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
Abstract
No abstract has been registered
Abstract
Global warming is predicted to adversely affect the reproduction of birds, especially in northern latitudes. A recent study in Finland inferred that declining populations of black grouse, Tetrao tetrix, could be attributed to advancement of the time of mating and chicks hatching too early—supporting the mismatch hypothesis. Here, we examine the breeding success of sympatric capercaillie, T. urogallus, and black grouse over a 38-year period in southeast Norway. Breeding season temperatures increased, being most pronounced in April. Although the onset of spring advanced nearly three weeks, the peak of mating advanced only 4–5 days. In contrast to the result of the Finnish study, breeding success increased markedly in both species (capercaillie: 62%, black grouse: 38%). Both brood frequency and brood size increased during the study period, but significantly so only for brood frequency in capercaillie. Whereas the frequency of capercaillie broods was positively affected by rising temperatures, especially during the pre-hatching period, this was not the case in black grouse. Brood size, on the other hand, increased with increasing post-hatching temperatures in both species. Contrary to the prediction that global warming will adversely affect reproduction in boreal forest grouse, our study shows that breeding success was enhanced in warmer springs.
Abstract
National Red Lists are widely used prioritizing tools for nature conservation. However, status and trends of species vary with scale, and accounting for a larger spatial scale may provide complementary perspectives for nature conservation.We investigate effects of upscaling and influence of wider-scale distribution patterns for composition of Red Lists. We collated nationally red-listed forest species in Norway, Sweden and Finland, and extracted “Candidates for a Fennoscandian Red List” (CFRL), defined as species red-listed where they appear in the region. For each country, we compared composition of organism groups and forest type associations of species that were national CFRL to the nationally red-listed species not CFRL. European distribution patterns were compared to investigate how broader-scale distribution is reflected in national Red Lists. Among the 4830 nationally red-listed forest species in Fennoscandia, 58% were CFRL. The fraction of species in the different forest type and species groups differed significantly between the two spatial scales for several groups, although the overall differences in composition were relatively small. Red-listed species had more confined distribution patterns, suggesting that many nationally red-listed species owe their status to being at the edge of their distribution range. An up-scaling had a large effect on which species designated to a Red List, but a relatively small impact on which organism groups or forest types that contained most red-listed species. A regional perspective generated by compilation of national Red Lists can give valuable complementary information on the status of species and effects of scale.
Authors
Gunnar Austrheim Victoria Berger Marc Daverdin Winta Berhie Gebreyohanis Anders Lorentzen Kolstad James David Mervyn Speed Aurel M A Venete Stein Joar Hegland Erling Meisingset Atle Mysterud Erling Johan SolbergAbstract
No abstract has been registered
Abstract
Large herbivores gain nutritional benefits from following the sequential flush of newly emergent, high- quality forage along environmental gradients in the landscape, termed green wave surfing. Which landscape characteristics underlie the environmental gradi-ent causing the green wave and to what extent landscape characteristics alone explain individual variation in nutritional benefits remain unresolved questions. Here, we com-bine GPS data from 346 red deer (Cervus elaphus) from four partially migratory popula-tions in Norway with the satellite- derived normalized difference vegetation index (NDVI), an index of plant phenology. We quantify whether migratory deer had access to higher quality forage than resident deer, how landscape characteristics within sum-mer home ranges affected nutritional benefits, and whether differences in landscape characteristics could explain differences in nutritional gain between migratory and resident deer. We found that migratory red deer gained access to higher quality forage than resident deer but that this difference persisted even after controlling for land-scape characteristics within the summer home ranges. There was a positive effect of elevation on access to high- quality forage, but only for migratory deer. We discuss how the landscape an ungulate inhabits may determine its responses to plant phenol-ogy and also highlight how individual behavior may influence nutritional gain beyond the effect of landscape.
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No abstract has been registered
Authors
Kjersti Holt HanssenAbstract
No abstract has been registered
Abstract
This paper provides an overview of recent developments in remote and proximal sensing technologies and their basic applicability to various aspects of forest operations. It categorises these applications according to the technologies used and considers their deployment platform in terms of their being space-, airborne or terrestrial. For each combination of technology and application, a brief review of the state-of-the-art has been described from the literature, ranging from the measurement of forests and single trees, the derivation of landscape scale terrain models down to micro-topographic soil disturbance modelling, through infrastructure planning, construction and maintenance, to forest accessibility with ground and cable based harvesting systems. The review then goes on to discuss how these technologies and applications contribute to reducing impacts on forest soils, cultural heritage sites and other areas of special value or interest, after which sensors and methods necessary in autonomous navigation and the use of computer vision on forest machines are discussed. The review concludes that despite the many promising or demonstrated applications of remotely or proximately sensed data in forest operations, almost all are still experimental and have a range of issues that need to be addressed or improved upon before widespread operationalization can take place.
Abstract
No abstract has been registered
Authors
Victor Strimbu Liviu Theodor Ene Terje Gobakken Timothy G. Gregoire Rasmus Astrup Erik NæssetAbstract
Post-stratified model-assisted (MA) and hybrid (HY) estimators are used with repeated airborne laser scanning (ALS) strip sampling and national forest inventory field data for stratum-wise and overall estimation of aboveground biomass (AGB) stock and change. The study area covered the southern portion of the Hedmark County in Norway. Both MA and HY estimation substantially reduced the uncertainty in AGB change when compared with estimation using the field survey only. Relative efficiencies (relative variance) of 4.15 (MA) and 3.36 (HY) for overall estimates were found. The results suggest the MA estimator for single-time estimation and the HY as more appropriate for change estimation by cover class. With the HY estimator, a nested post-stratification scheme is demonstrated, combining cover classes with change classes, which enables detailed reporting for change according to cause within each cover class, and has the potential to improve the estimation precision. Finally, parametric bootstrapping is demonstrated as an empirical alternative to estimate the model-error component in the HY estimator. The model error estimated with parametric bootstrapping converged to the analytically determined value of the HY estimator within 1000 bootstrap samples.