Diversity of Bees at Different Altitudes in the Knuckles Forest Reserve

Abstract

A year around survey of bees carried out in the Knuckles mountain range at different altitudes having specific habitat types highlighted the effect of altitude and habitat on the presence and abundance of bees. The study was based on hourly counts of bees made once every month in five selected habitats; natural forest, managed cardamom, Patana grassland, cultivated home gardens and mixture of habitats including home gardens, scrublands and rice fields, situated at different altitudes ranging from 150 - 1350 m. The study recorded a total of 62 bee species belonging to 26 genera in 4 families representing more than ¾ of the total bee fauna recorded for Sri Lanka. The distribution of bee species decreased with increasing elevation. Areas under cardamom cultivation harboured the lowest number of bee species. Shannon diversity index gave the highest score for the bee diversity in home gardens. The finding of this study highlights the fact that the highest diversity of bees is at lower elevations where the climate is comparatively warmer. Furthermore, at lower elevations due to human settlements, the vegetation comprises a mixture of cultivated crops, flowering herbs and patches of natural vegetation providing a ready source of pollen and nectar for bees throughout the year. Key Words: Knuckles Forest Reserve, bees, altitude, climate, vegetation doi: 10.4038/cjsbs.v37i1.496 Cey. J. Sci. (Bio. Sci.) 37 (1): 61-72, 2008