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Burge D.,Institute for Sustainability science ISS | Bachmann H.J.,Institute for Sustainability science ISS | Mayer J.,Institute for Sustainability science ISS
Waste Management | Year: 2014

The production of compost and digestate from source-separated organic residues is well established in Europe. However, these products may be a source of pollutants when applied to soils. In order to assess this issue, composts, solid and liquid digestates from Switzerland were analyzed for heavy metals (Cd, Co, Cr, Cu, Ni, Pb and Zn) addressing factors which may influence the concentration levels: the treatment process, the composition, origin, particle size and impurity content of input materials, the season of input materials collection or the degree of organic matter degradation.Composts (n= 81) showed mean contents being at 60% or less of the legal threshold values. Solid digestates (n= 20) had 20-50% lower values for Cd, Co, Pb and Zn but similar values for Cr, Cu and Ni. Liquid digestates (n= 5) exhibited mean concentrations which were approximately twice the values measured in compost for most elements. Statistical analyses did not reveal clear relationships between influencing factors and heavy metal contents. This suggests that the contamination was rather driven by factors not addressed in the present study.According to mass balance calculations related to Switzerland, the annual loads to agricultural soils resulting from the application of compost and digestates ranged between 2% (Cd) and 22% (Pb) of total heavy metal loads. At regional scale, composts and digestates are therefore minor sources of pollution compared to manure (Co, Cu, Ni, Zn), mineral fertilizer (Cd, Cr) and aerial deposition (Pb). However, for individual fields, fertilization with compost or digestates results in higher heavy metal loads than application of equivalent nutrient inputs through manure or mineral fertilizer. © 2014 Elsevier Ltd.


Hoekstra N.J.,Teagasc | Hoekstra N.J.,Institute for Sustainability science ISS | Finn J.A.,Teagasc | Hofer D.,Institute for Sustainability science ISS | And 2 more authors.
Biogeosciences | Year: 2014

Increased incidence of drought, as predicted under climate change, has the potential to negatively affect grassland production. Compared to monocultures, vertical belowground niche complementarity between shallow- and deep-rooting species may be an important mechanism resulting in higher yields and higher resistance to drought in grassland mixtures. However, very little is known about the belowground responses in grassland systems and increased insight into these processes may yield important information both to predict the effect of future climate change and better design agricultural systems to cope with this. This study assessed the effect of a 9-week experimental summer drought on the depth of water uptake of two shallow-rooting species (Lolium perenne L. and Trifolium L.) and two deep-rooting species (Cichorium intybus L. and Trifolium pratense L.) in grassland monocultures and four-species mixtures by using the natural abundance δ18O isotope method. We tested the following three hypotheses: (1) drought results in a shift of water uptake to deeper soil layers, (2) deep-rooting species take up a higher proportion of water from deeper soil layers relative to shallow-rooting species, and (3) as a result of interspecific interactions in mixtures, the water uptake of shallow-rooting species becomes shallower when grown together with deep-rooting species and vice versa, resulting in reduced niche overlap. The natural abundance δ18O technique provided novel insights into the depth of water uptake of deep- and shallow- rooting grassland species and revealed large shifts in depth of water uptake in response to drought and interspecific interactions. Compared to control conditions, drought reduced the proportional water uptake from 0-10 cm soil depth (PCWU0-10) of L. perenne T. repens and C. intybus in monocultures by on average 54%. In contrast, the PCWU0-10 of T. pratense in monoculture increased by 44%, and only when grown in mixture did the PCWU0-10 of T. pratense decrease under drought conditions. In line with hypothesis (2), in monoculture, the PCWU0-10of shallow-rooting species L. perenne and T. repens was 0.53 averaged over the two drought treatments, compared to 0.16 for the deep-rooting C. intybus. Surprisingly, in monoculture, water uptake by T. pratense was shallower than for the shallow-rooting species (PCWU0-10 Combining double low line 0.68). Interspecific interactions in mixtures resulted in a shift in the depth of water uptake by the different species. As hypothesised, the shallow-rooting species L. perenne and T. repens tended to become shallower, and the deep-rooting T. pratense made a dramatic shift to deeper soil layers (reduction in PCWU0-10 of 58% on average) in mixture compared to monoculture. However, these shifts did not result in a reduction in the proportional similarity of the proportional water uptake from different soil depth intervals (niche overlap) in mixtures compared to monocultures. There was no clear link between interspecific differences in depth of water uptake and the reduction of biomass production under drought compared to control conditions (drought resistance). Cichorium intybus the species with water uptake from the deepest soil layers was one of the species most affected by drought. Interestingly, T. pratense which was least affected by drought, also had the greatest plasticity in depth of water uptake. This suggests that there may be an indirect effect of rooting depth on drought resistance, as it determines the potential plasticity in the depth of water uptake. © 2014 Author(s).


