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CEBC-Chizé, 22nd to 24th March 2017 Abstracts Session 1: 22nd March 2017 – 1:45pm – 4:00pm An indicator of the pollination service at a local scale based on crop pollinator dependence Gabrielle Martin*, Colin Fontaine, Emmanuelle Porcher Centre d'Ecologie et des Sciences de la Conservation CESCO-MNHN, Paris The developments of new farming methods since the 60s have increased agricultural productivity (Tilman et al. 2002). However, one major downside of agricultural intensification is a loss of biodiversity in agroecosystems, among which pollinators (Biesmeijer et al. 2006; Potts et al. 2010; Garibaldi et al. 2011). Nowadays, 35 % of global crop production for human food derive from crops that depend to some extent on pollination services (Klein et al. 2007) and 3-8 % of world crop production could be lost in the absence of pollinators (Aizen et al. 2009). Deguines et al. (2014) found that benefits of agricultural intensification decrease with increasing pollinator dependence, to the extent that intensification failed to increase yield of pollinator-dependant crops and decreased stability of yield over time. Consequently, benefits from agricultural intensification may be offset by reductions in pollination services. At present, there is no consensus about an indicator of pollination service to measure this phenomenon. In this study, we define direct, nationwide measures of pollination effectiveness and stability of the major crops in France according to their dependence on insect pollinators and compare them with the Relative Pollination Potential (Zulian et al. 2013). We used a dataset reporting the yield of 56 major crops between 2000 and 2010, at a departmental scale in France and combined it with information on crop pollinator dependence to produce two measures related to pollination based on mean yield and on yield variability. These measures are used to map pollination efficiency for the first time in France. Experimental assessment of insect pollination on rapeseed yield and oil quality in farmer’s field demonstrates positive effect of pollinator richness Thomas Perrot*, Sabrina Gaba, Jean-Luc Gautier, Marylin Roncoroni, Alexis Saintilan, Antony Stoquert, Thierry FanjasMercère & Vincent Bretagnolle Agroécologie, AgroSup Dijon, INRA, Univ. Bourgogne Franche-Comté, FR-21000 Dijon ; CEBC – CNRS, Chizé Pollination is an ecosystem service on which humans depends through its link to food production. Some crops, e.g. oilseed rape (Brassica napus L.), are pollinated by a broad range of insects such as by honeybees, wild bees, and hoverflies. According to experimental studies, oilseeds rape production can be increased by 10-50% by insect pollination, however these results are often obtained by comparison between presence-absence of pollinators not with pollinators gradients. Moreover, no study has investigated the effect of pollinators on the oil’s fatty acid composition while rapeseed is cultivated for oil. Here, we quantified the contribution of insect pollination on rapeseed production in terms of yield and oil quality in real farmers’ fields. We selected 352 rapeseeds plants into 73 fields in 3 consecutive years along a gradient of landscape to investigated effect of pollinators on yield and oil seed composition. In addition, 93 fields are followed by farmer’s survey to confirm effect of pollinators at field level. On each plant, we quantified total seed mass and oil composition on one control branch and one branch where pollinators were excluded using bags. Comparison between these two branch permit to estimate insect contribution. Abundance and richness of pollinator’s species in landscape are quantified by pan-traps. We show insect contribution to yield is to 27% and increase with pollinators richness whatever at the plant or field level. Pollinator’s richness also increases quality of the production by decreasing saturated acid in oil. This study confirms the crucial role of pollinator’s diversity in crop production. CEBC-Chizé, 22nd to 24th March 2017 Flowers and insects of managed field strips in Belgium: flower resources, flower-insect interactions and temporal considerations. Pierre Ouvrard*, Anne-Laure Jacquemart GENA-POP, UC Louvain Pollinator decrease is of concern for biodiversity conservation and crop production. In Europe, several agri-environmental schemes (AES) are proposed to support flower visitors. Increasing areas are devoted to these schemes. Nevertheless, their role and importance in pollinator support remain unknown. Our aim was to study the quantity and composition of floral resources (pollen and nectar) and the diversity and abundance of flower visitors for a particular Belgian AES, the flowered strips. To analyse plant-pollinator networks, we performed the observations during two years, in 4 sites. Blossom periods were concentrated on June, July and August (87% of observed floral units) with 4 main species (Daucus carota, Lotus corniculatus, Medicago sativa and Trifolium repens). Two sown species (Medicago lupulina and Silene x hampeana) were nearly not visited (0 to 3 records). Main visitors belonged to 3 groups: bumblebees (31% of B. lapidarius OTU), honeybees (17%) and diverse Diptera (19%). On the 52 flowering species, Centaurea jacea received 53% of insect visits while 22% of visits were distributed over 25 other plant species. Floral resources greatly differed among the visited species as nectar production varied from less than 0.5 to 2700 µg of sugar/day/floral unit and pollen from 0.01 to 16 µl of pollen/day/floral unit. In conclusion, floral resources are provided to common insect species by the flowered strips in summer by both sown and spontaneous unsown species. Combine pesticide reduction and intercropping to optimize functional biodiversity in agroecosystems. Catherine Souty-Grosset, Marion Poussin, Julia Clause*, Nathalie Pourtau, Laurence Maurousset Laboratoire Ecologie et Biologie des Interactions – CNRS, Poitiers Using sustainable farming practices is encouraged by the French government to decrease the use of pesticides and their associated damages on ecosystems and on food security. For example, intercropping, i.e. simultaneously growing two or more crop types on one field, is commonly used in low-input cropping systems. The different crop types benefit each other through their complementary use of natural resources such as light, moisture or soil nutrients, their competition with weeds, and by favouring a diversity of crop auxiliaries that control pests. We collaborated with a local network of organic farmers to assess the impact of intercropping cereals and legumes on soil macrofauna (carabids, terrestrial isopods, earthworms) and on associated ecosystem services. A higher richness of carabid species was found in the intercropping plots than in the pure stands. Results for species diversity varied with plots. Overall, zoophagous carabid species -acting as biocontrols of insect pest- were strongly associated with weed species whereas phytophagous carabid species was associated with crop species. A higher richness and diversity of woodlice -acting on litter decomposition and in turn organic matter mineralization- was found in intercropping plots than in pure stands. Additionally, we measured the performances (proteins, starch and sugar contents) of faba beans grown in intercropping with different densities of cereals. Faba beans performed best under low cropping density and were less sensitive to diseases in intercropping than in pure stands. Data are still being analyzed to link results of macrofauna, plant performances, weed densities, soil properties, abiotic factors and yield. CEBC-Chizé, 22nd to 24th March 2017 Coming faster in an intensive agricultural landscape: impact of the surrounding on garden bird’s visits Pauline Pierret*; Benoît Fontaîne, Frédéric Jiguet CESCO (Centre for Ecology and Conservation Sciences) –MNHN, Paris The link between agricultural changes and bird population declines is well documented and investigations often focused on reproductive success. However, few studies investigated on survival and especially on winter although changes in practices make winter bird survival even harder, chiefly for seed-eating passerines, by reducing seed availability. Nevertheless, more and more people supply birds with food in their gardens so we expect those gardens to play a major role in maintaining populations by acting as havens, notably in an intensive landscape. Using for the first time the French Garden Birds program (a national citizen science program), we crossed bird winter counts with an agricultural intensity indicator (the Input Cost per hectare index - “IC/ha”) to study the link between the coming of birds in gardens and the intensification of surrounding landscape. We found differences in phenology of visiting. In fact, the arrival of birds in gardens is faster in intensive landscapes. Furthermore, we found an interaction between the species degree of dependence to agricultural landscape and the IC/ha indicator. The arriving in intensive landscape is even faster for the more dependent birds. As some seed-eaters were recently placed on the French IUCN Red List of species of conservation concern, these results provide a glimpse of hope by suggesting that food supply, in winter