We assessed bee diversity and abundance in 8 different habitats in Vancouver, Canada, in order to determine the potential of various urban sites to support bees. Habitats examined included, botanical gardens, community gardens, weedy-abandoned fragments, flowerbeds near old growth forests, isolated flowerbeds, traditional backyards, naturescape backyards and naturescape parks. Naturescape areas are mowed unfrequently and have a deliberately planted diversity of native plants to promote native wildlife. Apis mellifera L. were scarce in all habitats, suggesting a decline in managed honey bees due to parasitic mites recently introduced to the region. Bombus species were the most abundant wild bees, and 30 different bee species were collected in total, including Andrena spp., Ceratina spp., Halictus spp., Lasioglossum spp., Megachile spp., Melissodes spp., and Osmia spp. Botanical gardens, flowerbeds near old growth forests, and community organic gardens with plants such as heather, laurel, and catoneaster showed the highest diversity and abundance of wild bees early in the season. Bee populations in weedy-abandoned fragments peaked later in the summer when buttercups, clover and hairy cat's ear were blooming. Isolated flowerbeds with tulips, petunias and daffodils had poor diversity and abundance of bees throughout the year. Other important bee plants in the Vancouver area included weeping willow, holly, and cherry. Native plants such as salmonberry and vine maple were attractive to a variety of bees, but they produce low densities of flowers and would require high-density plantings in order to sustain large bee populations. Dead wood, sandy banks and dry stems of red elderberry and blackberry were important nesting sites for wild bees. Our study shows that urban areas have potential to be important pollinator reservoirs, especially in community gardens, naturescape areas, and weedy-abandoned fragments. Urban planners should consider these observations for promoting beneficial insects like bees.
Keywords: pollination, wild bees
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA