Sown flowering strips can benefit beneficial arthropod groups (pollinators and natural enemies) on farmland and enhance the delivery of arthropod-mediated ecosystem services in crops. However, not all flowering plants may be useful for beneficial arthropod taxa, as differences in floral traits associated with nectar accessibility (e.g. nectar-holder depth) determine resource use. Therefore, increasing the number of distinct floral traits in flower mixes may be an effective way to manage multiple arthropod-mediated ecosystem services in farmland. Here, the response of pollinators and natural enemies in cider-apple orchards to three functionally-distinct flower mixes ('open-nectar plant' mix, 'concealed-nectar plant' mix, and a third 'multi-functional' mix that contained all species in distinct mixes), sown in flowering strips between rows of trees were assessed, and compared to areas under existing management (mown grass), as well as the effects on arthropod-mediated ecosystem services (pollination and pest control) in orchards. Observations of flower visitation revealed a dichotomy in floral resource use by beneficial arthropod groups, with pollinators more abundant in plots sown with the concealed-nectar plant mix, whereas natural enemies were more abundant in plots sown with the open-nectar plant mix. When mixtures were combined, plots sown with the multi-functional mix attracted both suites of beneficial arthropods. Although effects of flower strips on ecosystem service delivery (yield, pest pressure) were less clear, there was some evidence that flower strips influenced service provision (increased predation of sentinel prey), and the abundance of key taxa (Andrena solitary bees). The link between visitation by andrenids during blossom in spring and fruit set was the clearest link found between beneficial arthropods and yield in cider-apple orchards. This thesis provides clear evidence that a trait-based approach to designing flower mixes enables sown flowering strips to support beneficial arthropod taxa and enhance multiple ecosystem services in cider orchards, and quantifies the important role that beneficial arthropods play in supporting crop production.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:742532 |
| Date | January 2014 |
| Creators | Campbell, Alistair J. |
| Publisher | Lancaster University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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