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    Influence of Pore Characteristics on the Fate and Distribution of Newly Added Carbon 

    Quigley, Michelle Y.; Negassa, Wakene C.; Guber, Andrey K.; Rivers, Mark L.; Kravchenko, Alexandra N.
    Frontiers in Environmental Science 2018; 6: Art. 51
    Pores create a transportation network within a soil matrix, which controls the flow of air, water, and movement of microorganisms. The flow of air, water, and movement of microbes, in turn, control soil carbon dynamics. Computed microtomography (μCT) allows for the visualization of pore structure at micron scale, but quantitative information on contribution of pores to the fate and protection of soil carbon, essential for modeling, is still lacking. This study uses the natural difference between carbon isotopes of C3 and C4 plants to determine how the presence of pores of different sizes affects spatial distribution patterns of newly added carbon immediately after plant termination and then after 1-month incubation. We considered two contrasting soil structure scenarios: soil with the structure kept intact and soil for which the structure was destroyed via sieving. For the experiment, soil was collected from 0–15 cm depth at a 20-year continuous maize (Zea mays L., C4 plant) experiment into which cereal rye (Secale cereale L., C3 plant) was planted. Intact soil fragments (5–6mm) were procured after 3 months rye growth in a greenhouse. Pore characteristics of the fragments were determined through μCT imaging. Each fragment was sectioned and total carbon, total nitrogen, d13C, and d15N were measured. The results indicate that, prior to incubation, greater presence of 40–90μm pores was associated with higher levels of C3 carbon, pointing to the positive role of these pores in transport of new C inputs. Nevertheless, after incubation, the association became negative, indicating greater losses of newly added C in such pores. These trends were statistically significant in destroyed-structure soil and numerical in intact-structure soil. In soils of intact-structures, after incubation, higher levels of total carbon were associated with greater abundance of 6.5–15 and 15–40μm pores, indicating a lower carbon loss associated with these pores. The results indicate that, in the studied soil, pores of 40–90μm size range are associated with the fast influx of new C followed by its quick decomposition, while pores <40μmtend to be associated with C protection.
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    Cross-Cultural Comparison between German, French and Dutch Consumer Preferences for Meat Substitutes 

    Weinrich, Ramona
    Sustainability 2018; 10(6): Art. 1819
    Sustainability is becoming an increasingly important consideration for consumers when purchasing food. As meat production has a significant impact on the environment, meat substitutes are becoming more and more popular in Europe. However, consumers who regularly buy meat substitutes are still the exception. Although there are some initial results indicating why this proportion is still low, most research has been concentrated in the Netherlands. This paper aims to compare reasons for consuming or not consuming meat substitutes in three European countries—Germany, the Netherlands and France. As very little is known about the underlying reasons, an explorative approach was chosen. Focus group discussions were carried out in all three countries, six altogether. The results show that all participants can enumerate meat substitutes. The main reason for not consuming meat substitutes is the taste of meat. Further, eating habits seem to be fixed and convenience might also be an impediment to reducing meat consumption in favour of meat substitutes, as is confusion regarding healthy eating.
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    Measuring Public Concerns? Developing a Moral Concerns Scale Regarding Non-Product Related Process and Production Methods 

    Sonntag, Winnie; Spiller, Achim
    Sustainability 2018; 10(5): Art. 1375
    In recent years, citizens have been more frequently scrutinizing non-product related process and production methods (npr-PPM) of various products, such as food, out of moral considerations. In 2014, theWorld Trade Organization’s (WTO) Dispute Settlement Body reached a landmark decision and accepted an European Union (EU)-wide import ban of seal products under the justification of Art. XX (a) General Agreement on Tariffs and Trade (GATT) due to “public moral concerns”. However, up to now there has been no valid and reliable scale to quantify moral concerns. Therefore, we developed a tool—the Moral Concerns Scale (MCS)—to measure moral concerns of a society about, for example, animal welfare or child labor in a valid and reliable manner for npr-PPM. This scale was developed and tested in two independent studies with German citizens (in 2016 and 2017) using three case studies: hens laying eggs in battery cages, the inhumane killing of seals, and the use of child labor. According to the results of both studies, the reliability and validity of the developed scale can be confirmed.
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    Root Differentiation of Agricultural Plant Cultivars and Proveniences Using FTIR Spectroscopy 

