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.
2022
Abstract
No abstract has been registered
Abstract
In Norway, the effect of drainage on grassland yields has received little attention for decades. Low level of drainage may be a reason for low grassland production. Therefore, a drainage experiment was established in a western Norwegian ley, on a sandy silt soil with a high capacity for water storage. The plots had six and twelve meters drain spacing, as well as undrained. There were two or three cuts, and fertilization of 190 or 290 kg N yr-1 ha-1. Drainage intensity gave a small significant increase in yield. N loss in drainage water increased with drainage intensity. The yield increase is likely too small to justify drainage, but the intervention might still be worthwhile due to increased N efficiency and a more manageable risk of compaction. A precise quantification of the hydrological effects is hard due to inherent soil variability.
Abstract
In Norway, the effect of drainage on grassland yields has received little attention for decades. Low levels of drainage may be a reason for low grassland production. Therefore, a drainage experiment was established in a western Norwegian ley, on a sandy silt soil with a high capacity for water storage. The plots had six- and twelve-metres drain spacing, as well as an undrained treatment. For each drainage treatment there were two or three cuts per year, and fertilization of 190 or 290 kg N yr-1 ha-1. Drainage intensity gave a small significant increase in yield. N loss in drainage water increased with drainage intensity. The small herbage yield increase is unlikely by itself to justify drainage, but the drainage installation might still be worthwhile due to increased N efficiency and a more manageable risk of compaction. Precise quantification of the hydrological effects is hard to make due to the inherent soil variability.
Abstract
No abstract has been registered
Authors
Lars T. Havstad John Ingar Øverland Trygve S. Aamlid Trond Gunnarstorp Geir Kjølberg Knudsen Jon SælandAbstract
Desiccation with diquat about one week before seed harvest has been common practise in Norwegian clover seed production. However, after withdrawal of diquat in 2020, clover seed growers no longer have desiccators available. In 2019 and 2020, six field trials in red clover and two field trials in white clover were carried out to evaluate alternative chemical products at different rates and at two different spraying dates, either early at 50% mature seed heads and / or late at 65% mature seed heads. Products included, either for one or two years, was Spotlight Plus (carfentrazonethyl), Beloukha (pelargonic acid), Glypper (glyphosate), Gozai (Pyraflufen-ethyl), Harmonix LeafActive (acetic acid), Harmonix FoliaPlus (pelargonic acid), Flurostar (fluroxypyr) and Saltex (sodium chloride) and liquid urea-based fertilizers. In addition, swathing was examined as an alternative in two red clover trials in 2020. While none of the tested chemicals were superior to diquat, the most promising alternatives were Harmonix FoliaPlus and Harmonix LeafActive in red clover or Harmonix FoliaPlus in white clover. Although usually less effective than these products, Beloukha also had an acceptable desiccation effect, especially when sprayed early and late. Swathing before harvest, using finger bar cutters, was an effective drying method under favourable weather conditions.
2021
Authors
Simo Maduna Jon Aars Ida Marie Bardalen Fløystad Cornelya Klutsch Eve Marie Louise Zeyl Fiskebeck Øystein Wiig Dorothee Ehrich Magnus Andersen Lutz Bachmann Andrew E. Derocher Tommi Nyman Hans Geir Eiken Snorre HagenAbstract
Loss of Arctic sea ice owing to climate change is predicted to reduce both genetic diversity and gene flow in ice-dependent species, with potentially negative consequences for their long-term viability. Here, we tested for the population-genetic impacts of reduced sea ice cover on the polar bear (Ursus maritimus) sampled across two decades (1995–2016) from the Svalbard Archipelago, Norway, an area that is affected by rapid sea ice loss in the Arctic Barents Sea. We analysed genetic variation at 22 microsatellite loci for 626 polar bears from four sampling areas within the archipelago. Our results revealed a 3–10% loss of genetic diversity across the study period, accompanied by a near 200% increase in genetic differentiation across regions. These effects may best be explained by a decrease in gene flow caused by habitat fragmentation owing to the loss of sea ice coverage, resulting in increased inbreeding of local polar bears within the focal sampling areas in the Svalbard Archipelago. This study illustrates the importance of genetic monitoring for developing adaptive management strategies for polar bears and other ice-dependent species.
