D3234: Assessing bumble bee niche partitioning along Pikes Peak

Niche partitioning between bumble bee species is fundamental to predicting how climate change
may drive local population declines. Despite southern range losses due to climate change,
bumble bees have largely remained within their latitudinal distribution s, instead shifting upwards
in elevation to remain within habitable environmental conditions. Elevational range shifts in
bumble bees affect niche partitioning, which allows for the simultaneous coexistence of several
species of bumble bees . Their similar morphologies and dependence on pollen and nectar for
food predict that bumble bee communities are largely shaped by interspecific competition for
floral resources. In the summers of 2019, 2020, and currently in 2021, bumble bee foraging data
has been collected across 2348 meters of habitat in Pikes Peak, Colorado. This data will assess
patterns of niche partitioning among bumble bee species, allowing us to predict how bumble bee
communities may be affected by climate change. From foraging data collected in 2019, certain
bumble bee niches overlap more than others using Bray-Curtis dissimilarity. For example, B.
bifarius and B. sylvicola are two medium-tongued bees with similar plant foraging (.50
Bray-Curtis) and morphology. However, B. sylvicola occupies a higher elevation range and a
shorter foraging timeline. If climate change were to drive B. bifarius into higher elevations, we
may see greater niche overlap between species, threatening the species with the lower fitness.
With further data in the coming months, a clearer display of niche overlap will allow for more
accurate predictions of how bumble bee species may fare with increasing temperatures.