    Legner, Nicole; Meinen, Catharina; Rauber, Rolf
    Frontiers in Plant Science 2018; 9: Art. 748
    The differentiation of roots of agricultural species is desired for a deeper understanding of the belowground root interaction which helps to understand the complex interaction in intercropping and crop-weed systems. The roots can be reliably differentiated via Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR). In two replicated greenhouse experiments, six pea cultivars, five oat cultivars as well as seven maize cultivars and five barnyard grass proveniences (n = 10 plants/cultivar or provenience) were grown under controlled conditions. One root of each plant was harvested and five different root segments of each root were separated, dried and measured with FTIR-ATR spectroscopy. The results showed that, firstly, the root spectra of single pea and single oat cultivars as well as single maize and single barnyard grass cultivars/proveniences separated species-specific in cluster analyses. In the majority of cases the species separation was correct, but in a few cases, the spectra of the root tips had to be omitted to ensure the precise separation between the species. Therefore, species differentiation is possible regardless of the cultivar or provenience. Consequently, all tested cultivars of pea and oat spectra were analyzed together and separated within a cluster analysis according to their affiliated species. The same result was found in a cluster analysis with maize and barnyard grass spectra. Secondly, a cluster analysis with all species (pea, oat, maize and barnyard grass) was performed. The species split up species-specific and formed a dicotyledonous pea cluster and a monocotyledonous cluster subdivided in oat, maize and barnyard grass subclusters. Thirdly, cultivar or provenience differentiations within one species were possible in one of the two replicated experiments. But these separations were less resilient.
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    Patterns and Sources of Spatial Heterogeneity in Soil Matrix From Contrasting Long Term Management Practices 

    Quigley, Michelle Y.; Rivers, Mark L.; Kravchenko, Alexandra N.
    Frontiers in Environmental Science 2018; 6: Art. 28
    With the advent of computed microtomography (μCT), in situ 3D visualization of soil at micron scale became easily achievable. However, most μCT-based research has focused on visualization and quantification of soil pores, roots, and particulate organic matter (POM), while little effort has been put in exploring the soil matrix itself. This study aims to characterize spatial heterogeneity of soil matrix in macroaggregates from three differing long term managements: conventionally managed and biologically based row-crop agricultural systems and primary successional unmanaged system, and explore the utility of using grayscale gradients as a proxy of soil organic matter (SOM). To determine spatial characteristics of the soil matrix, we completed a geostatistical analysis of the aggregate matrix. It demonstrated that, while the treatments had the same range of spatial correlation, there was much greater overall variability in soil from the biologically based system. Since soil from both managements have the same mineralogy and texture, we hypothesized that greater variability is due to differences in SOMdistributions, driven by spatial distribution patterns of soil pores. To test this hypothesis, we applied osmium (Os) staining to intact micro-cores from the biologically based management, and examined Os staining gradients every 4μm from 26 to 213μm from pores of biological or non-biological origin. Biological pores had the highest SOM levels adjacent to the pore, which receded to background levels at distances of 100–130μm. Non-biological pores had lower SOM levels adjacent to the pores and returned to background levels at distances of 30–50μm. This indicates that some of the spatial heterogeneity within the soil matrix can be ascribed to SOM distribution patterns as controlled by pore origins and distributions. Lastly, to determine if the grayscale values could be used as a proxy for SOM levels, gradients of grayscale values from biological and non-biological pores were compared with the Os gradients. Grayscale gradients matched Os gradients for biological pores, but not non-biological pores due to an image processing artifact. Grayscale gradients would, therefore, be a good proxy for SOM gradients near biological origin pores, while their use for non-biological pores should be conducted with caution.
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    Characterization of cocoa production, income diversification and shade tree management along a climate gradient in Ghana. 

