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

Abstract

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.