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Luscher A.,Institute for Sustainability science | Mueller-Harvey I.,University of Reading | Soussana J.F.,French National Institute for Agricultural Research | Rees R.M.,Scotland’s Rural College | Peyraud J.L.,French National Institute for Agricultural Research
Grass and Forage Science | Year: 2014

European grassland-based livestock production systems face the challenge of producing more meat and milk to meet increasing world demands and to achieve this using fewer resources. Legumes offer great potential for achieving these objectives. They have numerous features that can act together at different stages in the soil-plant-animal-atmosphere system, and these are most effective in mixed swards with a legume proportion of 30-50%. The resulting benefits include reduced dependence on fossil energy and industrial N-fertilizer, lower quantities of harmful emissions to the environment (greenhouse gases and nitrate), lower production costs, higher productivity and increased protein self-sufficiency. Some legume species offer opportunities for improving animal health with less medication, due to the presence of bioactive secondary metabolites. In addition, legumes may offer an adaptation option to rising atmospheric CO2 concentrations and climate change. Legumes generate these benefits at the level of the managed land-area unit and also at the level of the final product unit. However, legumes suffer from some limitations, and suggestions are made for future research to exploit more fully the opportunities that legumes can offer. In conclusion, the development of legume-based grassland-livestock systems undoubtedly constitutes one of the pillars for more sustainable and competitive ruminant production systems, and it can be expected that forage legumes will become more important in the future. © 2014 The Authors. Grass and Forage Science Published by John Wiley & Sons Ltd.


Hartmann M.,Institute for Sustainability science | Hartmann M.,Swiss Federal Institute of forest | Frey B.,Swiss Federal Institute of forest | Mayer J.,Institute for Sustainability science | And 2 more authors.
ISME Journal | Year: 2015

Low-input agricultural systems aim at reducing the use of synthetic fertilizers and pesticides in order to improve sustainable production and ecosystem health. Despite the integral role of the soil microbiome in agricultural production, we still have a limited understanding of the complex response of microbial diversity to organic and conventional farming. Here we report on the structural response of the soil microbiome to more than two decades of different agricultural management in a long-term field experiment using a high-throughput pyrosequencing approach of bacterial and fungal ribosomal markers. Organic farming increased richness, decreased evenness, reduced dispersion and shifted the structure of the soil microbiota when compared with conventionally managed soils under exclusively mineral fertilization. This effect was largely attributed to the use and quality of organic fertilizers, as differences became smaller when conventionally managed soils under an integrated fertilization scheme were examined. The impact of the plant protection regime, characterized by moderate and targeted application of pesticides, was of subordinate importance. Systems not receiving manure harboured a dispersed and functionally versatile community characterized by presumably oligotrophic organisms adapted to nutrient-limited environments. Systems receiving organic fertilizer were characterized by specific microbial guilds known to be involved in degradation of complex organic compounds such as manure and compost. The throughput and resolution of the sequencing approach permitted to detect specific structural shifts at the level of individual microbial taxa that harbours a novel potential for managing the soil environment by means of promoting beneficial and suppressing detrimental organisms. © 2015 International Society for Microbial Ecology.


Albrecht M.,Linc Global | Albrecht M.,Institute for Sustainability science | Padron B.,Linc Global | Bartomeus I.,CSIC - Doñana Biological Station | Traveset A.,Linc Global
Proceedings of the Royal Society B: Biological Sciences | Year: 2014

Compartmentalization-the organization of ecological interaction networks into subsets of species that do not interact with other subsets (true compartments) or interact more frequently among themselves than with other species (modules)-has been identified as a key property for the functioning, stability and evolution of ecological communities. Invasions by entomophilous invasive plants may profoundly alter the way interaction networks are compartmentalized. We analysed a comprehensive dataset of 40 paired plant-pollinator networks (invaded versus uninvaded) to test this hypothesis. We show that invasive plants have higher generalization levels with respect to their pollinators than natives. The consequences for network topology are that-rather than displacing native species fromthe network-plant invaders attracting pollinators into invaded modules tend to play new important topological roles (i.e. network hubs, module hubs and connectors) and cause role shifts in native species, creating larger modules that are more connected among each other.While the number of true compartmentswas lower in invaded compared with uninvaded networks, the effect of invasion on modularitywas contingent on the studysystem. Interestingly, the generalization level of the invasive plants partially explains this pattern, with more generalized invaders contributing to a lower modularity. Our findings indicate that the altered interaction structure of invaded networks makes them more robust against simulated random secondary species extinctions, but more vulnerable when the typically highly connected invasive plants go extinct first. The consequences and pathways by which biological invasions alter the interaction structure of plant-pollinator communities highlighted in this study may have important dynamical and functional implications, for example, by influencing multi-species reciprocal selection regimes and coevolutionary processes. © 2014 The Authors Published by the Royal Society. All rights reserved.


