Hopp til hovedinnholdet

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.

2020

To document

Abstract

The effective size of a population (Ne), which determines its level of neutral variability, is a key evolutionary parameter. Ne can substantially depart from census sizes of present-day breeding populations (NC) as a result of past demographic changes, variation in life-history traits and selection at linked sites. Using genome-wide data we estimated the long-term coalescent Ne for 17 pinniped species represented by 36 population samples (total n = 458 individuals). Ne estimates ranged from 8,936 to 91,178, were highly consistent within (sub)species and showed a strong positive correlation with NC (R2adj = 0.59; P = 0.0002). Ne/NC ratios were low (mean, 0.31; median, 0.13) and co-varied strongly with demographic history and, to a lesser degree, with species’ ecological and life-history variables such as breeding habitat. Residual variation in Ne/NC, after controlling for past demographic fluctuations, contained information about recent population size changes during the Anthropocene. Specifically, species of conservation concern typically had positive residuals indicative of a smaller contemporary NC than would be expected from their long-term Ne. This study highlights the value of comparative population genomic analyses for gauging the evolutionary processes governing genetic variation in natural populations, and provides a framework for identifying populations deserving closer conservation attention.

To document

Abstract

In order to predict the effects of climate change on the global carbon cycle, it is crucial to understand the environmental factors that affect soil carbon storage in grasslands. In the present study, we attempted to explain the relationships between the distribution of soil carbon storage with climate, soil types, soil properties and topographical factors across different types of grasslands with different grazing regimes. We measured soil organic carbon in 92 locations at different soil depth increments, from 0 to 100 cm in southwestern China. Among soil types, brown earth soils (Luvisols) had the highest carbon storage with 19.5 ± 2.5 kg m−2, while chernozem soils had the lowest with 6.8 ± 1.2 kg m−2. Mean annual temperature and precipitation, exerted a significant, but, contrasting effects on soil carbon storage. Soil carbon storage increased as mean annual temperature decreased and as mean annual precipitation increased. Across different grassland types, the mean carbon storage for the top 100 cm varied from 7.6 ± 1.3 kg m−2 for temperate desert to 17.3 ± 2.9 kg m−2 for alpine meadow. Grazing/cutting regimes significantly affected soil carbon storage with lowest value (7.9 ± 1.5 kg m−2) recorded for cutting grass, while seasonal (11.4 ± 1.3 kg m−2) and year-long (12.2 ± 1.9 kg m−2) grazing increased carbon storage. The highest carbon storage was found in the completely ungrazed areas (16.7 ± 2.9 kg m−2). Climatic factors, along with soil types and topographical factors, controlled soil carbon density along a soil depth in grasslands. Environmental factors alone explained about 60% of the total variation in soil carbon storage. The actual depth-wise distribution of soil carbon contents was significantly influenced by the grazing intensity and topographical factors. Overall, policy-makers should focus on reducing the grazing intensity and land conversion for the sustainable management of grasslands and C sequestration.

Abstract

This is a report on the potential of NanoPro™ to reduce the rate of two commonly used fungicides for control of Microdochium patch (Microdochium nivale), the economically most important turfgrass disease in Scandinavia. The experiment was conducted from 14 Sept. 2018 to 1 May 2019 on an annual bluegrass golf green at the NIBIO Turfgrass Research Center Landvik. Use of NanoPro™ at a rate of 292 ml/ha in tank mixture with the systemic fungicide Delaro® SC 325 or/and the contact fungicide Medallion® TL produced the same level of disease control with a 30-60% reduction in fungicide dosage as with full fungicide dosage without additive. NanoPro™ was more effective with Medallion® TL than with Delaro® SC 325. We conclude that NanoPro™ may have a big potential in Scandinavia and other countries where authorities require reduced fungicide use. The experiment should be repeated one more year before giving final recommendations.

Abstract

No abstract has been registered

To document

Abstract

Purpose Sorption could be a way to concentrate nutrients in diluted waste streams to bring more nutrients back to agriculture. The aim of this work was to model the fate of sorbed NH4+ content in liquid waste streams by adding nitrogen (N) sorbed to a sorbent, zeolite, and study its effect on early growth and potential leaching losses. Methods A pot experiment with two soil types and wheat as test crop was conducted. Mineral N in soil was measured, and a leaching experiment performed. 15N labelled ammonium was sorbed to zeolite. The fertilizer effect was then compared to ammonium fertilizer applied the conventional way, with and without zeolite. Results Early uptake of sorbed ammonium was reduced by 56% compared to ammonium applied conventionally, and soil uptake compensated only very early. Nitrate concentration in leachates was reduced by 12% in sandy soil when N was applied sorbed to zeolite. However, leaching of water through the profile increased 71% when N was applied sorbed to zeolite, so that there was only a tendency to lower N losses when N was applied sorbed to zeolite. Conclusion Ammonium-N sorbed to zeolite is less plant available than conventionally applied N but may also be less prone to leaching losses.

To document

Abstract

Members of the smoothhound shark genus Mustelus display a widespread distribution pattern across ocean basins with a high degree of sub-regional endemism. The patterns and processes that resulted in smoothhound biodiversity and present-day distribution remain largely unknown. We infer the phylogenetic relationships of the genus Mustelus, based on sequence data (3474 bp) from three mitochondrial genes (CR, NADH-2 and 12S-16SrRNA) and a nuclear gene (KBTBD2) from seven species of Mustelus distributed across the eastern Atlantic- and Indo-Pacific oceans. Using the CR and KBTBD2 dataset, we infer the phylogeographic placement of Old World Mustelus, with particular reference to species from southern Africa. Using a near-complete phylogeny of the genus including Old World and New World species of Mustelus and publicly available sequences of the NADH-2 gene, we found supporting evidence indicating a major cladogenic event separating placental and aplacental species. Biogeographical analyses further revealed that the radiation of Mustelus in the southern African region was driven primarily by long-distance dispersal during the upper Miocene to lower Pleistocene. The placement of the placental blackspotted smoothhound Mustelus punctulatus at the base of the placental non-spotted clade suggests the secondary loss of black spots in the genus, and this was also supported by the ancestral state reconstruction. The results furthermore suggest that the Southern Hemisphere species of the genus arose from multiple separate dispersal events from the Northern Hemisphere which is in line with the earliest record of Mustelus in the Northern Hemisphere.