Bumble Bee Species Distribution And Genetic Structure Of Bombus Vagans In The Southern Appalachians

Bumble bees (Bombus spp.) have faced significant declines worldwide in the past 60 years due to anthropogenic factors. Lacking routine monitoring of populations, their fate is uncertain. With decreased population numbers, bumble bees suffer lower genetic diversity. Sufficient dispersal will help maintain genetic diversity and enable bumble bees to survive anthropogenic stressors. This study evaluated the relative abundance and distribution of Bombus species along a 900 km MegaTransect in the southern Appalachians using citizen scientists and examined the population genetics and dispersal preferences of Bombus vagans using microsatellite markers and Circuitscape geospatial modeling. Ten species were identified of the 3700 bees sampled at three National parks. Species diversity was skewed by one abundant species, Bombus impatiens. Two species of concern, Bombus affinis and Bombus terricola, were absent from surveys. Bombus vagans genetic analysis indicated low levels of inbreeding, but overall genetic diversity was stable. Bombus vagans isolation by resistance models had better fit with genetic data than isolation by distance models. A potential cryptic species was identified at one site. Circuitscape models indicated dispersal preference of high solar radiation, habitat openness, and imperviousness, which seemed to follow rural roadways. Management strategies should be directed towards creating roadside pollinator habitat.