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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    Pathologists and entomologists must join forces against forest pest and pathogen invasions
    Jactel, Hervé ; Desprez-Loustau, Marie Laure ; Battisti, Andrea ; Brockerhoff, Eckehard ; Santini, Alberto ; Stenlid, Jan ; Björkman, Christer ; Branco, Manuela ; Dehnen-Schmutz, Katharina ; Douma, Jacob C. ; Drakulic, Jassy ; Drizou, Fryni ; Eschen, René ; Franco, José Carlos ; Gossner, Martin M. ; Green, Samantha ; Kenis, Marc ; Klapwijk, Maartje J. ; Liebhold, Andrew M. ; Orazio, Christophe ; Prospero, Simone ; Robinet, Christelle ; Schroeder, Martin ; Slippers, Bernard ; Stoev, Pavel ; Sun, Jianghua ; Dool, Robbert van den; Wingfield, Michael J. ; Zalucki, Myron P. - \ 2020
    NeoBiota 58 (2020). - ISSN 1619-0033 - p. 107 - 127.
    Capacity building - Detection - Disease - Exotic - Forest health - Fungi - Identification - Insects - Interdisciplinarity - Management

    The world's forests have never been more threatened by invasions of exotic pests and pathogens, whose causes and impacts are reinforced by global change. However, forest entomologists and pathologists have, for too long, worked independently, used different concepts and proposed specific management methods without recognising parallels and synergies between their respective fields. Instead, we advocate increased collaboration between these two scientific communities to improve the long-term health of forests. Our arguments are that the pathways of entry of exotic pests and pathogens are often the same and that insects and fungi often coexist in the same affected trees. Innovative methods for preventing invasions, early detection and identification of non-native species, modelling of their impact and spread and prevention of damage by increasing the resistance of ecosystems can be shared for the management of both pests and diseases. We, therefore, make recommendations to foster this convergence, proposing in particular the development of interdisciplinary research programmes, the development of generic tools or methods for pest and pathogen management and capacity building for the education and training of students, managers, decision-makers and citizens concerned with forest health.

    Autonomous and informed decision-making : The case of colorectal cancer screening
    Douma, Linda N. ; Uiters, Ellen ; Verweij, Marcel F. ; Timmermans, Danielle R.M. - \ 2020
    PLoS ONE 15 (2020)5. - ISSN 1932-6203

    Introduction It is increasingly considered important that people make an autonomous and informed decision concerning colorectal cancer (CRC) screening. However, the realisation of autonomy within the concept of informed decision-making might be interpreted too narrowly. Additionally, relatively little is known about what the eligible population believes to be a 'good' screening decision. Therefore, we aimed to explore how the concepts of autonomous and informed decision-making relate to how the eligible CRC screening population makes their decision and when they believe to have made a 'good' screening decision. Methods We conducted 27 semi-structured interviews with the eligible CRC screening population (eighteen CRC screening participants and nine non-participants). The general topics discussed concerned how people made their CRC screening decision, how they experienced making this decision and when they considered they had made a 'good' decision. Results Most interviewees viewed a 'good' CRC screening decision as one based on both reasoning and feeling/intuition, and that is made freely. However, many CRC screening non-participants experienced a certain social pressure to participate. All CRC screening non-participants viewed making an informed decision as essential. This appeared to be the case to a lesser extent for CRC screening participants. For most, experiences and values were involved in their decision-making. Conclusion Our sample of the eligible CRC screening population viewed aspects related to the concepts of autonomous and informed decision-making as important for making a 'good' CRC screening decision. However, in particular the existence of a social norm may be affecting a true autonomous decision-making process. Additionally, the present concept of informed decision-making with its strong emphasis on making a fully informed and well-considered decision does not appear to be entirely reflective of the process in practice. More efforts could be made to attune to the diverse values and factors that are involved in deciding about CRC screening participation.

