A global synthesis reveals biodiversity-mediated benefits for crop production

Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield-related ecosystem services can be maintained by a few dominant species or rely on high richness remains unclear. Using a global database from 89 studies (with 1475 locations), we partition the relative importance of species richness, abundance, and dominance for pollination; biological pest control; and final yields in the context of ongoing land-use change. Pollinator and enemy richness directly supported ecosystem services in addition to and independent of abundance and dominance. Up to 50% of the negative effects of landscape simplification on ecosystem services was due to richness losses of service-providing organisms, with negative consequences for crop yields. Maintaining the biodiversity of ecosystem service providers is therefore vital to sustain the flow of key agroecosystem benefits to society. [Abstract copyright: Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).

Delivery of floral resources and pollination services on farmland under three different wildlife-friendly schemes

Management that enhances floral resources can be an effective way to support pollinators and pollination services. Some wildlife-friendly farming schemes aim to enhance the density and diversity of floral resources in non-crop habitats on farms, whilst managing crop fields intensively. Others, such as organic farming, aim to support ecological processes within both crop and non-crop habitats. How effective these different approaches are for supporting pollination services at the farm scale is unknown. We compared organic farming with two non-organic wildlife-friendly farming schemes: one prescriptive (Conservation Grade, CG) and one flexible (Entry Level Stewardship, ELS), and sampled a representative selection of crop and non-crop habitats. We investigated the spatial distribution and overall level of: (i) flower density and diversity, (ii) pollinator density and diversity and (iii) pollination services provided to Californian poppy (Eschscholzia californica) potted phytometer plants. Organic crop habitats supported a higher density of flowers, insect-wildflower visits, and fruit set of phytometers than CG or ELS crop habitats. Non-crop habitats supported a higher density of flowers and insect-flower visits than crop habitats on CG and ELS farms. Pollination services were higher on organic farms overall compared to CG or ELS. Pollinator diversity and density did not differ between schemes, at the point or farm level. CG farms received the highest total number of insect-wildflower visits. The findings support organic farming practices that increase floral resources in crop habitats, such as sowing clover or reduced herbicide usage, as mechanisms to enhance pollination services. However trade-offs with other ecosystem services are likely and these are discussed. The findings support the CG scheme as a way of supporting pollinators within farms where high wheat yields are required

Seed coating with a neonicotinoid insecticide negatively affects wild bees.

Understanding the effects of neonicotinoid insecticides on bees is vital because of reported declines in bee diversity and distribution and the crucial role bees have as pollinators in ecosystems and agriculture. Neonicotinoids are suspected to pose an unacceptable risk to bees, partly because of their systemic uptake in plants, and the European Union has therefore introduced a moratorium on three neonicotinoids as seed coatings in flowering crops that attract bees. The moratorium has been criticized for being based on weak evidence, particularly because effects have mostly been measured on bees that have been artificially fed neonicotinoids. Thus, the key question is how neonicotinoids influence bees, and wild bees in particular, in real-world agricultural landscapes. Here we show that a commonly used insecticide seed coating in a flowering crop can have serious consequences for wild bees. In a study with replicated and matched landscapes, we found that seed coating with Elado, an insecticide containing a combination of the neonicotinoid clothianidin and the non-systemic pyrethroid β-cyfluthrin, applied to oilseed rape seeds, reduced wild bee density, solitary bee nesting, and bumblebee colony growth and reproduction under field conditions. Hence, such insecticidal use can pose a substantial risk to wild bees in agricultural landscapes, and the contribution of pesticides to the global decline of wild bees may have been underestimated. The lack of a significant response in honeybee colonies suggests that reported pesticide effects on honeybees cannot always be extrapolated to wild bees