Walder F.,Institute for Sustainability science | Van Der Heijden M.G.A.,Institute for Sustainability science | Van Der Heijden M.G.A.,University of Zürich | Van Der Heijden M.G.A.,University Utrecht
Nature Plants | Year: 2015

Arbuscular mycorrhizal (AM) fungi are one of the most important groups of plant symbionts. These fungi provide mineral nutrients to plants in exchange for carbon. Although substantial amounts of resources are exchanged, the factors that regulate trade in the AM symbiosis are poorly understood. Recent evidence for the reciprocally regulated exchange of resources by AM fungi and plants has led to the suggestion that these symbioses operate according to biological market dynamics, in which interactions are viewed from an economic perspective, and the most beneficial partners are favoured. Here we present five arguments that challenge the importance of reciprocally regulated exchange, and thereby market dynamics, for resource exchange in the AM symbiosis, and suggest that such reciprocity is only found in a subset of symbionts, under specific conditions. We instead propose that resource exchange in the AM symbiosis is determined by competition for surplus resources, functional diversity and sink strength. © 2015 Macmillan Publishers Limited. All rights reserved.


van der Heijden M.G.A.,Institute for Sustainability science | van der Heijden M.G.A.,University of Zürich | van der Heijden M.G.A.,University Utrecht | Martin F.M.,University of Lorraine | And 2 more authors.
New Phytologist | Year: 2015

Almost all land plants form symbiotic associations with mycorrhizal fungi. These below-ground fungi play a key role in terrestrial ecosystems as they regulate nutrient and carbon cycles, and influence soil structure and ecosystem multifunctionality. Up to 80% of plant N and P is provided by mycorrhizal fungi and many plant species depend on these symbionts for growth and survival. Estimates suggest that there are c. 50 000 fungal species that form mycorrhizal associations with c. 250 000 plant species. The development of high-throughput molecular tools has helped us to better understand the biology, evolution, and biodiversity of mycorrhizal associations. Nuclear genome assemblies and gene annotations of 33 mycorrhizal fungal species are now available providing fascinating opportunities to deepen our understanding of the mycorrhizal lifestyle, the metabolic capabilities of these plant symbionts, the molecular dialogue between symbionts, and evolutionary adaptations across a range of mycorrhizal associations. Large-scale molecular surveys have provided novel insights into the diversity, spatial and temporal dynamics of mycorrhizal fungal communities. At the ecological level, network theory makes it possible to analyze interactions between plant-fungal partners as complex underground multi-species networks. Our analysis suggests that nestedness, modularity and specificity of mycorrhizal networks vary and depend on mycorrhizal type. Mechanistic models explaining partner choice, resource exchange, and coevolution in mycorrhizal associations have been developed and are being tested. This review ends with major frontiers for further research. © 2015 The Authors.


Sutter L.,Institute for Sustainability science | Sutter L.,University of Zürich | Albrecht M.,Institute for Sustainability science
Proceedings of the Royal Society B: Biological Sciences | Year: 2016

Insect pollination and pest control are pivotal functions sustaining global food production. However, they have mostly been studied in isolation and how they interactively shape crop yield remains largely unexplored. Using controlled field experiments, we found strong synergistic effects of insect pollination and simulated pest control on yield quantity and quality. Their joint effect increased yield by 23%, with synergistic effects contributing 10%, while their single contributions were 7% and 6%, respectively. The potential economic benefit for a farmer from the synergistic effects (12%) was 1.8 times greater than their individual contributions (7% each). We show that the principal underlying mechanism was a pronounced pestinduced reduction in flower lifetime, resulting in a strong reduction in the number of pollinator visits a flower receives during its lifetime. Our findings highlight the importance of non-additive interactions among ecosystem services (ES) when valuating, mapping or predicting them and reveal fundamental implications for ecosystem management and policy aimed at maximizing ES for sustainable agriculture. © 2016 The Author(s) Published by the Royal Society. All rights reserved.


Bender S.F.,Institute for Sustainability science | Bender S.F.,University of Zürich | Conen F.,University of Basel | Van der Heijden M.G.A.,Institute for Sustainability science | And 2 more authors.
Soil Biology and Biochemistry | Year: 2015

Arbuscular mycorrhizal fungi (AMF) can enhance plant nutrition and growth. However, their contribution to nutrient cycling in ecosystems is still poorly understood. Using experimental grassland microcosms filled with two different soil types (pasture and heath soil) and fertilized with different N forms (NO3 - or NH4 +), we tested the AMF contribution to N and P cycling including measurements of organic and inorganic leaching losses and N2O fluxes. We hypothesized that AMF enhance the sustainability of plant-soil systems by reducing nutrient losses and enhancing plant nutrient uptake. AMF reduced reactive and unreactive P leaching by 31%, enhanced plant P contents by 15% and increased P mobilization from soil by 18%. AMF reduced N2O fluxes and NH4 + leaching in both soils. Leaching of dissolved organic N was reduced by 24% in the heath soil only. Plant N contents were increased by 13% in the pasture soil but not affected in the heath soil. The microbial biomass N content was higher with AMF. This is the first comprehensive assessment of the influence of AMF on N and P cycling, including effects on inorganic and organic nutrient leaching losses and N2O emissions in a single study. We conclude that AMF can promote sustainable nutrient cycling but the effects on N cycling are context dependent. © 2014 Elsevier Ltd.