    Substantial differences occur between canopy and ambient climate : Quantification of interactions in a greenhouse-canopy system
    Westreenen, A. van; Zhang, N. ; Douma, J.C. ; Evers, J.B. ; Anten, N.P.R. ; Marcelis, L.F.M. - \ 2020
    PLoS ONE 15 (2020)5. - ISSN 1932-6203 - p. e0233210 - e0233210.

    Organ temperature and variation therein plays a key role in plant functioning and its responses to e.g. climate change. There is a strong feedback between organ, especially leaf, temperature and the climate within the canopy (canopy climate), which in turn interacts with the climate outside the canopy (ambient climate). For greenhouses, the determinants of this interplay and how they drive differences between canopy and ambient climate are poorly understood. Yet, as many experiments on both regular greenhouse crops and field crops are done in greenhouses, this is crucial to know. Therefore, we designed an experiment to quantify the differences between ambient and canopy climate and leaf temperature. A path analysis was performed to quantify the interactions between components of the greenhouse canopy-climate system. We found that with high radiation the canopy climate can be up to 5°C cooler than the ambient climate, while for cloudy days this was only 2°C. Canopy relative humidity (RH) was up to 25% higher compared to ambient RH. We showed that radiation is very important for these climate differences, but that this effect could be partly counteracted by turning off supplementary light (i.e. due to its indirect effects e.g. changing light distribution). Leaf temperature was substantially different, both higher and lower, from the canopy air temperature. This difference was determined by leaf area index (LAI), temperature of the heating pipe and the use of supplementary light, which all strongly influence radiation, either shortwave or thermal radiation. The difference between leaf and ambient air temperature could be decreased by decreasing the LAI or increasing the temperature of the heating pipe.

    Generalized AIC and chi-squared statistics for path models consistent with directed acyclic graphs
    Shipley, Bill ; Douma, Jacob C. - \ 2020
    Ecology 101 (2020)3. - ISSN 0012-9658
    Akaike Information Criterion - d-separation - directed acyclic graph - maximum likelihood - model selection - path analysis - piecewise SEM

    We explain how to obtain a generalized maximum-likelihood chi-square statistic, X2 ML, and a full-model Akaike Information Criterion (AIC) statistic for piecewise structural equation modeling (SEM); that is, structural equations without latent variables whose causal topology can be represented as a directed acyclic graph (DAG). The full piecewise SEM is decomposed into submodels as a Markov network, each of which can have different distributional assumptions or functional links and that can be modeled by any method that produces maximum-likelihood parameter estimates. The generalized X2 ML is a function of the difference in the maximum likelihoods of the model and its saturated equivalent and the full-model AIC is calculated by summing the AIC statistics of each of the submodels.

    No evidence of flowering synchronization upon floral volatiles for a short lived annual plant species: Revisiting an appealing hypothesis
    Fricke, Ute ; Lucas-Barbosa, Dani ; Douma, Jacob C. - \ 2019
    BMC Ecology 19 (2019)1. - ISSN 1472-6785
    Flowering onset - Flowering synchronization - Phenology - Plant-plant communication

    Background: Self-incompatible plants require simultaneous flowering mates for crosspollination and reproduction. Though the presence of flowering conspecifics and pollination agents are important for reproductive success, so far no cues that signal the flowering state of potential mates have been identified. Here, we empirically tested the hypothesis that plant floral volatiles induce flowering synchrony among self-incompatible conspecifics by acceleration of flowering and flower opening rate of non-flowering conspecifics. We exposed Brassica rapa Maarssen, a self-incompatible, in rather dense patches growing annual, to (1) flowering or non-flowering conspecifics or to (2) floral volatiles of conspecifics by isolating plants in separate containers with a directional airflow. In the latter, odors emitted by non-flowering conspecifics were used as control. Results: Date of first bud, duration of first flower bud, date of first flower, maximum number of open flowers and flower opening rate were not affected by the presence of conspecific flowering neighbors nor by floral volatiles directly. Conclusions: This study presents a compelling approach to empirically test the role of flower synchronization by floral volatiles and challenges the premises that are underlying this hypothesis. We argue that the life history of the plant as well as its interaction with pollinators and insect herbivores, as well as the distance over which volatiles may serve as synchronization cue, set constraints on the fitness benefits of synchronized flowering which needs to be taken into account when testing the role of floral volatiles in synchronized flowering.