in gardens, is not only a recreational activity but attracts seed-eaters and could help to improve their survival during the cold season, chiefly in an intensive landscape. Conflict of interests in the use of the ecosystem services of Patagonian meadows: grazing vs. carbon sequestration and nutrient retention. Enriquez Andrea Soledad*, María Victoria Cremona. “Soil and Water” of Instituto Nacional de Tecnología Agropecuaria (INTA), Argentina. Efforts to address climate change problems and to alleviate poverty are increasing globally. Changing land use and management practices to store and sequester carbon and nutrients is one of the key ways of addressing these issues. For this work, we studied the changes in carbon and nitrogen in Northern Patagonian meadows due to long-term overgrazing. These ecosystems provide key natural resources for the development and sustainability of rural environments in drylands. Due to a combination of weather conditions and misleading management strategies over more than one hundred years, around 30% of the Patagonian meadows are in different states of degradation. Our results show that long-term overgrazing has led to an overall reduction of 35 % of the total ecosystem carbon pool: less than 24% in above ground plant biomass, less than 52% below ground biomass, and less than 56% in soil. We also found an overall reduction of 43% in total nitrogen, and of 57% in ammonium. As carbon dioxide net ecosystem exchanges were always positive throughout the year, plant decomposition rates did not significantly vary or decreased, carbon and nitrogen contents remain high. We suggest that Patagonian meadows are able to resist moderate grazing intensities. However, because of related social and economic challenges associated with carbon sequestration projects, a more interdisciplinary work is needed to maintain ecosystem service benefits (including biodiversity and water management). Sustainable carbonfriendly land management along with poverty alleviation strategies are especially needed in the driest areas. CEBC-Chizé, 22nd to 24th March 2017 Session 2: 22nd March 2017 – 4:30pm – 18:00pm Importance of ground refuges for the biodiversity in agricultural hedgerows Lecq S., Loisel A., Brischoux F., Mullin S.J, Bonnet X. LETG - Université d’Angers In most agro-ecosystems, hedgerows provide important habitat for many species. Unfortunately, large scale destruction of hedges has stripped this structure from many landscapes. Replanting programs have attempted to restore hedgerow habitats, but the methods employed often fail to replace the unique microhabitats (complex matrix of stones, logs and roots found along the base of the hedge) that provided key refuges to an array of animal species. We examined the influence of ground refuges on animal diversity in an agricultural landscape. We used non-lethal rapid biodiversity assessments to sample invertebrate and vertebrate taxa in 69 hedges having different levels of herbaceous cover, tree cover, and refuge availability. We used co-inertia analyses to compare hedge characteristics with the animal biodiversity sampled. We also used a functional index (accounting for body mass, trophic level, and metabolic mode of the species sampled) to compare hedges. In addition, large sedentary predators (e.g. snakes) were used as indicators of shelter presence/quality and as bio-indicators of food web structures. Finally we used unbiased Chao-estimates to evaluate species richness. All results were convergent and show that complexity of the base of the hedge (e.g., bank size and stone abundance) positively influenced biodiversity and predator abundance. Guidelines to restore hedgerows should integrate refuges that can be constructed by retaining the materials that are extracted during the planting of the hedges. Estimating colonization and dormancy in weeds dynamics from standing flora occurrence observations Sebastian Le Coz, Matthieu Pluntz, Nathalie Peyrard, Pierre-Olivier Cheptou MIAT – INRA Toulouse, CEFE – CNRS Montpellier Estimating plants dynamics in the field is challenging because of the seed bank's unkown state. Recently Hidden Markov Models (HMM) have been proposed to model the joint dynamics of seed bank and standing flora while having abundance observations of standing flora. We go one step further and estimate parameters of plant dynamics from binary observations. The HMM model and the estimation methods are generic and can be applied to any annual plant species. A fully automatic classification procedure is then proposed to identify functional groups from the estimated parameters provided by the HMM. The approach has been used to analyze weeds' dynamics for different crop types. We used a unique data base from the Biovigilance project. The method classifies species with respect to their germination rate for different crop types. We obtained consistence between functional groups identified from the classification and biological knowledge of the weed species germination. This approach may result in a better weed species management. It can also be applied to any plant community where the seed bank's state is uncertain. CEBC-Chizé, 22nd to 24th March 2017 Do anticoagulant rodenticides affect the seasonal population dynamics of small mustelids? Fernandez-de-Simon, J.*, Coeurdassier, M., Lambin, X., Giraudoux, P. Laboratoire Chrono-environnement - UBFC-CNRS, Besançon Prey controlled with pesticides can indirectly poison predators. However, pesticides’ effects on predator dynamics has not been well documented. Temporal variations of small mustelid (weasels, stoats) abundance follow those of voles, their main prey. Grassland voles show population cycles, damaging pastures/hay fields. Some farmers control voles using anticoagulant rodenticides (ARs), poisoning non-target species feeding on intoxicated voles, like small mustelids. Whether this impacts their populations is not well known. Here, we study whether bromadiolone (an AR) affects small mustelid populations. Our hypothesis was that ARs decrease small mustelid abundance (SMA) by direct killing/prey declines. Using data of bromadiolone use (2008-2016), we selected 6 sites with no/very low treatment frequency, and 4 with high frequency. We estimated SMA, water vole (WVD) and common vole (CVD) densities in spring and autumn 2016, treatment periods. We estimated the abundance of foxes (FA) as small mustelids’ superpredators. We calculated the seasonal population change (SPC) of small mustelids as SPC = Ln (autumn SMA/spring SMA). SPC was modelled against bromadiolone treatments and other species’ abundance. All sites with high bromadiolone use showed negative SPC i.e. decreases in population abundance (mean SPC high bromadiolone use= -4.52, mean SPC no/low bromadiolone use= 0.4). Additionally, SPC was positively associated to WVD. Small mustelid abundance decreased at low water vole density but at higher water vole densities small mustelid abundance remained stable i.e. SPC close to 0. Finally, SPC was not related to the other variables (CVD, FA). Results point out that ARs may affect small mustelid population dynamics. Land-sea nutrient transfer to the Mediterranean Sea Augueres A.S.*, Barrier N., Fader M., Shi S., Bondeau A., Cramer W. Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale, Aix-en-Provence Key nutrients such as nitrogen, phosphorus and carbon are increasingly supplied to ecosystems due to anthropogenic activities, as agriculture and wastewater release. Part of these nutrients added to soils and rivers will ultimately flow to the sea, inducing important changes in the functioning of marine ecosystems. The Mediterranean region, characterized by an important agricultural activity and a wide range of socioeconomic status, is heavily subject to land use change due to population growth, urbanization and increasing food production. The objective of our study is to assess, and possibly predict, the amount of nutrients retained through the aquatic continuum and to quantify the part that is effectively transferred to the Mediterranean Sea. We thus developed a model describing the land to sea transfer of nitrogen and phosphorus from agricultural systems and cities to the Mediterranean Sea. Our model is then included in the LPJmL model, which describes the transient changes in carbon and water cycles due to land use change. Our model highlights the river catchments with the highest load of nutrients, as well as the main processes involved in each watershed. Our results could then be used to drive management decisions towards the most effective way to reduce nutrient loads in the Mediterranean region. CEBC-Chizé, 22nd to 24th March 2017 Interaction between biological control and pollination: An eco-evolutionary approach of ecosystemic services and implementation in designing tools for agro-landscape management Antoine Le Gal*, Jane Lecomte, Muriel Tichit ESE - Univ. Paris-Sud & SAD-APT – INRA, Paris Agriculture is a crucial activity for human societies whereas socio-agroecosystems faces some challenges. Agroecology is a scientific discipline (in addition of a movement or a set of practices, according to the various definitions) which tries to deal with these challenges, taking account of the impacts of agriculture on biodiversity and ecosystems, but also trying to manage ecosystem