Recent Submissions

  • Journal Article

    Supermarket Shopping and Nutritional Outcomes: A Panel Data Analysis for Urban Kenya 

    Demmler, Kathrin M.; Ecker, Olivier; Qaim, Matin
    World Development 2018; 102 p.292-303
    Overweight and obesity are growing health problems in many developing countries. Rising obesity rates are the result of changes in people’s diets and lifestyles. Income growth and urbanization are factors that contribute to these changes. Modernizing food retail environments may also play a certain role. For instance, the rapid spread of supermarkets in many developing countries could affect consumer food choices and thus nutritional outcomes. However, concrete evidence about the effects of supermarkets on consumer diets and nutrition is thin. A few existing studies have analyzed related linkages with cross-sectional survey data. We add to this literature by using panel data from households and individuals in urban Kenya. Employing panel regression models with individual fixed effects and controlling for other factors we show that shopping in supermarkets significantly increases body mass index (BMI). We also analyze impact pathways. Shopping in supermarkets contributes to higher consumption of processed and highly processed foods and lower consumption of unprocessed foods. These results confirm that the retail environment affects people’s food choices and nutrition. However, the effects depend on the types of foods offered. Rather than thwarting modernization in the retail sector, policies that incentivize the sale of more healthy foods—such as fruits and vegetables—in supermarkets may be more promising to promote desirable nutritional outcomes.
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  • Journal Article

    Land markets, Property rights, and Deforestation: Insights from Indonesia 

    Krishna, Vijesh V.; Kubitza, Christoph; Pascual, Unai; Qaim, Matin
    World Development 2017; 99 p.335-349
    We examine the emergence of land markets and their effects on forest land appropriation by farm households in Jambi Province, Sumatra, using micro-level data covering land use and land transactions for a period of more than 20 years (1992–2015). Based on a theoretical model of land acquisition by a heterogeneous farming population, different hypotheses are developed and empirically tested. Farm households involved in forest land appropriation differ from those involved in land market purchases in terms of migration status and other socioeconomic characteristics. In principle, these differences provide opportunities for market-induced deforestation. However, the appropriated forest land is not extensively traded, which we attribute to the lack of de jure property right protection and the resulting undervaluation in the market. While the de facto property right protection under customary law provides sufficient security within the village community, the sense of external tenure security is low when the land cannot be formally titled. Clearing forests for trading in the land market is, therefore, financially less lucrative for farm households than engaging in own cultivation of plantation crops, such as oil palm and rubber. We conclude that land markets did not have significant effects on deforestation. On the other hand, the emergence of land markets alone has also not been able to deter forest appropriation by local farm households.
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  • Journal Article

    Can mobile phones improve gender equality and nutrition? Panel data evidence from farm households in Uganda 

    Sekabira, Haruna; Qaim, Matin
    Food Policy 2017; 73 p.95-103
    Since 2000, mobile phone technologies have been widely adopted in many developing countries. Existing research shows that use of mobile phones has improved smallholder farmers’ market access and income. Beyond income, mobile phones can possibly affect other dimensions of social welfare, such as gender equality and nutrition. Such broader social welfare effects have hardly been analyzed up till now. Here, we address this research gap, using panel data from smallholder farm households in Uganda. Regression results show that mobile phone use is positively associated with household income, women empowerment, food security, and dietary quality. These results also hold after controlling for possible confounding factors. In addition to the householdlevel analysis, we also look at who within the household actually uses mobile phones. Gender-disaggregation suggests that female mobile phone use has stronger positive associations with social welfare than if males alone use mobile phones. We cautiously conclude that equal access to mobile phones cannot only foster economic development, but can also contribute to gender equality, food security, and broader social development. Further research is required to corroborate the findings and analyze the underlying causal mechanisms.
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  • Journal Article

    Trading off nutrition and education? A panel data analysis of the dissimilar welfare effects of Organic and Fairtrade standards 

