Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2017
Sammendrag
Conversion from agriculture to forestry is considered a measure for mitigation of atmospheric CO2 but the impacts on soil C and N processes remain still unclear. We investigated heterotrophic respiration (RH), specific carbon mineralization (CMIN) and nitrogen mineralization (NMIN) in Norway spruce (Picea abies (Karst.) L.) and oak (Quercus robur L.) chronosequences on former cropland by laboratory incubation. The RH was estimated as the release of C per gram soil and CMIN as the release of C per gram of soil organic matter (SOM). Seven Norway spruce stands (16–44 years), eight oak stands (4–43 years), a cropland, a 35 years old permanent pasture and a 200-year-old oak-dominated forest were sampled (0–5 cm and 5–15 cm soil layers) in early spring. The SOM content gradually increased with stand age in 0–5 cm but remained the same in the 5–15 cm soil layer. The RH in the 0–5 cm layer gradually increased with time since afforestation in both tree species while there was no change in CMIN. In 5–15 cm, neither RH nor CMIN changed significantly after afforestation, but oak stands had significantly higher RH than Norway spruce. The NMIN and nitrification in 0–5 cm significantly increased with stand age and only nitrification was higher in oak. In 5–15 cm, only NMIN in oak increased with stand age, but both NMIN and nitrification were significantly higher in oak than spruce. Cropland RH, CMIN and NMIN rates were comparable to those found within the first decades of afforestation, whereas the 200-year-old forest and the pasture generally had RH and NMIN rates similar to the older chronosequence stands. We conclude that potential RH and soil N mineralization increased with time since afforestation and were tree species specific. Soil organic C stock gains observed in this area during the first 45 years after afforestation were not driven by decreased SOM decomposability, leaving increased litter C inputs as a more likely explanation. The lower CMIN in the 200-year-old forest suggests that future studies should include older forests to assess if the stability of C and the retention of N may increase in a longer term perspective.
Forfattere
Maochuan Hu Takahiro Sayama Xingqi Zhang Kenji Tanaka Kaoru Takara Hong YangSammendrag
Low impact development (LID) has attracted growing attention as an important approach for urban flood mitigation. Most studies evaluating LID performance for mitigating floods focus on the changes of peak flow and runoff volume. This paper assessed the performance of LID practices for mitigating flood inundation hazards as retrofitting technologies in an urbanized watershed in Nanjing, China. The findings indicate that LID practices are effective for flood inundation mitigation at the watershed scale, and especially for reducing inundated areas with a high flood hazard risk. Various scenarios of LID implementation levels can reduce total inundated areas by 2%–17% and areas with a high flood hazard level by 6%–80%. Permeable pavement shows better performance than rainwater harvesting against mitigating urban waterlogging. The most efficient scenario is combined rainwater harvesting on rooftops with a cistern capacity of 78.5 mm and permeable pavement installed on 75% of non-busy roads and other impervious surfaces. Inundation modeling is an effective approach to obtaining the information necessary to guide decision-making for designing LID practices at watershed scales.
Forfattere
S. V. Bugmyrin K. F. Tirronen D. V. Panchenko Alexander Kopatz Snorre Hagen Hans Geir Eiken A. S. KuznetsovaSammendrag
We present data on the species composition of helminths in brown bears (Ursus arctos) from the Murmansk Region, Russia. The absence of any information about helminths of brown bear in the region necessitated the conduct of these studies. Samples were collected in 2014 and 2015 in the southern part of the Kola Peninsula from the White Sea coastal habitats. Annually, in the study area, 1–3 bears are legally hunted and biological samples for examination are very difficult to obtain. Therefore, we used fecal samples. We studied 93 feces and identified parasite eggs identified in 43 of them by morphometric criteria. The surveys revealed eggs of the following helminths: Dicrocoelium sp., Diphyllobothrium sp., Anoplocephalidae, Capillariidae, Baylisascaris sp., Strongylida 1, and Strongylida 2. These results represent the first reconnaissance stage, which allowed characterizing the taxonomic diversity and prevalence of parasites of brown bears of the Kola Peninsula.