services given by biodiversity. Two important challenges are 1) dealing with pests in a sustainable way and 2) stopping the decline of pollinisators. Indeed, biological control and pollination are two crucial regulating services for agroecosystem’s management and moreover, they sould be produced conjointly whereas we can imagine that tradeoff could also occur. Landscape and local management of semi-natural habitats have been implemented to manage the both services and results show some consequences on the populations of natural enemies, pests and pollinators. However, these results are still mixed, even when we consider a single service. We can invoke various hypothesis to explain these mixed results, and I chose to consider the potential interactions between the two services through the interactions between species into a community network in agroecosystems. Considering the framework of the “trophic chain” in Conservation Biological Control (CBC), I want to understand the possible consequences of adding mutualistic interactions through the relationship between plants and pollinators, in terms of ecological consequences (direct and indirect effects) and eco-evolutionnary consequences. In addition I would like to expand my model to the landscape scale in order to understand the influence of the landscape management and how to take account of these insights into public policy tools for that purpose. Spatially explicit modelling of regulating services for evaluation of their levels and trade-offs; exploration of concerted management strategies of agricultural territories through different scenarios. Nirina Ratsimba*, Aude Vialatte, Claude Monteil, Olivier Thérond DYNAFOR (Dynamiques et Ecologie des Paysages Agriforestiers) – INRA, Toulouse In agroecosystems, biodiversity-supported regulating services include many ecological and social components interacting with each other; several guilds can be involved in the delivery of a single service, and a single guild can contribute to several services. Habitats on which guilds directly depend are managed by multiple stakeholders. Understanding dynamics, trade-offs, complementarities or even synergies between those services is a challenge in itself: in order to support the development of an agroecological production, is it possible to suggest agricultural management modalities that benefit several services or do social compromises need to be considered? In the latter case, at which spatiotemporal scale? The thesis aims to develop a spatial model of regulating services in agricultural landscapes over seasons and years, according to different scenarios of agricultural management. The approach consists in coupling 2 actions. First, a bibliographic analysis will be conducted on the effects of spatial and temporal habitat heterogeneity in agricultural landscapes on regulating services and their interactions (focusing on top-down and bottom-up biological controls and pollination). Second, a spatial modelling of regulating services will be implemented in the multi-agent platform MAELIA which simulates landscape dynamics. Furthermore, the study will benefit from data provided by the experimental evaluation of the crop fields’ capacity to sustain the regulating services by supplying several resources to beneficial species (SEcoMod project). CEBC-Chizé, 22nd to 24th March 2017 Consequences of vineyard practices on Arthropods biodiversity in the region of Correns (Var, France) Chloé BLAISE*, Philippe PONEL, Julie BRASCHI Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale, Aix-en-Provence Viticulture covers less than 4% of the European Union agricultural area but it consumes more than 20% of the pesticides used in agriculture. Those phytosanitary products are often remanent in the environment and can affect the entire ecosystem, not just the target organisms. However, many taxa of arthropods play significant role in various ecosystem services, such as beneficial organisms recognized in biological control. They are also considered as bioindicators of healthy ecosystems. Since early 1980s, the municipality of Correns follows a sustainable management of its territory and became the "France's first organic village". The aim is to manage the Correns territory as a workshop site to monitor the consequences of organic agriculture on biodiversity. This study assesses the arthropod biodiversity of four agricultural practices, both in terms of specific and functional richness. The vineyard plots are sampled using pitfall traps for epigeal fauna and flight interception traps for flying insects. The method of Rapid Biodiversity Assessment is employed to assess the diversity of arthropods. Here we present the first results obtained during the 2016 sampling campaigns, suggesting different levels of biodiversity by management. Later, we plan to define bioindicator taxa related to vineyard management and identify their functional role in these agroecosystems. Effect of organic farming on arthropod pest abundance, disease pressure and natural pest control services in agrosystems: a meta-analysis. Muneret Lucile*, Djoudi El Aziz, Aviron Stéphanie, Pétillon Julien, Plantegenest Manuel, Thiéry Denis & Rusch Adrien Santé et Agroécologie du Vignoble, INRA & Université de Bordeaux ; Institut de Génétique, Environnement et Protection des Plantes, Rennes ; Biodiversité et Gestion des Territoires, Université de Rennes ; SAD-PAYSAGE, INRA Rennes Natural pest control is considered as a promising way to reduce pesticide use in agrosystems. Several studies have demonstrated that organic farming at the field scale enhances species richness and abundance of natural enemies. Due to an increase in natural enemy community diversity, higher levels of biological control are usually expected in organic farming. However, empirical studies about the effects of organic farming on natural pest control have shown contrasted results and no synthesis of this knowledge exists in the literature. Furthermore, previous studies indicated that insect pests might also benefit from organic farming suggesting complex relationships between farming practices, pest and natural enemy communities. In this study, we performed a meta-analysis investigating the effect of organic farming at the field scale on (i) weeds, (ii) arthropod pests, and (iii) pathogen infestation in different cropping systems as well as (iv) the level of natural pest control services. This study relies on a set of 126 published studies on (i) natural pest control (parasitism rates, predation rates) and (ii) pests or diseases pressure (incidence, severity, abundance, population dynamics) from studies that compare organic and conventional farming at the global scale. This ongoing work should provide new insights on the effects of farming systems on natural pest control services and pest communities in agroecosystems. Determinants of the reduction of herbicide use through Agricultural Environmental Schemes Auréliane Masson, Sabrina Gaba*, Elsa Martin Agroécologie, AgroSup Dijon, INRA, Univ. Bourgogne Franche-Comté, FR-21000 Dijon Several public policies have been set up at the regional, national and European levels to reduce the negative impacts of intensive agriculture. Here, we wonder what are the determinants – social, economic, etc. - of the reduction of herbicide use? We focus the determinants of farmers' adoption of agri-environmental schemes (AES). Many factors influence farmers’ adoption. First, the importance of farm incomes in total incomes have been shown to be negatively correlated to AES adoption. The same conclusion was observed with the total family time spent at work. A determinant which is important for the probability to contract is the total farm labour supply per year (family and non-family labour): the more workforce farmers already have, the more they contract. However, although several studies have investigated the determinant of AES adoption, others determinants such as the level of debts remain to be investigated. Moreover, determinants have generally been investigated independently without looking at social, economic and environmental motivations altogether. After conducting a literature review, we will therefore carry out an econometric analysis to evaluate the influence of a wide range of determinants based on survey questionnaire sent to farmers. In this presentation, we will present first results. CEBC-Chizé, 22nd to 24th March 2017 Session 3: 23nd March 2017 – 8:45am – 10:30am The stability of crop production: trade-offs in pollination-dependent agriculture Daniel Montoya*, Bart Haegeman, Sabrina Gaba, Claire de Mazancourt, Vincent Bretagnolle & Michel Loreau Agroécologie, AgroSup Dijon, INRA, Univ. Bourgogne Franche-Comté, FR-21000 Dijon ; CBTM, CNRS Moulis Historically, demand for increased crop production has been satisfied by agricultural practices that include land conversion into agricultural land and improvements in crop yield. The benefits of persisting in this approach are challenged by the existence of apparent yield plateaus for many major crops and of crop yield saturating responses to increasing levels of pesticides. Notably, despite the importance of yield stability and the empirical evidence that magnitude and stability of ecosystem functions do not necessarily co-vary positively, few studies on the stability of