Plant grass buffer strips/margins around arable or pasture fields

How is the evidence assessed?
  • Effectiveness
    not assessed
  • Certainty
    not assessed
  • Harms
    not assessed

Study locations

Key messages

  • Twenty-four studies evaluated the effects on butterflies and moths of planting grass margins around arable or pasture fields. Fifteen were in the UK, two were in each of Sweden, the Netherlands and the USA, and one was in each of China, France and Italy.

COMMUNITY RESPONSE (14 STUDIES)

  • Richness/diversity (14 studies): One of two replicated, controlled studies in the UK found that 2-m grass margins had a greater species richness of butterflies than cropped field edges, but 6-m grass margins did not. The other study found that the species richness of butterflies was similar in grass margins and cropped field edges. Five replicated, site comparison studies (including one paired study) in the USA, the UK and Italy found that wider grass margins (up to 6 m wide) had a greater species richness or diversity of butterflies, macro-moths and micro-moths than narrower or conventional width margins, although one of these studies found that the species richness of macro-moths was similar in wide and conventional grass margins. Three of four replicated studies (including three randomized, controlled studies and one site comparison study) in the UK and Sweden found that floristically enhanced grass buffers or wildflower strips had a greater species richness of butterflies than standard grass margins. The other study found that farms with floristically enhanced margins (along with other enhanced agri-environment scheme (AES) options) had a similar species richness of butterflies and moths to farms with standard grass margins (along with basic AES options) and farms with no grass margins or other AES options. One site comparison study in Sweden found that grass margins sown with legumes or a clover and grass ley had a higher species richness of butterflies and moths than uncultivated margins, but less than a species-rich pasture. One replicated study in the Netherlands found that the species richness of butterflies increased over time after the establishment of grass margins. One replicated, randomized, controlled, before-and-after study in the USA found that disking or burning grass margins did not affect the species richness of butterflies.

POPULATION RESPONSE (20 STUDIES)

  • Abundance (19 studies): Three of four replicated, controlled studies in the UK found that grass margins had a higher abundance of butterflies than cropped field edges. The other study found that the abundance of gatekeepers on grass margins increased over four years after they were sown, but was only higher than cropped field edges at one of three farms after 2–4 years. Three of six replicated, site comparison studies (including two paired studies) in the USA and the UK found that wider grass margins (up to 6 m wide) had a higher abundance of habitat-sensitive butterflies, macro-moths and micro-moths than narrower or conventional width margins. Two of these studies, and the other three studies, found that the abundance of disturbance-tolerant butterflies, macro-moths generally, and pale shining brown moths specifically, was similar in wide and conventional grass margins. Three replicated studies (including two randomized, controlled studies and one site comparison study) in the UK and Sweden found that floristically enhanced grass buffers or wildflower strips had a higher abundance of butterflies than standard grass margins. Two replicated, randomized, controlled studies in the UK found that farms with floristically enhanced margins (along with other enhanced agri-environment scheme (AES) options) had a higher abundance of some butterflies and micro-moths, a similar abundance of macro-moths, but a lower abundance of other butterflies, than farms with standard grass margins (along with basic AES options) and farms with no grass margins or other AES options. One site comparison study in Sweden found that grass margins sown with legumes or a clover and grass ley had a higher abundance of butterflies and moths than uncultivated margins or a species-rich pasture. Two replicated, before-and-after studies (including one randomized, controlled study) in the Netherlands and the USA found that mowing, disking or burning grass margins did not affect the abundance of butterflies and moths generally, or diamondback moths specifically, but that disking increased the abundance of disturbance-tolerant butterflies. One replicated, paired, site comparison study in the UK found that field margins had a similar abundance of butterfly and moth caterpillars to beetle banks established in the middle of fields.
  • Survival (1 study): One site comparison study in China found that the survival of marsh fritillary caterpillars in grass margins around lightly cultivated fields was lower, but survival of egg clusters similar, to in uncultivated, grazed meadows.

