The addition of flowering strips within croplands is an option available to land managers to conserve native arthropod communities and enhance the provision of important insect-mediated ecosystem services in agro-ecosystems. Here we present the results of a season-long study into how targeted floral mixes can be used to increase the populations of distinct suites of beneficial insects in cider apple orchards, and whether we can build ‘multi-functional’ flowering strips by combining targeted mixes, without introducing trade-offs in beneficial insect density.
Flower mixes were sown in 40 m strips between rows of apple trees in four intensively-managed, commercial cider orchards in Herefordshire, South-West England. The two ‘targeted’ mixes contained plant species that, from previous literature, were deemed attractive to either natural enemy groups, or bee pollinators; and a third ‘multi-functional’ (MF) mix that contained all species from each targeted mix, but sown at half the rate.
Flowering strips significantly out-performed areas under normal management (controls) in terms of flowering density, although MF plots could not match the abundances found in targeted mixes for individual plant species. Bee pollinators and natural enemies differed strongly in their preference for targeted mixes, with bee pollinators favouring the mix containing flowers with long, tubular corollae, whereas natural enemies preferred the targeted mix containing open-nectar plants. MF plots were able to attract double the number of beneficial insects groups and equivalent visitation frequencies of bee pollinators. However, visitation by natural enemy groups was reduced by 50 % in MF plots relative to preferred targeted mixes.