Forfattere
Hugh Cross Jørn Henrik Sønstebø Nina Elisabeth Nagy Volkmar Timmermann Halvor Solheim Isabella Børja Håvard Kauserud Tor Carlsen Barbara Rzepka Katarzyna Wasak Adam Vivian-Smith Ari HietalaSammendrag
High biodiversity is regarded as a barrier against biological invasions. We hypothesized that the invasion success of the pathogenic ascomycete Hymenoscyphus fraxineus threatening common ash in Europe relates to differences in dispersal and colonization success between the invader and the diverse native competitors. Ash leaf mycobiome was monitored by high-throughput sequencing of the fungal internal transcribed spacer region (ITS) and quantitative PCR profiling of H. fraxineus DNA. Initiation of ascospore production by H. fraxineus after overwintering was followed by pathogen accumulation in asymptomatic leaves. The induction of necrotic leaf lesions coincided with escalation of H. fraxineus DNA levels and changes in proportion of biotrophs, followed by an increase of ubiquitous endophytes with pathogenic potential. H. fraxineus uses high propagule pressure to establish in leaves as quiescent thalli that switch to pathogenic mode once these thalli reach a certain threshold – the massive feedback from the saprophytic phase enables this fungus to challenge host defenses and the resident competitors in mid-season when their density in host tissues is still low. Despite the general correspondence between the ITS-1 and ITS-2 datasets, marker biases were observed, which suggests that multiple barcodes provide better overall representation of mycobiomes.
Forfattere
R. Drenkhan Halvor Solheim A. Bogacheva T. Riit K. Adamson T. Drenkhan T. Maaten Ari HietalaSammendrag
Dieback of European ash was first observed in Europe in the early 1990s. The disease is caused by the invasive ascomycete Hymenoscyphus fraxineus, proposed to originate from Far East Asia, where it has been considered a harmless saprotroph. This study investigates the occurrence of H. fraxineus in tissues of local ash species in the Russian Far East, and assesses its population-specific genetic variation by ITS sequencing. Shoot dieback symptoms, characteristic of H. fraxineus infection on European ash, were common, but not abundant, on Fraxinus mandshurica and Fraxinus rhynchophylla trees in Far East Russia. High levels of pathogen DNA were associated with necrotic leaf tissues of these ash species, indicating that the local H. fraxineus population is pathogenic to their leaves. However, the low levels of H. fraxineus DNA detected in shoots with symptoms, the failure to isolate this fungus from such tissues, and the presence of other fungi with pathogenic potential in shoots with symptoms indicate that local H. fraxineus strains may not be responsible (or their role is negligible) for the observed ash shoot dieback symptoms in the region. Conspicuous differences in ITS rDNA sequences detected between H. fraxineus isolates from Russian Far East and European populations suggest that the current ash dieback epidemic in Europe might not directly originate from the Russian Far East. Revision of the herbarium material shows that the earliest specimen of H. fraxineus was collected in 1962 from the Russian Far East and the oldest H. fraxineus specimen of China was collected in 2004.
Forfattere
Marie Trydeman Knudsen John E. Hermansen Christel Cederberg Felix Herzog Jim Vale Philippe Jeanneret Jean-Pierre Sarthou Jürgen K. Friedel Katalin Balázs Wendy Fjellstad Max Kainz Sebastian Wolfrum Peter DennisSammendrag
Life Cycle Assessment (LCA) is a widely used tool to assess environmental sustainability of products. The LCA should optimally cover the most important environmental impact categories such as climate change, eutrophication and biodiversity. However, impacts on biodiversity are seldom included in LCAs due to methodological limitations and lack of appropriate characterization factors. When assessing organic agricultural products the omission of biodiversity in LCA is problematic, because organic systems are characterized by higher species richness at field level compared to the conventional systems. Thus, there is a need for characterization factors to estimate land use impacts on biodiversity in life cycle assessment that are able to distinguish between organic and conventional agricultural land use that can be used to supplement and validate the few currently suggested characterization factors. Based on a unique dataset derived from field recording of plant species diversity in farmland across six European countries, the present study provides new midpoint occupation Characterization Factors (CF) expressing the Potentially Disappeared Fraction (PDF) to estimate land use impacts on biodiversity in the ‘Temperate Broadleaf and Mixed Forest’ biome in Europe. The method is based on calculation of plant species on randomly selected test sites in the biome and enables the calculation of characterization factors that are sensitive to particular types of management. While species richness differs between countries, the calculated CFs are able to distinguish between different land use types (pastures (monocotyledons or mixed), arable land and hedges) and management practices (organic or conventional production systems) across countries. The new occupation CFs can be used to supplement or validate the few current CF's and can be applied in LCAs of agricultural products to assess land use impacts on species richness in the ‘Temperate Broadleaf and Mixed Forest’ biome.
