Restore or create grassland/savannas

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

Study locations

Key messages

  • Four studies evaluated the effects on butterflies and moths of restoring or creating grassland or savanna. Three studies were in the USA and one was in Italy.


  • Richness/diversity (1 study): One replicated, paired, site comparison study in Italy found that created semi-natural grasslands had a greater diversity of butterflies than adjacent conifer forests, but a lower diversity than species-rich pastures.


  • Abundance (4 studies): Two site comparison studies (including one replicated, paired study) in Italy and the USA found that created semi-natural grasslands, and restored grasslands and oak barrens, had a higher abundance of butterflies and regal fritillaries than adjacent conifer forests, species-rich pastures or unmanaged or remnant prairies. One site comparison study in the USA found that prairies restored 5–10 years ago by seeding with native species, mowing, and weeding or applying herbicide, had a greater abundance of Fender’s blue eggs than a prairie restored 1–2 years ago, and a similar abundance to remnant prairies. One study in the USA reported that restored prairie supported a translocated population of regal fritillaries for at least three years after restoration.


  • Behaviour change (1 study): One site comparison study in the USA found that Fender’s blue butterflies spent a similar proportion of time laying eggs in prairies restored 5–10 years ago by seeding with nectar species, mowing, and weeding or applying herbicide, and in remnant prairies.

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 study in 1998–2004 on former cropland in Iowa, USA (Shepherd & Debinski 2005) reported that restored prairie supported a translocated regal fritillary Speyeria idalia population. In 2001, the first year after translocation to a restored prairie, no butterflies were seen, but in 2002, one year after a second release, 84 adults were recorded. In the following two years, 11–12 fritillaries were observed in planted violet plots and other areas on 1–2 days/year. On 15 days in 2004, between 1–23 fritillaries were seen/day. Within a 2,083-ha reserve, 1,250 ha of former cropland were restored to tallgrass prairie (no further detail provided). The remaining land contained scattered remnant prairie patches. In 1998 and 1999, prairie violets Viola pedatifida were planted in five plots at each of four sites across the reserve. Each plot contained 99 violets planted in a grid (9 × 11 m), 1 m apart. In July 2000 and August–September 2001, seven female fritillaries were caught and brought to the restored prairie. Fritillaries were placed in mesh cages (0.6 × 0.6 m or 1.8 × 1.8 m) directly over violet plants, and provided with nectar from cut flowers and moved to new violet plants each day. In June–August 2001–2004, butterflies were surveyed or opportunistically recorded across the site.

    Study and other actions tested
  2. A site comparison study in 2009–2010 in three restored fields in Oregon, USA (Carleton & Schultz 2013) found that older restored prairie had a higher density of Fender’s blue butterfly Plebejus icarioides fenderi eggs than recently restored prairie. Five to 10 years after restoration, the host plant Kincaid’s lupine Lupinus oreganus had more butterfly eggs (0.04–0.16 eggs/leaf) than 1–2 years after restoration (0.002–0.004 eggs/leaf), but similar numbers to intact habitat (0.09–0.13 eggs/leaf). Lupine density was also higher 5–10 years after restoration (5.1–9.0 leaves/m2) than 1–2 years after restoration (0.3–1.3 leaves/m2), but lower than in intact prairie (54.5 leaves/m2). The time spent laying eggs by females was similar in older restored habitat (3–10%) and intact habitat (11%). From 2000, 2004 and 2008, three former fields (0.1–0.6 ha) were restored by seeding with native Fender’s blue nectar species and Kincaid’s lupine for 1–4 years. Restoration sites were adjacent to 3.5 ha of intact prairie. Restored areas were mown, and either hand weeded or treated with herbicide to reduce the spread of non-native plants. At the end of the 2009 and 2010 flight seasons, the number of lupine leaves and the number of Fender’s blue eggs were sampled in the restored and intact prairie. In May–June 2009, female butterflies were observed in restored (38 females) and intact (116 females) prairie, and the percentage of time spent laying eggs was recorded.

    Study and other actions tested
  3. A replicated, paired, site comparison study in 2010 three alpine grassland and forest sites in the Aosta Valley, Italy (Rolando et al. 2013) found that created semi-natural grasslands had a higher abundance and diversity of butterflies than adjacent conifer forest, and a higher abundance but lower diversity of butterflies than nearby species-rich pastures. On created grasslands, the total number of butterflies recorded (1,133 individuals) was higher than on pastures (759 individuals) or in forests (1,060 individuals). However, species diversity on created grasslands was lower than on pastures but higher than in forests (data presented as model results). Created semi-natural grassland strips (>15-years-old) were occasionally grazed by cattle in summer, and used as ski-pistes in winter. Species-rich pastures were grazed annually by cattle. From 20 July–20 August 2010, butterflies were surveyed on twenty 300-m transects in each of three habitats: created grassland, adjacent coniferous forest, and nearby pastures.

    Study and other actions tested
  4. A site comparison study in 2014 in a restored grassland and oak barren landscape in Indiana, USA (Shuey et al. 2016) reported that regal fritillary Speyeria idalia were found across a landscape restored by planting and rotational burning. Results were not tested for statistical significance. Eighteen years after restoration began, on four restoration sites with high plant diversity, the abundance of regal fritillaries peaked at 17 butterflies/30-minute transect, compared to 12 butterflies/transect on two remnant prairies and a low plant diversity restoration site, 19 butterflies/transect in an old field, and 0 butterflies/transect in an agricultural field. Prior to restoration, authors reported that regal fritillaries were only found at three small sites in the landscape. Beginning in 1996, over 3,240 ha of agricultural land was restored to native grassland and oak barrens by planting seed mixes containing nearly all known locally native species (>620 species). In addition, seeds (<1 ounce/year) and plugs (<1,000 plants/year) of arrowleaf violet Viola sagittata and bird’s-foot violet Viola pedata were planted as host plants. The area was managed to control invasive species and, once established, patches were burned on a three-year rotation. From May–September 2014, butterflies were surveyed every two weeks on 30-minute transects at nine sites across the landscape: four restoration sites with high plant diversity, one restoration site with low plant diversity, two remnant prairies, one old field, and one site still in agricultural production, none of which had been burned during the previous year.

    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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Butterfly and Moth Conservation

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Butterfly and Moth Conservation
Butterfly and Moth Conservation

Butterfly and Moth Conservation - Published 2022

Butterfly and Moth Synopsis

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