Evaluation of Bee Diversity within Different Sweet Cherry Orchards in the Sultandaği Reservoir (Turkey)

Many varieties of sweet cherry are self-incompatible. Therefore, sweet cherry orchards require a huge population of pollinator bees to carry out an adequate amount of pollen transfer between the different varieties. Our study was conducted to evaluate the differences in the richness and diversity of these pollinators within very closely located sweet cherry orchards, and to understand the underlying effects causing these differences. The study was conducted in the Sultandağı Reservoir (Turkey) which covers the towns of Sultandağı (Afyonkarahisar) and Akşehir (Konya). In order to avoid a sampling bias, Malaise traps were used to collect bee samples. Sampling collections were repeated for three years; from 2007 to 2009, between April and May. The traps were set in the bud-swell period and lifted in the green-fruit period. Climatic data were taken from meteorology stations near the orchards. Vegetation in the surrounding areas was also inspected. The composition of pollinator bee species was determined and compared between orchards. In total, 83 bee species and 38 plant species were recorded. It was found that Halictidae is the most abundant and richest group among the pollinator bees. The effects of the quantity of the Malaise traps on bee sampling success were also tested. It was found that one trap per 325 trees is enough for an adequate sampling. Apart from the annual fluctuations of bee richness in the orchards, general differences in the bee diversity among orchards might be affected by the surrounding vegetation and especially from different agricultural practices such as tilling the ground.