Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Opportunities for soil sustainability in Europe
Putten, W.H. van der; Ramirez, Kelly S. ; Poesen, Jean ; Winding, A. ; Lemanceau, Philippe ; Lisa, Lenka ; Simek, Miloslaw ; Moora, M. ; Setala, Heikki ; Zaitsev, A. ; Economou-Eliopoulos, Maria ; Hornung, E. ; Wall, David ; Angelis, P. de; Lipiec, Jerzy ; Briones, M.J.I. ; Hedlund, Katarina ; Heijden, M. ; Six, Johan ; Bardgett, Richard D. ; Powlson, D. ; Goulding, K. ; Norton, Michael - \ 2018
European Academies Science Advisory Council (EASAC) (EASAC policy report 36) - ISBN 9783804738980 - 48 p.
Crop traits drive soil carbon sequestration under organic farming
García-Palacios, Pablo ; Gattinger, Andreas ; Bracht-Jørgensen, Helene ; Brussaard, Lijbert ; Carvalho, Filipe ; Castro, Helena ; Clément, Jean Christophe ; Deyn, Gerlinde De; Hertefeldt, Tina D'; Foulquier, Arnaud ; Hedlund, Katarina ; Lavorel, Sandra ; Legay, Nicolas ; Lori, Martina ; Mäder, Paul ; Martínez-García, Laura B. ; Martins da Silva, Pedro ; Muller, Adrian ; Nascimento, Eduardo ; Reis, Filipa ; Symanczik, Sarah ; Paulo Sousa, José ; Milla, Rubén - \ 2018
Journal of Applied Ecology 55 (2018)5. - ISSN 0021-8901 - p. 2496 - 2505.
climate change mitigation - crop residue - ecological intensification - leaf nitrogen - meta-analysis - organic farming - resource economics traits - soil carbon stocks

Organic farming (OF) enhances top soil organic carbon (SOC) stocks in croplands compared with conventional farming (CF), which can contribute to sequester C. As farming system differences in the amount of C inputs to soil (e.g. fertilization and crop residues) are not enough to explain such increase, shifts in crop residue traits important for soil C losses such as litter decomposition may also play a role. To assess whether crop residue (leaf and root) traits determined SOC sequestration responses to OF, we coupled a global meta-analysis with field measurements across a European-wide network of sites. In the meta-analysis, we related crop species averages of leaf N, leaf-dry matter content, fine-root C and N, with SOC stocks and sequestration responses in OF vs. CF. Across six European sites, we measured the management-induced changes in SOC stocks and leaf litter traits after long-term ecological intensive (e.g. OF) vs. CF comparisons. Our global meta-analysis showed that the positive OF-effects on soil respiration, SOC stocks, and SOC sequestration rates were significant even in organic farms with low manure application rates. Although fertilization intensity was the main driver of OF-effects on SOC, leaf and root N concentrations also played a significant role. Across the six European sites, changes towards higher leaf litter N in CF also promoted lower SOC stocks. Our results highlight that crop species displaying traits indicative of resource-acquisitive strategies (e.g. high leaf and root N) increase the difference in SOC between OF and CF. Indeed, changes towards higher crop residue decomposability was related with decreased SOC stocks under CF across European sites. Synthesis and applications. Our study emphasizes that, with management, changes in crop residue traits contribute to the positive effects of organic farming (OF) on soil carbon sequestration. These results provide a clear message to land managers: the choice of crop species, and more importantly their functional traits (e.g. leave and root nitrogen), should be considered in addition to management practices and climate, when evaluating the potential of OF for climate change mitigation.

Combined effects of agrochemicals and ecosystem services on crop yield across Europe
Gagic, Vesna ; Kleijn, David ; Báldi, András ; Boros, Gergely ; Jørgensen, Helene Bracht ; Elek, Zoltán ; Garratt, Michael P.D. ; Groot, Arjen de; Hedlund, Katarina ; Kovács-Hostyánszki, Anikó ; Marini, Lorenzo ; Martin, Emily A. ; Pevere, Ines ; Potts, Simon G. ; Redlich, Sarah ; Senapathi, Deepa ; Steffan-Dewenter, Ingolf ; Świtek, Stanislaw ; Smith, Henrik G. ; Takács, Viktória ; Tryjanowski, Piotr ; Putten, Wim H. van der; Gils, Stijn van; Bommarco, Riccardo - \ 2017
Ecology Letters 20 (2017)11. - ISSN 1461-023X - p. 1427 - 1436.