    Meemken, Eva-Marie; Spielman, David J.; Qaim, Matin
    Food Policy 2017; 71 p.74-85
    Millions of smallholder farmers in developing countries participate in different types of sustainability standards. A growing body of literature has analyzed the welfare effects, with mixed results. Yet, there are important knowledge gaps. First, most existing studies have looked at the effects of one standard in one country. When comparing between studies it is unclear whether dissimilar outcomes are the result of different standards or different local conditions. Second, most studies have used cross-section data, so that selectivity issues remain a challenge. Third, existing work has primarily analyzed effects in terms of purely economic indicators, such as prices and income, ignoring other dimensions of household welfare. We address these shortcomings using panel data from small-scale coffee producers in Uganda and comparing the effects of two of the most popular sustainability standards, namely Organic and Fairtrade. Welfare effects are analyzed in terms of household expenditures, child education, and nutrition. Results show that Organic and Fairtrade both have positive effects on total consumption expenditures. However, notable differences are observed in terms of the other outcomes. Organic contributes to improved nutrition but has no effect on education. For Fairtrade it is exactly the other way around. We explore the mechanisms behind these differences.
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  • Journal Article

    Biodiversity effects on ecosystem functioning in a 15-year grassland experiment: Patterns, mechanisms, and open questions 

    Weisser, Wolfgang W.; Roscher, Christiane; Meyer, Sebastian T.; Ebeling, Anne; Luo, Guangjuan; Allan, Eric; Beßler, Holger; Barnard, Romain L.; Buchmann, Nina; Buscot, François; et al.
    Engels, ChristofFischer, ChristineFischer, MarkusGessler, ArthurGleixner, GerdHalle, StefanHildebrandt, AnkeHillebrand, Helmutde Kroon, HansLange, MarkusLeimer, SophiaLe Roux, XavierMilcu, AlexandruMommer, LiesjeNiklaus, Pascal A.Oelmann, YvonneProulx, RaphaelRoy, JacquesScherber, ChristophScherer-Lorenzen, MichaelScheu, StefanTscharntke, TejaWachendorf, MichaelWagg, CameronWeigelt, AlexandraWilcke, WolfgangWirth, ChristianSchulze, Ernst-DetlefSchmid, BernhardEisenhauer, Nico
    Basic and Applied Ecology 2017; 23 p.1-73
    In the past two decades, a large number of studies have investigated the relationship between biodiversity and ecosystemfunctioning, most of which focussed on a limited set of ecosystem variables. The Jena Experiment was set up in 2002 toinvestigate the effects of plant diversity on element cycling and trophic interactions, using a multi-disciplinary approach. Here,we review the results of 15 years of research in the Jena Experiment, focussing on the effects of manipulating plant speciesrichness and plant functional richness. With more than 85,000 measures taken from the plant diversity plots, the Jena Experimenthas allowed answering fundamental questions important for functional biodiversity research.First, the question was how general the effect of plant species richness is, regarding the many different processes that take placein an ecosystem. About 45% of different types of ecosystem processes measured in the ‘main experiment’, where plant speciesrichness ranged from 1 to 60 species, were significantly affected by plant species richness, providing strong support for the viewthat biodiversity is a significant driver of ecosystem functioning. Many measures were not saturating at the 60-species level,but increased linearly with the logarithm of species richness. There was, however, great variability in the strength of responseamong different processes. One striking pattern was that many processes, in particular belowground processes, took severalyears to respond to the manipulation of plant species richness, showing that biodiversity experiments have to be long-term,to distinguish trends from transitory patterns. In addition, the results from the Jena Experiment provide further evidence thatdiversity begets stability, for example stability against invasion of plant species, but unexpectedly some results also suggestedthe opposite, e.g. when plant communities experience severe perturbations or elevated resource availability. This highlights theneed to revisit diversity–stability theory.Second, we explored whether individual plant species or individual plant functional groups, or biodiversity itself is moreimportant for ecosystem functioning, in particular biomass production. We found strong effects of individual species and plantfunctional groups on biomass production, yet these effects mostly occurred in addition to, but not instead of, effects of plantspecies richness.Third, the Jena Experiment assessed the effect of diversity on multitrophic interactions. The diversity of most organismsresponded positively to increases in plant species richness, and the effect was stronger for above- than for belowground organisms,and stronger for herbivores than for carnivores or detritivores. Thus, diversity begets diversity. In addition, the effect on organismicdiversity was stronger than the effect on species abundances.Fourth, the Jena Experiment aimed to assess the effect of diversity on N, P and C cycling and the water balance of theplots, separating between element input into the ecosystem, element turnover, element stocks, and output from the ecosystem. While inputs were generally less affected by plant species richness, measures of element stocks, turnover and output were oftenpositively affected by plant diversity, e.g. carbon storage strongly increased with increasing plant species richness. Variables ofthe N cycle responded less strongly to plant species richness than variables of the C cycle.Fifth, plant traits are often used to unravel mechanisms underlying the biodiversity–ecosystem functioning relationship. Inthe Jena Experiment, most investigated plant traits, both above- and belowground, were plastic and trait expression dependedon plant diversity in a complex way, suggesting limitation to using database traits for linking plant traits to particular functions.Sixth, plant diversity effects on ecosystem processes are often caused by plant diversity effects on species interactions.Analyses in the Jena Experiment including structural equation modelling suggest complex interactions that changed withdiversity, e.g. soil carbon storage and greenhouse gas emission were affected by changes in the composition and activity of thebelowground microbial community. Manipulation experiments, in which particular organisms, e.g. belowground invertebrates,were excluded from plots in split-plot experiments, supported the important role of the biotic component for element and waterfluxes.Seventh, the Jena Experiment aimed to put the results into the context of agricultural practices in managed grasslands. Theeffect of increasing plant species richness from 1 to 16 species on plant biomass was, in absolute terms, as strong as the effect ofa more intensive grassland management, using fertiliser and increasing mowing frequency. Potential bioenergy production fromhigh-diversity plots was similar to that of conventionally used energy crops. These results suggest that diverse ‘High NatureValue Grasslands’ are multifunctional and can deliver a range of ecosystem services including production-related services.A final task was to assess the importance of potential artefacts in biodiversity–ecosystem functioning relationships, causedby the weeding of the plant community to maintain plant species composition. While the effort (in hours) needed to weed aplot was often negatively related to plant species richness, species richness still affected the majority of ecosystem variables.Weeding also did not negatively affect monoculture performance; rather, monocultures deteriorated over time for a number ofbiological reasons, as shown in plant-soil feedback experiments.To summarize, the Jena Experiment has allowed for a comprehensive analysis of the functional role of biodiversity in anecosystem. A main challenge for future biodiversity research is to increase our mechanistic understanding of why the magnitudeof biodiversity effects differs among processes and contexts. It is likely that there will be no simple answer. For example, amongthe multitude of mechanisms suggested to underlie the positive plant species richness effect on biomass, some have receivedlimited support in the Jena Experiment, such as vertical root niche partitioning. However, others could not be rejected in targetedanalyses. Thus, from the current results in the Jena Experiment, it seems likely that the positive biodiversity effect results fromseveral mechanisms acting simultaneously in more diverse communities, such as reduced pathogen attack, the presence of moreplant growth promoting organisms, less seed limitation, and increased trait differences leading to complementarity in resourceuptake. Distinguishing between different mechanisms requires careful testing of competing hypotheses. Biodiversity researchhas matured such that predictive approaches testing particular mechanisms are now possible.
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  • Journal Article

