Over the 110 years of records that the team examined, bumblebees have lost about 185 miles (300 km) from the southern edge of their range in Europe and North America, the scientists estimate. With the period between 1901 and 1974, they found that bees have started to die out in both Europe and America, at the same time.
After studying all the data, they drew conclusions about how the northern and southern limits of different bumblebee species shifted over the past century.
“For the North American species that I work on, we know that about a third of them are in decline and in some cases this has been quite dramatically, more than 90 per cent”, said co-author York University environmental studies Professor Sheila Colla.
“This paper is important because it reinforces the understanding that species will not all be able to shift their ranges in order to adapt to a changing climate”, Sacha Vignieri, associate editor of Science magazine, said. This is because while the bumblebees are dying off in the south, they don’t feel like going north. A speculated theory is that bumblebees are thrown into a biological limbo, a mishap of their own survival instinct brought up by a deep chemical imbalance due to warm weather.
Normal Carreck, Science Director at global Bee Research Association, said the study helps them look in another direction.
Apart from lethal infections, loss of habitats and pesticides, the global warming has posed a serious threat to the range here bumblebees exist in Europe and North America.
Scientists at Ottawa revealed that cause and effect of the decline in the the world’s bumblebee population. As a result, unlike most insects, they’re good at staying warm in cool environments.
Not sure what to expect, she began to collect bees at gardens and put them in coolers where they fell asleep.
What are the other downsides of bumblebee species declining? This has come as a surprise, even given the apparently limited flying ability of this key pollinator of economically important fruit and vegetable crops. Ecologist Lawrence Harder of the University of Calgary has been studying and observing bumblebees for the past 35 years. The loss in the species range meant that their populations had declined and were on the road to extinction.
Kerr said dramatic action should be considered: a proposal called “assisted migration” involving a large-scale relocation of bee populations into new areas where they might thrive.
Dr Leif Richardson, from the University of Vermont, said, “These findings could spell trouble for many plants, including some crops like blueberries that depend on bumblebees for pollination”.
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