Agricultural intensification - biological pest control - ecological intensification - fertilisers - insecticides - landscape complexity - soil organic carbon - yield loss

Simultaneously enhancing ecosystem services provided by biodiversity below and above ground is recommended to reduce dependence on chemical pesticides and mineral fertilisers in agriculture. However, consequences for crop yield have been poorly evaluated. Above ground, increased landscape complexity is assumed to enhance biological pest control, whereas below ground, soil organic carbon is a proxy for several yield-supporting services. In a field experiment replicated in 114 fields across Europe, we found that fertilisation had the strongest positive effect on yield, but hindered simultaneous harnessing of below- and above-ground ecosystem services. We furthermore show that enhancing natural enemies and pest control through increasing landscape complexity can prove disappointing in fields with low soil services or in intensively cropped regions. Thus, understanding ecological interdependences between land use, ecosystem services and yield is necessary to promote more environmentally friendly farming by identifying situations where ecosystem services are maximised and agrochemical inputs can be reduced.

Report on Economic Models Calibrated to Case-Study Landscapes
Brady, M. ; Sahlin, Ullrika ; Clough, Y. ; Bailey, A. ; Cong, R.G. ; Elek, Zoltan ; Hedlund, K. ; Koellner, T. ; Marini, L. ; Olsson, O. ; Poppenborg, Patrick ; Redlich, Sarah ; Switek, Stanislaw ; Takacs, Viki ; Gils, S.H. van; Smith, H.G. - \ 2016
FP7 Project Liberation
Global soil biodiversity atlas
Orgiazzi, A. ; Bardgett, R.D. ; Barrios, E. ; Behan-Pelletier, V. ; Briones, M.J.I. ; Chotte, J.L. ; Deyn, G.B. de; Eggleton, P. ; Fierer, N. ; Fraser, T. ; Hedlund, K. ; Jeffery, S. ; Johnson, N.C. ; Jones, A. ; Kandeler, E. ; Kaneko, N. ; Lavelle, P. ; Lemanceau, P. ; Miko, L. ; Montanarella, L. ; Moreira, F.M.S. ; Ramirez, K.S. ; Scheu, S. ; Singh, B.K. ; Six, J. ; Putten, W.H. van der; Wall, D.H. - \ 2016
Luxembourg : European Union (EUR ) - ISBN 9789279481697 - 176 p.
New ways of proving knowledge to tackle food and nutrition security: what should the EU do? : Expo 2015 EU Scientific Steering Committe: recommendations
Fischler, F. ; Wilkinson, D. ; Benton, T.G. ; Daniel, Hannelore ; Darcy-Vrillon, B. ; Hedlund, K. ; Heffernan, P. ; Kok, E.J. ; Jakubczyk, E. ; Sorlini, C. ; Swinnen, J. ; Braun, J. von; Ash, K. ; Guerreri, F. ; Buckwell, A. ; Frewen, M. ; Karlsson, M. - \ 2015
Milaan, Italy : EU - Scientific Steering Committee - ISBN 9789279534768 - 64 p.
On the value of soil biodiversity and ecosystem services
Pascual, U. ; Termansen, M. ; Hedlund, K. ; Brussaard, L. ; Faber, J.H. ; Foudi, S. ; Lemanceau, P. ; Liv-Jørgensen, S. - \ 2015
Ecosystem Services 15 (2015). - ISSN 2212-0416 - p. 11 - 18.
This paper provides a framework to understand the source of the economic value of soil biodiversity and soil ecosystem services and maps out the pathways of such values. We clarify the link between components of the economic value of soil biodiversity and their associated services of particular relevance to soils. We contend that soil biodiversity and associated ecosystem services give rise to two main additive value components in the context of risk and uncertainty: an output value and an insurance value. These are illustrated with examples from soil ecology and a simple heuristic model. The paper also points towards the challenges of capturing such values highlighting the differences between private (individual) and public (global) sources of value.