    Variation in plastic responses to light results from selection in different competitive environments-A game theoretical approach using virtual plants
    Bongers, Franca J. ; Douma, Jacob C. ; Iwasa, Yoh ; Pierik, Ronald ; Evers, Jochem B. ; Anten, Niels P.R. - \ 2019
    PLoS Computational Biology 15 (2019)8. - ISSN 1553-734X - p. e1007253 - e1007253.

    Phenotypic plasticity is a vital strategy for plants to deal with changing conditions by inducing phenotypes favourable in different environments. Understanding how natural selection acts on variation in phenotypic plasticity in plants is therefore a central question in ecology, but is often ignored in modelling studies. Here we present a new modelling approach that allows for the analysis of selection for variation in phenotypic plasticity as a response strategy. We assess selection for shade avoidance strategies of Arabidopsis thaliana in response to future neighbour shading signalled through a decrease in red:far-red (R:FR) ratio. For this, we used a spatially explicit 3D virtual plant model that simulates individual Arabidopsis plants competing for light in different planting densities. Plant structure and growth were determined by the organ-specific interactions with the light environment created by the vegetation structure itself. Shade avoidance plastic responses were defined by a plastic response curve relating petiole elongation and lamina growth to R:FR perceived locally. Different plasticity strategies were represented by different shapes of the response curve that expressed different levels of R:FR sensitivity. Our analyses show that the shape of the selected shade avoidance strategy varies with planting density. At higher planting densities, more sensitive response curves are selected for than at lower densities. In addition, the balance between lamina and petiole responses influences the sensitivity of the response curves selected for. Combining computational virtual plant modelling with a game theoretical analysis represents a new step towards analysing how natural selection could have acted upon variation in shade avoidance as a response strategy, which can be linked to genetic variation and underlying physiological processes.

    Plant slaat alarm met geur
    Douma, J.C. - \ 2019
    Planten communiceren via geurstoffen, kunnen we die boodschap kraken?
    Douma, J.C. - \ 2019
    Wageningen : Wageningen University & Research
    What makes a volatile organic compound a reliable indicator of insect herbivory?
    Douma, Jacob C. ; Ganzeveld, Laurens N. ; Unsicker, Sybille B. ; Boeckler, Andreas ; Dicke, Marcel - \ 2019
    Plant, Cell & Environment 42 (2019)12. - ISSN 0140-7791 - p. 3308 - 3325.
    biogenic volatile organic compound (BVOC) - emission - herbivore induced plant volatile (HIPV) - hydroxyl radical - nitrate radical - oxidation - ozone - Populus nigra

    Plants that are subject to insect herbivory emit a blend of so-called herbivore-induced plant volatiles (HIPVs), of which only a few serve as cues for the carnivorous enemies to locate their host. We lack understanding which HIPVs are reliable indicators of insect herbivory. Here, we take a modelling approach to elucidate which physicochemical and physiological properties contribute to the information value of a HIPV. A leaf-level HIPV synthesis and emission model is developed and parameterized to poplar. Next, HIPV concentrations within the canopy are inferred as a function of dispersion, transport and chemical degradation of the compounds. We show that the ability of HIPVs to reveal herbivory varies from almost perfect to no better than chance and interacts with canopy conditions. Model predictions matched well with leaf-emission measurements and field and laboratory assays. The chemical class a compound belongs to predicted the signalling ability of a compound only to a minor extent, whereas compound characteristics such as its reaction rate with atmospheric oxidants, biosynthesis rate upon herbivory and volatility were much more important predictors. This study shows the power of merging fields of plant–insect interactions and atmospheric chemistry research to increase our understanding of the ecological significance of HIPVs.

