Providing foraging resources for bumblebees in intensively farmed landscapes

Published source details Pywell R.F., Warman E.A., Carvell C., Sparks T.H., Dicks L.V., Bennett D., Wright A., Critchley C.N.R. & Sherwood A. (2005) Providing foraging resources for bumblebees in intensively farmed landscapes. Biological Conservation, 121, 479-494.
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This study is summarised as evidence for the following.

	Action	Category
	Leave field margins unsprayed within the crop (conservation headlands) Action Link
	Sow uncropped arable field margins with a native wild flower seed mix Action Link
	Leave arable field margins uncropped with natural regeneration Action Link
	Leave cultivated, uncropped margins or plots (includes 'lapwing plots') Action Link
	Leave headlands in fields unsprayed (conservation headlands) Action Link
	Plant nectar flower mixture/wildflower strips Action Link

Leave field margins unsprayed within the crop (conservation headlands)

A replicated controlled trial (Pywell et al. 2005) in East Anglia and the West Midlands, England, found no significant difference in bumblebee species richness and abundance when 16 conservation headlands were compared with paired conventional field margins. In both types of field margin, a few species of plant contributed to the vast majority of foraging visits by bumblebees, mainly creeping thistle Cirsium arvense and spear thistle C. vulgare.
Sow uncropped arable field margins with a native wild flower seed mix

In a replicated controlled trial in central and eastern England (Pywell et al. 2005), bumblebee foraging activity and species richness were significantly enhanced at 28 uncropped field margins sown with a 'wildlife seed mixture', compared to paired control sites of conventionally managed cereal or 16 'conservation headlands'. The seed mixture contained grasses, and annual and perennial broad-leaved herbs. This result was dependent upon key forage species being included in the seed mixture, including red clover Trifolium pratense, bird's-foot trefoil Lotus corniculatus and borage Borago officinalis, the latter being of particular importance to short-tongued bumblebee species such as Bombus terrestris and B. lucorum.
Leave arable field margins uncropped with natural regeneration

Bumblebee foraging activity and species richness were significantly enhanced on 18 uncropped, regularly cultivated field margins where natural regeneration had been allowed to take place for five years, compared to paired control sites of conventionally managed cereal, in East Anglia and the West Midlands, England (Pywell et al. 2005). The uncropped margins had significantly more plant species than either conservation headlands or uncropped margins sown with a wildflower seed mix. However, two species considered to be pernicious weeds, spear thistle and creeping thistle C. arvense were key forage plants for the bumblebees, so this option may lead to conflict between agricultural and conservation objectives.The naturally regenerated field margins supported fewer bumblebees (18 individuals and 2.7 species/100 m on average) than margins sown with a wild flower seed mixture (29 bumblebees, 3.0 species/100 m), but the two treatments were not directly compared in the analysis.
Leave cultivated, uncropped margins or plots (includes 'lapwing plots')

A controlled trial on paired sites in 2003 on Arable Stewardship Pilot Scheme farmland in the UK (Pywell et al. 2005) found that bumblebee Bombus spp. foraging activity and species richness were significantly enhanced on uncropped, regularly cultivated field margins where natural regeneration had been allowed to take place for five years, compared to sites of conventionally managed cereal. The uncropped margins had significantly more plant species than either conservation headlands or uncropped margins sown with a wildflower seed mix. However, two species considered to be pernicious weeds, spear thistle Cirsium vulgare and creeping thistle C. arvense were key forage plants for the bumblebees, so this option may lead to conflict between agricultural and conservation objectives. Bumblebee numbers were estimated through paired surveys on field margins and conventionally-managed cereal field margins. Foraging bumblebees were recorded along 100 x 6 m transects and the plant species on which bumblebees were observed feeding was noted. Twenty 0.5 x 0.5 m quadrats were used along the bumblebee transects to record the presence of all plant species.
Leave headlands in fields unsprayed (conservation headlands)

A replicated controlled paired-sites comparison in 2003 in East Anglia and the West Midlands, UK (Pywell et al. 2005) found no significant difference in bumblebee Bombus spp. species richness and abundance when 16 conservation headlands were compared with paired conventional field margins. In both types of field margin, a few species of plant contributed to the vast majority of foraging visits by bumblebees, mainly creeping thistle Cirsium arvense and spear thistle C. vulgare. Nineteen farms were surveyed in East Anglia, and 17 farms in the West Midlands. Three agri-environment scheme (Arable Stewardship Pilot Scheme (ASPS)) options were studied: field margins sown with a wildlife seed mixture (28 sites), conservation headlands with no fertilizer (16 sites), naturally regenerated field margins (18 sites). Fifty-eight conventional cereal field margins were used as a control, and paired with ASPS sites. Bumblebees were surveyed along 100 x 6 m or 50 x 6 m transects twice, in July and August. Vegetation was surveyed in twenty 0.5 x 0.5 m quadrats.
Plant nectar flower mixture/wildflower strips

A replicated, controlled, paired sites comparison in 2003 in central and eastern England (Pywell et al. 2005) found bumblebee Bombus spp. foraging activity and species richness were significantly enhanced at 28 uncropped field margins sown with a ‘wildlife seed mixture’, compared to paired control sites of conventionally managed cereal or 16 ‘conservation headlands’. Wildlife seed mixture margins contained significantly more grass, non-grass and perennial plant species than control sites, with over double the total number of species. Flowering herbaceous plants were more abundant and diverse in wildlife seed margins, and these margins provided the widest range of forage species. This result was dependent upon key forage species being included in the seed mixture, including red clover Trifolium pratense, bird’s-foot trefoil Lotus corniculatus and borage Borago officinalis, the latter being of particular importance to short-tongued bumblebee species such as Bombus terrestris and B. lucorum. The seed mixture contained grasses, and annual and perennial broadleaved herbs. Nineteen farms were surveyed in East Anglia, and 17 farms in the West Midlands. Three agri-environment scheme (Arable Stewardship Pilot Scheme) options were studied: field margins sown with a wildlife seed mixture (28 sites), conservation headlands with no fertilizer (16 sites), naturally regenerated field margins (18 sites). Fifty-eight conventional cereal field margins were used as a control, and paired with Arable Stewardship Pilot Scheme sites. Bumblebees were surveyed along 100 x 6 m or 50 x 6 m transects twice, in July and August. Vegetation was surveyed in twenty 0.5 x 0.5 m quadrats.