    Abdulai, Issaka; Jassogne, Laurence; Graefe, Sophie; Asare, Richard; Van Asten, Piet; Läderach, Peter; Vaast, Philippe
    PLOS ONE 2018; 13(4): Art. e0195777
    Reduced climatic suitability due to climate change in cocoa growing regions of Ghana is expected in the coming decades. This threatens farmers' livelihood and the cocoa sector. Climate change adaptation requires an improved understanding of existing cocoa production systems and farmers' coping strategies. This study characterized current cocoa production, income diversification and shade tree management along a climate gradient within the cocoa belt of Ghana. The objectives were to 1) compare existing production and income diversification between dry, mid and wet climatic regions, and 2) identify shade trees in cocoa agroforestry systems and their distribution along the climatic gradient. Our results showed that current mean cocoa yield level of 288kg ha-1yr-1 in the dry region was significantly lower than in the mid and wet regions with mean yields of 712 and 849 kg ha-1 yr-1, respectively. In the dry region, farmers diversified their income sources with non-cocoa crops and off-farm activities while farmers at the mid and wet regions mainly depended on cocoa (over 80% of annual income). Two shade systems classified as medium and low shade cocoa agroforestry systems were identified across the studied regions. The medium shade system was more abundant in the dry region and associated to adaptation to marginal climatic conditions. The low shade system showed significantly higher yield in the wet region but no difference was observed between the mid and dry regions. This study highlights the need for optimum shade level recommendation to be climatic region specific.
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    The Effects of Diversification Activities on the Technical Efficiency of Organic Farms in Switzerland, Austria, and Southern Germany 

    Lakner, Sebastian; Kirchweger, Stefan; Hoop, Daniel; Brümmer, Bernhard; Kantelhardt, Jochen
    Sustainability 2018; 10(4): Art. 1304
    The diversification of farms can be a result of multifunctional farming, however, in some cases at the cost of lower farm efficiency. In our paper we investigate the influence of para-agricultural diversification on productivity and the technical efficiency of organic farms in Austria, Switzerland, and Southern Germany. We show the benefits and drawbacks of diversification for organic farms, which go beyond the core agricultural production (para-agriculture). We do this by estimating a Stochastic Frontier (SF) combined with a metafrontier model. The data-set consists of bookkeeping data with 1704 observations in the years 2003 to 2005. Para-agricultural diversification activities have a significant effect on both productivity and technical efficiency of organic farms: The farm output in Austria and Switzerland is positively influenced by diversification, whereas we observe a rather small effect in Southern Germany. On the other hand, diversification can reduce farms’ technical efficiency, as it is the case in Switzerland and Germany. Furthermore, our study confirms previous results that agricultural subsidies significantly influence the technical efficiency of organic farms. We also show expected changes of input use driven by increased farm diversification. View Full-Text
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    The effect of the H−1 scaling factors τ and ω on the structure of H in the single-step procedure 

    Martini, Johannes W. R.; Schrauf, Matias F.; Garcia-Baccino, Carolina A.; Pimentel, Eduardo C. G.; Munilla, Sebastian; Rogberg-Muñoz, Andres; Cantet, Rodolfo J. C.; Reimer, Christian; Gao, Ning; Wimmer, Valentin; et al.
    Simianer, Henner
    2018-04-13; 50(1): Art. 16
    Background The single-step covariance matrix H combines the pedigree-based relationship matrix A with the more accurate information on realized relatedness of genotyped individuals represented by the genomic relationship matrix G. In particular, to improve convergence behavior of iterative approaches and to reduce inflation, two weights τ and ω have been introduced in the definition of H−1, which blend the inverse of a part of A with the inverse of G. Since the definition of this blending is based on the equation describing H−1, its impact on the structure of H is not obvious. In a joint discussion, we considered the question of the shape of H for non-trivial τ and ω . Results Here, we present the general matrix H as a function of these parameters and discuss its structure and properties. Moreover, we screen for optimal values of τ and ω with respect to predictive ability, inflation and iterations up to convergence on a well investigated, publicly available wheat data set. Conclusion Our results may help the reader to develop a better understanding for the effects of changes of τ and ω on the covariance model. In particular, we give theoretical arguments that as a general tendency, inflation will be reduced by increasing τ or by decreasing ω.
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    Fertilizer Effect of Phosphorus Recycling Products 

