The use of farmland by butterflies: a study on mixed farmland and field margins

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

A replicated, controlled study in 1996–2003 on three arable farms in Essex, UK (Field et al. 2007b, same experimental set-up as Field & Mason 2005, Field et al. 2005, Field et al. 2006, Field et al. 2007a) found that planted grass margins which farmers were paid to create had higher butterfly abundance than cropped field edges without grass margins. Butterfly abundance was higher in both 2-m-wide (64 individuals/km) and 6-m-wide (54 individuals/km) sown agri-environment scheme grass margins than in cropped field edges (19–24 individuals/km). Meadow brown Maniola jurtina abundance was higher in 2-m (15 individuals/km) and 6-m (22 individuals/km) margins than in cropped field edges (4–5 individuals/km), but abundance was similar for gatekeeper Pyronia tithonus (grass margin: 7–9; cropped: 5–6 individuals/km) and golden skipper Thymelicus spp. (grass margin: 5–14; cropped: 2–13 individuals/km). In October 1996–1997, three 2-m-wide margins were sown with grass seed (4–6 species) and left uncut after the first year, and three 6-m-wide margins were established through natural regeneration or by sowing (6–9 species), and cut annually after 15 July, according to Countryside Stewardship Scheme requirements. Butterfly abundance was monitored weekly in summer 1997–2000 and 2003 in the six grass margins and five cropped field edges.

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

Plant grass buffer strips/margins around arable or pasture fields

A replicated, controlled study in 1996–2003 on three arable farms in Essex, UK (Field et al. 2007b, same experimental set-up as Field & Mason 2005, Field et al. 2005, 2006, 2007a) found that planted grass margins had higher butterfly abundance than cropped field edges without grass margins. Butterfly abundance was higher in both 2-m-wide (64 individuals/km) and 6-m-wide (54 individuals/km) sown grass margins than in cropped field edges (19–24 individuals/km). Meadow brown Maniola jurtina abundance was higher in 2-m (15 individuals/km) and 6-m (22 individuals/km) margins than in cropped field edges (4–5 individuals/km), but abundance was similar for gatekeeper Pyronia tithonus (grass margin: 7–9; cropped: 5–6 individuals/km) and golden skipper Thymelicus spp. (grass margin: 5–14; cropped: 2–13 individuals/km). In October 1996–1997, three 2-m-wide margins were sown with grass seed (4–6 species) and left uncut after the first year, and three 6-m-wide margins were established through natural regeneration or by sowing (6–9 species), and cut annually after 15 July. Butterfly abundance was monitored weekly in summer 1997–2000 and 2003 in the six grass margins and five cropped field edges.

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

Create uncultivated margins around intensive arable or pasture fields

A replicated, controlled study in the summers of 1997-2000 and 2003 in Essex, UK (Field et al. 2007) found that naturally regenerated 6 m margins had higher plant species richness (35 species) than grass-sown 6 m-margins (20 species), seven years after margin establishment under the Countryside Stewardship Scheme. Butterfly (Lepidoptera) abundance was higher in 6 m-wide Countryside Stewardship Scheme margins (naturally regenerated and grass-sown margins not distinguished) than in control margins. Comparisons between 6 m-margins (naturally regenerated and grass-sown margins not distinguished) and control sections showed 54 vs 19 butterflies/km/visit. The meadow brown butterfly Maniola jurtina also occurred in higher numbers in Countryside Stewardship Scheme field margins: 6 m-margins (naturally regenerated and grass-sown margins not distinguished) and their control sections had 22 vs 5/km/visit. Butterfly abundance and species richness did not change over the study period in either 6 m-margins or in a transect across farmland. Six metre-margins were established on three farms either through natural regeneration or by sowing with a grass-seed mixture, and all cut annually after 15 July.

Plant grass buffer strips/margins around arable or pasture fields

A replicated, controlled study in the summers of 1997-2000 and 2003 in Essex, UK (Field et al. 2007b) found that butterfly (Lepidoptera) abundance was higher in 2 m and 6 m-wide Countryside Stewardship Scheme margins than in control margins (field edges without established grass margins). Comparisons between grass-sown 2 m-margins and control sections showed 64 vs 24 butterflies/km/visit and 54 vs 19 for 6 m-margins (study does not distinguish between the effects of sown and naturally regenerated 6 m-margins). The meadow brown butterfly Maniola jurtina also occurred in higher numbers in Countryside Stewardship Scheme field margins, 2 m-margins and their control sections had 15 vs 4 individuals/km/visit, 6 m-margins had 22 vs 5/km/visit. Butterfly abundance and species richness did not change over the study period in either 2 or 6 m-margins or in a transect across farmland. Plant species richness declined significantly within sown field margins of both widths from 1998 to 2003 as the sown grass species became dominant. Sown 6 m-margins had lower plant species richness in 2003 (20 species) compared with naturally regenerated 6 m-margins (35 species). Eleven margins were studied on three farms. Two metre-margins were sown with a grass-only seed mixture and the vegetation left uncut after the first year. Six metre-margins were established through natural regeneration or by sowing, all cut annually after 15 July. This study was part of the same experimental set-up as Field et al. 2005, Field & Mason 2005, Field et al. 2006, Field et al. 2007a.