Corrigendum: Delivery of crop pollination services is an insufficient argument for wild pollinator conservation

There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these ecosystem services have become a key argument for biodiversity conservation. However, it is unclear how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops. Dominant crop pollinators persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments

Delivery of crop pollination services is an insufficient argument for wild pollinator conservation

There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these ecosystem services have become a key argument for biodiversity conservation. However, it is unclear how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops. Dominant crop pollinators persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments

Pollinator fauna, landscape and spacial scale of pollen flow of brassica napus l. (brassicaceae)

Interest in pollen-borne gene dispersal has grown with the cultivation of genetically modified plants. To date both experimental data and models of oilseed rape (OSR) Brassica napus pollen movement at the landscape scale do not clearly differentiate between wind- and insect-mediated dispersal. Estimations of pollen-borne gene dispersal would be valuable for managing potential escapes of transgenes. Our study provides clear evidence that a large variety of insect species can transfer viable pollen between oilseed rape plants over considerable distances (>1.1 km). Insect’s diversity according to geographical site and years. However, the majority of pollinator have OSR pollen in their body hairs, only 39.4% of the insects caught on male-sterile flowers carried OSR pollen. Although we could not determine with precision the role of the wind and the insects in the OSR pollination, it would seem that insects take part in a more important way in pollination of plants present in edges of fields, thus increasing cross pollination rate. Our results provide valuable data to improve models of pollen dispersal for entomophilous crops at the landscape scale. These models are essential to help land-managers reduce pollen-borne gene dispersal from genetically modified plants to wild relative and field planted with non-GM cropsL’intérêt pour la dispersion des gènes via le pollen a augmenté avec les cultures de plantes génétiquement modifiées. A ce jour, les données expérimentales ainsi que la modélisation portant sur les mouvements du pollen de colza, Brassica napus L., à l’échelle du paysage ne différencie pas clairement la part du vent et des insectes dans cette dispersion. Cependant, l’estimation de la dispersion des gènes par le pollen reste une condition nécessaire pour la gestion des risques d’échappement des (trans-)gènes vers l’environnement et les cultures conventionnelles. A travers cette thèse, nous avons pu mettre en évidence qu’une grande diversité d’insectes pollinisateurs pouvait transporter du pollen viable entre différentes plantes de colza sur des distances importantes (>1.1 km). La diversité d’insectes varie d’une région à l’autre et d’une année sur l’autre. Cependant, bien que la majorité des insectes sur une zone de grande production de colza ait du pollen de cette culture sur leur corps, seulement 39,4 % des insectes capturés sur des plantes mâle-stériles transportent du pollen de colza viable. Bien que nous n’ayons pas pu déterminer avec précision la part du vent et des insectes dans le pollinisation du colza, il semblerait que les insectes participent de façon plus importante à la pollinisation de plantes présentes en bordures de champs, augmentant ainsi le taux de pollinisation croisée. Nos résultats fournissent des données fiables pour améliorer les modèles de dispersion pollinique pour des cultures entomophiles à l’échelle du paysage. Ces modèles sont essentiels pour l’aide à la gestion afin de réduire la dispersion des gènes par le pollen des cultures génétiquement modifiées vers les plantes sauvages ou les cultures conventionnelle

Faune pollinisatrice, paysage et échelle spatiale des flux de pollen chez brassica napus l. (brassicaceae)

