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Providing evidence to improve practice

Individual study: Sowing field margins with a pollen and nectar seed mix enhances the density and diversity of bumblebees Bombus spp., on arable farms in England

Published source details

Pywell R.F., Warman E.A., Hulmes L., Hulmes S., Nuttall P., Sparks T.H., Critchley C.N.R. & Sherwood A. (2006) Effectiveness of new agri-environment schemes in providing foraging resources for bumblebees in intensively farmed landscapes. Biological Conservation, 129, 192-206


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Increase the diversity of nectar and pollen plants in the landscape for bees Bee Conservation

In a replicated controlled trial in thirty-two 10 km grid squares across England (Pywell et al. 2006), the abundance of long-tongued bumblebees, mostly common carder bee B. pascuorum and garden bumblebee B. hortorum, recorded on trial field margins (various planting treatments) was positively correlated with the total number of pollen and nectar-mix agri-environment agreements in each 10 km square. There is no record of the numbers of long-tongued bumblebees in these grid squares before the agreements were implemented.

Manage the agricultural landscape to enhance floral resources Farmland Conservation

A replicated controlled trial in 2004 in thirty-two 10 km grid squares across England (Pywell et al. 2006) found the abundance of long-tongued bumblebees Bombus spp., mostly common carder bee B. pascuorum and garden bumblebee B. hortorum, recorded on trial field margins (various planting treatments, including sown grass and wildflower margins) was positively correlated with the total number of pollen and nectar mix agri-environment agreements in each 10 km square. There is no record of the numbers of long-tongued bumblebees in these grid squares before the agreements were implemented. Bumblebees were counted on a 100 x 6 m transect in each of 151 field margins, once in July and once in August.

Sow uncropped arable field margins with an agricultural nectar and pollen mix Bee Conservation

In a replicated controlled trial in thirty-two 10 km grid squares across England (Pywell et al. 2006), there were significantly more bumblebee species and more individuals on field margins sown 1-2 years previously with a pollen and nectar mix (average >3 species and 86 bees/transect) than on grassy margins (average 1.3-1.4 species and 6-8 bees/transect) or cropped margins (average 0.1 species and 0.2 bees/transect). There were more bumblebee individuals, but not more bumblebee species on pollen and nectar mix margins (average 86 bees/transect) than on wildflower-sown margins (43 bees/transect). The abundance of long-tongued bumblebees (mostly common carder bee B. pascuorum and garden bumblebee B. hortorum) was positively correlated with the number of pollen and nectar-mix agreements in each 10 km square.

Provide grass strips at field margins for bees Bee Conservation

A replicated, controlled trial of the 6 m wide sown grassy field margin agri-environment option at 32 sites across England (Pywell et al. 2006) found that grassy margins had more species, and a higher abundance of foraging bumblebees, than conventionally cultivated and cropped field margins (on average 6-8 bees of 1.3-1.4 species per transect on grassy margins, compared to 0.2 bees of 0.1 species/transect for cropped margins). Older grassy margins, sown more than three years previously, did not attract more foraging bumblebees than those sown in the previous two years.

Sow uncropped arable field margins with a native wild flower seed mix Bee Conservation

In a replicated controlled trial in thirty-two 10 km grid squares across England (Pywell et al. 2006), there were significantly more bumblebee species and more individuals on field margins sown with a wildflower seed mix (average >3 species and 43 bees/transect) than on grassy margins (average 1.3-1.4 species and 6-8 bees/transect) or cropped margins (average 0.1 species and 0.2 bees/transect).

Plant grass buffer strips/margins around arable or pasture fields Farmland Conservation

A replicated, controlled trial in 2004 in thirty-two 10 km grid squares across England, UK (Pywell et al. 2006) found that 6 m-wide sown grass margins had more bumblebee Bombus spp. species, and a higher abundance of foraging bumblebees, than conventionally cultivated and cropped field margins (on average 6-8 bumblebees of 1.3-1.4 species/transect on grassy margins, compared to 0.2 bumblebees of 0.1 species/transect for cropped margins). Older grassy margins, sown more than three years previously, did not attract more foraging bumblebees than those sown in the previous two years. Field margins were 6 m-wide and part of agri-environment scheme agreements. Five field margin types were investigated: grass mix (sown between 1993 and 2000), grass mix (sown between 2002 and 2003), grass and wildflower mix (sown between 1999 and 2003), ‘pollen and nectar’-rich margin (sown between 2002 and 2003), control cropped margins. Grass mixes typically included species such as cocksfoot Dactylis glomerata and timothy Phleum pretense. All five margin types were surveyed within each 10 km grid square (excluding the grass and wildflower mix which was not present in all squares), giving a total of 151 margins. Bumblebees were counted on a 100 x 6 m transect in each field margin, once in July and once in August.

Plant nectar flower mixture/wildflower strips Farmland Conservation

A replicated controlled trial in 2004 in thirty-two 10 km grid squares across England (Pywell et al. 2006) found significantly more bumblebee species Bombus spp. in field margins sown with wildflower or ‘pollen and nectar’ seed mixes (more than 3 bumblebee species/transect) than in grassy margins (1.3-1.4 spp./transect) and control cropped margins (0.1 spp./transect). Pollen and nectar margins had more individuals (86 bees/transect) than any other treatment. Wildflower margins had more individuals (43/transect) than grassy (6-8/transect) and control cropped margins (0.2/transect). Field margins were 6 m-wide and part of agri-environment scheme agreements. Five field margin types were investigated: grass and wildflower mix (sown between 1999 and 2003), ‘pollen and nectar’-rich margin (sown between 2002 and 2003), grass mix (sown between 1993 and 2000), grass mix (sown between 2002 and 2003), control cropped margins. Wildflower mixes were variable in species composition but typically consisted of perennial wildflowers, fine-leaved and tussock-grass species, sown in an 80% grass:20% wildflower ratio by weight. ‘Pollen and nectar’ mixes typically consisted of at least four nectar-rich wildflower species (such as clover Trifolium spp. and bird’s-foot trefoil Lotus corniculatus) and four grass species sown in an 80% grass:20% wildflower ratio by weight. All five margin types were surveyed within each 10 km grid square (excluding the grass and wildflower mix which was not present in all squares), giving a total of 151 margins. Bumblebees were counted on a 100 x 6 m transect in each field margin, once in July and once in August.