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.
2019
Forfattere
Jordi Doltra Patricia Gallejones Jørgen E. Olesen Sissel Hansen Randi Berland Frøseth Maike Krauss Jarosław Stalenga Krzysztof Jończyk Adela Martínez-Fernández Gaio Cesare PaciniSammendrag
Soil fertility building measures should be explored at the short and long-term for an adequate evaluation of their impact on sustaining yields and of its environmental consequences in crop rotations under organic farming. For such a purpose, process-based crop models are potential useful tools to complement and upscale field observations under a range of soil and climatic conditions. Organic rotations differ in soil fertility dynamics in comparison to conventional farming but very few modelling studies have explicitly considered this specific situation. Here, we evaluate the FASSET model to predict the effects of different fertility management options in organic crop rotations on dry matter (DM) and nitrogen (N) yield, and soil N dynamics, including N2O emissions. For that, we used data from seven short and long-term field experiments in different agro-climatic environments in Europe (Norway, Denmark, Poland, Switzerland, Italy and Spain) including climate, soil and management data. Soil fertility building measures covered fertilization type, green manures, cover crops, tillage, crop rotation composition and management (organic or conventional). Model performance was evaluated by comparing observed and simulated values of crop DM and N yield, soil mineral N and nitrous oxide (N2O) emissions using five complementary statistical indices. The model closely reproduced most observed DM and N yield trends and effects of soil fertility building measures in arable crops, particularly in cereals. Contrary, yields of grass-clover, especially N, were generally reproduced with low degree of accuracy. Model performance for simulating soil mineral N depended on site and the availability of soil and management information. Although high uncertainty was associated to the simulation of soil N dynamics, differences of cumulative N2O emissions between fertility building measures were reflected in model outputs. Aspects for modelling improvement include cover crop growth and decomposition, biological N fixation (BNF) or weed and pest soil-crop interactions. It is concluded that FASSET can be successfully used to investigate the impact of fertilization type, green manures, tillage and management (organic or conventional) on crop productivity and to a certain extent on soil N dynamics including soil N2O emissions at different soils and climates in organic farming in Europe.
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Sammendrag
Interspecific brood parasitism is common in many animal systems. Brood parasites enter the nests of other species and divert host resources for producing their own offspring, which can lead to strong antagonistic parasite–host coevolution. Here, we look at commonalities among social insect species that are victims of brood parasites, and use phylogenetic data and information on geographical range size to predict which species are most probably to fall victims to brood parasites in the future. In our analyses, we focus on three eusocial hymenopteran groups and their brood parasites: (i) bumblebees, (ii) Myrmica ants, and (iii) vespine and polistine wasps. In these groups, some, but not all, species are parasitized by obligate workerless inquilines that only produce reproductive-caste descendants.We find phylogenetic signals for geographical range size and the presence of parasites in bumblebees, but not in ants and wasps. Phylogenetic logistic regressions indicate that the probability of being attacked by one or more brood parasite species increases with the size of the geographical range in bumblebees, but the effect is statistically only marginally significant in ants. However, non-phylogenetic logistic regressions suggest that bumblebee species with the largest geographical range sizes may have a lower likelihood of harbouring social parasites than do hosts with medium-sized ranges. Our results provide new insights into the ecology and evolution of host–social parasite systems, and indicate that host phylogeny and geographical range size can be used to predict threats posed by social parasites, as well to design efficient conservation measures for both hosts and their parasites. This article is part of the theme issue ‘The coevolutionary biology of brood parasitism: from mechanism to pattern’.
Forfattere
Paal KrokeneSammendrag
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Forfattere
Rene Friedland Gerald Schernewski Ulf Gräwe Inga Greipsland Dalila Palazzo Marianna PastuszakSammendrag
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Forfattere
Signe Nybø Erik Framstad Simon Jakobsson Marianne Evju Anders Lyngstad Hanne Sickel Anne Sverdrup-Thygeson Joachim Paul Töpper Vigdis Vandvik Liv Guri Velle Per Arild AarrestadSammendrag
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Forfattere
Arnfinn NesSammendrag
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Forfattere
Mohamed Neji Anais Gorel Dario Isidro Ojeda Alayon Jerome Duminil Chedly Kastally Kathy Steppe Adeline Fayolle Olivier J. HardySammendrag
With the ongoing climate change, African rainforests are expected to experience severe drought events in the future. In Africa, the tropical genus Erythrophleum (Fabaceae) includes two forest sister timber tree species displaying contrasting geographical distributions. Erythrophleum ivorense is adapted to wet evergreen Guineo-Congolian forests, whereas E. suaveolens occurs in a wider range of climates, being found in moist dense forests but also in gallery forests under a relatively drier climate. This geographical distribution pattern suggests that the two species might cope differently to drought at the genomic level. Yet, the genetic basis of tolerance response to drought stress in both species is still uncharacterized. To bridge this gap, we performed an RNA-seq approach on seedlings from each species to monitor their transcriptional responses at different levels of drought stress (0, 2 and 6 weeks after stopping watering seedlings). Monitoring of wilting symptoms revealed that E. suaveolens displayed an earlier phenotypic response to drought stress than E. ivorense. At the transcriptomic level, results revealed 2020 (1204 down-regulated/816 up-regulated) and 1495 differentially expressed genes (DEGs) in response to drought stress from a total of 67,432 and 66,605 contigs assembled in E. ivorense and E. suaveolens, respectively. After identifying 30,374 orthologs between species, we found that only 7 of them were DEGs shared between species, while 587 and 458 were differentially expressed only in E. ivorense or E. suaveolens, respectively. GO and KEGG enrichment analysis revealed that the two species differ in terms of significantly regulated pathways as well as the number and expression profile of DEGs (Up/Down) associated with each pathway in the two stress stages. Our results suggested that the two studied species react differently to drought. E. suaveolens seems displaying a prompt response to drought at its early stage strengthened by the down-regulation of many DEGs encoding for signaling and metabolism-related pathways. A considerable up-regulation of these pathways was also found in E. ivorense at the late stage of drought, suggesting this species may be a late responder. Overall, our data may serve as basis for further understanding the genetic control of drought tolerance in tropical trees and favor the selection of crucial genes for genetically enhancing drought resistance.