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.
2025
Abstract
This study presents information about the variability between and within populations of Norway spruce in lammas shoot formation. Assessments of lammas shoots were conducted in two short-term trials involving full sib families of Norway spruce from two complete diallel crosses, each originating from a natural population. These assessments were made over two growing seasons when the trees were six and seven years from seed, during which early summer temperatures varied significantly. The trees were grown on former agricultural land with large variation in soil fertility across the field. The proportion of trees with lammas shoots varied among blocks, ranging from 1 to 14 %, with the highest values in the blocks with the most fertile soil conditions. A substantial variation was also found among families from each population regarding the percentage of trees with lammas shoots, varying among half-sib families from 2 to 20 % and 1 to 19 % in the two populations, respectively. The largest part of this genetic variation was additive, with high values for the general combining ability (GCA) variance components and low values of the specific combining ability (SCA), maternal and reciprocal components. Estimates of narrow sense heritability were 0.40 for transformed lammas shoot scores in both diallels. Generally, families with an early start and early cessation of shoot elongation had the highest frequency of lammas shoots. In one of the diallels, families with a high lammas shoot percentage also had the highest number of ramicorn branches in a field trial at age 12 and 26 years from seed.
Abstract
This study presents information about the variability between and within populations of Norway spruce in lammas shoot formation. Assessments of lammas shoots were conducted in two short-term trials involving full sib families of Norway spruce from two complete diallel crosses, each originating from a natural population. These assessments were made over two growing seasons when the trees were six and seven years from seed, during which early summer temperatures varied significantly. The trees were grown on former agricultural land with large variation in soil fertility across the field. The proportion of trees with lammas shoots varied among blocks, ranging from 1 to 14 %, with the highest values in the blocks with the most fertile soil conditions. A substantial variation was also found among families from each population regarding the percentage of trees with lammas shoots, varying among half-sib families from 2 to 20 % and 1 to 19 % in the two populations, respectively. The largest part of this genetic variation was additive, with high values for the general combining ability (GCA) variance components and low values of the specific combining ability (SCA), maternal and reciprocal components. Estimates of narrow sense heritability were 0.40 for transformed lammas shoot scores in both diallels. Generally, families with an early start and early cessation of shoot elongation had the highest frequency of lammas shoots. In one of the diallels, families with a high lammas shoot percentage also had the highest number of ramicorn branches in a field trial at age 12 and 26 years from seed
Abstract
No abstract has been registered
Abstract
The limited standards for the rigorous and objective use of mitochondrial genomes (mitogenomes) can lead to uncertainties regarding the phylogenetic relationships of taxa under varying evolutionary constraints. The mitogenome exhibits heterogeneity in base composition, and evolutionary rates may vary across different regions, which can cause empirical data to violate assumptions of the applied evolutionary models. Consequently, the unique evolutionary signatures of the dataset must be carefully evaluated before selecting an appropriate approach for phylogenomic inference. Here, we present the bioinformatic pipeline and code used to expand the mitogenome phylogeny of the order Carcharhiniformes (groundsharks), with a focus on houndsharks (Chondrichthyes: Triakidae). We present a rigorous approach for addressing difficult-to-resolve phylogenies, incorporating multi-species coalescent modelling (MSCM) to address gene/species tree discordance. The protocol describes carefully designed approaches for preparing alignments, partitioning datasets, assigning models of evolution, inferring phylogenies based on traditional site-homogenous concatenation approaches as well as under multispecies coalescent and site heterogenous models, and generating statistical data for comparison of different topological outcomes. The datasets required to run our analyses are available on GitHub and Dryad repositories.
Abstract
Observations of two apparent phenotypic expressions (morphodemes) of the composite thallus of the lichen-forming ascomycete species Ricasolia amplissima (Scop.) De Not. (formerly Lobaria amplissima (Scop.) Forss.) inspired us to investigate the morphological and genetic variation of the species in Norway. The morphodemes differ in thallus shape and occurrence of apothecia and/or cephalodia, each dominating in climatically different parts of southern Norway. We investigated the morphology of herbarium collections as well as fresh samples from various areas, including localities where the two morphodemes occur together. The nrITS barcode marker was sequenced to investigate the genetic variation along the climatic gradient of the Hardangerfjord area. We also included barcode sequences of specimens from other parts of the world in order to establish if the Norwegian pattern of variation has a wider geographical significance. Results suggest that the genetic variation found in Ricasolia amplissima corresponds to morphology independently of geography/climate. The two haplotype groups cluster in two distinct sister clades, however, the within-species variation is too small to justify taxonomic recognition. Specimens with the cephalodiate morphodeme and its haplotypes are mainly found in the oceanic west, whereas specimens with apotheciate morphodemes and its haplotypes occur mainly in the drier eastern parts. The results can be interpreted as 1) immigration to Norway from different gene pools in separate glacial refugia, or, 2) natural selection for water efficient cephalodiate morphodemes in the oceanic west and apotheciate (sexually reproducing) in drier suboceanic east parts of Norway. We argue that within-species genetic variation should always be considered before conservation actions such as transplants of lichen thalli are taken.