Forfattere
Merete Wiken Dees Renata Lebecka Juliana Perminow Robert Czajkowski Anna Grupa Agata Motyka Sabina Zoledowska Jadwiga Śliwka Ewa Lojkowska May Bente BrurbergSammendrag
Soft rot and blackleg of potato caused by pectinolytic bacteria lead to severe economic losses in potato production worldwide. To investigate the species composition of bacteria causing soft rot and black leg of potato in Norway and Poland, bacteria were isolated from potato tubers and stems. Forty-one Norwegian strains and 42 Polish strains that formed cavities on pectate medium were selected for potato tuber maceration assays and sequencing of three housekeeping genes (dnaX, icdA and mdh) for species identification and phylogenetic analysis. The distribution of the species causing soft rot and blackleg in Norway and Poland differed: we have demonstrated that mainly P. atrosepticum and P. c. subsp. carotovorum are the causal agents of soft rot and blackleg of potatoes in Norway, while P. wasabiae was identified as one of the most important soft rot pathogens in Poland. In contrast to the other European countries, D. solani seem not to be a major pathogen of potato in Norway and Poland. The Norwegian and Polish P. c. subsp. carotovorum and P. wasabiae strains did not cluster with type strains of the respective species in the phylogenetic analysis, which underlines the taxonomic complexity of the genus Pectobacterium. No correlation between the country of origin and clustering of the strains was observed. All strains tested in this study were able to macerate potato tissue. The ability to macerate potato tissue was significantly greater for the P. c. subsp. carotovorum and Dickeya spp., compared to P. atrosepticum and P. wasabiae.
Forfattere
Pierrick Francois Denis Stévant Celine Rebours Annelise Sabine ChapmanSammendrag
© The Author(s) 2017. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/)
Forfattere
Jianbao Li Xianjin Huang Hong Yang Xiaowei Chuai Changyan WuSammendrag
As China's industrialization and urbanization have grown rapidly in recent years, China's CO2 emissions rose from 3405.1799 Mt to 10,249.4630 Mt from 2000 to 2013, and it has reached the highest levels in the word since 2006. Chinese government has emphasized the importance of reducing carbon emissions and set the target of reducing carbon intensity to 60e65% of 2005 levels by 2030. Investigating the convergence of carbon intensity can identify the convergence rate, which is helpful in guiding allocations of carbon intensity reduction. The Yangtze River Delta is one of the key carbon emission regions in China, with higher urbanization levels and larger carbon emissions; thus, we employed prefecture-level panel data derived from grid data between 2000 and 2010 to examine whether the convergence of carbon intensity exists across prefecture-level cities in the Yangtze River Delta. Spatial panel data models were utilized to investigate b-convergence of carbon intensity. The results indicated that carbon intensity showed divergence during 2002e2004 and s-convergence over other periods (2000e2002 and 2004 e2010). Carbon intensity exhibited stochastic convergence, indicating that the shocks to carbon intensity relative to the average level of carbon intensity are only transitory. There was a spatial spillover effect and b-convergence of carbon intensity, suggesting that prefecture-level cities with higher carbon intensity would decrease rapidly in the Yangtze River Delta. Our results highlight the importance of considering the present state of carbon intensity, spatial factors, and socioeconomic factors such as industrial structure and economic levels during allocation planning for reducing carbon intensity.
Forfattere
Ioannis Dimitriou Blas Mola-YudegoSammendrag
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