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Trouve R.,University of Natural Resources and Life Sciences, Vienna | Trouve R.,Agro ParisTech | Drapela T.,University of Natural Resources and Life Sciences, Vienna | Drapela T.,Research Institute of Organic Agriculture FiBL Austria | And 3 more authors.
Biology and Fertility of Soils

Invasion of non-native species is among the top threats for the biodiversity and functioning of native and agricultural ecosystems worldwide. We investigated whether the herbivory of the slug Arion vulgaris (formerly Arion lusitanicus; Gastropoda), that is listed among the 100 worst alien species in Europe, is affected by soil organisms commonly present in terrestrial ecosystems (i.e. earthworms-Annelida: Lumbricidae and arbuscular mycorrhizal fungi-AMF, Glomerales). We hypothesized that slug herbivory would be affected by soil organisms via altered plant nutrient availability and plant quality. In a greenhouse experiment, we created a simple plant community consisting of a grass, a forb, and a legume species and inoculated these systems with either two earthworm species and/or four AMF taxa. Slugs were introduced after plants were established. Earthworms significantly reduced total slug herbivory in AMF-inoculated plant communities (P = 0.013). Across plant species, earthworms increased leaf total N and secondary metabolites, AMF decreased leaf thickness. Mycorrhizae induced a shift in slug feeding preference from non-legumes to legumes; the grass was generally avoided by slugs. AMF effects on legume herbivory can partly be explained by the AMF-induced increase in total N and decrease in C/N ratio; earthworm effects are less clear as no worm-induced alterations of legume plant chemistry were observed. The presence of earthworms increased average AMF colonization of plant roots by 140 % (P < 0.001). Total shoot mass was significantly increased by AMF (P < 0.001). These data suggest that the feeding behavior of this invasive slug is altered by a belowground control of plant chemical quality and community structure. © 2013 The Author(s). Source

Zaller J.G.,University of Natural Resources and Life Sciences, Vienna | Parth M.,University of Natural Resources and Life Sciences, Vienna | Szunyogh I.,University of Natural Resources and Life Sciences, Vienna | Semmelrock I.,University of Natural Resources and Life Sciences, Vienna | And 5 more authors.
BMC Ecology

Background: Biodiversity loss and species invasions are among the most important human-induced global changes. Moreover, these two processes are interlinked as ecosystem invasibility is considered to increase with decreasing biodiversity. In temperate grasslands, earthworms serve as important ecosystem engineers making up the majority of soil faunal biomass. Herbivore behaviour has been shown to be affected by earthworms, however it is unclear whether these effects differ with the composition of plant communities. To test this we conducted a mesocosm experiment where we added earthworms (Annelida: Lumbricidae) to planted grassland communities with different plant species composition (3 vs. 12 plant spp.). Plant communities had equal plant densities and ratios of the functional groups grasses, non-leguminous forbs and legumes. Later, Arion vulgaris slugs (formerly known as A. lusitanicus; Gastropoda: Arionidae) were added and allowed to freely choose among the available plant species. This slug species is listed among the 100 worst alien species in Europe. We hypothesized that (i) the food choice of slugs would be altered by earthworms' specific effects on the growth and nutrient content of plant species, (ii) slug herbivory will be less affected by earthworms in plant communities containing more plant species than in those with fewer plant species because of a more readily utilization of plant resources making the impacts of earthworms less pronounced.Results: Slug herbivory was significantly affected by both earthworms and plant species composition. Slugs damaged 60% less leaves when earthworms were present, regardless of the species composition of the plant communities. Percent leaf area consumed by slugs was 40% lower in communities containing 12 plant species; in communities containing only three species earthworms increased slug leaf area consumption. Grasses were generally avoided by slugs. Leaf length and number of tillers was increased in mesocosms containing more plant species but little influenced by earthworms. Overall shoot biomass was decreased, root biomass increased in plant communities with more plant species. Earthworms decreased total shoot biomass in mesocosms with more plant species but did not affect biomass production of individual functional groups. Plant nitrogen concentrations across three focus species were 18% higher when earthworms were present; composition of plant communities did not affect plant quality.Conclusions: Given the important role that both herbivores and earthworms play in structuring plant communities the implications of belowground-aboveground linkages should more broadly be considered when investigating global change effects on ecosystems. © 2013 Zaller et al.; licensee BioMed Central Ltd. Source

Drapela T.,University of Natural Resources and Life Sciences, Vienna | Drapela T.,Research Institute of Organic Agriculture FiBL Austria | Frank T.,University of Natural Resources and Life Sciences, Vienna | Heer X.,2 Eichenweg 6 | And 3 more authors.
European Journal of Entomology