crop yield have been attempted. Here, we develop a model for crop yield dynamics in a spatially heterogeneous agricultural landscape to explore possible trade-offs between crop production (yield mean and stability) and biodiversity conservation (pollinators) in agroecosystems. We focus on how landscape composition (proportion of semi-natural habitat within the agricultural landscape) and crop pollination dependence shape these trade-offs and how they influence the mean and stability of pollinators, and that of crop yield. We find that agricultural practices impose trade-offs in pollinationdependent agriculture between provisioning and regulating/cultural services in agroecosystems, such as between crop area and semi-natural habitat for pollinator communities, which not only affect the production of crops, but also their stability. These trade-offs are conditioned by mechanisms associated with the pollinator dependence of crops, and the crop relative responsiveness. Agriculture has become more pollinator-dependent over time, and, in order to develop more efficient and sustainable management policies, it is essential to understand the mechanisms driving these tradeoffs. Reproductive success of a wild plant and bee abundance in grasslands are influenced by proportion and configuration of flowering oilseed rape in the landscape Colin Van Reeth*, Nadia Michel, Christian Bockstaller, Chloé Fournier & Gaël Caro Laboratoire Agronomie Environnement, INRA & Université de Lorraine Wild bees (Hymenoptera, Apoidea, Anthophila) are major pollinator of wild plants and crops. Evidences of bee decline urge scientists to focus on its causes in order to preserve bee diversity and to maintain the pollination service provided. Oilseed rape (OSR) provides a highly rewarding food resource for some species. Some scientists have thus proposed that OSR may lessen bee decline in agro-ecosystems. However, flowering OSR by attracting some pollinators may influence pollinator community and wild co-flowering plants in semi-natural habitats such as permanent grasslands. The aim of this study was to evaluate the influence of the proportion and configuration of flowering OSR in the landscape on the abundance of four pollinator groups and the reproductive success of a wild plant in permanent grasslands. During OSR blooming period, we captured 3 761 pollinators and evaluated the reproductive success of Cardamine pratensis in 22 permanent grasslands. Our results showed that proportion of OSR and, to a lesser extent, its aggregation influenced C. pratensis reproductive success and the abundance of honeybee, social Halictidae and solitary bees. Proportion of OSR in the landscape had positive effect on solitary and social Halictidae bee abundance, but a negative effect on honeybee abundance and C. pratensis reproductive success. OSR aggregation reduced honeybee and social Halictidae bee abundance, but enhanced solitary species abundance and C. pratensis reproductive success. Our results highlighted the risk represented by OSR for pollination success of co-flowering plants, and the necessity of considering both composition and configuration aspects to assess landscape influences on bees. CEBC-Chizé, 22nd to 24th March 2017 The effect of organic farming on honeybee colony performance Wintermantel D.*, Jean-François Odoux, Joël Chadoeuf & Vincent Bretagnolle CEBC-CNRS, Chizé Modern farming has been implicated in both biodiversity losses and pollinator declines. Particularly the decline of the European honeybee has raised concerns of farmers and beekeepers alike. Organic farming, a less intensive form of agriculture in which synthetic pesticides are banned, has been shown to benefit pollinators such as wild bees. However, it remains unclear whether honeybees benefit from organic farming, due to their distinct life history and foraging behavior. Several aspects of organic farming might be conducive to bees. For instance, bees might suffer fewer insecticide poisonings and have access to more diverse weeds due to the absence of synthetic herbicides or the large proportion of grassland in organic farms. Weeds are an important food resource for honeybees, particularly in the flower scarcity period between the blooms of mass-flowering rapeseed and sunflower. To test effects of farming practices on honeybee colonies, we monitored the performance of 50 colonies, which were placed each year in ten different locations of a 450km2 large study site with known land use. Food reserves, brood production and adult population size of these colonies, were recorded every two weeks during the beekeeping season. This enabled us to assess how honeybee colonies respond to a gradient of organic farmland at different spatial scales. We observed positive effects of organic farming during the flower scarcity period. Especially, honey reserves profited from organic farmland in a 500-2500 m radius. These results suggest organic farming may promote colony performance in a period critical to the survival of honeybee colonies. Agroforestry systems in Mediterranean protected landscapes: from individual decisions to collective arrangements Clara Therville*, Martine Antona UPR GREEN - CIRAD, Campus international de Baillarguet, Montpellier Among the diversity of agro-ecological practices that intend to reach both food production and environmental issues, agroforestry systems (AFS) have the specificity to integrate woody vegetation, crops and/or livestock on the same area of land. As such, AFS have a lasting impact on landscapes and are of interest as a boundary object between different spaces, temporalities and stakeholders. Here we explore how AFS reveals a diversity of social-ecological processes and their dynamics. We conducted interviews in two French Mediterranean protected areas with stakeholders concerned by AFS. We identified: i) the main AFS present in the protected areas as well as their dynamic and; ii) the stakeholders, institutional arrangements and policies involved for each type of AFS. We describe the diversity of AFS and the variety of stakeholders they involve, who have their own representations and interests and who need to cooperate for the management of shared AFS. We compare two contrasted landscapes: i) intensely used agricultural landscapes where AFS are promoted by environmental stakeholders to complexify landscapes and promote soil, water and biodiversity preservation; and ii) marginal mountainous areas where silvopastoral systems are affected both by fire prevention, forestry production and maintenance of open environments. In both cases, ongoing social-ecological changes call into question the arrangements implemented by stakeholders, inducing new challenges for the actors. In a third phase, participatory methods such as serious games could be useful to collectively explore the future of these systems, and beyond them, of these landscapes and territories. CEBC-Chizé, 22nd to 24th March 2017 Session 4: 23nd March 2017 – 11:00am – 12:30am Combining a population dynamic model to a crop model in order to investigate plant-herbivore interactions under a spatio-temporal context Romain Bertrand*, Guillaume Robaldo, Hélène Raynal, André Chanzy, Michel Loreau & Jean Clobert SETE – CNRS Moulis It is well established that animals and their habitats interact. Habitat impacts animal populations through environmental conditions (such as resource availability and microclimate) and landscape connectivity, while animals modify habitat conditions in return by consuming biomass for instance (in the case of a vegetation-herbivore system). However, current models mainly focus on the effect of habitat on animals considering that climate conditions are not changed by vegetation locally and/or inferring resource availability from punctual observations. Furthermore, models rarely account for the feedback effect of animals on habitat. Here, we present a simulation model aiming to investigate the plant-herbivore interactions in a more realistic and dynamic ways through the combination of an animal population dynamic model and a crop model. The population dynamic model is mechanistic, spatially explicit and semi-stochastic, and simulates the lifecycle of every individual (i.e. dispersion, survival and reproduction). It is fed at different dates by spatial layers of carrying capacity and habitat connectivity which summarized the habitat quality for the animal. Such habitat conditions are directly dependant on microclimatic conditions, soil occupancy, biomass production and agricultural treatments simulated by the crop model STICS at a daily frequency. In return, the size of the herbivore population in each spatial cell determines the crop biomass consumed across the study area which is used to correct the biomass values in the STICS model. The model is generic, and we illustrate the originality of such approach by applying the model to the context of an agricultural system invaded by an aphid species. Untangling the effects of local and landscape structure on pest predation by natural enemies in an intensive crop agroecosystem Camille Coux*, Adrien Rusch, Sabrina Gaba, Vincent Bretagnolle CEBC-CNRS, Chizé In agricultural crops, the use of biological control to reduce pest damages thanks to predation by natural enemies is an important ecosystem service. Unfortunately, the numerous