    GWAS for Meat and Carcass Traits Using Imputed Sequence Level Genotypes in Pooled F2-Designs in Pigs 

    Falker-Gieske, Clemens; Blaj, Iulia; Preuß, Siegfried; Bennewitz, Jörn; Thaller, Georg; Tetens, Jens
    G3: Genes, Genomes, Genetics 2019; 9(9) p.2823-2834
    In order to gain insight into the genetic architecture of economically important traits in pigs and to derive suitable genetic markers to improve these traits in breeding programs, many studies have been conducted to map quantitative trait loci. Shortcomings of these studies were low mapping resolution, large confidence intervals for quantitative trait loci-positions and large linkage disequilibrium blocks. Here, we overcome these shortcomings by pooling four large F2 designs to produce smaller linkage disequilibrium blocks and by resequencing the founder generation at high coverage and the F1 generation at low coverage for subsequent imputation of the F2 generation to whole genome sequencing marker density. This lead to the discovery of more than 32 million variants, 8 million of which have not been previously reported. The pooling of the four F2 designs enabled us to perform a joint genome-wide association study, which lead to the identification of numerous significantly associated variant clusters on chromosomes 1, 2, 4, 7, 17 and 18 for the growth and carcass traits average daily gain, back fat thickness, meat fat ratio, and carcass length. We could not only confirm previously reported, but also discovered new quantitative trait loci. As a result, several new candidate genes are discussed, among them BMP2 (bone morphogenetic protein 2), which we recently discovered in a related study. Variant effect prediction revealed that 15 high impact variants for the traits back fat thickness, meat fat ratio and carcass length were among the statistically significantly associated variants.
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  • Journal Article

