Effectiveness of pollination by wild bees as influenced by landscape composition and distance from natural habitat

Abstract

Bees are an animal pollinator often utilized by fruit growers. While honey bees have historically been used for crop pollination, they are currently facing a number of threats to their population. Wild bees present a potential source of pollination services for crops to supplement those provided by honey bees. However, landscape composition and the availability of foraging and nesting resources might affect wild bee abundance and therefore pollination services. We looked at wild bee pollination in cranberry marshes in Wisconsin. The objectives of this research were to determine (1) if wild bees could provide pollination services equivalent to those provided by honey bees, (2) if wild bee pollination varied with landscape composition and (3) if distance from edge of natural habitat affected pollination by wild bees. Sites were chosen so that the surrounding landscape varied from below 35% to above 60% of agriculture or wooded area within 2 km of sites. Pan traps were placed in cranberry marshes to measure wild bee abundance. Sentinel plants, including sunflower and buckwheat, were placed in cranberry fields and visitation rates and seed count were recorded to represent pollination success. Wild bee abundance was found to be positively correlated with surrounding woodland, but was not significantly correlated with surrounding agriculture. Seed number did not significantly vary in the presence or absence of honey bees or with surrounding agriculture or wooded area. It was, however, significantly affected by an interaction between honey bee presence and surrounding agriculture. Seed number did not significantly differ at increasing distances from natural habitat. Based on these observations, wild bees may be a viable alternative to honey bees depending on habitat composition.

Made publicly available on 5/27/14 at the request of the author.