mechanisms driving the efficiency of the predation function in agroecosystems are and often confounding. In this study, we investigated how local covariates and farming landscape structure affect predation rates of crop pest species in an intensive agricultural landscape in mid-west France. In 2016, predation rates of aphid and weed seeds of one species were quantified in a total of 120 fields, comprising four different types of crops as well as grasslands, selected along two landscape gradients: proportion of grassland in a 1 km radius and distance to the nearest grassland. We used an information-theoretic selection framework to test our hypotheses for several competing sets of models of increasing complexity. In addition to local effects linked to the experimental design and the focal plot, we included landscape metrics testing whether the predation rates within crops depended on the distance from the nearest grassland, which would suggest a dispersion-limited predation function, or if predation rates depended rather on the proportion of grasslands around the focal crop, following a spill-over dynamics from highly predated fields to less-predated ones. We found that predation rates varied across crop types, being maximal in grasslands and cereal crops, especially in smaller sized fields and organic farming systems, and that the predation dynamics in both aphids and weed seeds depended primarily on the distance and proportion of grasslands in the landscape. CEBC-Chizé, 22nd to 24th March 2017 Effects of tillage and herbicide intensification on wheat crops attractiveness for bats: a comparison of three conventional and one organic farming systems Kévin Barré*, Romain Julliard, Isabelle Le Viol, Christian Kerbiriou & François Chiron CESCO-MNHN, Paris In a European collapse context of many farming species, solutions should be found to stop these losses. Due to intensification of the most part of agriculture, improvements are easily accessible such as input and soil tillage reduction. Such changes are known to have positive effects on biodiversity. However, in some cases negative effects are detected (e.g. birds), especially for conservation tillage (i.e. non inversion of soil). Thus, there is no consensus about tillage reduction effects, due to plentiful possibilities to perform it. Farming practice differences between types of conservation tillage are explain by interventions (i.e. weed control method) in intercrop period. Moreover, tillage reduction and more generally farming practices effects on bats have been poorly studied. We tested in an intensive farming landscape for wheat, the relative effects of 4 farming systems on bats. We studied 2 systems of conservation tillage having different levels of tillage (superficial or no-till) and herbicide quantities to control weeds, as well as controls with 1 conventional and 1 organic system which used ploughing. Our study revealed the importance of the weed control method in efficiency of conservation tillage systems for bats. Indeed, results show that herbicide quantity have high negative effects in ploughing and conservation tillage systems. Our results suggest that is better to control weeds using a bit of herbicide and superficial tillage rather than only a lot of herbicides with no-till. Finally, we did not detect differences between conservation tillage system using a bit of herbicide and organic system only using ploughing. A possible evolutionary response of leaf fungi pathogens of cereals to changes in fertilization level. Pierre-Antoine Précigout*, David Claessen, Corinne Robert Écologie fonctionnelle et écotoxicologie des agroécosystèmes-INRA, Paris ; Mathématiques Eco-Evolutives-Institut de Biologie de l'Ecole Normale Supérieure, Paris We use a model of life history evolution of crop fungal pathogens aiming to understand how they adapt to fertilization. We focus on a single pathogen life history trait, the latent period, important for pathogen resource allocation strategies and canopy colonization. We implement three fertilization scenarios corresponding to major effects of nitrogen fertilization on cereals: increase in (i) metabolites in leaves, (ii) leaf lifespan and (iii) canopy leaves density. We find that spores production increases with higher fertilization. We use two fitness measures to identify putative evolutionary responses of latent period to changes in fertilization. When fitness is defined as annual spores production, we predict a positive correlation between the optimal latent period and fertilization. By contrast, the model predicts a negative relationship between the optimal latent period and fertilization when fitness is defined as the within-season exponential growth rate of the pathogen. We hypothesize that if the critical step in the co-dynamics of multiple strains is the colonization of new fields then the limiting step will likely be the amount of spores in next year’s inoculum, which will influence the early steps of epidemics. In that case, the strain that produces most spores over a season is likely to win the competition, and evolution should maximize annual spores production. If, on the other hand, the competition between strains is mainly experienced by within-season competition for healthy crop tissue, then the rate of spread through the canopy will be critical. We predict that reducing fertilization will change the aggressiveness profiles of different biotrophic fungius species or strains in the field. CEBC-Chizé, 22nd to 24th March 2017 Session 5: 23nd March 2017 – 13:45pm – 16:00pm Can we economically afford significant reduction in herbicide and nitrogen use? Experimental evidence in real fields says, yes we can! Rui Catarino*, Sabrina Gaba & Vincent Bretagnolle CEBC-CNRS, Chizé ; Agroécologie, AgroSup Dijon, INRA, Univ. Bourgogne Franche-Comté, FR-21000 Dijon In Europe, several policies to limit the environmental externalities of agrochemicals have been implemented in the past decade. Yet, herbicides and fertilizers consumed over this period either have remained fairly constant or have increased. One main reason is that the fear of potential indirect negative effects on food production, hence profits. However, recent empirical studies have failed to detect a positive correlation between agrochemical use intensity and both productivity and profitability. With the present study we investigated in real farming conditions the relationships between economic benefits and weed control and nitrogen input. Through an innovative factorial experimental design set with farmers in their fields, we quantified the economic value of weed control and nitrogen use. The experiment accounted for soil variability and degree of management intensity in farming practices that ranged from organic to highly intensive users of agrochemicals. In each field, nitrogen and weed control were experimentally manipulated in intensity, allowing interactive and crossed analyses of determinants of wheat production and their economic impacts. Our results suggest that a significant proportion of farmers are not behaving optimally. Firstly, weed competition has, at best, no influence on conventional farmers’ yields. This implies that weed control strategies mainly reduce economic return. Secondly, the current nitrogen application rates are higher than what would be economically optimal, given both the costs and the benefits of nitrogen application. These findings demonstrate that there is a space for the implementation of strategies aiming at reducing certain agrochemicals, in a win-win scenario for farmers and environment. The influence of different burning regimes on diversity and abundance of bees in rangelands in Namibia Kristin M. Krewenka*, Michael Kruspe, Kai Schütte Biodiversity, Evolution and Ecology of Plants - University of Hamburg In arid to semi-arid savannas, fire is an important management tool for the conservation of biodiversity in this ecosystem. The savanna in Southern Africa is used for grazing by large herbivores and cattle. Degradation of this vegetation type, caused by intensive anthropogenic use and inadequate management practises like overgrazing and poorly conducted fire management schemes is an important topic in the conservation and restoration debate. Insects and their interactions play a crucial role in delivering biotic ecosystem services that stabilize this fragile ecosystem. Bees are important pollinators of wild plants and crops, ensuring sexual reproduction of flowering plants. The impact of different fire regimes on the diversity and the interactions of flower visiting bees are not documented for this region up to now. On the Waterberg plateau in Namibia we sampled flower visitors, using pan traps on four plots with different burning histories. Our results show, that the community structure of bees was significantly influenced by the burning frequency. Overall abundance of bees was highest on the less disturbed plot compared to the more recently burned ones and diversity of bees seems to be positively correlated with the flowering tree diversity. Small ground-nesting species and solitary bees seemed to be negatively affected by recent fire events, while the abundance of medium sized to large bee species and social bees was promoted by recent fires. Our results indicate that fire events are shaping bee