Strong phenological shifts among bumblebee species in North America can help predict extinction risk

Abstract

Biological responses to climate change can affect species' survival prospects, and failures to track favourable climate conditions can increase extinction risk. Two predominant strategies to mitigate climate change are spatial and temporal shifts, however the trade-offs between these responses for vital pollinator taxa are unknown. Also, the phylogenetic pattern of climate-driven phenology shifts is poorly understood. Here, we analyze emergence and peak phenology for 20 Bombus species across Canada and the United States during baseline (1954–1970) and modern (2004–⁠2012) periods to assess whether Bombus phenology varies with spring onset. We find that bumblebee species which maintain phenological synchrony with spring onset demonstrated an improved persistence probability during the modern period compared to the baseline. Climate strongly explained variation in emergence and/or peak colony abundance phenology in 15 of 21 species included in the study. Phenology shifts were not found to be phylogenetically structured. This approach serves as a guide to analyzing spatio-temporal responses to climate change on a large scale across taxa.