Nemecek T.,Institute for Sustainability science | Schnetzer J.,Institute for Sustainability science | Reinhard J.,Empa - Swiss Federal Laboratories for Materials Science and Technology
International Journal of Life Cycle Assessment | Year: 2014

Purpose: The emission of greenhouse gases (GHG) is a key criterion in the environmental assessment of biofuels. Life cycle inventories taking into account the latest methodological developments are an essential prerequisite for this assessment. In the last years, substantial progresses in the modelling of nitrogen emissions relevant for the climate as well as in modelling the emissions from land use change (LUC) have been achieved. Therefore, the biomass production inventories in the ecoinvent database were revised to take into account these developments. Methods: The IPCC method tier 1 has been used for the assessment of N2O emissions. Induced emissions from NH3 and NO3 were included as well. Due to the importance of the latter emissions for N2O formation, these emissions have also been updated and harmonised. The Agrammon model was used for the NH3 emissions. The SALCA-NO3 model has been applied in the European inventories to estimate nitrate leaching, whilst in non-European inventories the SQCB-NO3 model has been used. The quantification of the land use change areas has been based on annualized, retrospective data of the last 20 years. All carbon pools (from aboveground biomass to soil organic carbon) were considered and differentiated on a regional level for all of the natural vegetation categories affected. Whenever possible, default values and methods from the IPCC 2006 were applied. Results and discussion: The changes for ammonia emissions were generally very small (-5 % on average). The nitrate emissions increased on average by +13 %, but this slight trend is the result of important downward and upward changes, whilst the average N2O emissions decreased by -26 %. For the existing inventories of soybean, palm oil and sugarcane production, significant increases of GHG emissions resulted from LUC modelling. This was mainly due to the consistent inclusion of all carbon stocks according to the IPCC guidelines. The calculation method can also result in important C sequestration effects in certain cases like African Jatropha production. Conclusions: The changes in greenhouse gas emissions due to the updated methodology were significant. This shows that life cycle assessment studies for biofuels using older methodological bases need to be revised and could lead to different conclusions. The implemented and cultivated superstructure for LUC modelling is modular and flexible and can be easily extended to other important crop activities. The new parameterisation functionality applied for the activities provides powerful means for the simple generation of site-specific activities. © 2014 Springer-Verlag Berlin Heidelberg.


Li Y.,Chinese Academy of Agricultural Sciences | Zhang X.,Chinese Academy of Agricultural Sciences | Zhang X.,Henan Agricultural University | Chen X.,Chinese Academy of Agricultural Sciences | And 4 more authors.
Scientific Reports | Year: 2015

As a pollen feeder, Propylea japonica would be directly exposed to Cry proteins in Bacillus thuringiensis (Bt)-transgenic rice fields. The effect of Cry1C-or Cry2A-containing transgenic rice pollen on the fitness of P. japonica was assessed using two dietary-exposure experiments in the laboratory. In the first experiment, larval developmental time of P. japonica was significantly longer when fed pollen from Bt rice lines rather than control pollen but other life table parameters were not significantly affected. In the second experiment, P. japonica was not affected when fed a rapeseed pollen-based diet containing purified Cry1C or Cry2A at concentrations that were >10-times higher than in pollen, but P. japonica was affected when the diet contained E-64 as a positive control. In both experiments, the stability and bioactivity of the Cry proteins in the food sources and the uptake of the proteins by P. japonica were confirmed. The results show that P. japonica is not sensitive to Cry1C or Cry2A proteins; the effect observed in the first experiment was likely attributable to unknown differences in the nutritional composition of Bt rice pollen. Overall, the data indicate that the growing of Cry1C-or Cry2A-transgenic rice should pose a negligible risk to P. japonica.


Schlaeppi K.,Institute for Sustainability science | Bulgarelli D.,University of Dundee
Molecular Plant-Microbe Interactions | Year: 2015

Plants host distinct microbial communities on and inside their tissues designated the plant microbiota. Microbial community profiling enabled the description of the phylogenetic structure of the plant microbiota to an unprecedented depth, whereas functional insights are largely derived from experiments using individual microorganisms. The binary interplay between isolated members of the plant microbiota and host plants ranges from mutualistic to commensalistic and pathogenic relationships. However, how entire microbial communities capable of executing both growth-promoting and growth-compromising activities interfere with plant fitness remains largely unknown. Ultimately, unravelling the net result of microbial activities encoded in the extended plant genome-the plant microbiome- will be key to understanding and exploiting the full yield potential of a crop plant. In this perspective, we summarize first achievements of plant-microbiome research, we discuss future research directions, and we provide ideas for the translation of basic science to application to capitalize on the plant microbiome at work. © 2015 The American Phytopathological Society.

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