| Abstract |
One dramatic impact of the acute decline in global biodiversity includes losses of once-common species and the potential cascading effects of their absences on ecosystems. Using 23 y of data, 14,457 surveys across 2.8 million km2 in the western United States, we demonstrate negative impacts of increasing temperatures and drought and identify nitroguanidine neonicotinoids as the pesticides most impacting the formerly common pollinator, the western bumble bee (Bombus occidentalis). By the 2050s, our most optimistic scenario predicts occupancy declines in almost half of ecoregions; more severe scenarios predict declines in all ecoregions ranging from 51 to 97%. The precipitous decline of this generalist species is a bellwether for loss across many taxa sensitive to environmental changes around the globe. |
| Authors |
William M. Janousek  , Margaret R. Douglas , Syd Cannings , Marion A. Clément , Casey M. Delphia , Jeffrey G. Everett , Richard G. Hatfield , Douglas A. Keinath , Jonathan B. Koch , Lindsie M. McCabe , John M. Mola , Jane E. Ogilvie , Imtiaz Rangwala , Leif L. Richardson , Ashley T. Rohde , James P. Strange , Lusha M. Tronstad  , Tabitha A. Graves
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