Effects of Habitat Fragmentation on the Nesting Dynamics of Desert Bees

Anthropogenic changes in land use and habitat fragmentation are thought to be greater drivers of declines in the abundance and species richness of pollinating insects such as bees (Hymenoptera: Apiformes) than agricultural intensification and pesticide use. Yet, few studies have examined how habitat fragmentation by urbanization affects pollinator nesting dynamics. We investigated the nesting dynamics of native solitary bee species that inhabit fragments of Sonoran Desert in Tucson, AZ. Specifically, we compared floral densities, nest completion, and nest attack rates of cavity-nesting bees in large (>2 ha) and small (