Evidence is increasing that numerous native and wild bee populations have dramatically decreased. Drivers of this decline are often linked to habitat loss through human land use change. While the effects of industrial agriculture on wild bees are well documented, the effects of urban development are less clear. Studies have produced varying accounts of urbanity’s effects on general wild bee abundance, diversity, and richness. There have been studies finding no significant effect, negative trends of urban development, and positive effects at intermediate development with no clear general trend. We propose that finding significant effects may require more attention be paid to smaller functional groups rather than full sets of sampled bees in order to utilize knowledge of group specific natural history. We studied bumble bees (Bombus) sampled in urban gardens and nature reserves from multiple cities in southeast Michigan. Environmental profiles of the sample sites were developed using the National Land Cover Database and US Census with GIS to address the following questions: How does the level of impervious space affect the bumble bee abundance and diversity at resource centers (urban gardens) in urban landscapes? How does the consideration of natural history and the landscape itself further elucidate our results?
Taking into account land use history and the natural history of the species sampled, we find significant negative effects of urban development on Bombus diversity and abundance. These effects differ greatly among the different subsections of the bees sampled. Using these differences provides further clues as to how bees in this genus respond to human land use change. Mainly, bees in the genus Bombus seem to be limited more by nesting space loss rather than changes in flowering resources.