Drivers of bee visitation to patches of urban and wildland California poppies, Eschscholzia californica: The interplay between resource characteristics and landscape context

An early-season survey assessed the visitation rates of bees to patches of California poppies, Eschscholzia californica, in both wildland and urbanized ecosystems in the East Bay cities of Berkeley, Emeryville, and Oakland, California. Floral resource characteristics (patch size and floral density), the landscape characteristics (distance to wildland, distance to riparian areas, distance to green space, land use, and traffic disturbance), and the regional landscape context (urban versus wildland) were examined for their impact on the visitation rates of eight taxonomic groups of bees that are common visitors to the California poppy. Although the mean observed visitor abundance and taxon richness between urban and wildland poppy patches did not differ significantly, the individual taxa did show divergent dominance patterns between the two landscapes. Generally, larger bodied species were significantly more abundant at wildland patches while smaller bodied species were more abundant at urban patches. At the community level, floral visitation was modelled by the size and density of the resource, and this trend was consistent between both landscapes. At the guild level, the visitation rates of larger bodied bees (Megachile spp.) and social bees (A. mellifera and B. vosensenskii) were modelled by resource patch size and floral density, while smaller bodied bees (members of the Family Halicitidea and Andrena spp.) were influenced by landscape characteristics such as distance to the wildland urban interface and distance to riparian areas.