A study led by Canadian researchers shows that bumblebees are disappearing in many areas where they lived several decades ago and climate change is to blame.
Unlike most animals—and for reasons not entirely known—bumblebees can’t move north to cope with warmer temperatures. They do not fare well in warmer climates because they evolved in cooler regions, away from the tropics. This makes them particularly vulnerable to changing climatic conditions, io9 reported.
To learn exactly how climate change is impacting bumblebees, researchers from Canada, the US and the UK analyzed the history of 67 bumblebee populations in North America and Europe from 1901 to 2010.
A survey of 423,000 observations of bees shows their populations have been on the decline since 1975; they are being squeezed north by approximately 9 km a year, and are now extinct in their southern ranges to the tune of 300 kilometers. The details of the study now appear at Science.
“Bumblebee species across Europe and North America are declining at continental scales,” noted lead author Jeremy T. Kerr at a recent news conference. “And our data suggest that climate change plays a leading, or perhaps the leading, role in this trend.”
The scientists also considered the role of habitat loss and pesticide use. They concluded that, while these factors are harmful to bumblebee populations, it is climate change that’s the primary culprit.
The decline in bumblebee populations is a problem because “we rely heavily on bees to pollinate our crops,” said Alana Pindar, a postdoctoral researcher at the University of Guelph in Ontario who co-authored the paper.
Wild bees are actually better pollinators than honeybees, and bumblebees are better pollinators than other wild bees because they are active for most of the year, from spring until fall, and can therefore pollinate a huge range of plants, she said.
