Create uncultivated margins around intensive arable or pasture fields

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 uncultivated margins had a lower abundance but similar species richness of butterflies and moths to sown margins. Results were not tested for statistical significance. Over two months, fewer butterflies and moths were recorded in two uncultivated field margins (38–44 individuals) than in two sown margins (58–75 individuals), but the number of species was similar (uncultivated: 7 species; sown: 6 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 uncultivated (one with diverse weeds, the other with diverse herbs and grasses on a ditch bank) and two 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). 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

   Referenced paper

   Lagerlöf J., Stark J. & Svensson B. (1992) Margins of agricultural fields as habitats for pollinating insects. Agriculture, Ecosystems & Environment, 40, 117-124.

2. A replicated, randomized, site comparison study in 1987–1991 in Oxfordshire, UK (Feber et al. 1994, same experimental set-up as Feber & Smith 1995, Feber et al. 1996) found that unsown field margins had fewer adult meadow brown Maniola jurtina than margins sown with wild grasses and non-woody broadleaved plants (forbs), and that margin management affected butterfly numbers. Fewer adult meadow browns were found on unsown, naturally regenerating margins (4–15 butterflies/50 m) than on sown margins (4–52 butterflies/50 m). However, unsown margins had more butterflies if they were left uncut (4–13 butterflies/50 m), or were cut in spring and autumn (7–15 butterflies/50 m), than if they were cut in summer (4–10 butterflies/50 m). There was no difference in the abundance of meadow brown caterpillars between unsown and sown, or uncut and cut, plots (3 caterpillars/plot). There were more meadow browns on all the experimental field margins than on narrow, unmanaged field boundaries of a neighbouring farm (numbers not given). In October 1987, two-metre-wide field margins around arable fields were rotovated, and either left to regenerate naturally or sown with a wildflower seed mix in March 1988. Within each unsown and sown margin, 50-m-long plots were managed in one of four ways, with eight replicates of each treatment: uncut; cut once in June; cut April and June; cut in April and September. Hay was collected after cutting. From June–September 1989, and April–September 1990–1991,  meadow brown adults were monitored weekly. In spring 1991, meadow brown caterpillars were sampled by sweep netting and visual searching.

   Study and other actions tested

   Referenced paper

   Feber R.E., Smith H. & Macdonald D.W. (1994) The effects of field margin restoration on the meadow brown butterfly (Maniola jurtina). British Crop Protection Council Monographs, 58, 295-300.

3. A site comparison study in 1988–1991 on two arable farms in Oxfordshire, UK (Feber & Smith 1995, same experimental set-up as Feber et al. 1994, 1996) reported that a farm where wider field margins had been established and fertilizer application excluded had a higher abundance and species richness of butterflies than a farm with conventional field margins. Results not tested for statistical significance. The abundance of eight species (including small skipper Thymelicus sylvestris, small heath Coenonympha pamphilus, gatekeeper Pyronia tithonus and meadow brown Maniola jurtina) was higher on a farm with wider (2-m) field margins than on a farm with conventional (0.5-m) margins. No species was more abundant on the conventional farm. In addition, two species (marbled white Melanargia galathea and common blue Polyommatus icarus) were only recorded on the farm with wide margins, resulting in a higher species richness (16 species) than the conventional farm (14 species). In 1988, the margins of 10 fields on one farm were extended from 0.5-m to 2-m wide, and fertilizer application was excluded. Margins were either left to regenerate naturally, or sown with grasses and non-woody broadleaved plants (forbs). Margins were either left uncut, or cut in some combination of April, June and September 1989–1991. In summer 1991, butterflies were surveyed for two months on transects on this farm and on a second, intensively managed farm with conventional field margins (number not given).

   Study and other actions tested

   Referenced paper

   Feber R.E. & Smith H. (1995) Butterfly Conservation on Arable Farmland. Pages 84-97 in: Ecology and Conservation of Butterflies . Chapman & Hall, London.