BEHAVIOUR (2 STUDIES)

  • Use (2 studies): One replicated, site comparison study in China found that grass margins around lightly cultivated fields were more likely to be occupied by marsh fritillary eggs and caterpillars than uncultivated, grazed meadows. One replicated, paired, site comparison study in France found that meadow brown butterflies used grass margins in a similar way to meadows.

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

  1. A site comparison study in 1989 on an arable farm in central Sweden (Lagerlöf et al. 1992) reported that sown grass margins had a higher abundance but similar species richness of butterflies and moths to uncultivated margins. Results were not tested for statistical significance. Over two months, more butterflies and moths were recorded in two sown grass margins (58–75 individuals) than in two uncultivated margins (38–44 individuals), but the number of species was similar (sown: 6 species; uncultivated: 7 species). Fewer butterflies (24 individuals) of more species (8 species) were recorded in a species-rich pasture. Four existing field margins and a species-rich pasture were compared. Two margins were sown (one with a mixture of legumes dominated by white melilot Melilota alba, the other with clover and ley grasses dominated by red clover Trifolium pratense) and two were uncultivated (one with diverse weeds, the other with diverse herbs and grasses on a ditch bank). From 19 June–22 August 1989, butterflies and moths were recorded in the morning and evening at each site, three times/week.

    Study and other actions tested
  2. A replicated, controlled, before-and-after study in 1996 in arable farmland in the Netherlands (Canters & Tamis 1999) found that mowing planted grass margins did not affect the abundance of moths and butterflies. After mowing, the abundance of moths and butterflies generally, and diamondback moth Plutella xylostella specifically, was similar to before mowing. Ten grass margins (3 × 900 m) on five farms were sown with grasses, including giant fescue Festuca gigantea, timothy Phleum pratense and cocksfoot Dactylis glomerata. Grassy margins were mown on approximately half of the farms at the beginning of July 1996. Moths and butterflies were sampled using two pyramid traps/margin, installed for a three-week period five times during the 1996 growing season.

    Study and other actions tested
  3. A replicated, paired, site comparison study in 1999 on five farms in the UK (Thomas et al. 2000) found that grass field margins had a similar abundance of butterfly and moth caterpillars to beetle banks established in the centre of fields. The abundance of butterfly and moth caterpillars did not differ significantly between field margins (0.5 individuals/sweep) and beetle banks (0.4 individuals/sweep). In summer 1999, butterfly and moth caterpillars were sampled by sweep-netting on 22 permanently established grass field margins and 22 beetle banks of different ages across five farms.

    Study and other actions tested
  4. A replicated, controlled study in 1996–2000 on three arable farms in Essex, UK (Field & Mason 2005, same experimental set-up as Field et al. 2005, 2006, 2007a, 2007b) found that the number of gatekeepers Pyronia tithonus on sown grass margins increased over four years, and was higher than on cropped field edges at one of three farms after 2–4 years. Gatekeeper abundance on 2-m-wide grass margins increased from 2.2 individuals/km to 12.9 individuals/km over four years after the margins were sown. However, abundance was significantly higher in grass margins than in cropped margins at only one of three farms after 2–4 years (grass margin: 9.1 individuals/km, cropped edges: 0.7 individuals/km; other farms grass margin: 6.8–11.9 individuals/km, cropped edges: 1.9–17.3 individuals/km). Thirteen grass margins (2 m wide, 141–762 m long) were established in October 1996–2000 by sowing one of three seed mixtures containing 4–6 grass species. Three field edges without margins (one on each farm, 133–343 m long) were used as controls. Gatekeeper abundance was monitored weekly along each grass margin and cropped edge in July and August 1997–2000.

    Study and other actions tested
  5. 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.

