Data from: Range-wide genetic analysis of an endangered bumble bee (Bombus affinis) reveals population structure, isolation by distance, and low colony abundance

Declines in bumblebee species ranges and abundances are documented across
multiple continents and have prompted the need for research to aid species
recovery and conservation. The rusty patched bumblebee (Bombus affinis) is
the first federally-listed bumblebee species in North America. We
conducted a range-wide population genetics study of B. affinis from across
all extant conservation units to inform conservation efforts. To
understand the species’ vulnerability and help establish recovery targets,
we examined population structure, patterns of genetic diversity, and
population differentiation. Additionally, we conducted site-level analysis
of colony abundance to inform prioritizing areas for conservation,
translocation, and other recovery actions. We find substantial evidence of
population structuring along an east-to-west gradient. Putative
populations show evidence of isolation by distance, high inbreeding
coefficients, and a range wide male diploidy rate of ~15%. Our results
suggest the Appalachians represents a genetically distinct cluster with
high levels of private alleles and substantial differentiation from the
rest of the extant range. Site-level analyses suggest low colony abundance
estimates for B. affinis compared to similar datasets of stable,
co-occurring species. These results lend genetic support to trends from
observational studies suggesting B. affinis has undergone a recent decline
and exhibits substantial spatial structure. The low colony abundances
observed here suggest caution in overinterpreting the stability of
populations even where B. affinis is reliably detected interannually.
These results help delineate informed management units, provide context
for the potential risks of translocation programs, and can help set clear
recovery targets for this and other threatened bumblebee species.