    Analysing continuous proportions in ecology and evolution: A practical introduction to beta and Dirichlet regression
    Douma, Jacob C. ; Weedon, James T. - \ 2019
    Methods in Ecology and Evolution 10 (2019)9. - ISSN 2041-210X - p. 1412 - 1430.
    beta regression - Dirichlet regression - fractions - non-count proportions - one augmented - proportions - transformations - zero augmented

    Proportional data, in which response variables are expressed as percentages or fractions of a whole, are analysed in many subfields of ecology and evolution. The scale-independence of proportions makes them appropriate to analyse many biological phenomena, but statistical analyses are not straightforward, since proportions can only take values from zero to one and their variance is usually not constant across the range of the predictor. Transformations to overcome these problems are often applied, but can lead to biased estimates and difficulties in interpretation. In this paper, we provide an overview of the different types of proportional data and discuss the different analysis strategies available. In particular, we review and discuss the use of promising, but little used, techniques for analysing continuous (also called non-count-based or non-binomial) proportions (e.g. percent cover, fraction time spent on an activity): beta and Dirichlet regression, and some of their most important extensions. A major distinction can be made between proportions arising from counts and those arising from continuous measurements. For proportions consisting of two categories, count-based data are best analysed using well-developed techniques such as logistic regression, while continuous proportions can be analysed with beta regression models. In the case of >2 categories, multinomial logistic regression or Dirichlet regression can be applied. Both beta and Dirichlet regression techniques model proportions at their original scale, which makes statistical inference more straightforward and produce less biased estimates relative to transformation-based solutions. Extensions to beta regression, such as models for variable dispersion, zero-one augmented data and mixed effects designs have been developed and are reviewed and applied to case studies. Finally, we briefly discuss some issues regarding model fitting, inference, and reporting that are particularly relevant to beta and Dirichlet regression. Beta regression and Dirichlet regression overcome some problems inherent in applying classic statistical approaches to proportional data. To facilitate the adoption of these techniques by practitioners in ecology and evolution, we present detailed, annotated demonstration scripts covering all variations of beta and Dirichlet regression discussed in the article, implemented in the freely available language for statistical computing, r.

    ‘Beperkte scope’ natuurlijke vijanden vraagt om geïntegreerde actie. Positieve neveneffecten breedwerkende groene middelen.
    Messelink, G.J. ; Douma, Jenette - \ 2019
    Ecological significance of light quality in optimizing plant defence
    Douma, Jacob C. ; Vries, Jorad de; Poelman, Erik H. ; Dicke, Marcel ; Anten, Niels P.R. ; Evers, Jochem B. - \ 2019
    Plant, Cell & Environment 42 (2019)3. - ISSN 0140-7791 - p. 1065 - 1077.
    Brassica nigra - competition - functional–structural plant modelling - growth-defence trade-off - herbivory - plant defence - red to far-red ratio - shade avoidance

    Plants balance the allocation of resources between growth and defence to optimize fitness in a competitive environment. Perception of neighbour-detection cues, such as a low ratio of red to far-red (R:FR) radiation, activates a suite of shade-avoidance responses that include stem elongation and upward leaf movement, whilst simultaneously downregulating defence. This downregulation is hypothesized to benefit the plant either by mediating the growth-defence balance in favour of growth in high plant densities or, alternatively, by mediating defence of individual leaves such that those most photosynthetically productive are best protected. To test these hypotheses, we used a 3D functional–structural plant model of Brassica nigra that mechanistically simulates the interactions between plant architecture, herbivory, and the light environment. Our results show that plant-level defence expression is a strong determinant of plant fitness and that leaf-level defence mediation by R:FR can provide a fitness benefit in high densities. However, optimal plant-level defence expression does not decrease monotonically with plant density, indicating that R:FR mediation of defence alone is not enough to optimize defence between densities. Therefore, assessing the ecological significance of R:FR-mediated defence is paramount to better understand the evolution of this physiological linkage and its implications for crop breeding.