    Deciphering bacterial and fungal endophyte communities in leaves of two maple trees with green islands 

    Wemheuer, Franziska; Wemheuer, Bernd; Daniel, Rolf; Vidal, Stefan
    Scientific Reports 2019; 9(1): Art. 14183
    Green islands (the re-greening of senescent leaf tissues) are particularly evident on leaves infected with fungal pathogens. To date, there is only a limited number of studies investigating foliar endophytic microorganisms in phytopathogen-infected leaves. Here, we analysed bacterial and fungal endophyte communities in leaves without green islands (control leaves; CL), within green island areas (GLA) and the surrounding yellow leaf areas (YLA) of leaves with green islands of Acer campestre and A. platanoides. GLA samples of A. campestre and A. platanoides were dominated by Sawadaea polyfida and S. bicornis, respectively, suggesting that these fungi might be responsible for the green islands. We detected a higher fungal richness and diversity in CL compared to GLA samples of A. campestre. Leaf status (CL, GLA, YLA) significantly altered the composition of fungal communities of A. campestre. This was related to differences in fungal community composition between YLA and GLA samples. Site was the main driver of bacterial communities, suggesting that bacterial and fungal endophytes are shaped by different factors. Overall, we observed Acer species-specific responses of endophyte communities towards the presence of green islands and/or leaf type, which might be attributed to several fungi and bacteria specifically associated with one Acer species.
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  • Journal Article

    Genetic diversity analysis of Thai indigenous pig population using microsatellite markers 

    Charoensook, Rangsun; Gatphayak, Kesinee; Brenig, Bertram; Knorr, Christoph
    Asian-Australasian Journal of Animal Sciences 2019; 32(10) p.1491-1500
    Objective: European pigs have been imported to improve the economically important traits of Thai pigs by crossbreeding and was finally completely replaced. Currently Thai indigenous pigs are particularly kept in a small population. Therefore, indigenous pigs risk losing their genetic diversity and identity. Thus, this study was conducted to perform large-scale genetic diversity and phylogenetic analyses on the many pig breeds available in Thailand. Methods: Genetic diversity and phylogenetics analyses of 222 pigs belonging to Thai native pigs (TNP), Thai wild boars (TWB), European commercial pigs, commercial crossbred pigs, and Chinese indigenous pigs were investigated by genotyping using 26 microsatellite markers. Results: The results showed that Thai pig populations had a high genetic diversity with mean total (TNA) and effective (Ne) number of alleles of 14.59 and 3.71, respectively, and expected heterozygosity (He) across loci (0.710). The polymorphic information content (PIC) per locus ranged between 0.651 and 0.914 leading to an average value above all loci of 0.789, and private alleles were found in six populations. The higher He compared to Ho in TNP, TWB, and the commercial pigs indicated some inbreeding within a population. The Nei's genetic distance, mean FST estimates, neighbour-joining tree of populations and individual, as well as multidimensional analysis indicated close genetic relationship between Thai indigenous pigs and some Chinese pigs, and they are distinctly different from European pigs. Conclusion: Our study reveals a close genetic relationship between Thai native pigs and Chinese pigs. The genetic introgression from European breeds is found in some Thai native pig populations, and signs of genetic erosion are shown. Private alleles found in this study should be taken into consideration for the breeding program. The genetic information from this study will be a benefit for both conservation and utilization of Thai pig genetic resources.
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  • Journal Article

    Inventory of Spatio-Temporal Methane Emissions from Livestock and Poultry Farming in Beijing 