4. A replicated, randomized, site comparison study in 1987–1991 in Oxfordshire, UK (Feber et al. 1996, same experimental set-up as Feber et al. 1994, Feber & Smith 1995) found that butterfly abundance and species richness were lower in unsown field margins than in margins sown with wild grasses and non-woody broadleaved plants (forbs), and that margin management affected butterfly numbers. From two years after establishment, both individual abundance (14–39 individuals/50 m) and species richness (6–9 species/50 m) of butterflies were lower in unsown, naturally regenerating margins than in sown margins (abundance: 21–91 individuals/50 m; richness: 7–10 species/50 m). However, in all three years, unsown margins had more butterflies if they were left uncut (abundance: 28–40 individuals/50 m; richness: 8–9 species/50 m), or were cut in spring and autumn (abundance: 29–44 individuals/50 m; richness: 8–9 species/50 m), than if they were cut in summer (abundance: 14–27 individuals/50 m; richness: 6–8 species/50 m). In autumn 1987, two-metre-wide field margins around arable fields were rotovated. In April 1988, they were either left to naturally regenerate or sown with a wildflower seed mix. Within each unsown and sown margin, 50-m-long plots were managed in one of four ways, with eight replicates of each treatment: uncut; cut once in June; cut April and June; cut in April and September. Hay was collected after cutting. Butterflies were monitored weekly from June–September 1989 and from April–September 1990 and 1991.

   Study and other actions tested

   Referenced paper

   Feber R.E., Smith H. & Macdonald D.W. (1996) The effects on butterfly abundance of the management of uncropped edges of arable fields. Journal of Applied Ecology, 33, 1191-1205.

5. A replicated, site comparison study in 1994–1996 on an arable farm in Gloucestershire, UK (Feber & Hopkins 1997) found that the abundance and diversity of butterflies was lower in unsown naturally regenerated field margins than in margins sown with wildflowers, and that margin management affected butterfly diversity. Unsown, naturally regenerated margins had a lower abundance (5–10 individuals) and diversity (3–6 species) of butterflies than sown wildflower margins (abundance: 15–16 individuals; diversity: 6–7 species). Cutting and subsequent grazing of naturally regenerated margins decreased butterfly diversity (3 species) but not abundance (5 individuals) compared to margins which were not cut or grazed (diversity: 6 species; abundance: 10 individuals). In 1994, two-metre margins were established around two organically managed arable fields by either natural regeneration or by sowing a seed mix containing five grasses and six wildflowers. In 1996, half of the margins were cut in June and grazed in July. The rest was left unmanaged. From May–September 1996, butterflies were monitored weekly along transects.

   Study and other actions tested

   Referenced paper

   Feber R.E. & Hopkins A. (1997) Diversity of plant and butterfly species on organic farmland field margins in relation to management. British Grassland Society Fifth Research Conference, University of Plymouth, Devon, UK, 8-10 September 1997, 63-64.

6. 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).

   Study and other actions tested

   Referenced paper

   Meek B., Loxton D., Sparks T., Pywell R., Pickett H. & Nowakowski M. (2002) The effect of arable field margin composition on invertebrate biodiversity. Biological Conservation, 106, 259-271.

7. 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.

   Study and other actions tested

   Referenced paper

   Field R.G., Gardiner T., Mason C.F. & Hill J. (2005) Agri-environment schemes and butterflies: the utilisation of 6 m grass margins. Biodiversity and Conservation, 14, 1969-1976.

