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.
2013
Abstract
This study combines tree-ring and charcoal data to explore possible drivers of the charcoal record and its spatial variation in a boreal Norwegian forest landscape. Peat and mineral soil samples were collected in a multiple site sampling approach and the amount of charcoal in the peat is related to fire history, Holocene climate variation, major shifts in the vegetation composition, and fuel availability. Dendrochronologic dating was used to reveal the fire history over the last 600 years with spatial and temporal accuracy, and AMS radiocarbon dating of 20 peat columns and their charcoal records from four peatlands was used to elucidate the fire history over the Holocene. The average amount of charcoal was about 2.5 times higher in the mineral soil than in the peat (270 versus 100 g/m², respectively), and there were considerable between- and within-site variations. There was no relationship between the age of a given peatland and its content of charcoal, nor between the amount of charcoal in a given peatland and in the neighboring mineral soil. Although most of the charcoal mass in the peatlands was found in parts of the peat columns originating from relatively warm climatic periods and from the period before the local establishment of Norway spruce (Picea abies), charcoal accumulation rates (per 1000 yr) were higher during cold climatic periods and similar before and after spruce establishment. Recent fires showed up to a low degree in the peat columns. On fine spatial scales (1–10 m), fuel quality and distribution together with fire behaviour throughout millennia are likely to be responsible for variations in the charcoal record. On the landscape scale (100–1000 m), the charcoal records were site-specifically idiosyncratic, presumably due to topography, distribution of fire breaks and fuel types, and human land use, coupled with long-term variations inherent in these factors.
Abstract
Several studies have recently reported that common species are more important for species richness patterns than rare species. However, most such studies have been based on broad-scale atlas data. We studied the contribution of different species occupancy, i.e. number of plots occupied, to species richness patterns emerging from species data in 50 by 50 m plots within six 140–200 ha forests in Norway. The study included vascular plants, lichens, bryophytes, and polypore fungi. We addressed the following questions: 1) are common species more correlated with species richness than rare species? 2) How do occupancy classes combine at various levels of species richness? 3) Which occupancy class is best in identifying the overall most species-rich sites (hotspots) by sampling? The results showed that rare species were better correlated with species richness than common species when the information content was accounted for, that high species richness was associated with a higher proportion of less frequent species, and that the best occupancy class for local hotspot identification was species present in 10–30% of the plots within a forest. We argue that the observed correlations between overall richness and sub-assembly richness are primarily structured by the combination of the distributions of species richness and species occupancy. Although these distributions result from general ecological processes, they may also be strongly affected by idiosyncratic elements of the individual datasets caused by the specific environmental composition of a study area. Hence, different datasets collected in different areas may lead to different results regarding the relative importance of common versus rare species, and such effects should be expected on both broad and fine spatial scales. Despite these effects, we suggest that infrequent species will tend to be more strongly correlated to species richness at local scales than at broader scales as a result of more right-skewed species-occupancy distributions.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
In this study, a technique based on wireless sensor networks (WSN) for matching mother reindeer to their calves in order to identify the ownership of the calves is presented. This task is currently performed using manual techniques which are stressful on the animals and herders alike. Various potential WSN technologies are considered. RFID technology was given greater interest as it is widely used in animal identification. A method based on Wi-Fi enabled active RFID tags is proposed in this work. This technique entails the temporary attachment of Wi-Fi enabled RFID tags to the necks of the calf and mother reindeers and to monitor the location of those tags using the Wi-Fi network. A detailed discussion of localization algorithms to monitor the location of the tags and to determine the correlation between any pairs of tags which indicate mother and her calf is presented. This work aims to pave the way for the use of wireless sensor networks for the purpose of matching mother reindeer to their calves and for other matching purposes in animal welfare and industry.
Abstract
In this study, a technique based on wireless sensor networks (WSN) for matching mother reindeer to their calves in order to identify the ownership of the calves is presented. This task is currently performed using manual techniques which are stressful on the animals and herders alike. Various potential WSN technologies are considered. RFID technology was given greater interest as it is widely used in animal identification. A method based on Wi-Fi enabled active RFID tags is proposed in this work. This technique entails the temporary attachment of Wi-Fi enabled RFID tags to the necks of the calf and mother reindeers and to monitor the location of those tags using the Wi-Fi network. A detailed discussion of localization algorithms to monitor the location of the tags and to determine the correlation between any pairs of tags which indicate mother and her calf is presented. This work aims to pave the way for the use of wireless sensor networks for the purpose of matching mother reindeer to their calves and for other matching purposes in animal welfare and industry.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
No abstract has been registered