Increase or maintain the proportion of natural or semi‐natural habitat in the farmed landscape

Supporting evidence from individual studies

1. A before-and-after study in 1987–1991 on an arable farm in Saarland, Germany (Reck 1993) reported that increasing the area of meadows and field margins, and the length of field edges, increased the species richness of butterflies and burnet moths. Results were not tested for statistical significance. Four years after the semi-natural habitat was created, 24 species of butterflies and burnet moths were present on the farm, compared to 20 species before creation. Marbled white Melanargia galathea were present at eight survey sites in 1991, compared to one site in 1987. In 1987, on an intensively managed 30-ha farm with large fields, semi-natural meadows and field margins were created by sowing regional plant species including rosebay willowherb Epilobium angustifolium, danewort Sambucus ebulus, heather Calluna vulgaris and regional meadow seeds. The length of field edges was increased from 7,200 m to 17,420 m. From May–August 1987–1988 and 1991, butterflies and burnet moths were surveyed at sample sites (number not specified) across the whole farm.

   Study and other actions tested

   Referenced paper

   Reck H. (1993) Creating new habitats on intensively used farmland, the ‘Pappelhof’ in Saarland: A project supported by the German government. Natur und Landschaft: Zeitschrift fur Naturschutz und Landschaftspflege, 68, 394-403.

2. A replicated, site comparison study in 2002–2003 in 38 field margins in an arable region of Minnesota, USA (Davros et al. 2006) found that the abundance of four of eight butterfly species was higher in margins surrounded by more woodland habitat. In areas with more woodland in the surrounding landscape, the abundance of four out of eight butterfly species (orange and clouded sulphur Colias spp., monarch Danaus plexippus and regal fritillary Speyeria idalia) was higher. However, the abundance of one species (least skipper Ancyloxypha numitor) was lower in more wooded landscapes (data presented as model results). A total of 38 field margins (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/margin, halfway between the water course and crop field. The habitat in a 1-km radius surrounding the midpoint of each transect was classified as “herbaceous habitat”, “crops”, “wooded”, “wetland” or “developed” areas (see paper for details).

   Study and other actions tested

   Referenced paper

   Davros N.M., Debinski D.M., Reeder K.F. & Hohman W.L. (2006) Butterflies and continuous conservation reserve program filter strips: Landscape considerations. Wildlife Society Bulletin, 34, 936-943.

3. A replicated, site comparison study in 2003–2004 on 24 arable farms in Scania, Sweden (Rundlöf & Smith 2006) found that farms in more diverse landscapes had a higher abundance and species richness of butterflies and burnet moths than farms in intensively farmed landscapes. On farms in diverse landscapes, both the abundance (3.6–4.5 individuals/50 m) and species richness (1.4–1.6 species/50 m) of butterflies and burnet moths were higher than on farms in intensively farmed landscapes (abundance: 0.4–1.7 individuals/50 m; richness: 0.3–0.9 species/50 m). Twelve arable farms in diverse landscapes (15% arable land, 19% pasture, small fields (average: 31,600 m²)), and 12 arable farms in intensively farmed landscapes (70% arable land, 3% pasture, large fields (average: 60,200 m²)) were selected. From June–August 2003 and May–August 2004, butterflies and burnet moths were surveyed 5–6 times/year along 400–750 m routes along cereal field boundaries. Individuals occurring 5 m into the crop and in adjacent 2-m uncultivated margins were counted.

   Study and other actions tested

   Referenced paper

   Rundlöf M. & Smith H.G. (2006) The effect of organic farming on butterfly diversity depends on landscape context. Journal of Applied Ecology, 43, 1121-1127.

4. A replicated, site comparison study in 2006–2007 in 15 sites of oil palm plantation in East Sabah, Malaysia (Koh 2008) found higher butterfly species in areas where the ground coverage of weeds had been maintained, but no effect of maintaining epiphytes or ferns. Sites with a higher percentage of ground cover of weeds had higher butterfly species richness. However, the number of nearby trees with high epiphyte growth, and the percentage ground coverage of ferns, had no effect on species richness. Additionally, there was higher butterfly species richness in sites where a higher proportion of old growth forest within the surrounding 1 km radius had been maintained. All results are presented as statistical tests. In September–October 2006 and March–April 2007, butterflies were counted along 100 m transects in 15 plantations. There were 3–10 transects at each site and each was surveyed 1–3 times over the entire sampling period. Only butterfly species known to occur in Malaysian primary forest were included in analyses, and Hesperiidae and Lycaenidae were excluded because of identification difficulties. Varying proportions of weeds, epiphytes and ferns had previously been removed at each site by plantation workers (the removal was not part of the study and removal details are not included). At the start and end of transects researchers counted the proportion of the nearest 10 palm trees with >50% epiphyte coverage, and the percentage of ground covered by ferns and weeds.

