Summary1. Pollination services from wild insects contribute to crop productivity around the world, but are at risk of decline in agricultural landscapes. Using highbush blueberry as a model system, we tested whether wildflower plantings established adjacent to crop fields would increase the abundance of wild pollinators during crop bloom and enhance pollination and yield. 2. Plantings were seeded in 2009 with a mix of 15 perennial wildflower species that provided season-long bloom and increased plant density and floral area during the subsequent 3 years. 3. Honeybees visiting blueberry flowers had similar abundance in enhanced and control fields in all 4 years of this study, whereas wild bee and syrphid abundance increased annually in the fields adjacent to wildflower plantings. 4. Crop pollination parameters including percentage fruit set, berry weight and mature seeds per berry were significantly greater in fields adjacent to wildflower plantings 3 and 4 years after seeding, leading to higher crop yields and with the associated revenue exceeding the cost of wildflower establishment and maintenance. 5. Synthesis and applications. We suggest that provision of forage habitat for bees adjacent to pollinator-dependent crops can conserve wild pollinators in otherwise resource-poor agricultural landscapes. Over time, these plantings can support higher crop yields and bring a return on the initial investment in wildflower seed and planting establishment, also insuring against loss of managed pollinators. Further understanding of the importance of planting size, location and landscape context will be required to effectively implement this practice to support crop pollination.

Enhancing pollination services LA Garibaldi et al. 440www.frontiersinecology.org

Floral plantings are promoted to foster ecological intensification of agriculture through provisioning of ecosystem services. However, a comprehensive assessment of the effectiveness of different floral plantings, their characteristics and consequences for crop yield is lacking. Here we quantified the impacts of flower strips and hedgerows on pest control (18 studies) and pollination services (17 studies) in adjacent crops in North America, Europe and New Zealand. Flower strips, but not hedgerows, enhanced pest control services in adjacent fields by 16% on average. However, effects on crop pollination and yield were more variable. Our synthesis identifies several important drivers of variability in effectiveness of plantings: pollination services declined exponentially with distance from plantings, and perennial and older flower strips with higher flowering plant diversity enhanced pollination more effectively. These findings provide promising pathways to optimise floral plantings to more effectively contribute to ecosystem service delivery and ecological intensification of agriculture in the future.

No abstract

Wildflower plantings can support local abundance of natural enemies, but their influence on biological control of pests in adjacent crop fields is less well documented. To test whether biological control is enhanced by these plantings, we established native, perennial wildflowers in areas adjacent to highbush blueberry fields. Once wildflowers were established we found greater abundance of natural enemies in the fields adjacent to wildflower plantings compared with those adjacent to unenhanced control field perimeters. Predaceous arthropods, including spiders, hoverflies, and lady beetles, were among the most common natural enemies observed and collected in the blueberry fields. Using corn earworm eggs, Helicoverpa zea (Lepidoptera: Noctuidae), as sentinel prey we found a similar pattern of biological control, with higher biological control services index values in fields adjacent to the wildflower plantings than in the unenhanced control fields. Our results provide evidence for the ability of wildflower plantings to support natural enemy populations in agricultural landscapes, and to potentially provide local enhancement of biological control in adjacent crops.