    Guo, Yixuan; Wang, Yidong; Chen, Shufeng; Zheng, Shunan; Guo, Changcheng; Xue, Dongmei; Kuzyakov, Yakov; Wang, Zhong-Liang
    Sustainability 2019; 11(14): Art. 3858
    Livestock and poultry farming sectors are among the largest anthropogenic methane (CH4) emission sources, mainly from enteric fermentation and manure management. Previous inventories of CH4 emission were generally based on constant emission factor (EF) per head, which had some weaknesses mainly due to the succession of breeding and feeding systems over decades. Here, more reliable long-term changes of CH4 emissions from livestock and poultry farming in Beijing are estimated using the dynamic EFs based on the Intergovernmental Panel on Climate Change (IPCC) Tier 2 method, and high-resolution spatial patterns of CH4 emissions are also estimated with intensive field survey. The results showed that the estimated CH4 emissions derived by dynamic EFs were approximately 13–19% lower than those based on the constant EF before 2010. After 2011, however, the dynamic EFs-derived CH4 emissions were a little higher (3%) than the constant EF method. Temporal CH4 emissions in Beijing had experienced four developing stages (1978–1988: stable; 1989–1998: slow growth; 1999–2004: rapid growth and reached hot moments; 2005–2014: decline) during 1978–2014. Over the first two decades, the contributions of pigs (45%) and cattle (46%) to annual CH4 emission were similar; subsequently, the cattle emitted more CH4 compared to the pigs. At a spatial scale, Shunyi, Daxing, and Tongzhou districts with more cattle and pigs are the hotspots of CH4 emission. In conclusion, the dynamic EFs method obviously improved the spatio-temporal estimates of CH4 emissions compared to the constant EF approach, and the improvements depended on the period and aquaculture structure. Therefore, the dynamic EFs method should be recommended for estimating CH4 emissions from livestock and poultry farming in the future.
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  • Journal Article

    Drought vulnerability and risk assessments: state of the art, persistent gaps, and research agenda 

    Hagenlocher, Michael; Meza, Isabel; Anderson, Carl C.; Min, Annika; Renaud, Fabrice G.; Walz, Yvonne; Siebert, Stefan; Sebesvari, Zita
    Environmental Research Letters 2019; 14(8): Art. 083002
    Reducing the social, environmental, and economic impacts of droughts and identifying pathways towards drought resilient societies remains a global priority. A common understanding of the drivers of drought risk and ways in which drought impacts materialize is crucial for improved assessments and for the identification and (spatial) planning of targeted drought risk reduction and adaptation options. Over the past two decades, we have witnessed an increase in drought risk assessments across spatial and temporal scales drawing on a multitude of conceptual foundations and methodological approaches. Recognizing the diversity of approaches in science and practice as well as the associated opportunities and challenges, we present the outcomes of a systematic literature review of the state of the art of people-centered drought vulnerability and risk conceptualization and assessments, and identify persisting gaps. Our analysis shows that, of the reviewed assessments, (i) more than 60% do not explicitly specify the type of drought hazard that is addressed, (ii) 42% do not provide a clear definition of drought risk, (iii) 62% apply static, index-based approaches, (iv) 57% of the indicator-based assessments do not specify their weighting methods, (v) only 11% conduct any form of validation, (vi) only ten percent develop future scenarios of drought risk, and (vii) only about 40% of the assessments establish a direct link to drought risk reduction or adaptation strategies, i.e. consider solutions. We discuss the challenges associated with these findings for both assessment and identification of drought risk reduction measures, and identify research needs to inform future research and policy agendas in order to advance the understanding of drought risk and support pathways towards more drought resilient societies.
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  • Journal Article

    Author Correction: Microbial spatial footprint as a driver of soil carbon stabilization 

    Kravchenko, A. N.; Guber, A. K.; Razavi, B. S.; Koestel, J.; Quigley, M. Y.; Robertson, G. P.; Kuzyakov, Y.
    Nature Communications 2019; 10(1): Art. 4103
    An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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  • Journal Article

    Are consumers at the base of the pyramid willing to pay for nutritious foods? 

    Chege, Christine G.K.; Sibiko, Kenneth W.; Wanyama, Rosina; Jager, Matthias; Birachi, Eliud
    Food Policy 2019; 87: Art. 101745
    Base of the Pyramid (BoP) consumers living in the urban informal settlements of developing countries spend over 60% of their income on food, yet malnutrition and micronutrient deficiency remain widespread among these populations, pointing to the inadequacy of the foods they consume in terms of quality and quantity. In this paper we examine BoP consumers’ willingness to pay (WTP) for nutritious multi-composite porridge flour (improved flour) in the informal settlements of East Africa. The analysis is based on experimental data collected from 600 households in the informal settlements of Kampala, Uganda and Nairobi, Kenya (300 in each country) in 2016. We use Tobit regression models to analyse determinants of WTP for the improved porridge flour. Results show that both Kenyan and Ugandan BoP consumers are willing to pay a premium for the improved porridge flour. In addition, providing nutrition information about the flour, characteristics of household head, economic status of the household, and presence of young children between six and 59 months in the household, influence WTP for the safe and nutritious porridge flour. The paper concludes by providing recommendations for enhancing nutrition among poor consumers in the informal settlements of developing countries.
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  • Journal Article

