Changing farming practices have played a major role in the decline of the bumble bee, according to new research. The big drop in haymaking and the rise of silage is driving out the bees, whose numbers have declined by 60 per cent since 1970.
"We suggest that the widespread replacement of hay with silage, which results in earlier and more frequent mowing and a reduction in late summer wildflowers, has played a major role in bumble bee declines," say the researchers from several Irish universities.
Once a common sight in the countryside in clover, hedgerows and around the edges of fields, most of the 20 or so species of bumblebee are in decline, and two have become extinct. Five bumble bee species are designated UK Biological Action Plan species, in recognition of their decline, with three more species scheduled for inclusion.
Exactly why there has been such a sharp decline is not clear, and there have been a number of theories, including climate change and intensive farming.
In the new study, reported in Biological Conservation, researchers point the finger at the decline in haymaking. Traditional hay meadows were not cut until after the flowers that attract bees have flowered. But with silage, grass is cut more frequently and early in the season so plants cannot flower. More intensive farming means the edges of fields are cultivated and are no longer wildlife havens.