Bumblebees are losing large sections of the southern portion of their ranges, but unlike other species, which are compensating by moving further north as the climate warms, bumblebees are not heading north. Instead, their range areas are shrinking, causing their populations to decline.
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Researchers found that a geographic squeeze occurred on both continents over the past 40 years. Numbers show that the loss of range is around 300km across the time period, or around 9km each year from the southern extents of their range.
After studying all the data, they drew conclusions about how the northern and southern limits of different bumblebee species shifted over the past century.
A team of researchers from the USA, Canada and Europe has revealed about the pessimistic state of bumblebees whose survival is being threatened due to climate change.
They compared changes in individual bee species’ northward movements in recent decades, against baseline bumblebee activity from 1901 to 1974, when the climate was cooler.
The report in the journal Science on Thursday is the first of its kind to point to the role of climate change in worldwide bee decline, which until now has largely been blamed on pesticide use, parasites, disease and loss of areas for habitat. Scientists at Ottawa varsity have been studying the affects of global warming on the bumblebee population and the findings show that bumblebees are dying off at alarming rates.
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.
Bumblebees are helpful because they pollinate fruit trees, wildflowers and plants along with other important crops, and are an invaluable service to the agriculture. “Climate change may be making things too hot for them in the south, but warming conditions are not pulling them north as we would expect”, University of Calgary ecologist Paul Galpern said. Kerr said, “The scale and pace of these losses are unprecedented”. “The bumblebees that are in decline were doing fine 50 years ago”. Bumblebees, which are seen as a key component in the pollination of food crops and wild plant life, are under threat from climate change, which significantly reduced their habitat.
Since wild bees are a mystery, the researchers examined more than 420,000 historical and current records of many species of bumblebees and declare the problem is environmental rather than chemical.
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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.