communities in savanna habitats and that these implications should be considered for management. CEBC-Chizé, 22nd to 24th March 2017 A multi-seasonal model of plant-nematode interactions and its use for durable plant resistance deployment strategies. * Samuel Nilusmas , Mathilde Mercat , Thomas Perrot , Suzanne Touzeau, Vincent Calcagno, Caroline Djian Caporalino, Philippe Castagnone-Sereno, Ludovic Mailleret Institut Sophia AgroBiotech, Nice Root-knot nematodes of the genus Meloidogyne are soil-borne, little mobile, polyphagous pests which are causing important economic losses of vegetables or small fruits production. They attack plant roots to feed and reproduce and have a major impact on crop yield. The control of root-knot nematodes in horticultural crops is now based on the deployment of plants bearing natural resistance genes. However, these genes are rare and the emergence of virulent nematode variants, which are adapted to the resistance, challenges the durability of such methods. Because virulent root-knot nematodes exhibit a reduced fitness on susceptible crops, combining both resistant and susceptible plants can help increase the efficacy and sustainability of resistance-based nematode control. Since nematodes have poor intrinsic dispersal ability, the association between resistant and susceptible plants should rely on crop rotation over cropping seasons, rather than on spatial arrangements. We proposed a semi-discrete model describing the population dynamics of plant roots and of nematodes within and over cropping seasons. This model, inspired by epidemiological concepts, was fitted to literature data on the within cropping season dynamics of susceptible tomato plants and avirulent nematodes; it was then extended to also account for resistant plants and virulent parasites. The model was used to compute optimal crop rotation strategies with respect to the minimization of an epidemiological criterion called AUDPC (area under the disease progress curve) to increase crop yield over different time horizons. Weed cohort succession as a main driver of weed diversity dynamic throughout winter cereal cropping season in both presence and absence of crop species Mahaut L.*, Perronne R., Fried G., Gaba S. Agroécologie, AgroSup Dijon, INRA, Univ. Bourgogne Franche-Comté, FR-21000 Dijon ; LSV-ANSES, Campus international de Baillarguet Ecological succession theory predicts that soon after disturbance, community diversity results from species colonization while competitive interaction plays an increasing influential with time since disturbance. While weeds species in arable fields face frequent disturbances, they also face intense competition for light as they are over-dominated by the crop species. Thus, both colonization and competition may shape weeds community diversity in arable fields. Using a semiexperimental approach, we analysis the evolution of weed diversity throughout time in 56 winter cereal cropping seasons. We use the crop sowing date as proxy of the last disturbance. We predict that in the absence of the crop species, weed diversity increases with time since crop sowing date until arable field’s carrying capacity is reached. Conversely, in the presence of the crop, we expect competition for light to prevent the establishment of late germinating species and select for shade tolerant species so that weed diversity showed a hump-shaped relationship with time since crop sowing date. We found a hump-shaped relationship between weed diversity and time since crop sowing date both in presence of absence of the crop species. A functional diversity analysis revealed that the hump-shaped curve results from the succession of autumn and spring germinating weed species. However, weed richness was always higher in the absence of the crop, revealing that crop competition structure weed diversity since crop sowing date. This analysis suggests that competition may occur in early successional stage plant community as long as species colonization is not limiting. CEBC-Chizé, 22nd to 24th March 2017 Session 6: 23nd March 2017 – 16:30pm – 17:30pm Ecological mechanisms shaping weed assembly in intensive farmland landscapes Bourgeois Bérenger*, Gaba Sabrina, Plumejeaud Christine and Bretagnolle Vincent Agroécologie, AgroSup Dijon, INRA, Univ. Bourgogne Franche-Comté, FR-21000 Dijon ; CEBC – CNRS, Chizé The ecological mechanisms shaping plants assemblages are multiple and scale-dependent. While the differentiation of resource patches may govern assembly rules at intermediate scales, the role dispersal processes is expected to decrease and the one of species interaction to increase from large to fine spatial scale. In this study, we investigate the contribution of these three processes to weed assembly based on a hierarchical sampling design conducted in 454 arable fields of the LTSER Zone Atelier ‘Plaine & Val de Sèvre’ from 2014 to 2016 . Using multiplicative diversity partitioning, the total field weed diversity was decomposed into four metrics, corresponding to differences in species richness between sampling scales (subplots, plots, field core-margin) and mean subplot richness. Between-plot difference in species richness was the main component of weed diversity, but its contribution decreased when the total field weed diversity increased while between-subplot difference in species richness and mean subplot richness increased. Even if plots within field core corresponded to similar resources patches (according to Ellenberg indices), we showed that the dispersion of plant height within subplots increased with the total field diversity. Furthermore, field core weed richness strongly increased with the richness of field margin, and to a lesser extent with the cover of organic fields within 1000m. All together, these results demonstrate that the increase of field weed diversity is related to small-scale (i.e. subplot) community diversification due mainly to niche-partitioning and short-distance dispersal from margin, and provide new insights on the assembly rules of weed communities. Why and how include land use change modelling in regional land planning? Example from a French Mediterranean Region Mathilde Hervé*, Cécile Albert, Alberte Bondeau & Thierry Tatoni IMBE (Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale), Aix-en-Provence Regional land planning use data on land use and land cover to design future protected areas (Vimal et al. 2012). Because of the potentially far-reaching consequences of this identification of priority areas, a robust and reliable method is needed. With a sensitivity analysis, we showed that human footprint method, developed by Vimal et al. (2012), is very sensitive to the way to include agriculture as a stressor (Hervé et al. 2016). Therefore, it is important to use finer information and to apply impact coefficients adapted to the local context. Moreover, including expected future land use in the diagnostic permits to propose more reliable results for conservation managers. Many maps of possible future land use and land cover have been produced in the last years, following various scenarios (for example Dendoncker et al., 2007). Therefore, how to use these different possible maps in future land planning is an issue. Here, we present some ways to mobilize global scenarios for a regional land planning in the Provence Alpes Côte d’Azur Region (France). First, we propose a way to test the likelihood of future land use and land cover maps for the regions with comparison with the past trends. Second, we use some of these scenarios to develop a participative approach. Using workshops with stakeholders at local and regional scale, some scenarios and maps can be design by stakeholders themselves. Technological scenarios and participative scenarios can be finally compared to determine, thanks to coefficients derived from a literature review from the Mediterranean region, future issues for biodiversity conservation in this region. CEBC-Chizé, 22nd to 24th March 2017 Review of studies on crop-weed interactions reveals a lack of methodological standardization Xavier Laviron*, Sabrina Gaba, Joël Chadoeuf Agroécologie, AgroSup Dijon, INRA, Univ. Bourgogne Franche-Comté, FR-21000 Dijon Intensive management practices have been conducted since the 1950's to reduce the impact of weed competition on crop production. It is now widely recognized that the intensive use of herbicides has led to air, water and soil pollution, as well as massive biodiversity loss. Several public policies have been implemented to reduce herbicide use. However, is it possible to reduce herbicides while keeping sustainable agricultural production? We addressed this question by reviewing studies investigating the relationship between crop yield, weeds and herbicides from 1970 to 2016. A query to Web of Science surprisingly showed a mere number of 54 articles. We considered methodological choices such as the variety of metrics used to measure crop-weed competition or the herbicide used. Among the 40 articles for which full text was available, the dominant crops were wheat and corn. Most studies were conducted in experimental fields, 12% in actual farms and only 5 % in greenhouses. 