The classification of impending disappearance is considered the highest before the definitive extinction is declared.
About 42 of Canada's 850 bee species are bumblebees – important pollinators for crops, including apples, tomatoes, blueberries, and legumes, as well as trees, shrubs, and wildflowers.
Professor Laurence Packer of York University points out that many of the 42 bumblebee species show substantial declines in population.
"This decline of important pollinators will have upstream impacts on the entire ecosystem," said Packer.
As the number of bumblebee species declines, plants are pollinated in a different way.
Mr Packer explains that bees have special preferences. Thus, when certain species are lost, the flowers they prefer are less pollinated.
The findings of York University researchers are detailed in a new study published in the Journal of Insect Conservation, April 17th.
The researchers found that the extent of occurrence of American drone decreased by about 70% and its relative abundance decreased by 89% from 2007 to 2016, compared to the period between 1907 and 2006.
The study ranks the risk of extinction of the American drone at a higher level than the latest assessment of a federal advisory committee that the species was the subject of special concern for extinction, rather than imminent risk.
"We looked at historical data over a 100-year period and compared it over the last 10 years. We found a decrease of about 89% in abundance compared to other bees. This is really worrying, "said Victoria MacPhail, a colleague of Mr. Packer.
She cites as possible explanations climate change and the loss of natural habitats caused by the development of agriculture.