Hagenbucher S.,Institute for Sustainability science ISS | Wackers F.L.,Lancaster University | Romeis J.,Institute for Sustainability science ISS
Biology Letters | Year: 2014

Cotton produces insecticidal terpenoids that are induced by tissue-feeding herbivores. Damage by Heliothis virescens caterpillars increases the terpenoid content, which reduces the abundance of aphids. This effect is not evident in Bt-transgenic cotton, which is resistant to H. virescens. We determined whether induction of terpenoids by caterpillars influences the host quality of Aphis gossypii for the parasitoid Lysiphlebus testaceipes and whether this interaction is influenced by Bt cotton. The exposure of parasitoids to terpenoids was determined by quantifying terpenoids in the aphids. We detected several terpenoids in aphids and found a positive relationship between their concentrations in plants and aphids. When L. testaceipes was allowed to parasitize aphids on Bt and non-Bt cotton that was infested or uninfested with H. virescens, fewer parasitoid mummies were found on infested non-Bt than on Bt cotton. Important parasitoid life-table parameters, however, were not influenced by induced resistance following H. virescens infestation, or the Bt trait. Our study provides an example of a tritrophic indirect interaction web, where organisms are indirectly linked through changes in plant metabolites. © 2014 The Author(s) Published by the Royal Society. All rights reserved.


Schubiger F.X.,Institute for Sustainability science ISS | Boller B.,Institute for Sustainability science ISS
European Journal of Plant Pathology | Year: 2016

Crown rust samples were collected in 2004 on rust infected Italian and perennial ryegrass leaves at 28 sites in 11 European countries. Out of these 28 rust collections, 112 single-pustule isolates were produced to determine virulence frequency and complexity on 32 ryegrass genotypes. A high level of virulence diversity was observed within and between individual sampling sites. In total, 107 pathotypes with different virulence combination were found. Of these, just five combinations occurred twice. All 32 individuals were susceptible to at least two single-pustule isolates using a detached-leaf segment test. In the field, the 32 genotypes differed greatly in their susceptibility to crown rust. Nevertheless, the correlation between mean susceptibility in the field and virulence frequency of the 32 differentials was significant. The three most resistant genotypes in the field were also the genotypes with the lowest virulence frequency. Genetic analysis of resistance to crown rust in three genotypes of perennial ryegrass led to the identification of three dominant resistance genes: Pclol1, Pclol2 and Pclol3. Each of the three genes conferred resistance to a limited number of single-pustule isolates and was ineffective against at least one single-pustule isolate. The patterns of resistance reaction to specific single-pustule isolates provide evidence that the three R-genes represent distinct crown rust resistance genes in ryegrass. Moreover, the data demonstrate clearly the existence of pathotype specificity in crown rust of Lolium species. © 2015, Koninklijke Nederlandse Planteziektenkundige Vereniging.