    Touch and plant defence : volatile communication with neighbours
    Douma, Jacob C. ; Anten, Niels P.R. - \ 2019
    Journal of Experimental Botany 70 (2019)2. - ISSN 0022-0957 - p. 371 - 374.
    Plants use many cues to get the latest news on their environment, from different parts of the light spectrum predicting future shading by neighbours, to volatiles released by insect-infested plants preparing neighbouring plants for future attack, or touch providing information about impending mechanical stress or herbivore attacks. Markovic et al. (2019) have now shown that gentle touching of leaves leads to emission of volatiles that can activate the same set of defence genes in neighbouring plants as were up-regulated in the touched plant.
    Legacy effects of diversity in space and time driven by winter cover crop biomass and nitrogen concentration
    Barel, J.M. ; Kuijper, T.W.M. ; Boer, W. de; Douma, Bob ; Deyn, G.B. de - \ 2018
    Journal of Applied Ecology 55 (2018)1. - ISSN 0021-8901 - p. 299 - 310.
    1. Plant diversity can increase nitrogen cycling and decrease soil-borne pests, which are feedback mechanisms influencing subsequent plant growth. The relative strength of these mechanisms is unclear, as is the influence of preceding plant quantity and quality. Here, we studied how plant diversity in space and time influences subsequent crop growth.
    2. During 2 years, we rotated two main crops (Avena sativa, Cichorium endivia) with four winter cover crop (WCC) species in monocultures and mixtures. We hypothesized that, relative to monocultures, WCC mixtures promote WCC biomass (quantity) and nitrogen concentration (quality), soil mineral nitrogen, soil organic matter, and reduce plant-feeding nematode abundance. Additionally, we predicted that preceding crops modified WCC legacies. By structural equation modelling (SEM), we tested the relative importance of WCC shoot biomass and nitrogen concentration on succeeding crop productivity directly and indirectly via nitrogen cycling and root-feeding nematode abundance.
    3. WCC shoot biomass, soil properties and succeeding Avena productivity were affected by first-season cropping, whereas subsequent Cichorium only responded to the WCC treatments. WCC mixtures’ productivity and nitrogen concentration showed over- and under-yielding, depending on mixture composition. Soil nitrogen and nematode abundance did not display WCC mixture effects. Soil organic matter was lower than expected after Raphanus sativus + Vicia sativa mixture. Subsequent Avena productivity depended upon mixture composition, whereas final Cichorium productivity was unresponsive to WCC mixtures. SEM indicated that WCC legacy effects on subsequent Avena (R2 = 0.52) and Cichorium (R2 = 0.59) productivity were driven by WCC biomass and nitrogen concentration, although not by the quantified soil properties.
    4. Synthesis and applications. Through understanding plant–soil feedback, legacy effects of plant species and species mixtures can be employed for sustainable management of agro-ecosystems. Biomass and nitrogen concentration of plants returned to the soil stimulate subsequent plant productivity. Winter cover crop quantity and quality are both manipulable with mixtures. The specificity of spatial and temporal diversity effects warrants consideration of plant species choice in mixtures and rotations for optimal employment of beneficial legacy effects.
    Data from: Legacy effects of diversity in space and time driven by winter cover crop biomass and nitrogen concentration
    Barel, J.M. ; Kuijper, T.W.M. ; Boer, W. de; Douma, J.C. ; Deyn, G.B. de - \ 2017
    crop rotation - soil oranic matter - soil mineral nitrogen - plant-feeding nematodes - plant-soil feedback - plant productivity - agroecology - winter cover crops - agriculture - plant diversity - Avena sativa - Cichorium endivia - Lolium perenne - Trifolium repens - Raphanus sativus - Vicia sativa