    An R Framework for the Partitioning of Linkage Disequilibrium between and Within Populations 

    Petrowski, Paul F.; King, Elizabeth G.; Beissinger, Timothy M.
    Journal of Open Research Software 2019; 7: Art. 15
    Patterns of linkage disequilibrium (LD) across the genome result from a myriad of contributing factors including selection and genetic drift. Natural selection can increase LD near individually selected loci, or it can influence LD between epistatically selected groups of loci. Statistics have previously been derived which compare levels of linkage disequilibrium in subpopulations relative to the total population. These statistics may be leveraged to identify loci that may be under selection or epistatic selection. This is a powerful approach, but to date no framework exists to support its use on a genome-wide scale. We present ohtadstats, an R package designed to facilitate the implementation of Ohta’s D statistics in a variety of use cases. Statistics calculated by this package can be used to determine whether a locus is under selection or not, and can provide insight into the nature of the selection that is taking place (hard sweep or epistatic selection). This package is available on the Comprehensive R Archive Network (CRAN).
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  • Journal Article

    Comparing “Leaf-to-Root”, “Nose-to-Tail” and Other Efficient Food Utilization Options from a Consumer Perspective 

    Nitzko, Sina; Spiller, Achim
    Sustainability 2019; 11(17): Art. 4779
    The efficient use of natural raw materials is a key element of sustainable development and is also gaining importance in the food sector. Consumers are increasingly realizing that food is too valuable to be used only partially. However, consumer acceptance is an important precondition for establishing efficient food utilization options. A total of 470 German consumers were surveyed through an online-questionnaire where they had to evaluate three options each for the efficient use of plant-based foods as well as animal-based foods with respect to eight different criteria. The results show that the six options differed significantly regarding consumer acceptance. The efficient use of plant-based foods (especially non-standard fruits/vegetables and the “leaf-to-root” principle) was more accepted than the efficient utilization of animal-based foods. Furthermore, it can be seen that options using the by-products in a natural form were considered more acceptable than those which subject the by-products to some form of processing. These results provide an insight into the views of consumers on food waste reduction strategies, which are frequently debated in the sustainability discussion.
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  • Journal Article

    Staatliche Eingriffe in die Lebensmittelwahl: Welche klimapolitischen Instrumente unterstützt die Bevölkerung? 

    Lemken, Dominic; Kraus, Katharina; Nitzko, Sina; Spiller, Achim
    GAIA - Ecological Perspectives for Science and Society 2018; 27(4) p.363-372
    Staatliche Eingriffe in den Lebensmittelkonsum der Deutschen sind im europäischen Vergleich eher selten. Politiker(innen) empfinden wohl Lenkungssteuern- oder Werbeverbote als unpopulär. Konkrete Maßnahmen zum Klimaschutz, etwa eine Klimasteuer auf importierte Flugwaren, stoßen jedoch auf breite Zustimmung und könnten durchaus zu Klimazielen beitragen. In view of climate change, policy approaches addressing the consumption side of nutrition are becoming increasingly relevant to lowering greenhouse gas (GHG) emissions. Yet, adequate policy instruments can be risky. They interfere with individual freedom of choice and can thus be unpopular. This study investigates the social acceptance of governmental interventions. The study explores four types of climate policy instruments of increasing depth of intervention: 1. information and education, 2. nudging, 3. taxation, 4. bans. Information and nudging are met with the largest degree of approval. Assuming that acceptance will decrease with the depth of intervention, the equally critical perception of taxation and bans is an exception. Apart from the depth of intervention, social acceptance also depends on the field of action. For instance, taxation of airfreight products would be widely accepted. The conclusion explores nutrition policy options motivated by climate policy considerations.
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  • Journal Article

    Measures for sustainable forest management in the tropics – A tree-ring based case study on tree growth and forest dynamics in a Central Amazonian lowland moist forest 

