DIVERSITY AND ABUNDANCE OF NATIVE BEE POLLINATORS ON BERRY CROPS AND NATURAL VEGETATION IN THE LOWER FRASER VALLEY, BRITISH COLUMBIA

Abstract

Native bee pollinators were collected and observed on cultivated blueberry, raspberry, and cranberry and on natural non-cultivated plants such as blackberry, buttercup, fireweed, thistle, and hairy cat's ear. Higher abundance and diversity of native bees were found on natural vegetation than on berry crops. Native bee populations on berry crops increased from 1981 to 1982, although diversity was similar. Native bees were not abundant enough to ensure adequate pollination of berry crops, and therefore, the use of managed honey bees is advisable. Pesticide impact, competition with managed honey bees, and habitat destruction have probably decreased native bee populations in agricultural areas of the Fraser Valley.The use of a standard measure of native pollinator abundance, bees observed/min/m², is recommended for future studies of this kind.