8. A replicated, paired, site comparison study in 2004 in 12 agricultural areas in southern Sweden (Öckinger & Smith 2007) found that uncultivated margins placed close to semi-natural grassland fragments had a higher abundance and species richness of grassland-dependent butterflies and burnet moths (Zygaenidae) than margins situated further from grassland. There was a higher abundance and species richness of butterflies and burnet moths in uncultivated margins which were next to semi-natural grasslands (abundance: 0.1–1.6 individuals/100 m²; richness: 0.1–1.7 species/100 m) than in margins which were >1 km from the nearest grassland (abundance: 0.0–0.9 individuals/100 m²; richness: 0.1–0.9 species/100 m). Butterfly abundance in margins close to grassland was similar to the grassland (0.5–1.2 individuals/100 m²), but species richness in the margins was lower than the grassland (0.9–2.0 species/100 m). In each of 12 areas, two uncultivated strips of perennial grassland bordering cultivated fields were surveyed. One strip was situated within 100 m of an area of grazed, semi-natural grassland (5–12 ha), and the other was >1 km from the nearest grassland >0.5 ha. From late May–early August 2004, grassland-dependent butterflies and burnet moths were surveyed six times on one 300-m transect/margin, and on a transect through each semi-natural grassland (150 m/ha).

   Study and other actions tested

   Referenced paper

   Öckinger E. & Smith H.G. (2007) Semi-natural grasslands as population sources for pollinating insects in agricultural landscapes. Journal of Applied Ecology, 44, 50-59.

9. A replicated, site comparison study in 2003–2004 in an arable field in Jokioinen, Finland (Kuussaari et al. 2011) reported that permanent, uncultivated field margins had a higher abundance and species richness of butterflies and day-flying moths than sown fallow plots or spring cereals. Results were not tested for statistical significance. In permanent, uncultivated margins the abundance (120 individuals/1,000 m) and species richness (9.4 species/plot) of butterflies and day-flying moths were higher than in temporary, in-field, sown fallow plots that were one-year-old (abundance: 2–3 individuals/1,000 m; richness: 0.5–0.7 species/plot) or two-years-old (abundance: 5–30 individuals/1,000 m; richness: 0.7–4.2 species/plot), or left as stubble (abundance: 17 individuals/1,000 m; richness: 4.2 species/plot). No butterflies or moths were recorded in spring cereal fields. Six species showed a significant preference for permanent margins over temporary fallow plots (Essex skipper Thymelicus lineola, ringlet Aphantopus hyperantus, Lewes wave Scopula immorata, shaded broad-bar Scotopteryx chenopodiata, silver-ground carpet Xanthorhoe montanata, black-veined moth Siona lineata). In 2003, ten permanently uncultivated, 250-m long, 2.5-m wide field margins next to a 16.5-ha field were selected. The field was divided into four blocks, each containing eight 0.3-ha plots. Six plots/block were sown with grasses in either 2003 or 2004 and left fallow (see paper for details), one plot/block was sown with spring barley in 2003 and left as stubble in 2004, and one plot/block was sown with spring barley in both years. In June–July 2004, butterflies and day-flying moths were recorded four times, two weeks apart, on one 250-m transect through each margin or plot.

   Study and other actions tested

   Referenced paper

   Kuussaari M., Hyvonen T. & Härmä O. (2011) Pollinator insects benefit from rotational fallows. Agriculture, Ecosystems & Environment, 143, 28-36.

10. A replicated, site comparison study in 2015 on seven arable farms in Germany (Sybertz et al. 2017) found that wider, longer, uncultivated permanent margins which were not mown in the summer had more butterfly species than narrower, shorter or summer-mown margins. All data were presented as model results. There were more butterfly species on longer or wider margins than on shorter or narrower margins. Margins which were completely mown in June or July had fewer butterfly species than margins which were only partially mown in June or July, or were mown at another time of year or not mown at all. On each of seven farms (58–700 ha), 10 permanent, unsprayed and uncropped arable field margins (≥50 m long and ≥1 m wide) were sampled.  Margins were managed by either complete mowing in June or July, partial mowing in June or July, or mowing at other times of year (including unmown margins). From June–August 2015, butterflies were surveyed six times along a 50–250 m transect in each margin.

    Study and other actions tested

    Referenced paper

    Sybertz J., Matthies S., Schaarschmidt F., Reich M. & von Haaren C. (2017) Assessing the value of field margins for butterflies and plants: How to document and enhance biodiversity at the farm scale. Agriculture, Ecosystems & Environment, 249, 165-176.