    Study and other actions tested
  6. A replicated, site comparison study in 2002–2003 in 38 buffer strips in an arable region of Minnesota, USA (Davros et al. 2006) found that wide grass buffer strips had a higher abundance of habitat-sensitive butterflies, a similar abundance of disturbance-tolerant butterflies, and a higher species richness and diversity of all butterflies, than narrow buffer strips. The abundance of habitat-sensitive butterflies, and the species richness and diversity of all butterflies, was higher in wide buffer strips than in narrower strips, but the abundance of disturbance-tolerant butterflies was similar in strips of different widths (data presented as model results). See paper for individual species results. A total of 38 buffer strips (8–148 m wide, and all >3 years old, >350 m long, >1 km apart and with <15% tree or shrub cover) between a crop field and a water course were surveyed. None of the strips were treated with insecticide or fertilizer, and most were infrequently spot-mown or spot-sprayed to control weeds. In July–August 2002 and June–August 2003, butterflies were surveyed twice/year along one 200-m transect/buffer strip, halfway between the water course and crop field. Butterfly species were classified as “disturbance-tolerant” (species commonly found in human-modified landscapes) and “habitat-sensitive” (species with specific habitat requirements often found only in natural areas).

    Study and other actions tested
  7. A replicated, controlled study in 1996–2000 on three arable farms in Essex, UK (Field et al. 2006, same experimental set-up as Field & Mason 2005, Field et al. 2005, 2007a, 2007b) found that 2-m-wide sown grass margins, but not 6-m-wide grass margins, had higher butterfly species richness than field edges without grass margins. Butterfly species richness was higher in 2-m-wide grass margins (8–9 species) than in cropped field edges without margins (5–7 species), but was not significantly different in 6-m-wide margins compared to cropped field edges (data not presented). Species richness was also higher on 2-m grass margins sown with a more diverse seed mixture, and was higher on 2-m grass-sown margins next to hedgerows than on margins without hedgerows (data not presented). In October 1996–1998, twenty-six margins were established on three farms: 13 grass-sown that were 2-m-wide, five grass-sown that were 6-m-wide, three naturally regenerated (6 m wide) and five cropped field edges (2  and 6 m wide). Grass-sown margins were established using seed mixtures containing 4–9 common grass species. Butterflies were monitored weekly in summer from 1997–2000 in suitable weather.

    Study and other actions tested
  8. A replicated, site comparison study in 2003 in 38 meadows in Hebei Province, China (Liu et al. 2006) found that lightly cultivated meadows with grass margins and intercrop were more likely to be occupied by marsh fritillary Euphydryas aurinia eggs and caterpillars than uncultivated, grazed meadows, but caterpillar survival was lower in the cultivated meadows. More meadows with some cultivation, including grass margins, contained egg clusters (9/11 meadows) and caterpillars (11/16 meadows) than entirely uncultivated, grazed meadows (eggs: 1/12; caterpillars: 5/22 meadows). In total, 179 egg clusters were found in cultivated meadows, compared to 70 egg clusters in grazed meadows (statistical significance not assessed). The mortality of egg clusters was similar in cultivated meadows (10% of 177 clusters) and grazed meadows (16% of 69 clusters), but the survival of pre-hibernation caterpillars was lower in cultivated meadows (23/164, 14%) than in grazed meadows (21/59, 33%). A total of 38 meadows (0.025 ha–3.200 ha) were studied. In 2003, sixteen meadows contained some cultivation (corn or potatoes), and were divided into cultivated habitat (grass strips within and around the crop, no grazing from April–October) and meadow habitat (meadows and fallow land, grazed by sheep and cattle). Another 22 meadows were entirely uncultivated and grazed. In June 2003, eleven cultivated and 12 uncultivated meadows were searched for egg clusters. These were marked and observed every other day until all hatched caterpillars had disappeared or begun overwintering. In September 2003, all 38 meadows were surveyed for caterpillar nests.