Roesch A.,Institute for Sustainability science ISS
German Journal of Agricultural Economics | Year: 2015

In future, standard output (SO) will be the economic variable used to define the target population from which the Swiss FADN sample is drawn. This study assesses the impact of the SO threshold on key economic variables at national level. The analysis demonstrates that raising the SO threshold will lead to higher average values of key economic variables such as work income per family labour unit. This result is confirmed by two entirely different approaches, the first of which takes the FADN data into account, and the second of which considers census data supplemented by imputed economic variables.


Baur I.,Institute for Sustainability science ISS | Binder C.R.,Ludwig Maximilians University of Munich
Ecological Economics | Year: 2015

Common property pastures (CPPs) in the Alps served as examples for successful self-governed resource use. During the past fewdecades, the situation has changed, and abandonment of marginal pastureswith subsequent forest regrowth has been widely observed. To better understand current drivers, challenges, and policy impacts on the sustainable governance of common property pastures, we present an application of Ostroms' general framework for analyzing social-ecological systems (SESs). We use system dynamics (SD) modeling to operationalize the SES framework for the case study region of Grindelwald, Switzerland. Based on formative scenario analysis, we identify four consistent simulation scenarios. The simulation results show that increasing loss of common property pastures and resulting afforestation can be expected. Scenario assessment shows that policy blueprints such as liberalization or increased government support do not halt but instead accelerate abandonment of common property pastures. We conclude by discussing options for sustainably governing CPPs. © 2015.


Meier E.S.,Institute for Sustainability science ISS | Hofer G.,Institute for Sustainability science ISS
Alpine Botany | Year: 2016

Little is known about the statistical consequences of plot size and their spatial arrangement when addressing biodiversity questions. Thus, we compared three vegetation plot sizes and two sampling designs with different spatial arrangements in alpine grasslands by analyzing their effects on common indices of alpha, beta and gamma plant species diversity. Data were collected in three 1-km2 squares in summer pastures in the subalpine and alpine zones in Switzerland. In each square, 45 nested plots were distributed according to systematic random sampling (i.e., when the focus is on the abundances of the vegetation types and species) and maximum variation sampling (i.e., when the focus is on the set of vegetation types and species occurring). To compare the effects of the plot sizes and sampling designs on estimates of gamma diversity, we also estimated gamma diversity from an exhaustive sampling of the squares. Compared with systematic random sampling, maximum variation sampling hardly affected the indices of alpha diversity, but resulted in higher indices of beta and gamma diversity. More importantly, alpha and gamma diversity were found to be higher as plot size increased, whereas beta diversity was lower in the larger plots. Gamma diversity from the exhaustive sample was most similar to gamma diversity from maximum variation sampling on the largest plot sizes. Moreover, results from a variation partitioning analysis showed that landscape variability and plot size had a much larger effect on species diversity estimates than the sampling design. In conclusion, studies focusing on the occurring set of vegetation types and species within a landscape may apply maximum variation sampling if the most important (environmental) gradients for the stratification are known. Studies also focusing on the abundance of vegetation types or species may apply systematic random sampling. © 2016 Swiss Botanical Society


Haller S.,Institute for Sustainability science ISS | Meissle M.,Institute for Sustainability science ISS | Romeis J.,Institute for Sustainability science ISS
Ecotoxicology | Year: 2016

Potentially adverse effects on ecosystem functioning by the planting of insect-resistant, genetically engineered plants or by the direct application of insecticidal compounds are carefully evaluated in pre-market risk assessments. To date, few studies have assessed the potential risks of genetically engineered crops or insecticidal compounds on the survival and fitness of dipteran species, despite their important contribution to ecosystem services such as decomposition in agricultural systems. Therefore, we propose that Drosophila melanogaster Meigen (Drosophilidae) be used as a surrogate species for the order Diptera and for the functional guild of soil arthropod decomposers in pre-market risk assessments. We developed two assays to assess the toxicity of gut-active insecticidal compounds to D. melanogaster. One assay uses groups of fly larvae, and the other uses individuals. Cryolite, a mineral pesticide, proved to be an adequate positive control. The effects of cryolite on D. melanogaster larvae were comparable between the two assays. Statistical power analyses were used to define the number of replications required to identify different effect sizes between control and treatment groups. Finally, avidin, E-64, GNA, and SBTI were used as test compounds to validate the individual-based assay; only avidin adversely affected D. melanogaster. These results indicate that both D. melanogaster assays will be useful for early tier risk assessment concerning the effects of orally active compounds on non-target dipterans. © 2016 Springer Science+Business Media New York


