The conservation status of nine bumble bee species in North America

The global decline of bumble bee pollinators (Bombus Latreille) has been documented across multiple species in North America, Europe and Asia. Localized extirpation of several species have been attributed to climate change, urbanization, pesticide use, pathogens and competition with introduced bumble bees, particularly agriculturally managed ones. Despite the growing evidence of decline of North American bumble bees, there have been no geographically or temporally broad investigations to assess the extent of their decline. Here we provide a novel quantitative assessment of the conservation status of nine bumble bee species endemic to North America using data from over 100 years of Natural History Collection specimen labels and current standardized surveys. From these data we calculate the probability that these nine bumble bee species are extant across several North American ecoregions, and incorporate these probabilities into an aerial framework to investigate potential clustering patterns of ‘extantness’ within their respective geographic distributions. These quantitative metrics may be useful in supporting legislative actions that facilitate the conservation of bumble bees, particularly when coupled with narrow geographic studies and anecdotal accounts of bumble bee decline or extirpation.