70 % assessed the effect of a single herbicide, and only 12 % three or more herbicides and only 16 % tested multiple doses of herbicides. Similarly, only 10 % considered more than ten weed species. Forty eight different metrics were used to quantify the impact of weeds on crop. 55 % of studies reported a negative impact of weeds on grain yield, compared to weed-free controls. One of the two studies reporting economic analysis, one mentioned an increase in net benefits. In this talk, we will present how studies results are closely linked to methodological choices. Does niche complementarity hold for below-ground resources? A case study using rice mixtures G. Montazeaud*, C. Violle, D. Luquet, H. Fréville, F. Fort CEFE – CNRS, Montpellier ; AGAP (Amélioration Génétique et Adaptation des Plantes) – INRA, Montpellier Reintroducing genetic diversity in agro-systems generates a growing interest for developing a more sustainable agriculture. Several ecological studies have shown a positive relationship between productivity and plant genetic diversity. Niche complementarity is one of the main theories, which predicts such relationship. Genotypes with different phenotypes are expected to have different ecological niches. Therefore, their association may limit competition and lead to a more efficient use of resources. Recent reviews on genotype mixtures in crops have shown that yields tend to be slightly higher in mixtures relative to monocultures. However, many studies have shown the reverse pattern. This calls for a better understanding of the mechanisms that drive plant-plant interactions. The aim of this study was to test for niche complementarity using four rice (Oryza sativa) genotypes grown in pots, by comparing the relative productivity of mixtures with monocultures, in two levels of P availability. Genotypes were chosen to represent significant phenotypic diversity in above- and below-ground traits. Two genotypes were Near-Isogenic Lines only differing by a specific zone identified as a QTL for root depth. Productivity was measured as above and below-ground biomass and was analyzed in relation with phenotypic dissimilarity between plants. Our results do not support the niche complementarity hypothesis since mixtures never produce more than the best monoculture and, sometimes, are even less productive. However, some traits appeared to explain plant interactions: mixtures productivity increased while dissimilarity in Specific Leaf Area increased and, at the opposite, increased while similarity in Adventious Specific Root Length increased. CEBC-Chizé, 22nd to 24th March 2017 Session 7: 24th March 2017 – 8:30am – 10:30am How to integrate agro-ecological farming practices in cultural systems? A case study in Brittany Puech Camille*, Brulaire Arnaud, Paraiso Jérôme, Faloya Vincent IGEPP – INRA, Rennes The environmental and health impacts of farming practices and the phasing-out of pesticides are leading most of agricultural sectors to question their cropping systems. Crops of the field vegetables sector are particularly sensitive to pests and require the implementation of alternative management methods. The study presented here is conducted in collaboration with various partners of the industrial field vegetable sector in Brittany, and aims to initiate a transition of cropping systems, integrating more and more innovative and sustainable agro-ecological techniques. A four farmers group was created to set up the co-design of innovative cropping systems. This process allowed farmers to reduce their use of agrochemical products, while integrating a variety of alternative farming practices in their systems, such as mechanical weeding, trap plants or biological control. For instance, a two years field trial was built to sow flower strips along farmers pea fields. Results of this experiment showed that i) flower strips create a pool of aphids natural enemies in crops, ii) these natural enemies provide a regulation of aphids which can substitute insecticides when pest pressure is not too strong, iii) implementing flower strips is easy to achieve for farmers and contribute to the societal value of their cropping system. The challenge of the project will then to spread this kind of “good technique” as much as possible to the field vegetable sector, using for instance farmers networks in agricultural cooperatives. This work will finally propose an interesting feedback on the transmission of agro-ecology research knowledge to farmland actors. Is anticoagulant rodenticide use disrupting the natural regulation of vole populations? A biomathematics modelling approach Javier Fernandez-de-Simon, Virgile Baudrot*, Geoffroy Couval, Michael Coeurdassier, Xavier Lambin, Patrick Giraudoux Laboratoire Chrono-environnement, UBFC-CNRS, Besançon Since the 1950’s, world technological/socio-economic changes led to increased pesticides’ use. Understanding pesticides’ impact at several temporal/spatial scales and at communities/ecosystems levels is still challenging. Grassland small mammals like voles can reach hundreds of individuals/ha, being perceived as pests. Anticoagulant rodenticides (ARs) are used to control voles during the low density and increase phases of their population cycles. Thus, ARs may act as a superpredator, interfering with the natural regulation of vole populations and contaminating vole predators indirectly by eating intoxicated voles. Secondary poisoning of abundant predators has been observed (e.g. foxes), but the effect on elusive small mustelids is unknown. Here, our objective was to explore the interactions between (i) ARs use (quantity, frequency and period) to control voles, (ii) intraguild predation/competition and (iii) secondary poisoning on predators. We consider small mustelids (stoats, weasels), that mostly eat voles, and generalist (foxes) predators with mainly voles and to a lesser extend mustelids as food items. We used differential equations to explore scenarios on chronic or acute episodes of spread of ARs and combining animal population dynamics, predator-prey interactions, and transfer of bromadiolone across the trophic chain. Our preliminary results show time lagged appearance of ARs peaks along the trophic levels, illustrated by different delays in population responses to ARs treatments. Though based on a simplified model, our simulations allows to identify which parameters were relevant to reach consensus between agricultural and conservation purposes. Thus, this modelling approach, tightly coupled with field research, provide baselines for optimal farming practices. CEBC-Chizé, 22nd to 24th March 2017 Effects of alley cropping system on weed, pollinators and natural enemies’ communities: the role of understory strips. Jean-Pierre Sarthou, Pierre-Eric Lauri, Delphine Mézière, Karim Barkaoui, Sébastient Boinot*. SYSTEM – INRA, Montpellier Alley cropping systems are based on association of trees and crops within a field. One consequence of the absence of tillage on tree rows is the development of understory vegetation strips favorable to perennial plants. The effects of trees and understory strips on weed and insects communities remain poorly studied, although these two components could be of major importance for the delivering of ecosystem services. As with other semi-natural habitats, these components could provide resources or winter refuges for pollinators and natural enemies, leading to more diverse and abundant communities and therefore contributing to the improvement of pollination and biological control services. Conversely, they could harbor pests able to colonize the crop area, which could negatively impact production. This research has two main objectives: (i) the study of weed, pollinators and natural enemies’ communities along a gradient of transition from pure crop systems towards more and more developed alley cropping systems, and (ii) the determination of plant communities’ characteristics that explain their functions in the agro-ecosystem. Weed and insects’ communities will be sampled in 30 fields in Gers (32), south-west France. Trees and understory strips will be characterized through their proportion within the field and their development stage. Functional structure of plant communities in the understory strips will also be assessed. This research will help to understand the effects of alley cropping systems on weed and insects’ communities. It will also deliver insights for the integration of understory strips in the conception of such systems for multiple services delivering. Effect of pastureland on tabanid community and implications in the epidemiology of tabanid-borne diseases in Europe Frédéric BALDACCHINO*, Cyril BERNARD, Stjepan KRČMAR, Claudio DE LIBERATO, Pierre JAY-ROBERT Department of Biodiversity and Molecular Ecology, Innovation and Research Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy Landscape is an important driver of the diversity and abundance of arthropods. To date, the impact of landscape has been rarely investigated for insect vectors despite their concern in veterinary health. Tabanid (Diptera: Tabanidae) are hematophagous cosmopolitan flies that are pests of livestock and transmit animal disease agents such as Besnoitia besnoiti and the equine infectious anaemia virus. By virtue of their diversity and their adaptability, tabanids have colonized a wide range of habitats, such as forests, pastures, wetlands, from sea level to alpine altitudes. Facing the reemergence of tabanid-borne