Gateway Gazette

Study Reveals Alarming Effects of Climate Change on Bumblebees

More than 100 years of data show bumblebees are losing vital habitat south, but also not expanding north

By Drew Scherban

Paul Galpern, co-author of study and assistant professor of landscape ecology in the Faculty of Environmental Design.
Paul Galpern, co-author of study and assistant professor of landscape ecology in the Faculty of Environmental Design.

Researchers from the University of Calgary and University of Ottawa have found that climate change is having a significant impact on bumblebee species in North America and Europe.

This astonishing find about the habitat range of bumblebees will be published in the journal Science.

Bumblebees are losing vital habitat in the southern regions of North America and Europe, but another pressing issue is that bumblebee species generally haven’t expanded north, explains Paul Galpern, assistant professor of landscape ecology in the Faculty of Environmental Design and co-author of the study.

“Climate change may be making things too hot for them in the south, but is not pulling them north as expected,” says Galpern.

For many wildlife species, when the climate warms, they respond by expanding into areas that used to be too cold for them, pushing into areas that are closer to the North Pole. Bumblebee species are experiencing a different fate and being held at the northern-most range while rapidly losing ground in the south.

Bumblebees losing geographical range as climate warms

"Bumblebee on gorse flower" by Neil Phillips from uk is licensed under CC BY 2.0
“Bumblebee on gorse flower” by Neil Phillips from uk is licensed under CC BY 2.0

“Picture a vise. Now picture the bumblebee habitat in the middle of the vise,” says Jeremy Kerr, professor and University Research Chair in Macroecology and Conservation Biology at the University of Ottawa and lead researcher of the study. “As the climate warms, bumblebee species are being crushed as the climate vise compresses their geographical ranges. The result is widespread, rapid declines of pollinators across continents; effects that are not due to pesticide use or habitat loss. It looks like it’s just too hot.”

It is this revelation that is the most concerning because a very important piece of the ecological puzzle is under threat.

“Bumblebee species play critical roles as wild pollinators, not just for crops, but for all sorts of plants,” says Galpern. “They provide an important service to ecosystems. They help plants produce fruits and seeds and this in turn provides both food and habitat for other animals and so on.”

With nearly half a million observations compiled from museum collections and citizen scientist collectors from North America and Europe over the last century, this rich historical record enabled researchers to track 31 bumblebee species in North America and 36 in Europe.

“We don’t know for sure what is causing a stagnation at the northern end of things. Bees should be able to start new colonies in places they did not historically occupy. But we don’t know why this is happening so slowly that it looks like the ranges are not moving at all,” says Galpern. “This all points to the fact that bumblebees are at risk, and the services that they provide are increasingly threatened by human-caused climate change.”

As this study demonstrates, creating strong environmental management practices is critically dependant on our ability to understand the changes that are taking place around us. Research on the impact of climate change, like the critical loss of habitat for pollinators described in this study, is a focus of our Human Dynamics in a Changing World research priority that encompasses how humans adapt to rapid change. This research area is also supported by two research platforms: Synthesis and Visualization, and Analytics and Simulations.

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Source University of Calgary

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