Create patches of bare ground for ground-nesting bees

Overall effectiveness category Awaiting assessment
Number of studies: 5
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Key messages

One replicated controlled trial in Germany and four small trials (three replicated, one not) have shown that artificially exposed areas of bare soil can be successfully colonised by ground-nesting solitary bees and wasps in the first or second year. We have captured no evidence for the effect of creating areas of bare ground on bee populations or communities on a larger scale.

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

Three scrapes with vegetation removed at Headley Heath, Surrey, England were being used by ground-nesting bees two or three years after they were created (Edwards 1996). The average densities of burrows attributed to ground-nesting bees and wasps were 2.3, 1.2 and 2.3 burrows/m2 for small (500 m2), medium (2,500 m2) and large (5,000 m2) scrapes respectively.
Study and other actions tested
Referenced paper
Edwards M. (1996) Entomological survey and monitoring, Headley Heath, 1995-1996. Unpublished report, Commissioned by the National Trust.
Nest density of ground-nesting bees and wasps was increased by removing plant cover, or digging and raising soil, in trial plots at five sandy grassland sites in Baden-Württemberg, southwest Germany in 1992, relative to five control sites (Wesserling & Tscharntke 1995). Digging and raising soil was more effective at increasing nest density. Raking was not very effective, because it generated a dense plant cover.
Study and other actions tested
Referenced paper
Wesserling J. & Tscharnkte T. (1995) Habitat selection of bees and digger wasps - experimental management of plots. Mitteilungen der Deutschen Gesellschaft für allgemeine und angewandte Entomologie, 697-701.
A study of artificially made scrapes on three lowland heaths in West Sussex, England (Edwards 1998) found between two and eight solitary bee species using the scrapes one to four years after they were created, with up to five of the species actively nesting.
Study and other actions tested
Referenced paper
Edwards M. (1998) Monitoring of bare ground for use by heathland insects. Unpublished report to the West Sussex Heathlands Project.
Severns (2004) created 1 m2 plots of mostly bare ground whilst planting seeds of the endangered legume Kincaid's lupine Lupine sulphureus spp. kincaidii, in an upland prairie restoration project in Oregon, USA. The bare ground was colonised by an increasing number of nesting solitary bees, mostly of the common species Lasioglossum anhypops, over the following three years. Three years later, there were 320 nests over 30 plots.
Study and other actions tested
Referenced paper
Severns P. (2004) Creating bare ground increases presence of native pollinators in Kincaid's lupine seeding plots (Oregon). Ecological Restoration, 22, 234-235.
Four shallow bays (3 x 5 m), with a rear vertical face (30 cm), were dug to attract ground-nesting bees and wasps at Shotover Hill, a heath degraded due to a long-term lack of grazing in Oxfordshire, southern England. All four bays were colonised in the first year with 80 solitary bee and wasp species recorded in the following three years (Gregory & Wright 2005).
Study and other actions tested
Referenced paper
Gregory S. & Wright I. (2005) Creation of patches of bare ground to enhance the habitat of ground-nesting bees and wasps at Shotover Hill, Oxfordshire, England. Conservation Evidence, 2, 139-141.

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?

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This Action forms part of the Action Synopsis:

Bee Conservation

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