Bumble bee phenology: Does spatial variation in temperature matter?

All organisms must cope with changing climates. Both mean temperatures and the frequency and intensity of extreme weather events are predicted to increase, generating novel conditions that may influence the timing of critical life history events (phenology) for diverse taxa. However, the degree to which spatial variation in temperature from local to regional scales affects phenology is largely unknown but may be critical to accurately predict climate change impacts. We investigated how temperature variation at different spatial scales altered phenology of bumble bees, critical pollinators in decline in part due to climate change. We measured timing of spring emergence as well as seasonal abundance of bumble bees for two years at three sites across an altitudinal gradient; we also measured air and soil microclimate temperatures at these sites for comparison with local weather station data. Together, these data allowed us to link temperature variation at different spatial scales with variation in phenology across bumble bee communities. Accounting for this variation will facilitate better predictions of pollinator responses to changing climates.