As Europe and North America warm, bumblebees should be able to fly north to cooler climes, writes Tim Radford. But they’re not: the bees’ range is receding in the south, but staying put in the north, and scientists fear their shrinking habitat will put many species at risk of extinction.
The humble bumblebee is feeling the squeeze from climate change.
Newly published research shows that its southern range is being reduced as the planet warms – and yet it seems to show no sign of migrating northwards to safety.
This unwillingness to head for cooler climes could prove disastrous, and has prompted some scientists to suggest that humans may need to intervene by creating refuges for the bees away from the heat.
Jeremy Kerr, a biologist at the University of Ottawa, Canada, and colleagues report in the journal Science that they generated a database of 423,000 local observations of 36 European and 31 North American species of the genus Bombus and mapped the patterns of change.
They found that in recent, increasingly warmer decades, bumblebees tended to disappear from the southernmost and hottest parts of their range, but did not shift north. In some cases, the insects’ range had shrunk by as much as 300 kilometres.
“Using long-term observations across Europe and North America over 110 years, we tested for climate change-related range shifts in bumblebee species across the full extents of their latitudinal and thermal limits and movements along elevation gradients”, the paper states.
“We found cross-continentally consistent trends in failures to track warming through time at species’ northern range limits, range losses from southern range limits, and shifts to higher elevations among southern species. These effects … underscore the need to test for climate impacts at both leading and trailing latitudinal and thermal limits for species.”
Continue reading at ENN affiliate, The Ecologist.
Bumblebee image via Shutterstock.