    Römer, Wilhelm; Steingrobe, Bernd
    Sustainability 2018; 10(4) p.1-18: Art. 1166
    Between 2004 and 2011 the German Government funded 17 different projects to develop techniques of phosphorus recycling from wastewater, sewage sludges, and sewage sludge ashes. Several procedures had been tested, such as precipitation, adsorption, crystallization, nano-filtration, electro-dialysis, wet oxidation, pyrolysis, ion exchange, or bioleaching. From these techniques, 32 recycling products were tested by five different institutes for their agronomic efficiency, that is, their plant availability, mainly in pot experiments. This manuscript summarizes and compares these results to evaluate the suitability of different technical approaches to recycle P from wastes into applicable fertilizers. In total, 17 products of recycled sewage sludge ashes (SSA), one meat and bone meal ash, one sinter product of meat and bone meal, one cupola furnace slag, nine Ca phosphates from crystallization or from precipitation, Seaborne-Ca-phosphates, Seaborne-Mg-phosphate, and 3 different struvites were tested in comparison to controls with water soluble P, that is, either single super phosphate (SSP) or triple super phosphate (TSP). Sandy and loamy soils (pH: 4.7–6.8; CAL-P: 33–49 ppm) were used. The dominant test plant was maize. Phosphorus uptake from fertilizer was calculated by the P content of fertilized plants minus P content of unfertilized plants. Calculated uptake from all products was set in relation to uptake from water soluble P fertilizers (SSP or TSP) as a reference value (=100%). The following results were found: (1) plants took up less than 25% P in 65% of all SSA (15 products); (2) 6 products (26%) resulted in P uptake of 25 and 50% relatively to water soluble P. Only one Mg-P product resulted in an uptake of 67%. With cupola furnace slag, 24% P uptake was reached on sandy soil and nearly the same value as TSP on loamy soil. The uptake results of Ca phosphates were between 0 and 50%. Mg-P products from precipitation processes consistently showed a better P supply in relation to comparable Ca-P compounds. With struvite the same P uptake as for water soluble P was reached. The fertilizer effect of the tested P recycling products can clearly be differentiated: TSP = struvite > Mg-P = sinter-P > Ca-P, cupola-slag > thermally treated sewage sludge ashes > meat-and-bone meal ash = Fe-P.
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    Improving market success of animal welfare programs through key stakeholder involvement: heading towards responsible innovation? 

    Purwins, Nina; Schulze-Ehlers, Birgit
    International Food and Agribusiness Management Review 2018; 21(4) p.543-558
    acceptance among both farmers and consumers. We contend that this lock-in originates from a lack of market orientation and consequential neglect of key stakeholders’ preferences in program design. Considering the case of a retailer-owned meat brand, we demonstrate the relevance of stakeholders’ inclusion when establishing animal welfare programs for pigs. Surveys among 62 farming members of a pig trading cooperative and 692 supermarket customers reveal the heterogeneity of beliefs and acceptance within both groups. While a Responsible Innovation approach, including key actors from the initial criteria selection, could be effective for raising acceptance, it would likely lead to lengthy time-to-market, prohibiting first-mover advantages. We suggest instead that beliefs and acceptance among farmers may be influenced through a communication strategy based on survey results and experimental research, as well as facilitating positive word-of-mouth.
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    Using Acceleration Data to Automatically Detect the Onset of Farrowing in Sows. 