   Study and other actions tested

   Referenced paper

   Koh L.P. (2008) Can oil palm plantations be made more hospitable for forest butterflies and birds? Journal of Applied Ecology, 45, 1002-1009.

5. A replicated, site comparison study in 1998–2005 in mixed farmland in Aargau, Switzerland (Roth et al. 2008) found that areas of semi-natural habitat initially supported more butterfly species than farmed land, but over time the number of species decreased in both semi-natural habitat and farmed land. When initially surveyed, there were more species of butterfly in sites managed as Ecological Compensation Areas (ECA, 7.3 species/plot) than in non-ECA sites (5.6 species/plot). However, between the first survey and the second survey, the number of butterfly species decreased overall, but the decreases were similar on ECA and non-ECA sites (both -1.1 species/plot). Most ECA sites were established between 1992 and 1998. Sites were surveyed twice, five years apart, with the first survey taking place in 1998–2000 and the second in 2003–2005. At 52 ECA sites and 35 non-ECA sites, butterflies were surveyed along a 10 x 250 m transect 11 times/year. The authors noted that ECAs were typically established on farmland with potential for maximum biodiversity gain, which may have affected the relative numbers of species found in the first survey.

   Study and other actions tested

   Referenced paper

   Roth T., Amrhein V., Peter B. & Weber D. (2008) A Swiss agri-environment scheme effectively enhances species richness for some taxa over time. Agriculture, Ecosystems & Environment, 125, 167-172.

6. A replicated, site comparison study in 2008 on 36 farms in central Scotland, UK (Fuentes-Montemayor et al. 2011) found that farms with more semi-natural habitat had a higher abundance and species richness of moths than farms with less semi-natural habitat. The abundance of both micro-moths and macro-moths, and the species richness of macro-moths, were all higher on farms with more semi-natural habitat (data presented as model results). However, the species richness of micro-moths, and the diversity of both groups, was similar between farms with more and less semi-natural habitat (data presented as model results). In 2004, eighteen farms enrolled in agri-environment schemes, and were paired with 18 similar but conventionally-managed farms, <8 km away. From June–September 2008, moths were collected for four hours, on one night/farm, using a 6 W heath light trap located next to either a field margin, watercourse margin, beetle bank, hedgerow or grassland on each farm. Paired farms were surveyed on the same night.

   Study and other actions tested

   Referenced paper

   Fuentes-Montemayor E., Goulson D. & Park K.J. (2011) The effectiveness of agri-environment schemes for the conservation of farmland moths: Assessing the importance of a landscape-scale management approach. Journal of Applied Ecology, 48, 532-542.

7. A replicated, site comparison study in 2009 in 60 arable farms in Uppland and Scania, Sweden (Jonason et al. 2011) found that butterfly and burnet moth species richness, but not abundance, was higher in farms surrounded by a greater proportion of forest-dominated land than those surrounded by a greater proportion of arable farmland. Farms within a 1 km radius with a higher proportion of forest-dominated land and a lower proportion of arable land had higher butterfly species richness compared to those with a higher proportion of arable land and a lower proportion of forest-dominated land (data presented as statistical results). However, the relative proportions of forest-dominated and arable land resulted in no difference in butterfly abundance. In June–August 2009, butterfly surveys were carried out in 40 organic and 20 conventionally-managed farms. On each farm, three 250 m transects were completed 5–6 times - one in an uncultivated margin of a cereal field, and two within the field at 50 m and 200 m from the margin transect. Butterflies Rhopalocera and burnet moths Zygaenidae were identified to species. The proportion of arable land within a radius of 1 km from each farm was calculated using remote sensing imagery. The proportion of arable land ranged from 20–80%.

   Study and other actions tested

   Referenced paper

   Jonason D., Andersson G.K., Öckinger E., Rundlöf M., Smith H.G. & Bengtsson J. (2011) Assessing the effect of the time since transition to organic farming on plants and butterflies. Journal of Applied Ecology, 48, 543-550.

8. A replicated, site comparison study in 2008–2009 in six vineyards in Canterbury Province, New Zealand (Gillespie & Wratten 2012) found that remnant native habitat patches had a higher abundance and species richness of butterflies than amongst the vines, on pasture or in planted native vegetation. In remnant habitat patches, the abundance (14 individuals/section) and species richness (0.7 species) of butterflies was higher than amongst the grape vines (abundance: 8 individuals/section; richness: 0.3 species), on pasture fields (abundance: 7 individuals/section; richness: 0.5 species), or in planted native vegetation (abundance: 3 individuals/section; richness: 0.5 species). See paper for individual species results. Six vineyards, each containing areas of remnant native vegetation (typically stands of matagouri Discaria toumatou and New Zealand bindweed Calystegia tuguriorum) and small (100–200 m²) areas of planted native shrubs and grasses, alongside grape vines and grazed pasture, were selected. From October 2008–April 2009, butterflies were surveyed 13 times (once/fortnight) along a fixed transect through the different habitat patches on each vineyard. Transects were split into 9–14 sections based on habitat type for analysis.

