Assessing the value of annual and perennial forage mixtures for bumblebees by direct observation and pollen analysis
Published source details Carvell C., Westrich P., Meek W.R., Pywell R.F. & Nowakowski M. (2006) Assessing the value of annual and perennial forage mixtures for bumblebees by direct observation and pollen analysis. Apidologie, 37, 326-340.
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This study is summarised as evidence for the following.
| Action | Category | |
|---|---|---|
Sow uncropped arable field margins with an agricultural nectar and pollen mix Action Link |  | |
Sow uncropped arable field margins with a native wild flower seed mix Action Link | | |
Plant nectar flower mixture/wildflower strips Action Link |  |
Sow uncropped arable field margins with an agricultural nectar and pollen mix
In a replicated trial (five plots) of field margin seed mixtures on a farm in North Yorkshire, Carvell et al. (2006) found that short-tongued bumblebees (B. terrestris, B. lucorum and B. pratorum) strongly preferred plots of annually sown cover crops including borage Borago officinalis and common melilot Melilotus officinalis over perennial wildflower seed mix. Total bumblebee abundance was higher on the annual agricultural nectar mix. On average 70% of pollen collected by buff-tailed bumblebee workers B. terrestris sampled in this study was from borage.
Sow uncropped arable field margins with a native wild flower seed mix
In a replicated trial (five plots) of field margin seed mixtures on a farm in North Yorkshire, Carvell et al. (2006) found that both common UK species of long-tongued bumblebee (B. pascuorum and B. hortorum) strongly preferred plots of perennial wildflower seed mix over annually sown agricultural nectar plants (including borage Borago officinalis, fodder radish Raphanus sativus and common melilot Melilotus officinalis), although total bumblebee abundance was highest on the annual agricultural nectar mix. On average 76% of pollen collected by common carder bee B. pascuorum workers sampled in this study was from red clover.
Plant nectar flower mixture/wildflower strips
A replicated trial in 2001-2003 on a farm in North Yorkshire, UK (Carvell et al. 2006) found highest bumblebee Bombus spp. abundance on plots sown annually with a cover crop mix of five herbaceous species (including borage Borago officinalis, fodder radish Raphanus sativus and common melilot Melilotus officinalis). Short-tongued bumblebees (B. terrestris, B. lucorum and B. pratorum) strongly preferred this annual seed mixture over two perennial grass and wildflower seed mixes. Long-tongued bumblebee species B. hortorum and B. pascuorum preferred the perennial grass and wildflower seed mixtures, but were not more abundant on the ‘diverse’ than the ‘basic’ mix. On average 70% of pollen collected by buff-tailed bumblebee workers B. terrestris was from borage, and 76% of pollen collected by common carder bee B. pascuorum workers came from red clover Trifolium pratense. Five 6 x 30 m plots of each seed mixture were established in April 2001 (the annual seed mixture plots re-sown each year after ploughing). Bumblebees were monitored May-August 2002-2003 in 4 x 30 m transects down the centre of each plot. Both perennial grass and wildflower mixes contained five grass species, the basic mix contained three herbaceous species (black knapweed Centaurea nigra, bird’s-foot trefoil Lotus corniculatus and red clover) and the diverse mix contained 18 herbaceous species.