    Study and other actions tested
  9. A replicated, controlled study in 1996–2000 on three arable farms in Essex, UK (Field et al. 2007a, same experimental set-up as Field & Mason 2005, Field et al. 2005, 2006, 2007b) found that planted grass margins had higher butterfly abundance than cropped field edges without margins. Butterfly abundance was higher in sown grass margins (67 individuals/km) than in cropped field edges (26 individuals/km). In sown grass margins abundance was higher for meadow brown Maniola jurtina (16 individuals/km) and golden skipper Thymelicus spp. (14 individuals/km) compared to cropped margins (meadow brown: 4; Thymelicus spp.: 1 individuals/km), but the abundance of gatekeeper Pyronia tithonus was similar (grass margin: 8; cropped margin: 5 individuals/km). Over four years, the total abundance of butterflies in the grass margins decreased (from 101 to 47 individuals/km), as did the abundance of Thymelicus spp. (32 to 3 individuals/km) and large skipper Ochlodes venata (15 to 1 individuals/km). However, the abundance of gatekeeper increased (2 to 13 individuals/km). In October 1996, thirteen 2-m-wide grass margins were sown (20 kg seed/ha), and were not cut after the first year. Butterfly abundance was monitored weekly from late June to early August 1997–2000 in grass margins and cropped field edges on each farm. All butterflies were recorded, but special note was taken of ‘key’ grassland species: meadow brown, gatekeeper, small skipper Thymelicus sylvestris, Essex skipper Thymelicus lineola and large skipper.

    Study and other actions tested
  10. 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.

    Study and other actions tested
  11. A replicated, randomized, controlled study in 2002–2006 on three farms in eastern England, UK (Pywell et al. 2007) found that grass-only field margins supported fewer butterflies than floristically-enhanced grass margins and pollen and nectar mixes. In grass-only margins, the abundance (12 individuals/plot) and species richness (5 species/plot) of butterflies was lower than in margins sown with either a grass and wildflower mix or a pollinating insect mix (abundance: 18–20 individuals/plot; richness: 6 species/plot). Management of the margins did not affect either the abundance or species richness of butterflies (data not presented). Field margin plots (6 × 30 m) were established in 2000–2001 using one of three seed mixes: a grass-only “Countryside Stewardship mix” (seven grass species, sown at 20 kg/ha), a floristically-enhanced “tussock grass mix” (seven grass species, 11 wildflowers, sown at 35 kg/ha) and a mixture of grasses and wildflowers designed for pollinating insects (four grass species, 16–20 wildflowers, sown at 35 kg/ha). Margins were managed in spring from 2003–2005 with one of three treatments: cut to 15 cm, soil disturbed by scarification until 60% of the area was bare ground, treated with grass-specific herbicide in spring at half the recommended rate. There were five replicates of each treatment combination on three farms. No further details provided.

    Study and other actions tested
  12. A replicated, paired, site comparison study in 2007 in four arable fields in Oxfordshire, UK (Merckx et al. 2009a, same experimental set-up as Merckx et al. 2009b, 2010, 2012) found a higher abundance of common farmland larger moth species in the margins and centres of fields with 6-m-wide perennial grass margins than in fields with standard 1-m margins, but this varied between species. Fields with 6-m-wide grass margins had 40% more moths of nine common species combined than fields with standard margins (data presented as model results). However, only two individual species (treble lines Charanyca trigrammica and brown-line bright-eye Mythimna conigera) were more abundant in fields with wide margins (data presented as model results). On the 32 nights (dusk till dawn) with suitable weather between 5 June and 14 July 2007, ten Heath pattern actinic light traps (6 W) were positioned in two arable fields/night: one in the centre of each field, and one in each field margin (1 m from hedgerow). All traps were >100 m apart and >50 m from hedgerow intersections. Traps were alternated between two pairs of fields each night, one with 6-m-wide perennial grass margins and the other with standard 1-m-wide margins. Moths were identified on the morning after capture.

