Incorporating citizen science, museum specimens, and field work into the assessment of extinction risk of the American Bumble bee (Bombus pensylvanicus De Geer 1773) in Canada

Many Bumble bee (Bombus) species are in decline and conservation efforts must be undertaken now to lessen or reverse the trend. For effective efforts to occur, the first step must be an accurate assessment of extinction risk. Yet only four of over forty Canadian Bombus species have been assessed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC), despite evidence of decline for numerous species in this genus. Here, we evaluated the status of the American Bumble bee, Bombus pensylvanicus De Geer 1773 in Canada. A challenge with species assessments is obtaining adequate occurrence data temporally and spatially. Citizen science is a field where volunteers can collect data similar to that of experts over a broader coverage than researchers could often cover alone. We used data from the Bumble Bee Watch citizen science program, a database of North American Bombus records representing field survey and collection records from the late-1800s, and our own field surveys to evaluate the status of B. pensylvanicus in Canada using the International Union for the Conservation of Nature (IUCN) Red List assessment criteria. We found that B. pensylvanicus’ Area of Occurrence has decreased by about 70%, its Extent of Occurrence by 37%, and its relative abundance by 89%, from 2007 to 2016 as compared to 1907–2006. These findings warrant an assessment of Critically Endangered using IUCN Red List criteria for B. pensylvanicus in Canada. Our findings will help inform management of B. pensylvanicus and exemplify the importance of citizen science programs for wildlife conservation.