diseases in Europe, we aimed to characterize the geographical distribution of tabanid fauna at a broad scale and to assess the impact of landscape and climate on tabanid community. To investigate this, we used a dataset including 38 tabanid samples from 7 European countries. We found that tabanid communities were spatially ordered along a marked gradient from Eastern to Western Europe using a non-metric multidimensional scaling ordination. A model-based analysis of the multivariate tabanid abundance data showed that both climatic and landscape variables, but not sampling method, had a significant additive effect on mean abundance. Using linear mixed-effects models, we found that the Shannon diversity index and Pielou’s evenness decreased when the surface of pastureland increased. Our results indicate that the distribution of tabanids may be heavily influenced by changes in landscape. Implications in the epidemiology of tabanid-borne diseases are discussed and illustrated by a recent survey conducted in an endemic area of equine infectious anaemia in Italy. CEBC-Chizé, 22nd to 24th March 2017 Plant-bird mutualisms in native forest fragments within agricultural landscapes: does size actually matter? Marine Aubert* Dave Kelly, Terrestrial Ecology, University of Canterbury, Christchurch, NZ Where native bird densities have been severely reduced, pollination and seed-dispersal services to plants relying on birds for reproduction may be failing, especially in small forest remnants. I aimed to detect a threshold area and isolation level under which the lack of interactions with birds adversely affected breeding systems of native plants. In 17 forest fragments ranging from small private covenants to large nature reserves on Banks Peninsula, New Zealand, I measured bird densities and found that habitat isolation rather than area affected bird densities and presence of native birds. I used as an indicator species the bird-pollinated, bird-dispersed native tree Fuchsia excorticata, which is prone to inbreeding depression, pollen and seed limitation. Pollen deposition measurements on Fuchsia flowers showed insufficient pollination of females in one third of the sites, suggesting that self-compatible hermaphrodites were likely experiencing high local selfing rates. Fruit removal rates, measured as an estimate of dispersal service, were increasing with site connectivity and native bird densities. Seed sets on female trees were larger in better connected sites. In germination trials set up to detect inbreeding depression, the difference in growth performance between offspring of naturally cross-pollinated females and self-compatible hermaphrodites was also reduced with increasing connectivity, suggesting higher self-pollination rates in isolated fragments. Increasing patch area only improved pollination service in sites smaller than 15 ha, and had otherwise minor and mostly negative effects on plant-bird mutualisms. Patch connectivity was the most important fragmentation parameter, positively affecting mutualist bird populations, dispersal service, and limiting inbreeding depression. CEBC-Chizé, 22nd to 24th March 2017 Session 8: 24th March 2017 – 11:00am – 11:30am The terrestrial isopod and soil quality bioindicator Armadillidium vulgare: a non-target organism to test a biocontrol Aurélien Lacouture*, Marion Poussin, Julia Clause, Catherine Souty-Grosset Laboratoire Ecologie et Biologie des Interactions – CNRS, Poitiers The soil hosts a well-diversified fauna that plays a key role in the decomposition of organic matter. Within this fauna, detritivores are really important in that they consume litter and they egest it as faecal pellets with modified chemical properties. The international working group « Traits Ecologiques et Biologiques des organIsmes des Sols » (TEBIS) aims at evaluating the changes of properties occurring from different ingested litters to egested faecal pellets for a range of detritivores, while following a unique protocol in different laboratories. In the terrestrial isopod Armadillidium vulgare, results showed that changes of pellet properties can be related to differences in the litter assimilation efficiency. Biopesticides can change the litter and the soil quality, thereby having a potential impact on the soil macrofauna. The use of extracts of two plant families -Alliacea and Crotalaria- is being developed to control root-knot nematodes Meloidogyne sp and bacterial pest Ralstonia solanacearum. In this context, it is necessary to study the potentially undesirable and nonintentional effects of this biocontrol method on non-target organisms such as Armadillidium vulgare. To do so, we can use the protocol based on the TEBIS protocol mentioned above. Armadillidium vulgare is put into contact with these biocontrol agents through its food or the soil at different concentrations, and mortality is tested. Other tests will likely be performed such as topical applications or avoidance tests to determine other impacts of this biocontrol. Study of weed seeds consumption by ground beetles under standardized conditions Deroulers P., Emeriau S., Gauffre B., Harismendy A., Bretagnolle V. CEBC – CNRS, Chizé Seedbank control has indeed been the cornerstone of agricultural management practices. Therefore, regulating weeds by using their predators, as a weed control strategy, is a prerequisite of decreasing herbicide use, and has attracted many studies investigating the possible contribution of both vertebrates and invertebrates as weed seed predators. In particular, carabids are claimed to be one of the most important invertebrate seed predators in agroecosystems. But today, there is no study which presents the potential of carabids as control agents of weed seeds. The aim of this paper is to define a protocol to have elements to estimate the potential role of ground beetles in the regulation of the weed seedbank. Fasting time, experimentation duration, substrate type are parameters which are tested and defined experimentally in this paper. Moreover, this protocol has been adapted to replicate tests with the same individual. This adaptation will allow determine, e.g. the functional response of ground beetles on weed seeds species. Tests are realized with common ground beetles species find in the LTSER « Zone Atelier Plaine & Val de Sèvre »: Harpalus dimidiatus, Harpalus affinis, Pseudoophonus rufipes, Poecilus cupreus and Amara similata. For the majority of our tests we used seed species Viola arvensis.To test the functionality of our experimentation we selected weed seeds species according to their weight and lipid content: Lolium multiflorum, Fallopia convolvulus, Geranium dissectum, Fumaria officinalis, Chenopodium album, Poa annua, Viola arvensis and Papaver rhoeas. Climatic conditions have been fixed for all tests: 25°C, 70% of humidity and a photoperiod of 17h/7h with climatic chambers. Fasting time has been determined at 3 days, to avoid over-weakening carabids and induce seeds consumption. Experimentation duration is 24h. And for replicated tests, mortality rate was the parameter which was to stay very low to apply our experimentation. A recovery period between experimentation and fasting time was necessary to safe the individual and to replicate tests with him. CEBC-Chizé, 22nd to 24th March 2017 Controlling pests with the landscape? Participatory modelling of farmer’s perspectives to learn about the social feasibility of this innovation Salliou Nicolas*, Vialatte Aude, Monteil Claude, Barnaud Cécile DYNAFLOR – INRA, Toulouse Landscape ecology findings suggest that landscapes with high proportions of semi-natural habitats can enhance biological control by natural enemies. As a consequence, landscape engineering favouring such landscape composition appears as a promising biodiversity friendly solution to reduce pesticide use. However, little is known about agricultural stakeholders’ interests about such innovation. Are they perceiving potential pest control benefits from landscape complexity? Under which conditions farmers could act together to favour such landscapes? Farmers’ representations of their social and ecological environment is directly connected with their farming practices and strategies. As such, eliciting these representations gives interesting insights about the feasibility of integrating the landscape into a pest regulating strategy. To explore farmer’s perspectives, we conducted a participatory research together with local stakeholders (farmers and advisors) of a fruit tree region in south-west France in which pesticides are used quite intensively by farmers. We developed several participatory modelling approaches adapted to stakeholders’ representations. Our results show that the local stakeholders mainly perceive the landscape and semi-natural habitats components as source of ecosystem disservices related with enhanced pest issues. We also found that in the farmers’ perspectives, even though they feel that higher landscape complexity can indeed foster higher biodiversity, they do not consider this strategy significantly beneficial for them. We consequently found a higher interest from agricultural stakeholders for landscape engineering solutions not as a pest regulating tool but as a common threat to be managed thus opening to innovative areawide landscape management approaches.