    Study and other actions tested
  13. A replicated, site comparison study in 2006 in four arable areas in Oxfordshire, UK (Merckx et al. 2009b, same experimental set-up as Merckx et al. 2009a, 2010, 2012) found that farms with wide perennial grass margins had a higher diversity, but not abundance, of larger moths than farms with standard narrow margins. Farms with 6-m-wide margins had a higher species diversity of moths than farms with 1-m-wide standard margins (data presented as model results). However, the abundance of moths was similar between wide (22–27 individuals) and standard (22–25 individuals) margins. Three permanent sampling sites were established >100 m apart and >50 m from hedgerow intersections at each of 16 farms. Farms were divided between four experimental groups: sampling in a 6-m-wide perennial grass margin adjacent to a mature (>15 m high) hedgerow tree, sampling in a standard 1-m margin adjacent to a hedgerow tree, sampling in a 6-m margin not adjacent to a hedgerow tree, and sampling in a 1-m margin not adjacent to a hedgerow tree. All farms were sampled once during each of 11 discrete fortnightly periods from mid-May to mid-October 2006 using standardized moth traps.

    Study and other actions tested
  14. A replicated study on six arable farms in the Netherlands (Musters et al. 2009) found that the number of butterfly species in sown grass field margins increased in the eight years following establishment. More than half of the transects had increased butterfly species richness in the 1–8 years following the establishment of margins (data presented as model results). Field margins (2–3 m wide) were sown with grasses on six farms across the Netherlands. All margins were mown at least once a year and cuttings removed. No nutrients, pesticides or herbicides were applied to any of the margins. Butterflies were counted on twenty-one 50-m transects along field margins on six farms. Transect counts were either every week from April–September, or 2–5 times during summer, for 2–8 years after the margins were established (exact years not given).

    Study and other actions tested
  15. A replicated, site comparison study in 2007 at four arable farms in south Sweden (Haaland & Gyllin 2010) found lower abundance and species richness of butterflies in grass margins (greenways or ‘beträdor’) than in sown wildflower strips. In grass margins, the abundance of butterflies (0.6–1.4 individuals/100 m) was lower than in wildflower strips (10.4 individuals/100 m). In total, 14% of the recorded butterflies were found in grass strips compared to 86% in the wildflower strips. Four species of butterfly were only found in the wildflower strips. Margins with adjacent bushes had higher abundance and species richness of butterflies than margins without bushes (data presented as model results). At three farms, 14 grass strips (total 6.8 km) were sown with a mixture of grass species in the 1990s, 2004 and 2005, and were cut several times a year. At one farm, six wildflower strips (total 2.9 km) were sown in the mid-1990s using either a commercial mix of wildflowers and grasses, or hay from a nearby meadow, and were cut once a year at the end of July. Butterflies were recorded on transects five times from June–September 2007.

    Study and other actions tested
  16. A replicated, site comparison study in 2006–2008 on four arable farms in Oxfordshire, UK (Merckx et al. 2010, same experimental set-up as Merckx et al. 2009a, 2009b, 2012) found that 6-m-wide grass margins did not have more pale shining brown moths Polia bombycina than 1–2-wide margins. The number of individuals caught in wide field margins (0.4–1.3 individuals/trap) was not significantly different to the number caught in standard width margins (0.3–1.0 individuals/trap). Four farms were assigned to one of four treatments, based on their most common boundary features: 6-m-wide perennial grass or 1–2-m-wide standard field margins, and with or without hedgerow trees (>15 m high, mostly pedunculated oak Quercus robur). From May–October 2006–2008, moths were sampled overnight, once/fortnight, using three 6 W Heath pattern actinic light traps/farm. In June–July 2007 and 2008, at one farm, an additional 8–10 traps were set for 32–33 nights/year, in margins with the same treatments across 4–5 fields (16–20 locations). All traps were 1 m from hedgerows (2–3 m high, 1.5–2.5 m wide), 5 m from trees (if applicable), >50 m from hedgerow intersections, and >100 m apart.

