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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.