Valuing Supporting Soil Ecosystem Services in Agriculture: A Natural Capital Approach
Brady, M.V. ; Hedlund, K. ; Cong, R.G. ; Hemerik, L. ; Hotes, S. ; Machado, S. ; Mattson, L. ; Schulz, E. ; Thomsen, I.K. - \ 2015
Agronomy Journal 107 (2015)5. - ISSN 0002-1962 - p. 1809 - 1821.
Soil biodiversity through its delivery of ecosystem functions and attendant supporting ecosystem services—benefits soil organisms generate for farmers—underpins agricultural production. Yet lack of practical methods to value the long-term effects of current farming practices results, inevitably, in short-sighted management decisions. We present a method for valuing changes in supporting soil ecosystem services and associated soil natural capital—the value of the stock of soil organisms—in agriculture, based on resultant changes in future farm income streams. We assume that a relative change in soil organic C (SOC) concentration is correlated with changes in soil biodiversity and the generation of supporting ecosystem services. To quantify the effects of changes in supporting services on agricultural productivity, we fitted production functions to data from long-term field experiments in Europe and the United States. The different agricultural treatments at each site resulted in significant changes in SOC concentrations with time. Declines in associated services are shown to reduce both maximum yield and fertilizer-use efficiency in the future. The average depreciation of soil natural capital, for a 1% relative reduction in SOC concentration, was 144 € ha–1 (SD 47 € ha–1) when discounting future values to their current value at 3%; the variation was explained by site-specific factors and the current SOC concentration. Moreover, the results show that soil ecosystem services cannot be fully replaced by purchased inputs; they are imperfect substitutes. We anticipate that our results will both encourage and make it possible to include the value of soil natural capital in decisions.
The role of research in global food and nutrition security - Discussion paper
Fischler, F. ; Wilkinson, D. ; Benton, T. ; Daniel, H. ; Darcy-Vrillon, B. ; Hedlund, K. ; Heffernan, P. ; Kok, E.J. ; Saarela, M. ; Jakubczyk, E. ; Sorlini, C. ; Swinnen, J. ; Braun, J. von; Ash, K. ; Rojas Briales, E. ; Buckwell, A. ; Frewen, M. ; Karlsson, M. - \ 2015
Milaan, Italy : EU - Scientific Steering Committee (Discussion paper / Expo 2015 EU Scientific Steering Committee ) - ISBN 9789279458309 - 32
voedselzekerheid - voeding en gezondheid - europese unie - innovaties - duurzaamheid (sustainability) - food security - nutrition and health - european union - innovations - sustainability
The present discussion document gives an overview of where European research can add the most value in relation to tackling food and nutrition security challenges and points to areas where we can expand our research potential. Moreover, it highlights the need to develop a governance structure that will allow sharing of best practices and facilitate the transfer of knowledge and innovation to feed the planet sustainably. It should stimulate a global discussion with stakeholders and the general public, ultimately shaping a legacy for Expo 2015.
Intensive agriculture reduces soil biodiversity across Europe
Tsiafouli, M.A. ; Thébault, E. ; Sgardelis, S. ; Ruiter, P.C. de; Putten, W.H. van der; Birkhofer, K. ; Hemerik, L. ; Vries, F.T. de; Bardgett, R.D. ; Brady, M. ; Bjornlund, L. ; Bracht Jörgensen, H. ; Christensen, S. ; Herfelt, T. D'; Hotes, S. ; Hol, W.H.G. ; Frouz, J. ; Liiri, M. ; Mortimer, S.R. ; Setälä, H. ; Stary, J. ; Tzanopoulos, J. ; Uteseny, C. ; Wolters, V. ; Hedlund, K. - \ 2015
Global Change Biology 21 (2015)2. - ISSN 1354-1013 - p. 973 - 985.
