Composition and Floral Resources of Bees and Butterflies in Kaya Muhaka Forest and Surrounding Farmlands, Kwale County, Kenya

ABSTRACT

The current global pollination crisis and the importance of insects in pollination service that maintains the native plant populations, agricultural enterprise, ecosystem resilience and food security do motivate the concern to conserve insect pollinators. Kaya forests are rich in biodiversity and endemism; they are potential sites for conservation of these pollinators in the coastal region of Kenya. However, they are threatened by illegal deforestation, charcoal burning, settlement and farming causing conservation threat to the pollinators. Understanding the composition of bee and butterfly communities and their response to the disturbance is essential if their conservation is to be successful in the area. The main objective of the study was to establish the composition of bees and butterflies along the disturbance gradient. The study examined the diversity and abundance of these pollinators and their floral resources along a disturbance gradient from the natural forest through the forest edge to farmlands. The study was carried out between April 2010 to September 2010 and data analysed using R software. Diversity, species richness, abundance and floral resources were examined in Kaya Muhaka forest, forest edge, surrounding fallow farmlands and crop fields. The survey was done at sampling points along two habitat zones in transition from the forest core to farmlands. Sampling was done using sweep nets within three permanent 50 m x 2 m belt transects at each sampling point. 36 belt transects were surveyed in 12 sampling points across the habitats for six months. Floral resources were identified and linked to the associated bees and butterflies. A total of 52 bee species and 66 butterfly species were recorded. The highest bee diversity was recorded in fallow farmlands and lowest in forest core. The diversity of bee species across the habitats was not statistically different. However, butterfly diversity was significantly higher in forest edge than in crop fields (P = 0.021). The lowest butterfly diversity was recorded in fallow farmlands. Both bees and butterflies were more abundant in the farmlands. Crop fields and forest edge were closely similar in bee and butterfly composition. Increasing distance from forest core had no significant effect on bee and butterfly diversity and abundance. The effect of floral resources richness on bee species richness was highly significant (P = 0.004). However, floral richness did not have significant effect on butterfly richness. Bees and butterflies were not evenly distributed in the habitats. These findings are important for understanding and management of insect pollinators in changing landscapes.