    Traulsen, Imke; Scheel, Christoph; Auer, Wolfgang; Burfeind, Onno; Krieter, Joachim
    Sensors 2018; 18(1) p.1-13: Art. 170
    The aim of the present study was to automatically predict the onset of farrowing in crate-confined sows. (1) Background: Automatic tools are appropriate to support animal surveillance under practical farming conditions. (2) Methods: In three batches, sows in one farrowing compartment of the Futterkamp research farm were equipped with an ear sensor to sample acceleration. As a reference video, recordings of the sows were used. A classical CUSUM chart using different acceleration indices of various distribution characteristics with several scenarios were compared. (3) Results: The increase of activity mainly due to nest building behavior before the onset of farrowing could be detected with the sow individual CUSUM chart. The best performance required a statistical distribution characteristic that represented fluctuations in the signal (for example, 1st variation) combined with a transformation of this parameter by cumulating differences in the signal within certain time periods from one day to another. With this transformed signal, farrowing sows could reliably be detected. For 100% or 85% of the sows, an alarm was given within 48 or 12 h before the onset of farrowing. (4) Conclusions: Acceleration measurements in the ear of a sow are suitable for detecting the onset of farrowing in individually housed sows in commercial farrowing crates.
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    Impact of Pore-Scale Wettability on Rhizosphere Rewetting 

    Benard, Pascal; Zarebanadkouki, Mohsen; Carminati, Andrea
    Frontiers in Environmental Science 2018; 6: Art. 16
    Vast amounts of water flow through a thin layer of soil around the roots, the rhizosphere, where high microbial activity takes place—an important hydrological and biological hotspot. The rhizosphere was shown to turn water repellent upon drying, which has been interpreted as the effect of mucilage secreted by roots. The effects of such rhizosphere water dynamics on plant and microbial activity are unclear. Furthermore, our understanding of the biophysical mechanisms controlling the rhizosphere water repellency remains largely speculative. Our hypothesis is that the key to describe the emergence of water repellency lies within the microscopic distribution of wettability on the pore-scale. At a critical mucilage content, a sufficient fraction of pores is blocked and the rhizosphere turns water repellent. Here we tested whether a percolation approach is capable to predict the flow behavior near the critical mucilage content. The wettability of glass beads and sand mixed with chia seed mucilage was quantified by measuring the infiltration rate of water drops. Drop infiltration was simulated using a simple pore-network model in which mucilage was distributed heterogeneously throughout the pore space with a preference for small pores. The model approach proved capable to capture the percolation nature of the process, the sudden transition from wettable to water repellent and the high variability in infiltration rates near the percolation threshold. Our study highlights the importance of pore-scale distribution of mucilage in the emergent flow behavior across the rhizosphere.
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    Meat Quality Derived from High Inclusion of a Micro-Alga or Insect Meal as an Alternative Protein Source in Poultry Diets: A Pilot Study 

    Altmann, Brianne; Neumann, Carmen; Velten, Susanne; Liebert, Frank; Mörlein, Daniel
    Foods 2018; 7(3): Art. 34
    The effects on meat quality resulting from alternative dietary protein sources (Spirulina and Hermetia meal) in poultry diets are studied to determine the overall suitability of these ingredients considering state-of-the-art packaging practices—highly oxygenated modified atmosphere packaging (HiOx MAP). We monitored standard slaughterhouse parameters, such as live weight, carcass weight, dressed yield, and pH at 20 min and 24 h post mortem. In addition, we studied the effects that 3 and 7-day storage in HiOx MAP has on the overall product physico-chemical and sensory properties. In addition to previously supported effects of HiOx MAP, we found that meat quality could be improved when Spirulina replaces 50% of the soy protein in broiler diets; however, this substitution results in a dark reddish-yellowish meat colour. On the other hand, the substitution with Hermetia larval meal results in a product that does not differ from the standard fed control group, with the exception that the breast filet has a more intense flavour that decreases over storage time. All-in-all Spirulina and Hermetia meal have the potential to replace soybean meal in broiler diets without deteriorating meat quality.
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    Birds of primary and secondary forest and shrub habitats in the peat swamp of Berbak National Park, Sumatra 

