A group of scientists headed by Dr Jeremy Kerr from the University of Ottawa, Canada, has discovered that climate change is rapidly shrinking the area where bumblebees are found in both Europe and North America.

“Pollinators are vital for food security and our economy, and widespread losses of pollinators due to climate change will diminish both,” said Dr Kerr, who along with colleagues examined more than 400,000 current and historical records of many species of bumblebees in geo-referenced databases.

“We need to figure out how we can improve the outlook for pollinators at continental scales, but the most important thing we can do is begin to take serious action to reduce the rate of climate change.”

“Bumblebees pollinate many plants that provide food for humans and wildlife. If we don’t stop the decline in the abundance of bumblebees, we may well face higher food prices, diminished varieties, and other troubles,” added team member Dr Leif Richardson from the University of Vermont.

With climate change, many species of animals have been observed to expand their territory. Not so bumblebees.

The scientists found that northern populations of many bumblebee species are staying put, while the southern range edge is retreating away from the equator.

“This was a surprise. The bees are losing range on their southern margin and failing to pick up territory at the northern margin, so their habitat range is shrinking,” Dr Richardson said.

The study shows that the culprit is not pesticides and it’s not land use changes, two other major threats to bumblebee populations and health. Instead, it shows clearly that this range compression tracks with warming temperatures.

The scientists found that bumblebees are shifting to areas of habitat at higher elevation in response to climate change.

“Moving upslope doesn’t necessarily mean they’ve lost area there yet, but, eventually, they may simply run out of hill,” Dr Richardson said.

Over the 110 years of records that the scientists examined, bumblebees have lost about 185 miles (300 km) from the southern edge of their range in Europe and North America.

The results will be published in the journal Science on July 10.

_____

Jeremy T. Kerr et al. 2015. Climate change impacts on bumblebees converge across continents. Science, vol. 349, no. 6244, pp. 177-180; doi: 10.1126/science.aaa7031