Bees' needs across a suburban-rural landscape mosaic
Wild bees can potentially compensate for recent declines in domesticated honey bees that are conventionally used for crop pollination. Little is known, however, about the relative contribution of wild bees to pollination services in southern Quebec and the habitat requirements of bees in the landscapes surrounding farms. We conducted bee biodiversity surveys both within apple, blueberry and raspberry farms when crops were in bloom as well in adjacent suburban and meadow habitats. We asked: 1) Does bee diversity promote fruit quality and production?, 2) Whether bee community composition differs amongst crop types?, 3) How does landscape composition and configuration impact wild bee species in and surrounding orchards? In total, 100 sites were sampled for wild and domesticated bees in 2012. Linear mixed models were used to study the correlations amongst landscape metrics, patterns of bee diversity and indices for pollination services.
A total of 157 wild bee species were found visiting fruit farms in our study region, one, incidentally, never having been recorded previously in the western hemisphere. Findings indicate that bee functional diversity positively predicts both apple fruit production and quality. Bee species assemblages in apple and small fruit farms are distinct but all communities become both functionally and taxonomically less diverse with agricultural intensification in the immediate landscape. Bee diversity is higher in landscapes that can provide continuous floral and nectar supplies for pollinators throughout the spring and summer. Specifically, meadowlands, forests, and suburban habitats all promote wild bee diversity as each have a staggered flowering phenology. We provide practical recommendations for landscape managers, agriculturalists, and suburban property owners to bolster bee biodiversity and pollination services.