Interest in pollen-borne gene dispersal has grown with the cultivation of genetically modified plants. To date both experimental data and models of oilseed rape (OSR) Brassica napus pollen movement at the landscape scale do not clearly differentiate between wind- and insect-mediated dispersal. Estimations of pollen-borne gene dispersal would be valuable for managing potential escapes of transgenes. Our study provides clear evidence that a large variety of insect species can transfer viable pollen between oilseed rape plants over considerable distances (>1.1 km). Insect’s diversity according to geographical site and years. However, the majority of pollinator have OSR pollen in their body hairs, only 39.4% of the insects caught on male-sterile flowers carried OSR pollen. Although we could not determine with precision the role of the wind and the insects in the OSR pollination, it would seem that insects take part in a more important way in pollination of plants present in edges of fields, thus increasing cross pollination rate. Our results provide valuable data to improve models of pollen dispersal for entomophilous crops at the landscape scale. These models are essential to help land-managers reduce pollen-borne gene dispersal from genetically modified plants to wild relative and field planted with non-GM cropsL’intérêt pour la dispersion des gènes via le pollen a augmenté avec les cultures de plantes génétiquement modifiées. A ce jour, les données expérimentales ainsi que la modélisation portant sur les mouvements du pollen de colza, Brassica napus L., à l’échelle du paysage ne différencie pas clairement la part du vent et des insectes dans cette dispersion. Cependant, l’estimation de la dispersion des gènes par le pollen reste une condition nécessaire pour la gestion des risques d’échappement des (trans-)gènes vers l’environnement et les cultures conventionnelles. A travers cette thèse, nous avons pu mettre en évidence qu’une grande diversité d’insectes pollinisateurs pouvait transporter du pollen viable entre différentes plantes de colza sur des distances importantes (>1.1 km). La diversité d’insectes varie d’une région à l’autre et d’une année sur l’autre. Cependant, bien que la majorité des insectes sur une zone de grande production de colza ait du pollen de cette culture sur leur corps, seulement 39,4 % des insectes capturés sur des plantes mâle-stériles transportent du pollen de colza viable. Bien que nous n’ayons pas pu déterminer avec précision la part du vent et des insectes dans le pollinisation du colza, il semblerait que les insectes participent de façon plus importante à la pollinisation de plantes présentes en bordures de champs, augmentant ainsi le taux de pollinisation croisée. Nos résultats fournissent des données fiables pour améliorer les modèles de dispersion pollinique pour des cultures entomophiles à l’échelle du paysage. Ces modèles sont essentiels pour l’aide à la gestion afin de réduire la dispersion des gènes par le pollen des cultures génétiquement modifiées vers les plantes sauvages ou les cultures conventionnelle

Faune pollinisatrice, paysage et échelle spatiale des flux de pollen chez brassica napus l. (brassicaceae)

L intérêt pour la dispersion des gènes via le pollen a augmenté avec les cultures de plantes génétiquement modifiées. A ce jour, les données expérimentales ainsi que la modélisation portant sur les mouvements du pollen de colza, Brassica napus L., à l échelle du paysage ne différencie pas clairement la part du vent et des insectes dans cette dispersion. Cependant, l estimation de la dispersion des gènes par le pollen reste une condition nécessaire pour la gestion des risques d échappement des (trans-)ge nes vers l environnement et les cultures conventionnelles. A travers cette thèse, nous avons pu mettre en évidence qu une grande diversité d insectes pollinisateurs pouvait transporter du pollen viable entre différentes plantes de colza sur des distances importantes (>1.1 km). La diversité d insectes varie d une région à l autre et d une année sur l autre. Cependant, bien que la majorité des insectes sur une zone de grande production de colza ait du pollen de cette culture sur leur corps, seulement 39,4 % des insectes capturés sur des plantes mâle-stériles transportent du pollen de colza viable. Bien que nous n ayons pas pu déterminer avec précision la part du vent et des insectes dans le pollinisation du colza, il semblerait que les insectes participent de façon plus importante à la pollinisation de plantes présentes en bordures de champs, augmentant ainsi le taux de pollinisation croisée. Nos résultats fournissent des données fiables pour améliorer les modèles de dispersion pollinique pour des cultures entomophiles à l échelle du paysage. Ces modèles sont essentiels pour l aide à la gestion afin de réduire la dispersion des gènes par le pollen des cultures génétiquement modifiées vers les plantes sauvages ou les cultures conventionnellesInterest in pollen-borne gene dispersal has grown with the cultivation of genetically modified plants. To date both experimental data and models of oilseed rape (OSR) Brassica napus pollen movement at the landscape scale do not clearly differentiate between wind- and insect-mediated dispersal. Estimations of pollen-borne gene dispersal would be valuable for managing potential escapes of transgenes. Our study provides clear evidence that a large variety of insect species can transfer viable pollen between oilseed rape plants over considerable distances (>1.1 km). Insect s diversity according to geographical site and years. However, the majority of pollinator have OSR pollen in their body hairs, only 39.4% of the insects caught on male-sterile flowers carried OSR pollen. Although we could not determine with precision the role of the wind and the insects in the OSR pollination, it would seem that insects take part in a more important way in pollination of plants present in edges of fields, thus increasing cross pollination rate. Our results provide valuable data to improve models of pollen dispersal for entomophilous crops at the landscape scale. These models are essential to help land-managers reduce pollen-borne gene dispersal from genetically modified plants to wild relative and field planted with non-GM cropsAVIGNON-Bib. numérique (840079901) / SudocSudocFranceF