    Plant diversity can increase nitrogen cycling and decrease soil-borne pests, which are feedback mechanisms influencing subsequent plant growth. The relative strength of these mechanisms is unclear, as is the influence of preceding plant quantity and quality. Here, we studied how plant diversity in space and time influences subsequent crop growth. During 2 years, we rotated two main crops (Avena sativa, Cichorium endivia) with four winter cover crop (WCC) species in monocultures and mixtures. We hypothesized that, relative to monocultures, WCC mixtures promote WCC biomass (quantity) and nitrogen concentration (quality), soil mineral nitrogen, soil organic matter, and reduce plant-feeding nematode abundance. Additionally, we predicted that preceding crops modified WCC legacies. By structural equation modelling (SEM), we tested the relative importance of WCC shoot biomass and nitrogen concentration on succeeding crop productivity directly and indirectly via nitrogen cycling and root-feeding nematode abundance. WCC shoot biomass, soil properties and succeeding Avena productivity were affected by first-season cropping, whereas subsequent Cichorium only responded to the WCC treatments. WCC mixtures’ productivity and nitrogen concentration showed over- and under-yielding, depending on mixture composition. Soil nitrogen and nematode abundance did not display WCC mixture effects. Soil organic matter was lower than expected after Raphanus sativus + Vicia sativa mixture. Subsequent Avena productivity depended upon mixture composition, whereas final Cichorium productivity was unresponsive to WCC mixtures. SEM indicated that WCC legacy effects on subsequent Avena (R2 = 0.52) and Cichorium (R2 = 0.59) productivity were driven by WCC biomass and nitrogen concentration, although not by the quantified soil properties. Synthesis and applications. Through understanding plant–soil feedback, legacy effects of plant species and species mixtures can be employed for sustainable management of agro-ecosystems. Biomass and nitrogen concentration of plants returned to the soil stimulate subsequent plant productivity. Winter cover crop quantity and quality are both manipulable with mixtures. The specificity of spatial and temporal diversity effects warrants consideration of plant species choice in mixtures and rotations for optimal employment of beneficial legacy effects.
    Grain legume cultivation and children’s dietary diversity in smallholder farming households in rural Ghana and Kenya
    Jager, I. de; Abizari, Abdul Razak ; Douma, J.C. ; Giller, K.E. ; Brouwer, I.D. - \ 2017
    Grain legume cultivation and children’s dietary diversity in smallholder farming households in rural Ghana and Kenya
    Jager, I. de; Abizari, Abdul Razak ; Douma, J.C. ; Giller, K.E. ; Brouwer, I.D. - \ 2017
    In: Abstracts: IUNS21st International Congress of Nutrition. - Karger (Annals of Nutrition & Metabolism suppl 2) - ISBN 9783318061925 - p. 1319 - 1319.
    Grain legume cultivation and children’s dietary diversity in smallholder farming households in rural Ghana and Kenya
    Jager, Ilse de; Abizari, Abdul Razak ; Douma, Jacob C. ; Giller, Ken E. ; Brouwer, Inge D. - \ 2017
    Food Security 9 (2017)5. - ISSN 1876-4517 - p. 1053 - 1071.
    Children - Dietary diversity - Ghana - Kenya - Legume production - SEM analysis
    Boosting smallholder food production can potentially improve children’s nutrition in rural Sub-Saharan Africa through a production-own consumption pathway and an income-food purchase pathway. Rigorously designed studies are needed to provide evidence for nutrition impact, but are often difficult to implement in agricultural projects. Within the framework of a large agricultural development project supporting legume production (N2Africa), we studied the potential to improve children’s dietary diversity by comparing N2Africa and non-N2Africa households in a cross-sectional quasi-experimental design, followed by structural equation modelling (SEM) and focus group discussions in rural Ghana and Kenya. Comparing N2Africa and non-N2Africa households, we found that participating in N2Africa was not associated with improved dietary diversity of children. However, for soybean, SEM indicated a relatively good fit to the posteriori model in Kenya but not in Ghana, and in Kenya only the production-own consumption pathway was fully supported, with no effect through the income-food purchase pathway. Results are possibly related to differences in the food environment between the two countries, related to attribution of positive characteristics to soybean, the variety of local soybean-based dishes, being a new crop or not, women’s involvement in soybean cultivation, the presence of markets, and being treated as a food or cash crop. These findings confirm the importance of the food environment for translation of enhanced crop production into improved human nutrition. This study also shows that in a situation where rigorous study designs cannot be implemented, SEM is a useful option to analyse whether agriculture projects have the potential to improve nutrition.