food-web structure - land-use intensity - taxonomic distinctness - community structure - phylogenetic diversity - arthropod communities - temporal variability - 7-year period - ecosystem - management
Soil biodiversity plays a key role in regulating the processes that underpin the delivery of ecosystem goods and services in terrestrial ecosystems. Agricultural intensification is known to change the diversity of individual groups of soil biota, but less is known about how intensification affects biodiversity of the soil food web as a whole, and whether or not these effects may be generalized across regions. We examined biodiversity in soil food webs from grasslands, extensive, and intensive rotations in four agricultural regions across Europe: in Sweden, the UK, the Czech Republic and Greece. Effects of land-use intensity were quantified based on structure and diversity among functional groups in the soil food web, as well as on community-weighted mean body mass of soil fauna. We also elucidate land-use intensity effects on diversity of taxonomic units within taxonomic groups of soil fauna. We found that between regions soil food web diversity measures were variable, but that increasing land-use intensity caused highly consistent responses. In particular, land-use intensification reduced the complexity in the soil food webs, as well as the community-weighted mean body mass of soil fauna. In all regions across Europe, species richness of earthworms, Collembolans, and oribatid mites was negatively affected by increased land-use intensity. The taxonomic distinctness, which is a measure of taxonomic relatedness of species in a community that is independent of species richness, was also reduced by land-use intensification. We conclude that intensive agriculture reduces soil biodiversity, making soil food webs less diverse and composed of smaller bodied organisms. Land-use intensification results in fewer functional groups of soil biota with fewer and taxonomically more closely related species. We discuss how these changes in soil biodiversity due to land-use intensification may threaten the functioning of soil in agricultural production systems.
Urban and agricultural soils: conflicts and trade-offs in the optimization of ecosystem services
Setälä, H. ; Bardgett, R.D. ; Birkhofer, K. ; Brady, M. ; Byrne, L. ; Ruiter, P.C. de; Vries, F.T. de; Gardi, C. ; Hedlund, K. ; Hemerik, A. ; Hotes, S. ; Liiri, M. ; Mortimer, S.R. ; Pavao-Zuckerman, M. ; Pouyat, R. ; Tsiafouli, M. ; Putten, W.H. van der - \ 2014
Urban Ecosystems 17 (2014)1. - ISSN 1083-8155 - p. 239 - 253.
biological-control - land-use - functional composition - united-states - landscapes - conservation - impact - carbon - infrastructure - sustainability
On-going human population growth and changing patterns of resource consumption are increasing global demand for ecosystem services, many of which are provided by soils. Some of these ecosystem services are linearly related to the surface area of pervious soil, whereas others show non-linear relationships, making ecosystem service optimization a complex task. As limited land availability creates conflicting demands among various types of land use, a central challenge is how to weigh these conflicting interests and how to achieve the best solutions possible from a perspective of sustainable societal development. These conflicting interests become most apparent in soils that are the most heavily used by humans for specific purposes: urban soils used for green spaces, housing, and other infrastructure and agricultural soils for producing food, fibres and biofuels. We argue that, despite their seemingly divergent uses of land, agricultural and urban soils share common features with regards to interactions between ecosystem services, and that the trade-offs associated with decision-making, while scale- and context-dependent, can be surprisingly similar between the two systems. We propose that the trade-offs within land use types and their soil-related ecosystems services are often disproportional, and quantifying these will enable ecologists and soil scientists to help policy makers optimizing management decisions when confronted with demands for multiple services under limited land availability.
Soil food web properties explain ecosystem services across European land use systems
Vries, F.T. de; Thebault, E.M.C. ; Liiri, M. ; Birkhofer, K. ; Tsiafouli, M. ; Bjornlund, L. ; Jorgensen, H.B. ; Brady, M.V. ; Christensen, S. ; Ruiter, P.C. de; Hertefeldt, T. d'; Frouz, J. ; Hedlund, K. ; Hemerik, L. ; Hol, W.H.G. ; Hotes, S. ; Mortimer, S.R. ; Setälä, H. ; Sgardelis, S.P. ; Uteseny, K. ; Putten, W.H. van der; Wolters, V. ; Bardgett, R.D. - \ 2013
Proceedings of the National Academy of Sciences of the United States of America 110 (2013)35. - ISSN 0027-8424 - p. 14296 - 14301.