    Darras, Kevin; Rahman, Dedi; Sugito, Waluyo; Mulyani, Yeni; Prawiradilaga, Dewi; Rozali, Agus; Fitriawan, Irfan; Tscharntke, Teja
    F1000Research 2018; 7: Art. 229
    Background: Tropical lowland rainforests are threatened by deforestation and degradation worldwide. Relatively little research has investigated the degradation of the forests of South-east Asia and its impact on biodiversity, and even less research has focused on the important peat swamp forests of Indonesia, which experienced major losses through severe fires in 2015. Methods: We acoustically sampled the avifauna of the Berbak National Park in 2013 in 12 sites split in three habitats: primary swamp forest, secondary swamp forest, and shrub swamp, respectively representing non-degraded, previously selectively logged, and burned habitats. We analysed the species richness, abundance, vocalisation activity, and community composition across acoustic counts, sites, feeding guilds and IUCN Red List categories. We also analysed community-weighted means of body mass, wing length, and distribution area. Results: The avifauna in the three habitats was remarkably similar in richness, abundance and vocalisation activity, and communities mainly differed due to a lower prevalence of understory insectivores (Old-World Babblers, Timaliidae) in shrub swamp. However primary forest retained twice as many conservation-worthy species as shrub swamp, which harboured heavier, probably more mobile species, with larger distributions than those of forest habitats. Conclusions: The National Park overall harboured higher bird abundances than nearby lowland rainforests. Protecting the remaining peat swamp forest in this little-known National Park should be a high conservation priority in the light of the current threats coming from wildlife trade, illegal logging, land use conversion, and man-made fires.
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    DArT, SNP, and SSR analyses of genetic diversity in Lolium perenne L. using bulk sampling. 

    Liu, Siyang; Feuerstein, Ulf; Luesink, Wilbert; Schulze, Sabine; Asp, Torben; Studer, Bruno; Becker, Heiko C.; Dehmer, Klaus J.
    BMC Genetics 2018; 19(1): Art. 10
    BACKGROUND: Lolium perenne L. is the most important forage grass species in temperate regions. It is also considered as a sustainable source of biomass for energy production. However, improvement in biomass yield has been limited by comparison with other major crops. More efficient utilisation of genetic resources and improved breeding schemes are required to advance L. perenne breeding. In an attempt to elucidate the extent of genetic diversity in L. perenne, 1384 DArT, 182 SNP and 48 SSR markers were applied to 297 accessions (Set I) contributed by three German breeding companies and the IPK Genebank. Due to the heterogeneous nature of Lolium accessions, bulk samples were used. Apart from germplasm set I, additional set II and set III was used to determine the reproducibility of marker system and judge the feasibility of bulk strategy in this study. RESULTS: By assessing different bulk sizes, 24 individuals per sample were shown to be a representative number of plants to discriminate different accessions. Among the 297 accessions, all marker types revealed a high polymorphism rate; 1.99, 2.00 and 8.19 alleles, were obtained per locus on average using DArTs, SNPs and SSRs, respectively. The Jaccard distance for DArT markers ranged from 0.00 to 0.73, the Modified Roger's distance (MRD) for SNP markers ranged from 0.03 to 0.52, and for SSR markers from 0.26 to 0.76. Gene diversity for dominant DArT and co-dominant SNP and SSR markers was found to be 0.26, 0.32 and 0.45, respectively. DArT markers showed the highest consistency and reproducibility. CONCLUSION: The resulting data were evaluated using a number of different classification methods, but none of the methods showed a clear differentiation into distinct genetic pools. With regard to hybrid breeding, this will possibly impede substantial progress towards increased biomass yields of L. perenne by utilising heterosis.
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    Building Adaptive Capacity in Changing Social-Ecological Systems: Integrating Knowledge in Communal Land-Use Planning in the Peruvian Amazon 