    When does it pay off to prime for defense? A modeling analysis
    Douma, Jacob C. ; Vermeulen, Peter J. ; Poelman, Erik H. ; Dicke, Marcel ; Anten, Niels P.R. - \ 2017
    New Phytologist 216 (2017)3. - ISSN 0028-646X - p. 782 - 797.
    Community - Fitness - Insect herbivory - Plant competition - Priming - Volatiles
    Plants can prepare for future herbivore attack through a process called priming. Primed plants respond more strongly and/or faster to insect attack succeeding the priming event than nonprimed plants, while the energetic costs of priming are relatively low. To better understand the evolution of priming, we developed a simulation model, partly parameterized for Brassica nigra plants, to explore how the fitness benefits of priming change when plants are grown in different biotic environments. Model simulations showed that herbivore dynamics (arrival probability, arrival time, and feeding rate) affect the optimal duration, the optimal investment and the fitness benefits of priming. Competition for light increases the indirect costs of priming, but may also result in a larger payoff when the nonprimed plant experiences substantial leaf losses. This modeling approach identified some important knowledge gaps: herbivore arrival rates on individual plants are rarely reported but they shape the optimal duration of priming, and it would pay off if the likelihood, severity and timing of the attack could be discerned from the priming cue, but it is unknown if plants can do so. In addition, the model generated some testable predictions, for example that the sensitivity to the priming cue decreases with plant age.
    Semi-natural habitats support biological control, pollination and soil conservation in Europe. A review
    Holland, John M. ; Douma, Jacob C. ; Crowley, Liam ; James, Laura ; Kor, Laura ; Stevenson, David R.W. ; Smith, Barbara M. - \ 2017
    Agronomy for Sustainable Development 37 (2017)4. - ISSN 1774-0746
    Agricultural policy - Agricultural research - Agroecology - Ecosystem services - Experimental design - Integrated pest management - Pollinators - Sustainable agriculture
    Semi-natural habitats are integral to most agricultural areas and have the potential to support ecosystem services, especially biological control and pollination by supplying resources for the invertebrates providing these services and for soil conservation by preventing erosion and run-off. Some habitats are supported through agri-environment scheme funding in the European Union, but their value for ecosystem service delivery has been questioned. An improved understanding of previous research approaches and outcomes will contribute to the development of more sustainable farming systems, improve experimental designs and highlight knowledge gaps especially for funders and researchers. Here we compiled a systematic map to allow for the first time a review of the quantity of evidence collected in Europe that semi-natural habitats support biological control, pollination and soil conservation. A literature search selected 2252 publications, and, following review, 270 met the inclusion criteria and were entered into the database. Most publications were of pest control (143 publications) with less on pollination (78 publications) or soil-related aspects (31). For pest control and pollination, most publications reported a positive effect of semi-natural habitats. There were weaknesses in the evidence base though because of bias in study location and the crops, whilst metrics (e.g. yield) valued by end users were seldom measured. Hedgerows, woodland and grassland were the most heavily investigated semi-natural habitats, and the wider landscape composition was often considered. Study designs varied considerably yet only 24% included controls or involved manipulation of semi-natural habitats. Service providers were commonly measured and used as a surrogate for ecosystem service delivery. Key messages for policymakers and funders are that they should encourage research that includes more metrics required by end users, be prepared to fund longer-term studies (61% were of only 1-year duration) and investigate the role of soils within semi-natural habitats in delivering ecosystem services.
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