    Worbes, Martin; Schöngart, Jochen
    PLOS ONE 2019; 14(8): Art. e0219770
    The conservation of tropical forests is recognized as one of the most important challenges for forestry, ecology and politics. Besides strict protection, the sustainable management of natural forests should be enhanced as a key part of the foundation for the maintenance of tropical rain forest ecosystems. Due to methodological reasons it has been complicated to attain reliable growth data to plan sustainable felling cycles and rotation periods. Tree ring analyses enable the estimation of growth rates over the entire life span of trees and their age as well as giving hints from forest dynamics in previous centuries. For tree ring analysis, stem disk samples were taken from three important commercial tree species (Cariniana micrantha, Caryocar villosum and Manilkara huberi) in the upland (terra firme) forests of the Precious Woods Amazon logging company near Itacoatiara, Brazil. Based on radiocarbon estimates of individual growth zones, the annual nature of tree rings was proven for the three species. Tree rings were measured and the results used together with height estimates to model diameter, height and volume growth. The age of the eldest tree, a C. micrantha, was 585 yrs with 165 cm in diameter. The species' diameter increments range from 0.20±0.12 cm yr-1 to 0.29±0.08 cm yr-1. At first sight, this is considerably lower than increments reported from other Amazonian or African timber species. Considering the respective wood density there is no significant difference in growth performance of dominant timber species across continents. The interpretation of lifetime tree ring curves indicate differences in shadow tolerance among species, the persistence of individuals in the understory for up to 150 years and natural stand dynamics without major disturbances. Management criteria should be adapted for the measured growth rates as they differed considerably from the Brazilian standards fixed by laws (felling cycle of 25-35 years and a common minimum logging diameter of 50 cm). Felling cycles should be increased to 32-51 years and minimum logging diameters to 63-123 cm depending on the species.
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  • Journal Article

    Impact of a phytogenic feed additive on growth performance, feed intake, and carcass traits of finishing steers 

    Brand, Tassilo; Hünerberg, Martin; McAllister, Tim A.; He, Maolong; Saleem, Atef M.; Shen, Yizhao; Miller, Bryan; Yang, Wenzhu
    Translational Animal Science 2019; 3(4)
    The purpose of this study was to evaluate the effect of a phytogenic feed additive (Digestarom [DA]; Biomin, Getzersdorf, Austria) on growth performance, feed intake, carcass traits, fatty acid composition, and liver abscesses of finishing steers. One hundred twenty Angus × Charolais crossbred steers (488 ± 26.5 kg) were used in a 110-d feeding experiment. Steers were blocked by weight and randomly assigned to 12 pens with 10 steers per pen. Each pen was allocated to one of three diets. Each diet contained 86.5% barley, 10.0% barley silage, and 3.5% vitamin and mineral supplement on a dry matter (DM) basis. The diets contained 0, 0.05, and 0.1 g DA/kg complete diet (DM basis), to achieve average daily DA intakes of 0 (control), 0.5 (LowDA), and 1.0 g (HighDA) per steer. Diets were prepared once daily and provided ad libitum. Two pens per treatment were equipped to record individual feed intake behavior. Steers were weighed every 28 d and carcass traits and liver scores were recorded at slaughter. Dry matter intake (average: 9.34 kg/d) did not differ (P > 0.05) among diets. Average daily gain tended to increase linearly as DA increased (control: 1.82; LowDA: 1.87; and HighDA: 1.95 kg/d; P < 0.09), but gain:feed ratio was not affected. Supplementation of DA affected longissimus muscle area quadratically (P = 0.05) with the largest area observed for LowDA. However, dressing percentage decreased linearly in response to increasing level of DA (P < 0.01). Total abscessed livers were not affected, whereas proportion of severe liver abscesses was numerically lower with DA (30.8% and 42.5% for LowDA and HighDA) compared to the control (50%).
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  • Journal Article

    Mycotoxigenic Fungi and Mycotoxins in Agricultural Crop Commodities in the Philippines: A Review 

