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.
2019
Abstract
Mediterranean climate areas are home to highly relevant and distinctive agro-ecosystems, where sustainability is threatened by water scarcity and continuous loss of soil organic carbon. In these systems, recycling strategies to close the loop between crop production (and agrorelated industries) and soil conservation are of special interest in the current context of climate change mitigation. Pyrolysis represents a recycling option for the production of energy and biochar, a carbonaceous product with a wide range of environmental and agronomic applications. Considering that biochar functionality depends on both the original biomass and the pyrolysis conditions, we produced and characterized 22 biochars in order to evaluate their potential to sequester C and modify soil physicochemical properties. The pore size distribution was a function of the original biomass and did not change with the temperature of pyrolysis. The highest number of pores within the size 0.2−30 μm, relevant for plant available water retention, was reached at 600 °C. However, ideal pyrolysis conditions to optimize C stability and hydrologic properties was reached at 400 °C in woody derived biochars, as higher temperatures lead to a nontransient hydrophobicity. This study highlights relevant physicochemical properties of locally derived biochars that can be used to tackle specific challenges in Mediterranean agroecosystems.
Authors
Arne BardalenAbstract
No abstract has been registered
Authors
Synnøve Smebye Botnen Marie Louise Davey Anders Aas Tor Carlsen Ella Thoen Einar Heegaard Unni Vik Philipp Dresch Sunil Mundra Ursula Peintner Andy F. S. Taylor Håvard KauserudAbstract
Aim Polar and alpine ecosystems appear to be particularly sensitive to increasing temperatures and the altered precipitation patterns linked to climate change. However, little is currently known about how these environmental drivers may affect edaphic organisms within these ecosystems. In this study, we examined communities of plant root‐associated fungi (RAF) over large biogeographical scales and along climatic gradients in the North Atlantic region in order to gain insights into the potential effects of climate variability on these communities. We also investigated whether selected fungal traits were associated with particular climates. Locations Austria, Scotland, Mainland Norway, Iceland, Jan Mayen and Svalbard. Taxa Root fungi associated with the ectomycorrhizal and herbaceous plant Bistorta vivipara. Methods DNA metabarcoding of the ITS1 region was used to characterize the RAF of 302 whole plant root systems, which were analysed by means of ordination methods and linear modelling. Fungal spore length, width, volume and shape, as well as mycelial exploration type (ET) of ectomycorrhizal (ECM) basidiomycetes were summarized at a community level. Results The RAF communities exhibited strong biogeographical structuring, and both compositional variation as well as fungal species richness correlated with annual temperature and precipitation. In accordance with general island biogeography theory, the least species‐rich RAF communities were found on Jan Mayen, a remote and small island in the North Atlantic Ocean. Fungal spores tended to be more elongated with increasing latitude. We also observed a climate effect on which mycelial ET was dominating among the ectomycorrhizal fungi. Main conclusions Both geographical and environmental variables were important for shaping root‐associated fungal communities at a North Atlantic scale, including the High Arctic. Fungal OTU richness followed general biogeographical patterns and decreased with decreasing size and/or increasing isolation of the host plant population. The probability of possessing more elongated spores increases with latitude, which may be explained by a selection for greater dispersal capacity among more isolated host plant populations in the Arctic.
Abstract
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Authors
Trond MæhlumAbstract
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Abstract
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’.
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Abstract
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Authors
Nicholas F. Britton Iulia Martina Bulai Stephanie Saussure Niels Holst Ezio VenturinoAbstract
The control of insect pests in agriculture is essential for food security. Chemical controls typically damage the environment and harm beneficial insects such as pollinators, so it is advantageous to identify targetted biological controls. Since predators are often generalists, pathogens or parasitoids are more likely to serve the purpose. Here, we model a fungal pathogen of aphids as a potential means to control of these important pests in cereal crops. Typical plant herbivore pathogen models are set up on two trophic levels, with dynamic variables the plant biomass and the uninfected and infected herbivore populations. Our model is unusual in that (i) it has to be set up on three trophic levels to take account of fungal spores in the environment, but (ii) the aphid feeding mechanism leads to the plant biomass equation becoming uncoupled from the system. The dynamical variables are therefore the uninfected and infected aphid population and the environmental fungal concentration. We carry out an analysis of the dynamics of the system. Assuming that the aphid population can survive in the absence of disease, the fungus can only persist (and control is only possible) if (i) the host grows sufficiently strongly in the absence of infection, and (ii) the pathogen transmission parameters are sufficiently large. If it does persist the fungus does not drive the aphid population to extinction, but controls it below its disease-free steady state value, either at a new coexistence steady state or through oscillations. Whether this control is sufficient for agricultural purposes will depend on the detailed parameter values for the system.
Authors
Steffen AdlerAbstract
No abstract has been registered