    Study and other actions tested
  17. A replicated, randomized, controlled study in 2008–2009 on two arable farms in Berkshire, UK (Blake et al. 2011) found that sowing wildflowers in grass buffer strips which have been scarified and treated with grass-specific herbicide increased the abundance, diversity and species richness of butterflies. Butterfly species richness was higher in plots that had been scarified, sown with wildflower seeds and treated with grass-specific herbicide (5.8 species/plot) compared with single treatment plots (scarification and seeding: 2.6; herbicide: 2.5 species/plot) and plots with no scarification, seeding or herbicide (3.7 species/plot). Butterfly abundance (6.8 individuals/plot) and diversity were higher in plots that were scarified, seeded and treated with herbicide than single treatment plots (scarification and seeding: 2.5, herbicide: 2.2 individuals/plot), but similar to plots with no scarification, seeding or herbicide (3.7 individuals/plot; diversity presented as model results). Six-metre-wide grass buffer strips were created on two arable farms in 2004 and managed under an Entry Level Stewardship agreement from 2005. In spring 2008, three blocks of four 25 × 4 m plots were established at each farm. One of four treatments was applied randomly to each plot: scarification in March 2008; application of grass-specific herbicide (“fluazifop-P-butyl”) in April 2008; scarification and herbicide application; and no scarification or herbicide. Scarification was always followed by sowing a seed mixture of nine wildflower species. All plots were cut to 15 cm in autumn, and cuttings left in place. From May–September 2008–2009, butterflies were surveyed twice on each of four days/year on a 25-m transect through the centre of each plot.

    Study and other actions tested
  18. A replicated, paired, site comparison study in 2008 on 30 farms in central Scotland, UK (Fuentes-Montemayor et al. 2011) found that grass field margins and beetle banks managed under agri-environment schemes (AES) had a higher abundance and species richness of micro-moths, but not macro-moths, than conventionally-managed field margins. In AES field margins and beetle banks, both the abundance (57 individuals) and species richness (24 species) of micro-moths were higher than in conventional field margins (abundance: 17 individuals; richness: 8 species). However, the abundance (294 individuals) and species richness (34 species) of all macro-moths, and the abundance (24 individuals) and species richness (6 species) of declining macro-moths on AES margins and banks were not significantly different from conventional margins (all macro-moths: 207 individuals, 38 species; declining macro-moths: 32 individuals, 10 species). In 2004, fifteen farms enrolled in AES, and were paired with 15 similar but conventionally-managed farms, <8 km away. On AES farms, 1.5–6-m-wide field margins or beetle banks were sown with grass mixes, and managed with restrictions on grazing and fertilizer and pesticide use. Field margins on conventional farms had no management restrictions. From June–September 2008, moths were collected for four hours, on one night/farm, using a 6 W heath light trap located next to one margin or bank on each farm. Paired farms were surveyed on the same night.