Meissle M.,Institute for Sustainability science ISS | Zund J.,Institute for Sustainability science ISS | Waldburger M.,Institute for Sustainability science ISS | Romeis J.,Institute for Sustainability science ISS
Scientific Reports | Year: 2014

Maize (Zea mays) pollen is highly nutritious and can be used by predatory arthropods to supplement or replace a carnivorous diet. We demonstrate that maize pollen can be utilized by larvae of the green lacewing, Chrysoperla carnea (Neuroptera: Chrysopidae) under laboratory conditions. Complete development on maize pollen was not possible, but 25% of neonates reached the third instar. When only one instar was fed with pollen and the other two instars with eggs of Ephestia kuehniella (Lepidoptera: Pyralidae), 58-87% of the larvae reached the pupal stage. The experiments included pollen produced by nine cultivars: three genetically modified (GM) cultivars expressing the Bacillus thuringiensis proteins Cry1Ab or Cry3Bb1, their corresponding non-transformed near-isolines, and three conventional cultivars. Maize cultivars were grown in two batches in a glasshouse. Their pollen differed by up to 59% in total protein content, 25% in C:N ratio, and 14% in grain diameter, but the differences were inconsistent and depended on the batch. Lacewing performance was not affected by maize cultivar. For environmental risk assessment of GM plants, in planta studies must consider the variability among conventional cultivars, individual plants, batches, and environmental conditions when evaluating the ecological significance of differences observed between GM and near-isolines.


Li Y.,Chinese Academy of Agricultural Sciences | Chen X.,Chinese Academy of Agricultural Sciences | Hu L.,Chinese Academy of Agricultural Sciences | Romeis J.,Chinese Academy of Agricultural Sciences | And 2 more authors.
Environmental Toxicology and Chemistry | Year: 2014

The effects of insect-resistant genetically engineered rice producing Cry1C protein derived from Bacillus thuringiensis (Bt) on Chrysoperla sinica (Tjeder) (Neuroptera: Chrysopidae) were assessed in laboratory bioassays. Survival and development of C. sinica larvae were not adversely affected when the larvae were fed a diet containing purified Cry1C protein at 200μg/g fresh weight, representing a worst-case exposure scenario; in contrast, C. sinica larvae were adversely affected when the diet contained avidin or potassium arsenate. Life table parameters of C. sinica adults did not differ when the adults were fed with Bt or non-Bt rice pollen together with a 2-M sucrose solution. Life table parameters of C. sinica adults also did not differ when the adults were fed an artificial diet with or without purified Cry1C protein at a nominal concentration that was approximately 20 times higher than that in rice pollen; in contrast, C. sinica adults were adversely affected when the diet contained potassium arsenate. In all bioassays with lacewings, the bioactivity and stability of the Cry1C protein in the diet and Cry1C protein uptake by the lacewings were confirmed by enzyme-linked immunosorbent assay (ELISA) and by bioassays with a Cry1C-sensitive lepidopteran. These results demonstrate that neither larvae nor adults of C. sinica are sensitive to Cry1C protein at concentrations higher than those encountered in the field, demonstrating that the growing of Bt rice producing Cry1C protein is unlikely to pose a risk to C. sinica. Environ Toxicol Chem 2014;33:1391-1397. © 2014 SETAC.

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