This study compared different mix types and margin management regimes to test how to increase resources for pollinating insects most effectively, as part of the SAFFIE research into margin management. The greatest increase in pollen and nectar sources and abundance of butterflies and bumblebees was achieved by including broad-leaved flowering plants in the mix. The effects of subsequent margin management were less marked. Scarification led to an increased diversity of broad-leaved flowering plants, and use of graminicide reduced the competition from grasses and an increase in flower abundance and number of bumblebee species.
Arable field margins sown with simple grass mixtures provide few pollen and nectar resources, as the dense grass sward suppresses the broad-leaved flowering plants. The primary pollen and nectar resources in such margins are often pernicious weeds such as thistles. However, such margins are important for hibernating beetles, spiders, small mammals and nesting bumblebees and birds, and some sown grasses are important food plants for some species of butterflies. Annual broad-leaved weeds are relatively poor pollen and nectar sources relative to perennial broad-leaved plants.
Reference: Pywell et al (2007) The SAFFIE project: enhancing the value of arable field margins for pollinating insects. Aspects of Applied Biology, 81: 239-245.