Impact of weed management against feral populations of oilseed rape on plant and pollinator communities in an openfield landscape

International audience(Introduction) Field margins (FM) defined as the whole crop edge are permanent non-crop habitats. FM can be biodiversity refuges and also potential relays for the spread of transgenes. The escape of oilseed rape (OSR, Brassica napus L.) from fields, whether genetically modified (GM) or not, can result in feral populations in field margins. Such GM feral populations can then potentially spread transgenes into wild and weedy species. Field margins must then be sprayed or mowed to control feral populations. Spraying herbicide onto or mowing FM may affect the plant community composition and pollinators. With concerns of a global pollination crisis, there is a need for improving pollinator habitat in highly modified landscapes. We make the assumption that OSR pollinators travel shorter distances if they find resources along their foraging path. • What are the specific components of plant abundance in field margins? • What is the maximum distance that OSR pollinators can travel in order to fertilize OSR feral plants

Solitary bee abundance and species richness in dynamic agricultural landscapes

Remerciements : F. Le Moal, R. YantierInternational audienceWe investigated the influence of the landscape structure on solitary bee abundance and species richness in an agricultural area of western France. We focused on the role of semi-natural habitats, oilseed rape (OSR) and other crops. Our originality was to consider not only the spatial heterogeneity of the crop field mosaic but also its temporal heterogeneity through the crop rotations. Solitary bees were caught with colored pan traps in 15 margins of OSR fields and 35 margins of non-OSR fields. We found that solitary bee abundance and species richness were higher in margins of OSR fields than in margins of non-OSR fields, showing that early spring-flying species widely use this mass flowering crop. However the high number of rare species in margins of non-OSR fields (21 species recorded exclusively in these margins) highlighted the importance of these margins for the conservation of solitary bee diversity. The influence of the landscape context on solitary bees showed contrasted results according to the type of margin and the spatial scale. At the finest spatial scale, abundance in margins of OSR fields increased with increasing proportion of non-flowering crops (cereals and temporary grasslands) in the current year. At large spatial scales, solitary bee abundance in margins of non-OSR fields was positively affected by the proportion of long-term grasslands. Moreover, the proportion of fields only sown with cereals during the last 5 years negatively affected abundance and species richness at the large scales whereas the proportion of mixed fields (at least 1 year of grassland in the rotation) had a positive effect on species richness. We showed that accounting for the cumulative effects of field cover and management through the crop rotations is relevant for studying solitary bee communities. The introduction of less intensive covers, such as temporary grasslands, in cereal rotations positively influences these communities

Spatial scale of insect-mediated pollen dispersal in oilseed rape in an open agricultural landscape

International audience1. Interest in pollen-borne gene dispersal has grown with the cultivation of genetically modified plants. To date, both experimental data and models of oilseed rape (OSR) Brassica napus pollen movement at the landscape scale do not clearly differentiate between wind- and insect-mediated dispersal. Estimations of insect-mediated gene dispersal would be valuable for managing potential escapes of transgenes. 2. To quantify the intensity and spatial scale of pollen dispersal by insect pollinators in an agricultural landscape, bait points made of flowering male-sterile OSR that attract OSR pollinators were located at six distances (10-1100 m) fromthe closest OSRfields and feral populations. Flower-visiting insects were caught by net on these male-sterile flowers and were rubbed onto the stigmas of male-sterile OSR plants grown in a pollen- proof greenhouse to do a manual pollination of their flowers. In this way we were able to assess the insects' OSR pollen load and seed production at each of the six distances. 3. A large diversity of insects carried OSR pollen and contributed to seed production, but not pollen beetles Meligethes aeneus. Logistic regression analyses of the seed-set success from the manual pollination demonstrated that seed set significantly increased with the proximity of OSR fields, the size of the pollinating insect, and the main daily temperature. Seed set was not affected by the pollinating insect's order or genus. Seed set, both observed and predicted by the model, was above zero for flowers pollinated with large bees caught at >1100 m fromthe nearest OSRfield. 4. Synthesis and applications. Our study provides clear evidence that a large variety of insect species can transfer viable pollen between OSRplants over considerable distances. However, only 39.4% of the insects caught on male-sterile flowers carried OSR pollen. Our results provide valuable data to improve models of pollen dispersal for entomophilous crops at the landscape scale. These models are essential to help land-managers reduce pollen-borne gene dispersal from genetically modified plants to wild and cultivated relatives