstract
No abstract has been registered
Abstract
Methods: In 2009, we resurveyed three plant sociological studies up to 85 years after the first surveys. Vegetation data were recorded from 1m2 non-permanently marked plots, and soil pH was measured. We applied restricted permutation tests to evaluate whether observed changes in vegetation (species richness, occurrence frequency, coverage) and in soil pH were significant and independent of plant community type. We compared species co-occurrences over time to study changes in species composition and to identify the species most likely causing these changes. Results: Total number of species and average number of species per plot has not changed and are 75 and 9, respectively. Occurrence frequency changed significantly for 34% of the 64 species tested (11 species increased, 11 decreased). Species cover decreased significantly for 27% of the species and increased for one species. Observed changes in frequency and cover are not significantly related with species’ functional groups or species affiliated with moist or dry habitats. Polygonum viviparum, Saxifraga cernua and Alopecurus borealis have changed most in co-occurring with other species. Soil pH increased significantly from 6.4 to 6.8. Conclusions: Our results suggest that the strong climatic warming in the High Arctic over the past decades has contributed to significant changes in the vegetation studied on Svalbard over the past 85 years. Internal community re-structuring and the overall stability in species richness may be explained by time-delayed responses of well-established communities, and/or by a limited size of the species pool in the area.
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No abstract has been registered
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No abstract has been registered
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No abstract has been registered
Abstract
In this study potential links between biodiversity, ecosystem service (ES) indicators and agricultural land use were examined. Semi-natural grasslands, either actively used for sheep grazing or abandoned, were surveyed and all vascular plant species recorded. Based on this survey, species richness (per 4 m2), fodder quality and quantity, as well as pollination, were estimated. We found lower species richness and indications of lower fodder quantity and quality, but of higher pollination in abandoned grasslands. The relationships between ES indicators and species richness were both negative and positive, and differed in managed and abandoned semi-natural grasslands.
Authors
Belachew Gizachew ZelekeAbstract
No abstract has been registered
Abstract
There is limited knowledge on the toxicological, physiological, and molecular effects attributed to organophosphate (OP) compounds currently used as flame retardants or additives in consumer products. This study investigated the effects on oxidative stress and lipid peroxidation in juvenile Atlantic salmon liver and brain samples after exposure to two OP compounds, tris(2-butoxyethyl) phosphate (TBOEP) and tris(2-chloroethyl) phosphate (TCEP). In this study, groups of juvenile Atlantic salmon were exposed using a semistatic experimental protocol over a 7-d period to 3 different concentrations (0.04, 0.2, or 1 mg/L) of TBOEP and TCEP. When toxicological factors such as bioaccumulation and bioconcentration, and chemical structural characteristics and behavior, including absorption to solid materials, are considered, these concentrations represent environmentally relevant concentrations. The concentrations of the contaminants were derived from levels of their environmental occurrence. The expression of genes related to oxidative stress—glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST)—and to lipid peroxidation—peroxisome proliferator-activated receptors (PPAR)—were determined using quantitative (real-time) polymerase chain reaction (PCR). The presence of PPAR proteins was also investigated using immunochemical methods. Levels of thiobarbituric acid-reactive substances (TBARS) in liver were used as a measure of lipid peroxidation. Overall, our data show an increase in lipid peroxidation, and this was associated with an augmented expression of genes from the glutathione family of responses. Interestingly, PPAR expression in liver after exposure to TBOEP and TCEP was consistently decreased compared to controls, while expression in brain did not show a similar trend. The results suggest that OP contaminants may induce oxidative stress and thus production of reactive oxygen substances (ROS), and modulate lipid peroxidation processes in organisms.