nitrogen mineralization - carbon sequestration - bacterial community - mycorrhizal fungi - biomass - scale - intensification - decomposition - biodiversity - agriculture
Intensive land use reduces the diversity and abundance of many soil biota, with consequences for the processes that they govern and the ecosystem services that these processes underpin. Relationships between soil biota and ecosystem processes have mostly been found in laboratory experiments and rarely are found in the field. Here, we quantified, across four countries of contrasting climatic and soil conditions in Europe, how differences in soil food web composition resulting from land use systems (intensive wheat rotation, extensive rotation, and permanent grassland) influence the functioning of soils and the ecosystem services that they deliver. Intensive wheat rotation consistently reduced the biomass of all components of the soil food web across all countries. Soil food web properties strongly and consistently predicted processes of C and N cycling across land use systems and geographic locations, and they were a better predictor of these processes than land use. Processes of carbon loss increased with soil food web properties that correlated with soil C content, such as earthworm biomass and fungal/bacterial energy channel ratio, and were greatest in permanent grassland. In contrast, processes of N cycling were explained by soil food web properties independent of land use, such as arbuscular mycorrhizal fungi and bacterial channel biomass. Our quantification of the contribution of soil organisms to processes of C and N cycling across land use systems and geographic locations shows that soil biota need to be included in C and N cycling models and highlights the need to map and conserve soil biodiversity across the world.
Ecosystem services: a useful concept for soil policy making!
Breure, A.M. ; Deyn, G.B. de; Dominati, E. ; Eglin, T. ; Hedlund, K. ; Orshoven, J. van; Posthuma, L. - \ 2012
Current Opinion in Environmental Sustainability 4 (2012)5. - ISSN 1877-3435 - p. 578 - 585.
carbon sequestration - climate-change - food security - biodiversity - restoration - diversity
This paper is based on the session ‘Ecosystem services: a useful concept for soil policy making?’ at the Wageningen Applied Soil Conference in September 2011. In that session it was shown from different angles that policy awareness of the dependence of humankind on ecosystem services has resulted in the development of tools for optimal allocation and quantification of ecosystem services and raising awareness to stakeholders and decision makers. A number of case studies provided practical applications of developed tools that show how an ecosystem services approach can work as a way to value ecosystems. The use of ecosystem services may lead to mitigation of soil degradation and at the same time increase production of services both to private land owners as well as to the society as common goods. In our opinion the results available to date show that quantifying the benefits of ecosystems is a way to support the positive view stated in the title and we encourage the development of decision support tools based on more extensive yet user friendly integrated approaches of resource management, sector planning, and priority setting in the near future.
Divergent composition but similar function of soil food webs of individual plants: plant species and community effects
Bezemer, T.M. ; Fountain, T. ; Barea, J.M. ; Christensen, S. ; Dekker, S.C. ; Duyts, H. ; Hal, R. van; Harvey, J.A. ; Hedlund, K. ; Maraun, M. ; Mikola, J. ; Mladenov, A.G. ; Robin, C. ; Ruiter, P.C. de; Scheu, H. ; Setälä, S. ; šmilauer, P. ; Putten, W.H. van der - \ 2010
Ecology 91 (2010)10. - ISSN 0012-9658 - p. 3027 - 3036.
microbial communities - diversity - stability - biodiversity - grassland - feedback - ecology - real - ecosystems - succession
Soils are extremely rich in biodiversity, and soil organisms play pivotal roles in supporting terrestrial life, but the role that individual plants and plant communities play in influencing the diversity and functioning of soil food webs remains highly debated. Plants, as primary producers and providers of resources to the soil food web, are of vital importance for the composition, structure, and functioning of soil communities. However, whether natural soil food webs that are completely open to immigration and emigration differ underneath individual plants remains unknown. In a biodiversity restoration experiment we first compared the soil nematode communities of 228 individual plants belonging to eight herbaceous species. We included grass, leguminous, and non-leguminous species. Each individual plant grew intermingled with other species, but all plant species had a different nematode community. Moreover, nematode communities were more similar when plant individuals were growing in the same as compared to different plant communities, and these effects were most apparent for the groups of bacterivorous, carnivorous, and omnivorous nematodes. Subsequently, we analyzed the composition, structure, and functioning of the complete soil food webs of 58 individual plants, belonging to two of the plant species, Lotus corniculatus (Fabaceae) and Plantago lanceolata (Plantaginaceae). We isolated and identified more than 150 taxa/groups of soil organisms. The soil community composition and structure of the entire food webs were influenced both by the species identity of the plant individual and the surrounding plant community. Unexpectedly, plant identity had the strongest effects on decomposing soil organisms, widely believed to be generalist feeders. In contrast, quantitative food web modeling showed that the composition of the plant community influenced nitrogen mineralization under individual plants, but that plant species identity did not affect nitrogen or carbon mineralization or food web stability. Hence, the composition and structure of entire soil food webs vary at the scale of individual plants and are strongly influenced by the species identity of the plant. However, the ecosystem functions these food webs provide are determined by the identity of the entire plant community. Read More:
Influences of space, soil, nematodes and plants on microbial community composition of chalk grassland soils
Yergeau, E. ; Bezemer, T.M. ; Hedlund, K. ; Mortimer, S.R. ; Kowalchuk, G.A. ; Putten, W.H. van der - \ 2010
Environmental Microbiology 12 (2010)8. - ISSN 1462-2912 - p. 2096 - 2106.
