Plant identity determines pollinator, natural enemy, herbivore, and decomposer abundances in flower plantings

Abstract Flower plantings in agricultural landscapes can contribute to sustainable crop production by enhancing pollination and biological control services. However, selecting plant species that promote multiple ecosystem services is challenging, since plants that favor pollinators may not equally foster natural enemies, and potential trade‐offs, such as inadvertently promoting crop pests, must be considered. This complexity increases when accounting for belowground effects. We evaluated 27 candidate plant species for their ability to host functionally important above‐ and belowground organisms—pollinators, natural enemies, herbivores, and decomposers—and assessed how plant characteristics such as floral area, timing of peak bloom, life cycle, and plant cover affect these organism groups. We found that certain plant species have the potential to support several groups of beneficial organisms, suggesting they can enhance multiple ecosystem services. Annual plants had higher abundances of both above‐ and belowground beneficial organisms compared to perennials. Greater plant cover was positively associated with hoverfly abundance. Several functionally important organism groups were positively correlated across plant species, but these positive correlations were not explained by shared responses to plant characteristics. Our findings underscore the significance of plant species identity and characteristics in designing flower plantings for enhancing biodiversity and ecosystem services and highlight the importance of including belowground organisms like nematodes in future studies. Our results for specific plant species and plant characteristics can be used to design flower mixtures supporting several ecosystem service providers while considering potential trade‐offs, thereby increasing the efficiency of flower plantings.