    Rodríguez, Lily; Cisneros, Elías; Pequeño, Tatiana; Fuentes, Maria; Zinngrebe, Yves
    Sustainability 2018; 10(2): Art. 511
    Building resilient sustainable social-ecological systems (SES) requires communities to enhance their adaptive capacities. Communal participative land-use planning (Zonificación Participativa Comunal—ZPC) is a tool designed for communities to integrating local and scientific knowledge to sustainably organize and manage their SES. Between 2006 and 2011, a ZPC was developed with communities in the buffer zone of Cordillera Azul National Park (Peru), where rapid demographic changes are converting pre-montane seasonally dry forest into agricultural land. Herein, we analyse how the ZPC enhanced adaptive capacity, enabling the SES to cope with environmental, political and economic changes. Based on qualitative, semi-structured interviews, communities are analysed along their capacities in the dimensions social capital, learning, adaptive management and governance. An analysis of yearly high-resolution forest cover data supports our findings. Deforestation activities in biologically sensitive zones decreased rapidly during the time of the ZPC implementation. We find that particularly the long-term presence of the bridging institution and the continuous testing and reflection of the integrated “hybrid knowledge” enabled communities to develop adaptive capacities. The analysis of ZPC our results reveals the enabling conditions for promoting the learning process to develop a sustainable land-use management in the context of migration and rapid changes.
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    How plant reproductive success is determined by the interplay of antagonists and mutualists 

    Grass, Ingo; Bohle, Victoria; Tscharntke, Teja; Westphal, Catrin
    Ecosphere 2018; 9(2): Art. e02106
    Plant reproductive success is often the outcome of mutualistic and antagonistic plant–animal interactions, which can be moderated by landscape composition. Studies addressing single plant–animal interactions are common, but studies simultaneously considering multiple plant–animal interactions in a landscape context are still scarce. We selectively excluded flower-visiting insects on phytometer plants and quantified how mutualistic and antagonistic interactions shaped the reproductive success of a common annual plant, wild mustard (Sinapis arvensis). Floral herbivory by larvae of rape pollen beetles (Meligethes spp.) strongly reduced fruit production, but could be minimized by insecticide application. Total seed production (the product of fruit production and seeds per fruit) strongly increased with pollinator visitation. On average, pollinator access to plants enhanced seed numbers by 754%. Insecticide treatment almost redoubled this number. The landscape composition (proportion of semi-natural habitats in 1000 m radius) surrounding phytometer plants did not affect plant–animal interactions, presumably due to the high dispersal ability of both the pollen beetles and the major pollinators (syrphid flies, bumblebees). In conclusion, pest control increased reproductive success only in the case of sufficient pollination.
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    Efficiency of different strategies to mitigate ascertainment bias when using SNP panels in diversity studies. 

    Malomane, Dorcus Kholofelo; Reimer, Christian; Weigend, Steffen; Weigend, Annett; Sharifi, Ahmad Reza; Simianer, Henner
    BMC Genomics 2018; 19(1): Art. 22
    BACKGROUND: Single nucleotide polymorphism (SNP) panels have been widely used to study genomic variations within and between populations. Methods of SNP discovery have been a matter of debate for their potential of introducing ascertainment bias, and genetic diversity results obtained from the SNP genotype data can be misleading. We used a total of 42 chicken populations where both individual genotyped array data and pool whole genome resequencing (WGS) data were available. We compared allele frequency distributions and genetic diversity measures (expected heterozygosity (He), fixation index (FST) values, genetic distances and principal components analysis (PCA)) between the two data types. With the array data, we applied different filtering options (SNPs polymorphic in samples of two Gallus gallus wild populations, linkage disequilibrium (LD) based pruning and minor allele frequency (MAF) filtering, and combinations thereof) to assess their potential to mitigate the ascertainment bias. RESULTS: Rare SNPs were underrepresented in the array data. Array data consistently overestimated Hecompared to WGS data, however, with a similar ranking of the breeds, as demonstrated by Spearman's rank correlations ranging between 0.956 and 0.985. LD based pruning resulted in a reduced overestimation of Hecompared to the other filters and slightly improved the relationship with the WGS results. The raw array data and those with polymorphic SNPs in the wild samples underestimated pairwise FSTvalues between breeds which had low FST(<0.15) in the WGS, and overestimated this parameter for high WGS FST(>0.15). LD based pruned data underestimated FSTin a consistent manner. The genetic distance matrix from LD pruned data was more closely related to that of WGS than the other array versions. PCA was rather robust in all array versions, since the population structure on the PCA plot was generally well captured in comparison to the WGS data. CONCLUSIONS: Among the tested filtering strategies, LD based pruning was found to account for the effects of ascertainment bias in the relatively best way, producing results which are most comparable to those obtained from WGS data and therefore is recommended for practical use.
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    Preliminary Investigation of Species Diversity of Rice Hopper Parasitoids in Southeast Asia. 

