Climate change has significantly increased the likelihood of bumblebees being driven to extinction in some areas of North America and Europe.
Research five years ago showed how warming had shrunk the 产别别蝉鈥� habitat across the two regions. However, it is difficult to separate the direct effects of climate change on the 产别别蝉鈥� chance of local extinction from other environmental pressures, such as their habitats vanishing.
To fill that gap, Tim Newbold at University College London and his colleagues analysed the temperature and rainfall records at more than 15,000 sites where at least one of 66 bumblebee species had been spotted between 2000 and 2014. They found that due to changes in climatic conditions, the probability of a site being occupied by bumblebees fell by an average of 46 per cent in North America and 17 per cent in Europe, relative to the long-term average last century.
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鈥淭his is the clearest signal so far of climate change already having had quite an important effect on the extinction and colonisation of bumblebee species,鈥� says Newbold.
The results were as he expected. The bees are large and furry as an adaptation to cold climates, so those in southern Europe and the south of North America, which were already at their upper temperature limits, were much more likely to go extinct and much less likely to colonise a new area.
To ensure it was climate change driving the shifts, the researchers controlled for changes in land use and the fact there are far more records of bumblebees in recent years. Still, one limitation is that record-keeping is patchy in places.
Losing bumblebees means losing pollinators essential to food production. Although they don鈥檛 pollinate the crops we rely on for the bulk of our calories, they provide much of the variety in our diets, pollinating nuts, berries and squashes.
If climate change continues, it will drive even stronger bumblebee declines in the future, says Newbold.
Warming is one of many threats to these insects, says Dave Goulson at the University of Sussex, UK. 鈥淏umblebees also suffer from many other pressures, particularly habitat loss and exposure to pesticides, and it seems likely that a rapidly warming future climate may be the final straw for many of them.鈥�
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