Abstract:

Understanding the relationships between trait diversity, species diversity and ecosystem functioning is essential for sustainable management. For functions comprising two trophic levels, trait matching between interacting partners should also drive functioning. However, the predictive ability of trait diversity and matching is unclear for most functions, particularly for crop pollination, where interacting partners did not necessarily co-evolve. World-wide, we collected data on traits of flower visitors and crops, visitation rates to crop flowers per insect species and fruit set in 469 fields of 33 crop systems. Through hierarchical mixed-effects models, we tested whether flower visitor trait diversity and/or trait matching between flower visitors and crops improve the prediction of crop fruit set (functioning) beyond flower visitor species diversity and abundance. Flower visitor trait diversity was positively related to fruit set, but surprisingly did not explain more variation than flower visitor species diversity. The best prediction of fruit set was obtained by matching traits of flower visitors (body size and mouthpart length) and crops (nectar accessibility of flowers) in addition to flower visitor abundance, species richness and species evenness. Fruit set increased with species richness, and more so in assemblages with high evenness, indicating that additional species of flower visitors contribute more to crop pollination when species abundances are similar. Synthesis and applications. Despite contrasting floral traits for crops world-wide, only the abundance of a few pollinator species is commonly managed for greater yield. Our results suggest that the identification and enhancement of pollinator species with traits matching those of the focal crop, as well as the enhancement of pollinator richness and evenness, will increase crop yield beyond current practices. Furthermore, we show that field practitioners can predict and manage agroecosystems for pollination services based on knowledge of just a few traits that are known for a wide range of flower visitor species. Despite contrasting floral traits for crops world-wide, only the abundance of a few pollinator species is commonly managed for greater yield. Our results suggest that the identification and enhancement of pollinator species with traits matching those of the focal crop, as well as the enhancement of pollinator richness and evenness, will increase crop yield beyond current practices. Furthermore, we show that field practitioners can predict and manage agroecosystems for pollination services based on knowledge of just a few traits that are known for a wide range of flower visitor species.

Author affiliation: Garibaldi, Lucas Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Rio Negro. Sede Andina; Argentina

Author affiliation: Bartomeus, Ignasi. Consejo Superior de Investigaciones Científicas. Estación Biológica de Doñana; España

Author affiliation: Bommarco, Riccardo. Swedish University of Agricultural Science; Suecia

Author affiliation: Klein, Alexandra M.. University of Freiburg; Alemania

Author affiliation: Cunningham, Saul A.. Csiro Land And Water; Australia

Author affiliation: Aizen, Marcelo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina

Author affiliation: Boreux, Virginie. University of Freiburg; Alemania

Author affiliation: Garratt, Michael P. D.. University of Reading; Reino Unido

Author affiliation: Carvalheiro, Luisa G.. University of Leeds; Reino Unido. Naturalis Biodiversity Center; Países Bajos. Universidade do Brasília; Brasil

Author affiliation: Kremen, Claire. University of California at Berkeley; Estados Unidos

Author affiliation: Morales, Carolina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina

Author affiliation: Schuepp, Christof. University of Bern; Suiza. University of Koblenz-Landau; Alemania

Author affiliation: Chacoff, Natacha Paola. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Freitas, Breno M.. Universidade Estadual Do Ceara; Brasil

Author affiliation: Gagic, Vesna. Swedish University of Agricultural Science; Suecia

Author affiliation: Holzschuh, Andrea. Georg-August-University; Alemania. Universität Würzburg; Alemania

Author affiliation: Klatt, Bjorn K.. Georg-August-University; Alemania. Lund University; Suecia

Author affiliation: Krewenka, Kristin M.. Georg-August-University; Alemania. Universitat Hamburg; Alemania

Author affiliation: Krishnan, Smitha. Swiss Federal Institute of Technology Zurich; Suiza

Author affiliation: Mayfield, Margaret M.. The University Of Queensland; Australia

Author affiliation: Motzke, Iris. University of Freiburg; Alemania. Georg-August-University; Alemania

Author affiliation: Otieno, Mark. Embu University College; Kenia

Author affiliation: Petersen, Jessica. Cornell University; Estados Unidos

Author affiliation: Potts, Simon G.. University of Reading; Reino Unido

Author affiliation: Ricketts, Taylor H.. University of Vermont; Estados Unidos

Author affiliation: Rundlof, Maj. Lund University; Suecia

Author affiliation: Sciligo, Amber. University of California at Berkeley; Estados Unidos

Author affiliation: Allesh Sinu, Palatty. Central University of Kerala; India

Author affiliation: Steffan Dewenter, Ingolf. Universität Würzburg; Alemania

Author affiliation: Taki, Hisatomo. Forestry and Forest Products Research Institute; Japón

Author affiliation: Tscharntke, Teja. Georg-August-University; Alemania

Author affiliation: Vergara, Carlos H.. Universidad de las Americas Puebla; México

Author affiliation: Viana, Blandina F.. Universidade Federal da Bahia; Brasil

Author affiliation: Woyciechowski, Michal. Jagiellonian University; Polonia