Utilisation of plant functional diversity in wildflower strips for the delivery of multiple agroecosystem services

Increased plant diversity in cropping systems can play an important role in agriculture by enhancing arthropod-mediated ecosystem services, including biological control and pollination. However, there is limited research investigating the concurrent influence of plant functional diversity within cultivated systems on different arthropod functional groups, the provision of multiple ecosystem services, and crop yield. During a field experiment, repeated over 2years, we measured the effect of increasing plant functional diversity on community structure of arthropod visitors, the abundance of multiple pests and induced crop damage, and fruit production in two varieties of tomato. Plant resources (floral and extra-floral nectar and pollen) were included within experimental plots in four levels, with each level increasing the plant functional group richness, based on floral morphology and availability of resources, in a replacement series. The presence of sown flower mixtures in experimental plots was associated with increased abundance and diversity of natural enemy functional groups and an enhanced abundance of bees (Hymenoptera: Apiformes). However, we only detected relatively small variability in arthropod visitors among types of mixtures, and increased abundance of natural enemies did not translate into stronger pest suppression or reduced crop damage. Lepidoptera pest damage was significantly higher in plots adjacent to wildflower strips, an ecosystem disservice, but a significantly higher crop productivity was recorded from these plots. Our results provide evidence that inclusion of non-crop plant resources in agroecosystems can improve the conservation of beneficial arthropods and may lead to increased crop productivity.