Leave field margins unsprayed within the crop (conservation headlands)

Overall effectiveness category Awaiting assessment
Number of studies: 3
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Study locations

Key messages

Two replicated controlled trials in England showed that conservation headlands do not attract more foraging bumblebees than conventional crop fields. One replicated trial found fewer bees on conservation headlands than in naturally regenerated, uncropped field margins in England.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

Kells et al. (2001) counted bumblebees Bombus spp. and honey bees Apis mellifera on 50 m transects in five 6 m wide field margins managed as conservation headlands, and ten naturally regenerated, uncropped field margins in the West Midlands, England. They recorded averages of less than three bees/transect in conservation headlands, compared to averages of between 10 and 50 bees/transect in naturally regenerated margins.
Study and other actions tested
Referenced paper
Kells A.R., Holland J.M. & Goulson D. (2001) The value of uncropped field margins for foraging bumblebees. Journal of Insect Conservation, 5, 283-291.
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.
Study and other actions tested
Referenced paper
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.
In a replicated controlled trial at six sites (two replicates/site) across central and eastern England, Carvell et al. (2007) found that unsprayed conservation headlands did not support more bumblebee individuals or species than conventional cropped field margins.
Study and other actions tested
Referenced paper
Carvell C., Meek W.R., Pywell R.F., Goulson D. & Nowakowski M. (2007) Comparing the efficacy of agri-environment schemes to enhance bumble bee abundance and diversity on arable field margins. Journal of Applied Ecology, 44, 29-40.

Please cite as:

Dicks, L.V., Showler, D.A. & Sutherland, W.J. (2010) Bee conservation: evidence for the effects of interventions. Pelagic Publishing, Exeter, UK

Where has this evidence come from?

List of journals searched by synopsis

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This Action forms part of the Action Synopsis:

Bee Conservation

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Restrict certain pesticides Action Link	Awaiting assessment	1	Synopsis Link
Convert to organic farming Action Link	Awaiting assessment	8	Synopsis Link
Leave field margins unsprayed within the crop (conservation headlands) Action Link	Awaiting assessment	3	Synopsis Link