The effect of arable field margin composition on invertebrate biodiversity

Provide grass strips at field margins for bees

A small replicated, controlled trial of field margin management options on two farms in North Yorkshire, England in one summer (Meek et al. 2002) did not find significantly more bumblebees on margins sown with tussocky grass than on naturally-regenerated margins or cropped margins. There were four replicates of each treatment.

Leave arable field margins uncropped with natural regeneration

A small replicated, controlled trial of field margin management options on two farms in North Yorkshire, England in one summer (Meek et al. 2002) did not find significantly more bumblebees Bombus spp. (species or individuals) on four naturally regenerated 6 m wide margins than on four cropped margins.

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

A small-scale replicated, controlled trial of field margin management options on two farms in North Yorkshire, England in one summer (Meek et al. 2002) found a significantly greater abundance of bumblebees Bombus spp. on four 6 m wide margins sown with a grass and wildflower seed mix than on four naturally regenerated, grass-sown or control cropped margins.

Plant grass buffer strips/margins around arable or pasture fields

A replicated, controlled study in 1999–2000 in four arable sites in North Yorkshire, UK (Meek et al 2002) found that along margins sown with a combination of tussocky grass seed and grass and wildflower mix or a grass and wildflower mix alone there was higher butterfly abundance than along those that naturally regenerated or were sown with cereal crop, but there was no difference in butterfly abundance between margins sown with tussocky grass seed and those that were left to regenerate naturally or those sown with cereal crop, and there was no difference in butterfly species richness between any of the treatments. There was no difference in butterfly abundance along margins sown with tussocky grass (average: 21 individuals) and those that regenerated naturally (average: 14). However, more butterflies were seen along margins where half their width was sown with tussocky grass and half sown with a wildflower and grass seed mix (average: 33), or their whole width was sown with wildflower and grass seed mix (average: 44), than on margins that regenerated naturally (average: 14) or were sown with cereal crop (average: 9). There was no difference in species richness between any of the treatments (see paper for details). Four 6 m wide margins of winter cereal fields (all adjacent to hedges) on two farms were split into 72 m long plots and sown in September 1999 with either a tussocky grass mix, a grass and wildflower mix, half the width tussocky grass and half grass and wildflower mix, cereal crop or left to regenerate naturally with no sowing. Butterflies were surveyed weekly from May–September 2000 using walking transects (21 surveys/field in total).

(Summarised by: Eleanor Bladon)

Create uncultivated margins around intensive arable or pasture fields

A replicated, controlled study in 1999–2000 in four arable sites in North Yorkshire, UK (Meek et al 2002) found that butterfly abundance was lower along uncultivated margins than along margins sown with a grass and wildflower seed mix or a combination of tussocky grass seed and grass and wildflower mix, but abundance was similar between uncultivated margins and those sown with tussocky grass seed alone or cereal crop, and species richness did not differ between treatments. There were fewer butterflies along margins which were left to regenerate without sowing (average: 14 individuals), margins sown with tussocky grass seed (average: 21) and margins sown with cereal crop (average: 9) than those sown with a grass and wildflower seed mix (average: 44) or a combination of tussocky grass seed and grass and wildflower seed mix (average: 33). There was no difference in species richness between any of the treatments see paper for details). Four 6 m wide margins of winter cereal fields (all adjacent to hedges) on two farms were split into 72 m long plots and sown in September 1999 with either a tussocky grass mix, a grass and wildflower mix, half the width tussocky grass and half grass and wildflower mix, cereal crop or left to regenerate naturally with no sowing. Butterflies were surveyed weekly from May–September 2000 using walking transects (21 surveys/field in total).

