A two-year comparison of native pollinators under strikingly different seasonal conditions in north Georgia

During the past two years, we have investigated the abundance and diversity of the native bees of North Georgia. During March-October 2010 and March-October 2011, approximately 3000 bees and thousands of pollinating flies were collected. Sampling was performed every 2-4 weeks in four different North Georgia Apple Orchards. The study was designed to intensively inventory native pollinator populations in apple orchards; however, this data can be applied in other agro-ecosystems as well. In addition, trends of species abundance, emergence period, and diversity were also examined. The 2011 season was unusual due to a very early apple bloom, which peaked before the first blooms opened during the 2010 season. This early bloom stemmed from a warm snap in February. Temperatures returned to average levels shortly thereafter. However, the warm snapped trigger an early apple bloom, but did not change the emergence schedule of the native bees. The reduced presence of all pollinators was striking during the initial onset of the apple bloom. However, general abundance of pollinators slowly returned to similar levels witnessed in 2010. The diversity of pollinators was similar in both years; however, species abundance was reduced. In the 2011 season, Tiphiids and muscoid-flies dominated the bloom. It appears the onset of bloom had little effect on diversity, with few species present earlier than 2010.