    Balendres, Mark Angelo O.; Karlovsky, Petr; Cumagun,Christian Joseph R.
    Foods 2019; 8(7): Art. 249
    The tropical, warm, and humid conditions that are favorable to the growth and development of mycotoxigenic fungi put the Philippines at a high risk of mycotoxin contamination. To date, seven mycotoxigenic Aspergillus species, four Fusarium species, and one Penicillium species have been isolated from various agricultural crop commodities in the country. There are five mycotoxin groups (aflatoxin, fumonisin, ochratoxin, nivalenol, and zearalenone) that have been detected in both the raw form and the by-products of major crops grown in the country. Since the first scientific report of aflatoxin contamination in the Philippines in 1972, new information has been generated on mycotoxins and mycotoxigenic fungi, but little has been known of other mycotoxins until the last two decades. Further, despite the increase in the understanding of mycotoxigenic fungi and mycotoxins in the country, very limited knowledge exists on practices and measures that control both the fungi and the toxins. This paper reviews the current literature on mycotoxigenic fungi and mycotoxins in the Philippines with emphasis on the last two decades and on other mycotoxins.
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  • Journal Article

    Bis-naphthopyrone pigments protect filamentous ascomycetes from a wide range of predators 

    Xu, Yang; Vinas, Maria; Alsarrag, Albatol; Su, Ling; Pfohl, Katharina; Rohlfs, Marko; Schäfer, Wilhelm; Chen, Wei; Karlovsky, Petr
    Nature Communications 2019; 10(1): Art. 3579
    It is thought that fungi protect themselves from predation by the production of compounds that are toxic to soil-dwelling animals. Here, we show that a nontoxic pigment, the bisnaphthopyrone aurofusarin, protects Fusarium fungi from a wide range of animal predators. We find that springtails (primitive hexapods), woodlice (crustaceans), and mealworms (insects) prefer feeding on fungi with disrupted aurofusarin synthesis, and mealworms and springtails are repelled by wheat flour amended with the fungal bis-naphthopyrones aurofusarin, viomellein, or xanthomegnin. Predation stimulates aurofusarin synthesis in several Fusarium species and viomellein synthesis in Aspergillus ochraceus. Aurofusarin displays low toxicity in mealworms, springtails, isopods, Drosophila, and insect cells, contradicting the common view that fungal defence metabolites are toxic. Our results indicate that bisnaphthopyrones are defence compounds that protect filamentous ascomycetes from predators through a mechanism that does not involve toxicity.
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  • Journal Article

    Leaf mechanisms involved in the response of Cydonia oblonga trees to water stress and recovery 

    Griñán, I.; Rodríguez, P.; Nouri, H.; Wang, R.; Huang, G.; Morales, D.; Corell, M.; Pérez-López, D.; Centeno, A.; Martin-Palomo, M.J.; et al.
    Hernández, F.Torrecillas, A.Galindo, A.
    Agricultural Water Management 2019; 221 p.66-72
    Quince tree (Cydonia oblonga Mill.) is known for bearing fruits that are rich in nutrients and health-promoting compounds while requiring low inputs of agrochemicals, and maintenance, but no information exists on the mechanisms developed at the level of leaf water relations to confront water stress and recovery. For this reason, the purpose of the present study was to identify the strategy (isohydric or anisohydric) by which quince plants cope with water stress and to further elucidate the resistance mechanisms developed in response to water stress and during recovery. In summer 2016, field-grown own rooted 17-years old quince trees (cv. BA-29) were subjected to two irrigation treatments. Control (T0) plants were drip irrigated (105% ETo) to ensure non-limiting soil water conditions, while T1 plants were irrigated at the same level as used in T0, except that irrigation was withheld for 42 days during the linear fruit growth phase, after which irrigation returned to the levels of T0 (recovery period). During the experimental period, T0 and T1 received a total of 374 and 143 mm water, respectively, including rain water. The quince trees exhibited extreme anisohydric behaviour under the experimental conditions. As water stress developed and during the recovery period, the plants exhibited high hydraulic conductivity, probably the result of resistance to cavitation. From the beginning of water stress to the time of maximum water stress, leaf turgor was maintained, possibly due to active osmotic adjustment (stress tolerance mechanism). This leaf turgor maintenance may have contributed to the high leaf conductance, and, therefore, good leaf productivity. The low quince leaf apoplastic water fraction under water stress could be considered as another drought tolerance characteristic because if the accumulation of water in the apoplasm is avoided a steeper gradient in water potential between the leaf and the soil can take place under water stress, thus favouring water absorption.
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