    Sann, Christina; Wemheuer, Franziska; Beaurepaire, Alexis; Daniel, Rolf; Erler, Silvio; Vidal, Stefan
    Insects 2018; 9(1) p.1-12
    Ongoing intensification of rice production systems in Southeast Asia is causing devastating yield losses each year due to rice hoppers. Their continuing development of immunity to resistant rice varieties and pesticide applications further complicates this problem. Hence, there is a high demand for biological control agents of rice hoppers. Egg parasitoid wasps are among the most important natural enemies of rice hoppers, such asNilaparvata lugensandNephotettixspp. However, our knowledge of their diversity is still very limited, due to their small size and the lack of available morphological information. Classifying these parasitoids is the first step to properly understanding their role in the rice agroecosystem. We used traditional morphological identification, as well as DNA sequencing of the 28S rRNA and the COI genes, to investigate the diversity of four important hopper egg parasitoid genera in the Philippines. Parasitoids of the generaAnagrus,Oligosita,Gonatocerus, andParacentrobiawere collected in eight study landscapes located in Luzon. Our findings illustrate that characterization of species diversity using morphological and molecular analyses were concordant only for the genusParacentrobia. The generaAnagrusandGonatocerusexhibited more genetic diversity than estimated with the morphological analysis, while the opposite was observed forOligosita. This is the first study investigating the molecular diversity of rice hopper parasitoids in the Philippines. More research combining morphological, behavioral, and molecular methods, as well as the establishment of a comprehensive DNA database, are urgently needed to assess the performance and suitability of these organisms as biocontrol agents.
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    Root-derived carbon and nitrogen from beech and ash trees differentially fuel soil animal food webs of deciduous forests. 

    Zieger, Sarah L; Ammerschubert, Silke; Polle, Andrea; Scheu, Stefan
    PloS one 2017; 12(12) p.1-14: Art. e0189502
    Evidence is increasing that soil animal food webs are fueled by root-derived carbon (C) and also by root-derived nitrogen (N). Functioning as link between the above- and belowground system, trees and their species identity are important drivers structuring soil animal communities. A pulse labeling experiment using 15N and 13C was conducted by exposing beech (Fagus sylvatica) and ash (Fraxinus excelsior) seedlings to 13CO2 enriched atmosphere and tree leaves to 15N ammonium chloride solution in a plant growth chamber under controlled conditions for 72 h. C and N fluxes into the soil animal food web of beech, associated with ectomycorrhizal fungi (EMF), and ash, associated with arbuscular mycorrhizal fungi (AMF), were investigated at two sampling dates (5 and 20 days after labeling). All of the soil animal taxa studied incorporated root-derived C, while root-derived N was only incorporated into certain taxa. Tree species identity strongly affected C and N incorporation with the incorporation in the beech rhizosphere generally exceeding that in the ash rhizosphere. Incorporation differed little between 5 and 20 days after labeling indicating that both C and N are incorporated quickly into soil animals and are used for tissue formation. Our results suggest that energy and nutrient fluxes in soil food webs depend on the identity of tree species with the differences being associated with different types of mycorrhiza. Further research is needed to prove the generality of these findings and to quantify the flux of plant C and N into soil food webs of forests and other terrestrial ecosystems.
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