Bee interactions with wild flora around organic and conventional coffee farms in Kiambu district, central Kenya

Abstract

Flower scarcity outside coffee flowering periods leads to a decline of pollinators' abundance and diversity possibly through death or migration. The objective of this study was to assess whether other flowering plants within and around coffee farms act as alternative floral resources that may impact on abundance and diversity of pollinators of coffee flowers. Bee pollinators of coffee were assessed and identified for a period of 27 months. Their abundance and diversity were examined within and around organically and conventionally managed coffee farms in Kiambu District in Kenya. This study provides evidence that 42 plant species from 19 families were alternative floral resources for bees that pollinate coffee. Bee pollinators of coffee were observed to visit coffee flowers as well as other flowering plants close by. Significant relationship existed between plant species and bee species richness in the organic farming (R²=0.5918; P<0.0001) and in conventional farming (R²=0.6744; P<0.0001). Therefore in coffee monocultures, presence of other flowering plants should be encouraged to support bee pollinators when coffee is not flowering and to enhance abundance and diversity of bees visiting coffee flowers.