Abiotic and biotic determinants of pollinator activity on smooth blackberry (Rubus canadensis) in Waldron Fen, Alanson, MI.

Abstract

The purpose of our experiment was to determine the abiotic and biotic variables that affect pollinator visitations rates of Rubus canadensis at Waldron Fen in northern Lower Michigan. Five 1m2 plots were set up, each testing a separate factor and/or acting as a control. These factors included: sunlight/large patch, shade, small patch, petals off, and petals on. Notes were also taken on temperature throughout the day. Number of pollinator visits—determined by pollinator contact with each blossom—was recorded for each plot in ten-minute intervals during two half-day and two all-day sessions. Our resulting data concluded that pollinator activity increased as the day progressed and the temperature rose in all but the sun and large patch plot. Additionally, the plots with direct sun and petals had significantly higher mean numbers of visits than the plot with petals removed as well as the plot in the shade. Finally, we observed that the smaller patch had a significantly higher mean number of visits than the large patch. All in all, we found pollination rates to be highest during the afternoon in warmer, drier conditions where petals were present on R. canadensis. The results from this experiment could prove useful in future experiments and studies of ideal conditions for high pollination rates.