    Study and other actions tested
  19. A replicated, randomized, paired, controlled study in 2005–2011 on an arable farm in Buckinghamshire, UK (Heard et al 2011) found that land managed under an agri-environment scheme, including planting grass margins, had a higher abundance, but not species richness, of butterflies and micro-moths than conventional farming, but there was no difference in abundance or species richness of other moths. Butterfly abundance was higher under enhanced Entry-Level Stewardship (ELS) (5,400 individuals/60 ha) and standard ELS (2,000 individuals/60 ha) than under conventional farming (1,400 individuals/60 ha). Micro-moth abundance was also higher under enhanced ELS (79 individuals) than standard ELS (32 individuals) or conventional farming (20 individuals). However, the abundance of macro-moths and threatened moths was similar under enhanced ELS (macro: 126; threatened: 6 individuals), standard ELS (macro: 79; threatened: 5 individuals) and conventional farming (macro: 79; threatened: 6 individuals). Species richness of all groups was similar under enhanced ELS (macro: 20; micro: 11; threatened: 3 species), standard ELS (macro: 20; micro: 8; threatened: 2 species) and conventional farming (macro: 18; micro: 5; threatened: 2 species) (butterfly data not presented). In 2005, a 1,000-ha farm was divided into five 180-ha blocks. Three 60-ha areas/block were assigned to three treatments: enhanced ELS (5% land removed from production, flower-rich margins sown with five grasses and six non-woody broadleaved plants “forbs”); standard ELS (1% land removed from production, 6-m margins sown with four grasses); conventional (margins only around hedges and watercourses) (see paper for other details). From May–August 2006–2011, butterflies were recorded four times/year on one 50-m transect/60-ha area, passing through all available habitats. In late-May 2007–2011 and late-July 2006–2011 moths were surveyed using Robinson light traps. One block was surveyed/night, with one trap/treatment.

    Study and other actions tested
  20. A replicated, site comparison study in 2006–2009 on 16 arable farms in Oxfordshire, UK (Merckx et al. 2012, same experimental set-up as Merckx et al. 2009a, 2009b, 2010) found that extended-width grass field margins, which farmers were paid to maintain under agri-environment schemes, had a higher species richness, but not abundance, of macro-moths than standard-width margins. The species richness of macro-moths in extended-width margins (105 species) was higher than in standard-width margins (92 species), but the abundance was similar (data not presented). Sixteen farms were categorized to one of four treatments, based on their most common agri-environment scheme habitat: extended 6-m-wide or standard 1-m-wide field margins, and with or without hedgerow trees (>15 m high, mostly pedunculated oak Quercus robur). All margins were well-established perennial grass strips, cut once every 2–3 years, ungrazed and unfertilized. From May–October 2006–2009, moths were sampled 40 times (once/fortnight), using three 6 W Heath pattern actinic light traps/farm. Traps were 1 m from hedgerows (2–3 m high, 1.5–2.5 m wide), 5 m from trees (if applicable), >50 m from hedgerow intersections, >100 m apart, and operated from dawn to dusk. Three farms (nine traps) were sampled/night.

    Study and other actions tested
  21. A replicated, paired, site comparison study in 2009 in a mixed farming region in Brittany, France (Delattre et al 2013) found that grass field margins were used by meadow brown Maniola jurtina butterflies in a similar way to meadows. Meadow brown flight patterns in grass field margins were similar to those in meadows (data presented as model results). In addition, meadow browns were more likely to fly along grass margins than across them. Meadow brown behaviour was studied in three pairs of grass field margins (5–20 m wide, 20–340 m long) and small meadows (0.05–5 ha), at sites 4–8.5 km apart. Grass field margins were mostly sown with a standard set of clover Trifolium spp. and grasses (Poacea). From June–August 2009, a total of 289 butterflies using field margins and 270 butterflies using meadows were followed individually from 15 m away, and the length and direction of their movements was recorded.

    Study and other actions tested
  22. A replicated, randomized, controlled, before-and-after study in 2007–2009 on a mixed farm in Mississippi, USA (Dollar et al. 2013) found that disking grass field margins increased the abundance, but not species richness, of disturbance-tolerant butterflies without affecting the abundance or species richness of grassland butterflies, while burning did not affect the abundance or species richness of any butterflies. The abundance of 18 disturbance-tolerant butterfly species was higher both one (10–14 individuals) and two (18 individuals) years after disking than on either burned (4–11 individuals) or undisturbed (4–14 individuals) margins. However, the species richness of disturbance-tolerant butterflies was similar between disked (7–9 species), burned (6–7 species) and undisturbed (6–8 species) margins. Both the abundance and species richness of 14 grassland butterfly species remained similar in disked (abundance: 0.6–1.4 individuals; richness: 2 species), burned (abundance: 0.3–1.3 individuals; richness: 1–3 species) and undisturbed (abundance: 0.5–1.3; richness: 1–3 species) margins. See paper for details of individual species. In spring 2004, grass margins totalling 79 ha were sown with a seed mix of common prairie species. Fifteen fields (containing 43 margins) were randomly assigned to one of three treatments: disking, burning and no disturbance. Within each disking field, one margin was disked in autumn 2007, and a different margin was disked in autumn 2008. Within each burning field, one margin was burned in spring 2008 and a different margin was burned in spring 2009. From June–August 2007–2009, butterflies were surveyed six times/year along three 50-m transects in the centre of each margin.