fatty-acid analysis - bacterial diversity - neighbor matrices - global patterns - ecological data - rhizosphere - protozoa - microorganisms - biogeography - gradient
Microbial communities respond to a variety of environmental factors related to resources (e.g. plant and soil organic matter), habitat (e.g. soil characteristics) and predation (e.g. nematodes, protozoa and viruses). However, the relative contribution of these factors on microbial community composition is poorly understood. Here, we sampled soils from 30 chalk grassland fields located in three different chalk hill ridges of Southern England, using a spatially explicit sampling scheme. We assessed microbial communities via phospholipid fatty acid (PLFA) analyses and PCR-denaturing gradient gel electrophoresis (DGGE) and measured soil characteristics, as well as nematode and plant community composition. The relative influences of space, soil, vegetation and nematodes on soil microorganisms were contrasted using variation partitioning and path analysis. Results indicate that soil characteristics and plant community composition, representing habitat and resources, shape soil microbial community composition, whereas the influence of nematodes, a potential predation factor, appears to be relatively small. Spatial variation in microbial community structure was detected at broad (between fields) and fine (within fields) scales, suggesting that microbial communities exhibit biogeographic patterns at different scales. Although our analysis included several relevant explanatory data sets, a large part of the variation in microbial communities remained unexplained (up to 92% in some analyses). However, in several analyses, significant parts of the variation in microbial community structure could be explained. The results of this study contribute to our understanding of the relative importance of different environmental and spatial factors in driving the composition of soil-borne microbial communities.
Long-term organic farming fosters below and aboveground biota: Implications for soil quality, biological control and productivity
Birkhofer, K. ; Bezemer, T.M. ; Bloem, J. ; Bonkowski, M. ; Christensen, S. ; Dubois, D. ; Ekelund, F. ; Fliessbach, A. ; Gunst, L. ; Hedlund, K. ; Mäder, P. ; Mikola, J. ; Robin, C. ; Setälä, H. ; Tatin-Froux, F. ; Putten, W.H. van der; Scheu, S. - \ 2008
Soil Biology and Biochemistry 40 (2008)9. - ISSN 0038-0717 - p. 2297 - 2308.
