Agri-environment schemes and butterflies: the utilisation of 6 m grass margins

Pay farmers to cover the costs of conservation measures (as in agri-environment schemes or conservation incentives)

A replicated, controlled study in 1996–2000 at two arable farms in Essex, UK (Field et al. 2005, same experimental set-up as Field & Mason 2005, Field et al. 2006, Field et al. 2007a, Field et al. 2007b) found that grass margins which farmers were paid to create had higher butterfly abundance, but not species richness, than in cropped field edges. More butterflies were recorded in sown or naturally regenerated agri-environment scheme grass margins (46 individuals/km) than in cropped field edges (21 individuals/km), but the species richness was similar (grass margin: 8; cropped edges: 9 species). Of the ‘key’ grassland butterfly species, only meadow brown Maniola jurtina was more abundant in grass margins (19 individuals/km) than in cropped field edges (9 individuals/km). More butterflies (125 individuals/km), including meadow brown (57 individuals/km), were found in a sown grass margin established next to a permanent set-aside field than on all other margin types (all butterflies: 32–41 individuals/km; meadow brown: 4–27 individuals/km). In 1996, eight 6-m-wide margins were established on two farms. Five were sown with grass seed mixtures (6 or 9 species) according to Countryside Stewardship Scheme requirements, and three were left to natural regeneration. One arable field edge without margins on each farm was used as a control. Butterfly abundance was monitored weekly from late June to early August 1997–2000. All butterflies were recorded, but special note was taken of ‘key’ grassland species: meadow brown, gatekeeper Pyronia tithonus, small skipper Thymelicus sylvestris, Essex skipper Thymelicus lineola, and large skipper Ochlodes venata.

(Summarised by: Andrew Bladon, edited from Farmland synopsis)

Plant grass buffer strips/margins around arable or pasture fields

A replicated, controlled study in 1996–2000 at two arable farms in Essex, UK (Field et al. 2005, same experimental set-up as Field & Mason 2005, Field et al. 2006, 2007a, 2007b) found that butterfly abundance, but not species richness, was higher in grass margins than in cropped field edges. More butterflies were recorded in sown or naturally regenerated grass margins (46 individuals/km) than in cropped field edges (21 individuals/km), but the species richness was similar (grass margin: 8; cropped edges: 9 species). Of the ‘key’ grassland butterfly species, only meadow brown Maniola jurtina was more abundant in grass margins (19 individuals/km) than in cropped field edges (9 individuals/km). More butterflies (125 individuals/km), including meadow brown (57 individuals/km), were found in a sown grass margin established next to a permanent set-aside field than on all other margin types (all butterflies: 32–41 individuals/km; meadow brown: 4–27 individuals/km). In 1996, eight 6-m-wide margins were established on two farms. Five were sown with grass seed mixtures (6 or 9 species) and three were left to natural regeneration. One arable field edge without margins on each farm was used as a control. Butterfly abundance was monitored weekly from late June to early August 1997–2000. All butterflies were recorded, but special note was taken of ‘key’ grassland species: meadow brown, gatekeeper Pyronia tithonus, small skipper Thymelicus sylvestris, Essex skipper Thymelicus lineola, and large skipper Ochlodes venata.

(Summarised by: Andrew Bladon, edited from Farmland synopsis)

Create uncultivated margins around intensive arable or pasture fields

A replicated, controlled study in 1996–2000 at two arable farms in Essex, UK (Field et al. 2005) found that butterfly abundance, but not species richness, was higher in grass margins than in cropped field edges. More butterflies were recorded in sown or naturally regenerated grass margins (46 individuals/km) than in cropped field edges (21 individuals/km), but the species richness was similar (grass margin: 8; cropped edges: 9 species). Of the ‘key’ grassland butterfly species, only meadow brown Maniola jurtina was more abundant in grass margins (19 individuals/km) than in cropped field edges (9 individuals/km). However, fewer butterflies (32–38 individuals/km), including meadow brown (4–5 individuals/km), were found in naturally regenerated margins than in sown margins (all butterflies: 41–125 individuals/km; meadow brown: 27–57 individuals/km). In 1996, eight 6-m-wide margins were established on two farms. Five were sown with grass seed mixtures (6 or 9 species) and three were left to natural regeneration. One arable field edge without margins on each farm was used as a control. Butterfly abundance was monitored weekly from late June to early August 1997–2000. All butterflies were recorded, but special note was taken of ‘key’ grassland species: meadow brown, gatekeeper Pyronia tithonus, small skipper Thymelicus sylvestris, Essex skipper Thymelicus lineola, and large skipper Ochlodes venata.

(Summarised by: Andrew Bladon, edited from Farmland synopsis)

Plant grass buffer strips/margins around arable or pasture fields

A replicated, controlled study in 1997-2000 in Essex, UK (Field et al. 2005) found that total butterfly (Lepidoptera) abundance, but not species richness, was higher in 6 m-wide grass margins (average 45.8 butterflies/km/visit) (study did not distinguish between sown and naturally regenerated grass margins) than in control cropped sections (average 20.9). Of the ‘key’ grassland butterfly species, only the meadow brown Maniola jurtina had greater abundance in grass margins (average 18.9 butterflies/km/visit) than in controls (average 8.9). Significantly more butterflies, including M. jurtina, were found in a sown grass margin established adjacent to a permanent set-aside field than on all other margin types. Sown grass margins (not adjacent to permanent set-aside fields) had the lowest abundance of gatekeeper Pyronia tithonus, skipper Thymelicus spp. and large skipper Ochlodes venata butterflies. Five grass margins were established on two farms according to the requirements of the Countryside Stewardship Scheme in 1996 and sown with grass seed mixtures (6 or 9 species). In addition, three margins were established by natural regeneration on one farm, and on both farms one arable field edge without margins was used as a control. Butterfly abundance was monitored weekly along transects from late June to early August 1997-2000. All butterflies were recorded, but special note was taken of ‘key’ grassland species: meadow brown, gatekeeper, small skipper Thymelicus sylvestris, Essex skipper T. lineola, and large skipper. This study is part of the same experimental set-up as Field & Mason 2005, Field et al. 2006, Field et al. 2007a, Field et al. 2007b.