   Study and other actions tested

   Referenced paper

   Gillespie M. & Wratten S.D. (2012) The importance of viticultural landscape features and ecosystem service enhancement for native butterflies in New Zealand vineyards. Journal of Insect Conservation, 16, 13-23.

9. 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 a higher proportion of uncropped habitat had a greater abundance and species richness of butterflies in early summer, but not in mid-summer. On farms where the proportion of uncropped habitat was >7.5%, the species richness of butterflies on field boundaries in early summer (2.9–3.0 species/100 m) was higher than on farms with <7.5% uncropped habitat (1.0–1.6 species/100 m). When the proportion of uncropped habitat was >10%, the abundance of butterflies in the wildlife habitat in early summer was higher than on farms with <10% uncropped habitat (data not presented). See paper for details of species groups. In spring 2007, twenty-four farms (12 in East Anglia and 12 in Wessex) were randomly assigned to two treatments: 16 farms with enhanced agri-environment scheme (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 Entry-level Stewardship (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

   Referenced paper

   Holland J.M., Smith B.M., Storkey J., Lutman P.J.W. & Aebischer N.J. (2015) Managing habitats on English farmland for insect pollinator conservation. Biological Conservation, 182, 215-222.

10. A replicated, site comparison study in 2009–2011 in 133 mixed farms in the Central Plateau, Switzerland (Stoeckli et al. 2017) found that farms managed with larger areas of semi-natural habitat had a higher abundance, but not species richness, of butterflies than farms with less semi-natural habitat. The abundance of butterflies on farms with more semi-natural habitat was higher than on farms with less semi-natural habitat, but there was no difference in butterfly species richness (data presented as model results). A total of 133 farms (17–34 ha, 13–91% arable crops) were managed with “Ecological Compensation Areas” under agri-environment schemes. Management included extensive and low-input meadows with reduced fertilizer and later cutting dates, and the presence of trees, hedgerows and wildflower patches. From May–September 2009–2011, butterflies were surveyed six times on 10–38 transects/farm, totalling 2,500 m/farm. Each transect ran diagonally through a single crop or habitat type, with all available crops and habitats represented. All visits to a farm were completed in a single year, and the species richness was summed across all visits. Total abundance of butterflies was calculated from the number recorded in each habitat, and the availability of each habitat across the farm. Semi-natural habitats on each farm were mapped between May and August.

    Study and other actions tested

    Referenced paper

    Stoeckli S., Birrer S., Zellweger-Fischer J., Balmer O., Jenny M. & Pfiffner L. (2017) Quantifying the extent to which farmers can influence biodiversity on their farms. Agriculture, Ecosystems & Environment, 237, 224-233.

11. A replicated, site comparison study in 2015 on seven arable farms in Germany (Sybertz et al. 2017) found that field margins on farms with more semi-natural habitat in the surrounding area had more butterfly species than margins on farms with less semi-natural habitat. The number of species of butterfly recorded on field margins was higher on farms with more semi-natural habitat within 1 km than on farms surrounded by less semi-natural habitat (data presented as model results). The amount of semi-natural habitat within 1 km of each of seven farms (58–700 ha) was estimated from aerial images. From June–August 2015, butterflies were surveyed six times along 10 permanent, unsprayed and uncropped arable field margins (≥1 m wide, 50–250 m long) on each farm.

    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.

12. A replicated, site comparison study in 2010–2014 in 50 agricultural areas in the Swiss Plateau, Switzerland (Zingg et al. 2018) found that landscapes with a greater proportion of semi-natural habitat, provided through agri-environment schemes, had a higher abundance and species richness of butterflies than landscapes with less semi-natural habitat. Agricultural areas with more than 20% of the land managed as semi-natural habitat had a higher abundance and species richness of all butterflies than areas with less than 10% semi-natural habitat. The abundance of farmland butterflies, and the species richness of threatened butterflies, was higher in landscapes with more semi-natural habitat than in landscapes with less semi-natural habitat (all data presented as model results). Fifty mixed farming areas (1 km²) were selected where 2.5–32.2% of agricultural land was managed under agri-environment schemes (primarily extensive meadows (cut or grazed once/year, no fertilizers or pesticides) and orchards). Butterflies were surveyed seven times along a 2.5-km transect through each 1-km² area in one of five years (2010–2014). Species were classified as “farmland species” if they occur in open habitat, and “threatened” species if they were listed as Near Threatened, Vulnerable or Critically Endangered on the Swiss RedList.

    Study and other actions tested

    Referenced paper

    Zingg S., Grenz J. & Humbert J. (2018) Landscape-scale effects of land use intensity on birds and butterflies. Agriculture, Ecosystems & Environment, 267, 119-128.