microbial community structure - food-web - agricultural systems - generalist predators - mycorrhizal fungi - alternative prey - biomass - nitrogen - agroecosystems - management
Organic farming may contribute substantially to future agricultural production worldwide by improving soil quality and pest control, thereby reducing environmental impacts of conventional farming. We investigated in a comprehensive way soil chemical, as well as below and aboveground biological parameters of two organic and two conventional wheat farming systems that primarily differed in fertilization and weed management strategies. Contrast analyses identified management related differences between ¿herbicide-free¿ bioorganic (BIOORG) and biodynamic (BIODYN) systems and conventional systems with (CONFYM) or without manure (CONMIN) and herbicide application within a long-term agricultural experiment (DOK trial, Switzerland). Soil carbon content was significantly higher in systems receiving farmyard manure and concomitantly microbial biomass (fungi and bacteria) was increased. Microbial activity parameters, such as microbial basal respiration and nitrogen mineralization, showed an opposite pattern, suggesting that soil carbon in the conventional system (CONFYM) was more easily accessible to microorganisms than in organic systems. Bacterivorous nematodes and earthworms were most abundant in systems that received farmyard manure, which is in line with the responses of their potential food sources (microbes and organic matter). Mineral fertilizer application detrimentally affected enchytraeids and Diptera larvae, whereas aphids benefited. Spider abundance was favoured by organic management, most likely a response to increased prey availability from the belowground subsystem or increased weed coverage. In contrast to most soil-based, bottom-up controlled interactions, the twofold higher abundance of this generalist predator group in organic systems likely contributed to the significantly lower abundance of aboveground herbivore pests (aphids) in these systems. Long-term organic farming and the application of farmyard manure promoted soil quality, microbial biomass and fostered natural enemies and ecosystem engineers, suggesting enhanced nutrient cycling and pest control. Mineral fertilizers and herbicide application, in contrast, affected the potential for top-down control of aboveground pests negatively and reduced the organic carbon levels. Our study indicates that the use of synthetic fertilizers and herbicide application changes interactions within and between below and aboveground components, ultimately promoting negative environmental impacts of agriculture by reducing internal biological cycles and pest control. On the contrary, organic farming fosters microbial and faunal decomposers and this propagates into the aboveground system via generalist predators thereby increasing conservation biological control. However, grain and straw yields were 23% higher in systems receiving mineral fertilizers and herbicides reflecting the trade-off between productivity and environmental responsibility.
Long-term effectiveness of sowing high and low diversity seed mixtures to enhance plant community development on ex-arable fields
Leps, J. ; Dolezal, J. ; Bezemer, T.M. ; Brown, V.K. ; Hedlund, K. ; Igual Arroya, M. ; Jörgensen, H.B. ; Lawson, C.S. ; Mortimer, S.R. ; Peix Geldart, A. ; Rodríguez Barrueco, C. ; Santa Regina, I. ; Smilauer, P. ; Putten, W.H. van der - \ 2007
Applied Vegetation Science 10 (2007)1. - ISSN 1402-2001 - p. 97 - 110.
life-history strategies - productivity relationships - european grasslands - species diversity - restoration - succession - land - biodiversity - vegetation - invasion
Questions: How is succession on ex-arable land affected by sowing high and low diversity mixtures of grassland species as compared to natural succession? How long do effects persist? Location: Experimental plots installed in the Czech Republic, The Netherlands, Spain, Sweden and the United Kingdom. Methods: The experiment was established on ex-arable land, with five blocks, each containing three 10 m x 10 m experiment tal plots: natural colonization, a low- (four species) and high-diversity (15 species) seed mixture. Species composition and biomass was followed for eight years. Results: The sown plants considerably affected the whole successional pathway and the effects persisted during the whole eight year period. Whilst the proportion of sown species (characterized by their cover) increased during the study period, the number of sown species started to decrease from the third season onwards. Sowing caused suppression of natural colonizing species, and the sown plots had more biomass. These effects were on average larger in the high diversity mixtures. However, the low diversity replicate sown with the mixture that produced the largest biomass or largest suppression of natural colonizers fell within the range recorded at the five replicates of the high diversity plots. The natural colonization plots usually had the highest total species richness and lowest productivity at the end of the observation period. Conclusions: The effect of sowing demonstrated dispersal limitation as a factor controlling the rate of early secondary succession. Diversity was important primarily for its 'insurance effect': the high diversity mixtures were always able to compensate for the failure of some species.
Plant species and functional group effects on abiotic and microbial soil properties and plant-soil feedback responses in two grasslands
Bezemer, T.M. ; Lawson, C.S. ; Hedlund, K. ; Edwards, A.R. ; Brooks, A.J. ; Igual, J.M. ; Mortimer, S.R. ; Putten, W.H. van der - \ 2006
Journal of Ecology 94 (2006)5. - ISSN 0022-0477 - p. 893 - 904.
