Planting for Bumble Bees Works

Last night I braved the snow and ice to attend a free lecture hosted by UEA at the Assembly Rooms in Norwich. Once I had managed not to get inveigled into a Christmas Party (wishful thinking – I think one look at my mac and notepad was enough for the greeter to point me in the direction of the lecture theatre) I was seated amongst an impressively large turn out.

Entitled ‘ Pollinators in Peirl: bees, genes and conservation’ the presentation was of recent research by Andrew Bourke and colleagues into UK Bumble Bees, their foraging habits and the effect on their population numbers of the UK’s Environmental Stewardship Scheme (includes planting a flower/grass mix specifically on farms). He started out by outlining some pollination facts, some of which you may be familiar with already: 1) 80% of wild plants and 75% of food crops are insect pollinated, 2) In 2005 it was estimated that the global economic value of insect pollination was $205 billion (approaching 10% of the total value of world agricultural output).

Over the last 100 years or so 9 of our 25 species of Bumble Bee are declining or extinct, 6 true and 6 cuckoo are OK and 1 new species is thriving. Reasons given for declining numbers of Bumble Bees included parasites / disease, habitat loss such as losses of flower-rich grasslands, hedgerows, legume crop rotations and clover leys and the increased use of fertilizers.

Without going into the details of the studies here, the researchers looked at numbers of Bumble Bees on patches sown with a mixture of 20% legumes (clover / birdsfoot trefoil) and 80% grass, compared to unsown patches. They found that the sown patches had greater densities of Bumble Bees, which increased as the surrounding land became more arable, showing their importance to the bees.

Interestingly, one member of the audience pointed out that he had used these seed mixes previously and had had difficulty keeping them going after a few years. However, he outlined his own management techniques using a much greater diversity of plants, which was not only self-sustaining but of wider benefit ecologically. Unfortunately he had had to undertake it at his own expense and I can’t see many farmers thinking that’s a good idea when the Stewardship Scheme is on offer – which is still better than nothing, if not ideal.

This is good news for our Plants for Bees project though. We plan to plant specific wildflowers as forage crops for both Honey and Bumble Bees, initially to tide our Bees over periods of foraging scarcity, but also to support them more generally. Although it might seem obvious to us that planting forage crops would help Bee populations, it’s useful to have some research to base our project on.