Climate change is having a large impact on bumblebees — important pollinators of numerous food crops – perhaps much more than habitat loss or pesticides, according to a new study co-authored by a University of Guelph researcher.

The study, which looked at 110 years’ worth of data, found that warming temperatures in North America and Europe are shrinking bumblebee ranges.

Alana Pindar, now a post-doctoral researcher in U of G’s School of Environmental Sciences (SES), examined the data while working with University of Ottawa biologist Jeremy Kerr.

Fruit plants such as tomatoes depend on bumblebees for buzz pollination, she said. Declining bumblebee populations could have a profound impact on farmers.

“This is the first paper of its kind, and we looked at more than 400,000 observations on two continents to test climate change related shifts in bumblebee species latitudinal and thermal range limits,” she said.

“What we found is that, unlike other species that have shown positive responses to climate change, bumblebees are not expanding their ranges north, despite warming temperatures. But at the same time, they are being pushed up from the south as it gets warmer there.”

In both North America and Europe, bumblebee species ranges were contracting, especially in the southern parts of both continents.

“When you combine climate change with the impact of land use changes and pesticides, this adds up to a recipe for extinction for some species,” Pindar said.

Along with SES professor Nigel Raine, holder of the Rebanks Family Chair in Pollinator Conservation, she looks at how bees respond to the interaction various stress factors.

“Climate change is definitely a large global issue, but there is the potential for smaller, localized solutions to help bumblebees and that is what we will be researching,” she said.

The study, “Cross-continental convergence of climate change impacts on bumblebees,” was published July 9 in the journal Science.