fatty-acid analysis - community structure - diversity - rhizosphere - vegetation - biota - dynamics - biomass - succession - management
1 Plant species differ in their capacity to influence soil organic matter, soil nutrient availability and the composition of soil microbial communities. Their influences on soil properties result in net positive or negative feedback effects, which influence plant performance and plant community composition. 2 For two grassland systems, one on a sandy soil in the Netherlands and one on a chalk soil in the United Kingdom, we investigated how individual plant species grown in monocultures changed abiotic and biotic soil conditions. Then, we determined feedback effects of these soils to plants of the same or different species. Feedback effects were analysed at the level of plant species and plant taxonomic groups (grasses vs. forbs). 3 In the sandy soils, plant species differed in their effects on soil chemical properties, in particular potassium levels, but PLFA (phospholipid fatty acid) signatures of the soil microbial community did not differ between plant species. The effects of soil chemical properties were even greater when grasses and forbs were compared, especially because potassium levels were lower in grass monocultures. 4 In the chalk soil, there were no effects of plant species on soil chemical properties, but PLFA profiles differed significantly between soils from different monocultures. PLFA profiles differed between species, rather than between grasses and forbs. 5 In the feedback experiment, all plant species in sandy soils grew less vigorously in soils conditioned by grasses than in soils conditioned by forbs. These effects correlated significantly with soil chemical properties. None of the seven plant species showed significant differences between performance in soil conditioned by the same vs. other plant species. 6 In the chalk soil, Sanguisorba minor and in particular Briza media performed best in soil collected from conspecifics, while Bromus erectus performed best in soil from heterospecifics. There was no distinctive pattern between soils collected from forb and grass monocultures, and plant performance could not be related to soil chemical properties or PLFA signatures. 7 Our study shows that mechanisms of plant-soil feedback can depend on plant species, plant taxonomic (or functional) groups and site-specific differences in abiotic and biotic soil properties. Understanding how plant species can influence their rhizosphere, and how other plant species respond to these changes, will greatly enhance our understanding of the functioning and stability of ecosystems.
Plant species diversity, plant biomass and responses of the soil community on abandoned land across Europe: idiosyncracy or above-belowground time lags
Hedlund, K. ; Santa Regina, I. ; Putten, W.H. van der; Leps, J. ; Díaz, T. ; Korthals, G.W. ; Lavorel, S. ; Brown, V.K. ; Gormsen, D. ; Mortimer, S.R. ; Rodríguez Barrueco, C. ; Roy, J. ; Smilauer, P. ; Smilauerová, M. ; Dijk, C. van - \ 2003
Oikos 103 (2003). - ISSN 0030-1299 - p. 45 - 58.
experimental grassland ecosystems - trophic-level biomasses - fatty-acid analysis - microbial communities - food-web - agricultural land - arable land - set-aside - biodiversity - productivity
We examined the relationship between plant species diversity, productivity and the development of the soil community during early secondary succession on former arable land across Europe. We tested the hypothesis that increasing the initial plant species diversity enhances the biomass production and consequently stimulates soil microbial biomass and abundance of soil invertebrates. We performed five identical field experiments on abandoned arable land in five European countries (CZ, NL, SE, SP and UK) which allowed us to test our hypothesis in a range of climate, soil and other environmental factors that varied between the experimental sites. The initial plant diversity was altered by sowing seed mixtures of mid-successional grassland species with two or five grass species, one or five legumes and one or five forbs. The results of low and high sown diversity treatments were compared with plots that were naturally colonized by species present in the seed bank. In three out of the five field sites, there was no correlation between plant species number and plant biomass production, one site had a positive and the other a negative relation. Treatments with a high diversity seed mixture had a higher biomass than the naturally colonized plots. However, there was no significant difference between high and low sown diversity plots at four out of five sites. The three-year study did not give any evidence of a general bottom-up effect from increased plant biomass on biomass of bacteria, saprophytic fungi or abundance of microarthropods. The biomass of arbuscular mycorrhizal was negatively related to plant biomass. The abundance of nematodes increased after abandonment and was related to plant biomass at four sites. Our results support the hypothesis that plant species diversity may have idiosyncratic effects on soil communities, even though studies on a longer term could reveal time lags in the response to changes in composition and biomass production of plant communities.
Aggregation pheromones of Drosophila immigrans, D. phalerata and D. subobscura.
Hedlund, K. ; Bartelt, R.J. ; Dicke, M. ; Vet, L.E.M. - \ 1996
Journal of Chemical Ecology 22 (1996). - ISSN 0098-0331 - p. 1835 - 1844.
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