The natural habitats of the Cape region are a world biodiversity hotspot, but the effect of this diversity on pollination and biological control services is unknown, as is the effect of the orchards on their surrounding habitats. Led by the University of Leeds and Stellenbosch University, we measured how differences in farm practices and differences in the availability of wild beneficial insects affect fruit production and suitability for export, domestic or processed food (e.g. juice) markets, and thus how it affects crop value and farm economics. We will also look at how the income generated by fruit production is distributed through the local and national economy, and thus the effects of livelihoods and wellbeing. Distinctions in practices and outcomes between large long-established orchards, and those recently established through the BEE (Black Economic Empowerment) programme were explored.
We found strongly significant impacts of proximity to natural habitat on the density of biocontrol insects in orchards: parasitoids in particular are more abundant in natural habitats than in the orchards. We are also finding strong effects of using HIPV lures to better survey these insects. The provision of floral resources in orchards has been shown to affect pollinator densities (in particular, of non-honeybees) and fruitset. Further results are still being analysed.
The landscape and floral resource findings corroborate the generality of trends tested so far in Europe and North America. The floral resources findings in particular show that the local growers' concerns of competition with crops for pollination are ill-founded. The utility of HIPV lures may be adopted more widely in assays of biocontrol organisms within agricultural landscapes.