Authors
Ida Marie Bardalen Fløystad Henrik Brøseth Ane-Sofie Bednarczyk Hansen Ingrid Helle Søvik Hans Geir Eiken Snorre HagenAbstract
Gjennom det nasjonale overvåkingsprogrammet for rovvilt i Norge ble det i 2020 samlet inn prøver til DNA-analyse med antatt opphav fra brunbjørn (Ursus arctos) for tolvte år på rad. Av 1361 innsamlede prøver i 2020, ble 1351 inkludert i den genetiske analysen (850 ekskrementprøver, 489 hårprøver, 10 vevsprøver og 2 urinprøver) og 67 % var positive for brunbjørn. Totalt gav 708 prøver (52 %) en godkjent DNA-profil, og det ble fra disse prøvene påvist 150 ulike brunbjørner; 65 hunnbjørner og 85 hannbjørner. Dette var en økning på 1,4 % (2 individer) sammenlignet med 2019. Dette er det høyeste antallet brunbjørn registrert siden 2011. Forekomsten av brunbjørn var, som i foregående år, hovedsakelig konsentrert i fylkene Troms og Finnmark (66), Innlandet (52) og Trøndelag (29). Av det totale antallet brunbjørner påvist i 2020 var 70 % (105 individer) tidligere påvist i Norge, noe som utgjør en økning i gjenfunn med 4 prosentpoeng i forhold til i fjor. Om man inkluderer gjenfunn fra Sverige, Finland og Russland utgjør det totale antallet gjenfunn 112 individer (75 %). Basert på prøver fra påviste hunnbjørner ble det estimert 8,5 ynglinger i Norge i 2020. Dette er det høyeste estimatet på antall ynglinger siden overvå-kingen startet i 2009. De estimerte ynglingene i 2020 fordeler seg med 3,1 i rovviltregion 5 (Inn-landet), 2,9 i region 6 (Trøndelag) og 2,5 i region 8 (Troms og Finnmark).
Authors
Annika Herrero Cornelya Klutsch Katja Holmala Simo Maduna Alexander Kopatz Hans Geir Eiken Snorre HagenAbstract
Conservation and management of large carnivores requires knowledge of female and male dispersal. Such information is crucial to evaluate the population’s status and thus manage ment actions. This knowledge is challenging to obtain, often incomplete and contradictory at times. The size of the target population and the methods applied can bias the results. Also, population history and biological or environmental influences can affect dispersal on differ ent scales within a study area. We have genotyped Eurasian lynx (180 males and 102 females, collected 2003–2017) continuously distributed in southern Finland (~23,000 km2 ) using 21 short tandem repeats (STR) loci and compared statistical genetic tests to infer local and sex-specific dispersal patterns within and across genetic clusters as well as geo graphic regions. We tested for sex-specific substructure with individual-based Bayesian assignment tests and spatial autocorrelation analyses. Differences between the sexes in genetic differentiation, relatedness, inbreeding, and diversity were analysed using popula tion-based AMOVA, F-statistics, and assignment indices. Our results showed two different genetic clusters that were spatially structured for females but admixed for males. Similarly, spatial autocorrelation and relatedness was significantly higher in females than males. How ever, we found weaker sex-specific patterns for the Eurasian lynx when the data were sepa rated in three geographical regions than when divided in the two genetic clusters. Overall, our results suggest male-biased dispersal and female philopatry for the Eurasian lynx in Southern Finland. The female genetic structuring increased from west to east within our study area. In addition, detection of male-biased dispersal was dependent on analytical methods utilized, on whether subtle underlying genetic structuring was considered or not, and the choice of population delineation. Conclusively, we suggest using multiple genetic approaches to study sex-biased dispersal in a continuously distributed species in which pop ulation delineation is difficult.
Authors
Cornelya Klutsch Simo Maduna Natalia Polikarpova Kristin Forfang Benedicte Beddari Karl Øystein Gjelland Paul Eric Aspholm Per-Arne Amundsen Snorre HagenAbstract
No abstract has been registered
Authors
Cornelya Klutsch Simo Maduna Natalia Polikarpova Kristin Forfang Benedicte Lissner Beddari Karl Øystein Gjelland Paul Eric Aspholm Per-Arne Amundsen Snorre HagenAbstract
Maintaining standing genetic variation is a challenge in human-dominated landscapes. We used genetic (i.e., 16 short tandem repeats) and morphological (i.e., length and weight) measurements of 593 contemporary and historical brown trout (Salmo trutta) samples to study fine-scale and short-term impacts of different management practices. These had changed from traditional breeding practices, using the same broodstock for several years, to modern breeding practices, including annual broodstock replacement, in the transnational subarctic Pasvik River. Using population genetic structure analyses (i.e., Bayesian assignment tests, DAPCs, and PCAs), four historical genetic clusters (E2001A-D), likely representing family lineages resulting from different crosses, were found in zone E. These groups were characterized by consistently lower genetic diversity, higher within-group relatedness, lower effective population size, and significantly smaller body size than contemporary stocked (E2001E) and wild fish (E2001F). However, even current breeding practices are insufficient to prevent genetic diversity loss and morphological changes as demonstrated by on average smaller body sizes and recent genetic bottleneck signatures in the modern breeding stock compared to wild fish. Conservation management must evaluate breeding protocols for stocking programs and assess if these can preserve remaining natural genetic diversity and morphology in brown trout for long-term preservation of freshwater fauna.