In large parts of Europe Pardosa spp. (Lycosidae) are among the most abundant wolf spiders in arable fields and potentially important natural control agents of pests. We studied the influence of landscape factors on activity density, adult body size and fecundity of P. agrestis in 29 winter oilseed rape fields (Brassica napus L.) in Eastern Austria using pitfall traps. Landscape data were obtained for eight circular landscape sections around each field (radii 250-2000 m). Multivariate regression models were used to analyze the data. Activity density was highest when the length of strips of grassy road-sides in the surroundings was highest and distance to the next grassy fallow lowest. Body size was negatively related to activity density and to the length of road-side strips and positively to woody areas in the vicinity of the fields. Clutch size was unrelated to any of the landscape factors tested but was positively correlated with female body size. Woody areas and grassy fallow in the close vicinity of the fields had a positive influence on number of offspring per female and total number of offspring. These results indicate that various non-crop components in the landscape surrounding oilseed rape fields can specifically influence the activity density and fitness-related traits of P. agrestis in crops. The possible role of Pardosa spp. in natural pest control is discussed. Source

Armengot L.,University of Barcelona | Armengot L.,Research Institute of Organic Agriculture FiBL | Blanco-Moreno J.M.,University of Barcelona | Barberi P.,SantAnna School of Advanced Studies | And 17 more authors.
Agriculture, Ecosystems and Environment

The adoption of non-inversion tillage practices has been widely promoted due to their potential benefits in reducing energy consumption and greenhouse emissions as well as improving soil fertility. However, the lack of soil inversion usually increases weed infestations and changes the composition of the weed community. Weed management is still a main drawback for the wider adoption of reduced tillage practices. However, it is not entirely clear whether these changes in weed communities are a consequence of non-random filters on the functional attributes of weed species and may thus affect the potential weed-crop competition relationship.Here, we analyse the changes in weed diversity, community composition, and the functional attributes of weed communities under reduced (non-inversion) and conventional (inversion) tillage. We discuss their potential effects on the competitiveness against crop production using data from two crops of seven on-going organic and low-input field trials in different climatic regions across Europe. Weeds were evaluated after post-emergence weed control methods. We used the community weighted mean values of the life form (annuals versus perennials), specific leaf area, seed weight, canopy height, seed bank longevity, soil nutrient conditions affinity, beginning of flowering and flowering span. Moreover, the effect of the crop type on the functional attributes was also evaluated.Overall, the tillage system affected the composition and functional attributes of the weed communities. Weed community changes may imply a reduction in weed-crop competition under both tillage systems. For instance, weed communities under reduced tillage were potentially less competitive because they were shorter and had less affinity to nutrients. On the other hand, weed communities under conventional tillage had potentially less seed production and a lower abundance of perennial species. Our study thus supports tillage as an important driver of the functional attributes of weed communities, but both tillage systems can have their downside. However, the crop type was overall more relevant than the tillage in determining most of the trait values of the weed communities. © 2016 Elsevier B.V. Source

Hortenhuber S.,Research Institute of Organic Agriculture FiBL Austria | Hortenhuber S.,University of Natural Resources and Life Sciences, Vienna | Piringer G.,University of Natural Resources and Life Sciences, Vienna | Zollitsch W.,University of Natural Resources and Life Sciences, Vienna | And 4 more authors.
Journal of Cleaner Production

The supply chain of a product is essential for understanding its environmental impacts. As parts of agricultural product supply chains, land use (LU) and land use change (LUC) are considered to be major contributors to global CO2 emissions. Nevertheless, LU and LUC (LULUC) are rarely included in GHG estimations for food and feedstuffs. Here we propose a method which can be used to derive emissions from LU and LUC on a regional level. Emissions are distributed over an accounting period chosen to match the physically occurring carbon fluxes. As fluxes from soil organic carbon persist for years or even for decades after a LUC episode, depending on the climatic conditions of the region, we apply 10 and 20 years as suitable accounting periods for tropical and temperate climate zones, respectively. We compare the proposed method with two other methods proposed in the literature. Using two types of feedstuffs (Brazilian soybean-meal and Austrian barley) as examples, we find that the other two methods produce mostly lower emission estimates in the case of Brazilian soybeans, and higher estimates for Austrian barley. We conclude that these differences are caused mainly by different accounting periods and by a (non)consideration of regional specificities. While analysing life cycles necessarily entails a well supported - but still arbitrary - setting of such system boundaries, we argue that the methodology presented here better reflects actually occurring carbon fluxes that we understand to be the foundation of any environmental product assessment. © 2013 Elsevier Ltd. All rights reserved. Source

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