(Summarised by: Eleanor Bladon)

Plant nectar flower mixture/wildflower strips

A replicated, controlled study in 1999–2000 in four arable sites in North Yorkshire, UK (Meek et al 2002) found that butterfly abundance was higher along margins sown with a grass and wildflower seed mix or a combination of grass and wildflower seed mix and tussocky grass seed than along margins left to regenerate naturally or those sown with cereal crop, but there was no difference in butterfly species richness between any of the treatments. More butterflies were seen along margins sown with a grass and wildflower seed mix (average: 44 individuals) or where half their width had been sown with grass and wildflower seed mix and half with tussocky grass seed (average: 33) than along margins which regenerated naturally (average: 14) or those sown with cereal crop seed (average: 9). However, there was no difference in butterfly abundance along margins sown with a grass and wildflower seed mix or a split margin of grass and wildflower seed mix and tussocky grass seed than along margins sown with tussocky grass seed alone (average: 21). There was no difference in species richness between any of the treatments (see paper for details). Four 6 m wide margins of winter cereal fields (all adjacent to hedges) on two farms were split into 72 m long plots and sown in September 1999 with either a tussocky grass mix, a grass and wildflower mix, half the width tussocky grass and half grass and wildflower mix, cereal crop or left to regenerate naturally. Butterflies were surveyed weekly from May–September 2000 using walking transects (21 surveys/field in total).

(Summarised by: Eleanor Bladon)

Plant grass buffer strips/margins around arable or pasture fields

A replicated, controlled study during the summer of 2000 in North Yorkshire, UK (Meek et al. 2002) found grass margins contained more plant species than cropped margins but fewer species than margins sown with a grass and wildflower mix. Bumblebee Bombus spp. abundance and butterfly (Lepidoptera) diversity did not differ between treatments. However there were more meadow brown butterflies Maniola jurtina in grass margins and grass and wildflower margins than in naturally regenerated or control cropped margins. Spring numbers of ground beetles (Carabidae) and ground-dwelling spiders (Araneae) were higher in all treatments compared with the crop. Harvestmen (Opiliones) preferred grass margins to the crop in autumn. Four margins of winter cereal fields, all adjacent to hedges, on two farms, were split into 72 m long plots and sown in September 1999 with a grass mix, grass and wildflower mix, cereal crop or left to regenerate naturally. Ground and canopy-dwelling invertebrates, butterflies and plants were surveyed from late April to late September 2000 using pitfall traps, sweep netting, transects and quadrats.

Create uncultivated margins around intensive arable or pasture fields

A small replicated, controlled trial in the summer of 2000 in North Yorkshire, UK (Meek et al. 2002) found that four naturally regenerated field margins had higher plant diversity, but not more bumblebees Bombus spp. or butterflies (Lepidoptera) (species or individuals) than four cropped margins. A number of rare or uncommon arable weeds were recorded in naturally regenerated margins, but also a much higher abundance of barren brome Anisantha sterilis than in any other treatment. Spring numbers of ground beetles (Carabidae) and ground-dwelling spiders (Araneae) were higher in naturally regenerated margins than cropped margins. Harvestmen (Opiliones) avoided naturally regenerated margins in favour of any sown habitat in autumn. Four margins of winter cereal fields, all adjacent to hedges, were split into 72 m long plots and sown in September 1999 with either grass, grass and wildflowers, cereal crop or left to regenerate naturally on two farms. Ground and canopy-dwelling invertebrates, butterflies and plants were surveyed from late April to late September 2000 using pitfall traps, sweep netting, transects and quadrats.

Plant nectar flower mixture/wildflower strips

A small-scale replicated, controlled trial in summer 2000 in North Yorkshire, UK (Meek et al. 2002) found significantly more bumblebees Bombus spp. and butterflies (Lepidoptera) on four 6 m-wide margins sown with a grass and wildflower seed mix than on four naturally regenerated, grass-sown or control cropped margins. Spring numbers of ground beetles (Carabidae) and ground-dwelling spiders (Araneae) were higher in all treatments compared with cropped margins. Margins sown with a grass and wildflower mix harboured more pollen beetles Meligethes spp. than naturally regenerated margins. Plant diversity was higher in margins sown with a grass and wildflower mix. Four margins of winter cereal fields (all adjacent to hedges) on two farms were split into 72 m-long plots and sown in September 1999 with either a grass mix, a grass and wildflower mix, cereal crop or left to regenerate naturally. Ground and canopy-dwelling invertebrates, bumblebees, butterflies and plants were surveyed from late April to late September 2000 using pitfall traps, sweep netting, transects and quadrats.