Authors
Tatsiana EspevigAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Kristian Hansen Håvard Steinshamn Sissel Hansen Matthias Koesling Tommy Dalgaard Bjørn Gunnar HansenAbstract
To evaluate the environmental impact across multiple dairy farms cost-effectively, the methodological frame- work for environmental assessments may be redefined. This article aims to assess the ability of various statistical tools to predict impact assessment made from a Life Cyle Assessment (LCA). The different models predicted estimates of Greenhouse Gas (GHG) emissions, Energy (E) and Nitrogen (N) intensity. The functional unit in the study was defined as 2.78 MJMM human-edible energy from milk and meat. This amount is equivalent to the edible energy in one kg of energy-corrected milk but includes energy from milk and meat. The GHG emissions (GWP100) were calculated as kg CO2-eq per number of FU delivered, E intensity as fossil and renewable energy used divided by number of FU delivered, and N intensity as kg N imported and produced divided by kg N delivered in milk or meat (kg N/kg N). These predictions were based on 24 independent variables describing farm characteristics, management, use of external inputs, and dairy herd characteristics. All models were able to moderately estimate the results from the LCA calculations. However, their precision was low. Artificial Neural Network (ANN) was best for predicting GHG emissions on the test dataset, (RMSE = 0.50, R2 = 0.86), followed by Multiple Linear Regression (MLR) (RMSE = 0.68, R2 = 0.74). For E intensity, the Supported Vector Machine (SVM) model was performing best, (RMSE = 0.68, R2 = 0.73), followed by ANN (RMSE = 0.55, R2 = 0.71,) and Gradient Boosting Machine (GBM) (RMSE = 0.55, R2 = 0.71). For N intensity predictions the Multiple Linear Regression (MLR) (RMSE = 0.36, R2 = 0.89) and Lasso regression (RMSE = 0.36, R2 = 0.88), followed by the ANN (RMSE = 0.41, R2 = 0.86,). In this study, machine learning provided some benefits in prediction of GHG emission, over simpler models like Multiple Linear Regressions with backward selection. This benefit was limited for N and E intensity. The precision of predictions improved most when including the variables “fertiliser import nitrogen” (kg N/ha) and “proportion of milking cows” (number of dairy cows/number of all cattle) for predicting GHG emission across the different models. The inclusion of “fertiliser import nitrogen” was also important across the different models and prediction of E and N intensity.
Authors
Atle Wibe Berit Marie Blomstrand Lisa Deiana Davide Bochicchio Tommy Ruud Richard Helliwell Matthias Koesling Anne Grete Kongsted Marina Štukelj Marina Spinu A Vasiu Andrew Richard Williams Amalie Camilla Pedersen Helena Meijer Stig Milan ThamsborgAbstract
No abstract has been registered
Authors
Chala Adugna Kufa Afework Bekele Anagaw Meshesha Atickem Desalegn Chala Diress Tsegaye Alemu Torbjørn Ergon Nils Christian Stenseth Dietmar ZinnerAbstract
Ethiopia is home to two subspecies of Colobus guereza, C. g. guereza and C. g. gallarum. Whereas C. g. guereza is listed as Least Concern by IUCN, the conservation status of C. g. gallarum is unclear, but according to a recent assessment, it will most likely be listed as Vulnerable, because of habitat loss due to agricultural expansion. We used climate data to model the habitat suitability for both taxa in a comparative study to identify suitable habitats within and outside of protected areas that may serve as Anthropocene refugia. Our ensemble models estimated 168,731 km2 as climatically suitable habitat for C. g. guereza and 69,542 km2 for C. g. gallarum with an overlap between the two taxa of 17.2 %. Areas that qualified as refugia, i.e., areas covered by forest, were 47,101 km2 (only 27.9 % of the total suitable habitat) and 8430 km2 (12.1 % of the suitable habitat) for C. g. guereza and C. g. gallarum, respectively. Of these, 39.8 % (C. g. guereza) and 53.7 % (C. g. gallarum) are within Ethiopia’s current protected area network. Given that potential Anthropocene refugia are found only partly within protected areas, conservation management should include this information when developing conservation strategies for both taxa. As the majority of suitable habitats for the two colobus taxa exist in non-forested regions, afforestation in these areas would be highly beneficial and is strongly recommended.