    Study and other actions tested
  23. A replicated, randomized, controlled study in 2007–2010 on 28 arable farms in Wessex and East Anglia, UK (Holland et al. 2015) found that farms with enhanced agri-environment scheme (AES) habitats, including floristically-enhanced grass buffer strips, had a higher abundance of some butterfly species than farms with simpler AES habitats, including standard grass margins. In early summer, farms with enhanced AES habitats had a higher abundance of blue (Lycaenidae: 0.05 individuals/100 m) and white (Pieridae: 0.46 individuals/100 m) butterflies along boundaries than farms with Entry Level Scheme (ELS) habitats (blues: 0.04; whites 0.21 individuals/100 m), but a lower abundance of skippers (Hesperiidae) in the AES habitat itself (enhanced: 0.00; ELS: 0.02 individuals/100 m). In mid-summer, enhanced AES farms had a higher abundance of white butterflies (0.69 individuals/100 m), but a lower abundance of brown butterflies (Satyridae: 0.16 individuals/100 m) in the AES habitat, and a lower abundance of blue butterflies (0.05 individuals/100 m) along boundaries than ELS farms (whites: 0.38; browns: 0.49; blues: 0.11 individuals/100 m). In spring 2007, twenty-four farms (12 in East Anglia and 12 in Wessex) were randomly assigned to two treatments: 16 farms with enhanced AES habitat (1.5–6.0 ha of floristically-enhanced grass mixes, wildflower strips, wild bird seed mixes and natural regeneration by annual cultivation); and eight farms with ELS habitat (1.5–6.0 ha of grass margins and game cover (usually maize)). Two additional ELS farms/region, already managed organically with 1.5 ha of ELS habitat, were also studied. From 2008–2010, butterflies were surveyed twice/year on 11 fixed 100-m transects, in mid-May–mid-June and mid-July–early August. Eight transects/site were located in AES habitat, and three transects/site were located on field boundaries away from the AES habitat.

    Study and other actions tested
  24. A replicated, site comparison study in 2014–2015 in 44 sites in a mixed farming region in Lombardy, Italy (Luppi et al. 2018) found that grass margins wider than 3 m had a higher species richness of butterflies than narrower margins. The species richness of butterflies in grass margins which were more than 3 m wide was higher than in margins which were less than 1 m wide (data presented as model results). In addition, margins where the vegetation was higher than 15 cm had more species than margins with vegetation shorter than 15 cm (data presented as model results). See paper for details on individual species groups. Arable fields with grass margins were divided into three width categories (<1 m, 1–3 m, >3 m) and three height categories (<15 cm, 15–50 cm, >50 cm). From April–September 2014–2015, butterflies were surveyed along 44 transects, divided into 8–26 × 50-m sections. In 2014, thirty transects were surveyed once/month, and in 2015 fourteen different transects were surveyed twice/month. Only transect sections along field margins were included (number not specified).

    Study and other actions tested
Please cite as:

Bladon A.J., Smith R.K. & Sutherland W.J. (2022) Butterfly and Moth Conservation: Global Evidence for the Effects of Interventions for butterflies and moths. Conservation Evidence Series Synopsis. University of Cambridge, Cambridge, UK.

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