Legally protect habitat

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

Study locations

Key messages

  • Nine studies evaluated the effects on butterflies and moths of legally protecting habitat. Six studies were in the UK and one was in each of Australia, Singapore and Ireland. Three of the studies used data from the same national monitoring scheme across different years.

COMMUNITY RESPONSE (3 STUDIES)

  • Richness/diversity (3 studies): One replicated, site comparison study in Singapore found that protected primary or secondary forest reserves had a higher species richness of butterflies than unprotected forest fragments. One replicated, paired, site comparison study in Ireland reported that raised bogs protected as Special Areas of Conservation (where restoration had sometimes taken place) had a similar species richness of moths to unprotected bogs. One replicated, site comparison study in the UK found that, in the first three years after protection as Sites of Special Scientific Interest (SSSI), woodland, grassland and heathland sites lost a similar proportion of 29 threatened butterfly species to unprotected sites.

POPULATION RESPONSE (7 STUDIES)

  • Abundance (7 studies): Three of five site comparison studies (including four replicated studies and one before-and-after study) in the UK and Ireland found that sites protected as National Nature Reserves or Sites of Special Scientific Interest (SSSI) (in one case also managed by coppicing), or surrounded by SSSIs, had a higher abundance of heath fritillary, all butterflies and 30/57 species of butterfly than unprotected sites. However, one of these studies only found the result using one of two sets of sites. The other two studies found that grasslands protected as National Nature Reserves or SSSIs and raised bogs protected as Special Areas of Conservation had a similar total abundance of moths, and change in abundance of chalkhill blue butterflies, to unprotected sites. However, one of these studies found mixed results for individual moth species. One replicated, site comparison study in the UK found that protected grasslands assessed as being in “Favourable” habitat condition had worse population trends for 4/8 butterfly species but better for 1/8 species than grasslands in “Unfavourable” condition. One study in Australia reported that after a grassland was designated as a local reserve, populations of golden sun-moth and pale sun-moth persisted for at least four years.

BEHAVIOUR (0 STUDIES)

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 before-and-after, site comparison study in 1980–1989 in two woodlands in Kent, UK (Warren 1991) reported that a woodland legally protected as a National Nature Reserve and managed by coppicing established a large population of heath fritillary Mellicta athalia, while over half of the colonies in a privately owned, unmanaged wood went extinct. Results were not tested for statistical significance. After four years of coppicing in one protected wood, the number of heath fritillaries peaked at 2,000 adults, and stabilized at around 800 adults after nine years, compared to “just a few individuals” when management began. In an unmanaged, unprotected wood, there were 800 adults across nine colonies in 1989, compared to over 10,000 adults across 20 colonies in 1980. From 1980–1989, a woodland protected as a National Nature Reserve was managed by coppicing one or two plots (1–5 ha) each year on a 15–20-year rotation. Plots were connected by wide rides and permanent glades. A nearby, privately owned woodland was not managed. From 1980–1989, butterflies were surveyed most years on timed counts along a zig-zag route covering the known flight areas at each site. The total yearly population at a site was estimated by multiplying the peak population count by three.

    Study and other actions tested
  2. A replicated, site comparison study in 1980–1984 in woodland, grassland and heathland sites (number not given) in central southern England, UK (Warren 1993) found that legally protected Sites of Special Scientific Interest (SSSI) had lost a similar number of threatened butterfly species as unprotected sites. In the first three years after SSSI designation was introduced, the extinction rate of threatened butterflies on protected sites (8.6%/decade) was not statistically different from unprotected sites (11.6%/decade). In 1981, sites containing important species were designated as statutory SSSIs under the Wildlife and Countryside Act. The number of extinctions of 29 threatened butterfly species from individual sites between 1980 and 1984 was recorded (no further details provided).

    Study and other actions tested
  3. A study in 1999–2004 in a grassland in Victoria, Australia (Douglas 2004) reported that a newly protected reserve continued to support populations of golden sun-moth Synemon plana and pale sun-moth Synemon selene. From 1999–2003, around 150–200 golden sun-moths, and 10–15 pale sun-moths, were recorded each year in a recently designated reserve. In February 1999, three Nhill morphs of the pale sun-moth were found on a 4.5-ha grassland known to support the golden sun-moth. The area had never been ploughed or fertilized, but had been sold to 10 separate owners for development. In 2000, the area was designated as a local reserve, and protected from development or human activities under a regional planning scheme. By 2003, most of the land had been purchased. From 2000–2004, information boards, signage and fencing were constructed. Most of the area was mown to 6–8 cm annually, normally in December. From 1999–2004, the number of each species of moth was recorded annually at the site.

    Study and other actions tested
  4. A replicated, site comparison study in 2002–2003 in four tropical rainforest reserves and 14 unprotected forest fragments in Singapore (Koh & Sodhi 2004) found that protected primary or secondary forest reserves had a higher species richness of butterflies than unprotected forest fragments. In protected forest reserves, the species richness of butterflies (8–27 species) was higher than in unprotected forest fragments (1–12 species). Protected forest reserves also had more unique species than unprotected forest fragments (data presented as model results). Four protected forest reserves (54–1,147 ha) consisted of old secondary and primary lowland tropical rainforest and freshwater swamp forest. Fourteen unprotected forest fragments (2–73 ha) contained patches of abandoned plantation and degraded secondary forest. From June 2002–June 2003, butterflies (excluding blues (Lycaenidae) and skippers (Hesperiidae)) were surveyed three times along one to fourteen 100-m transects/site.

    Study and other actions tested
  5. A replicated, site comparison study in 1994–2003 on hundreds of grassland reserves across England, UK (Davies et al. 2007) found that half of threatened or declining grassland butterfly species had worse population trends in protected areas where the habitat condition was assessed as “Favourable” than in protected areas with habitat in unfavourable condition. In protected areas assessed as being in “Favourable” condition, four out of eight threatened or declining grassland butterfly species (dark-green fritillary Argynnis aglaja, Duke of Burgundy Hamearis lucina, silver-studded blue Plebeius argus, small blue Cupido minimus) had worse population trends than in protected areas assessed as ““Unfavourable No Change” or “Unfavourable Declining”. One species (Adonis blue Polyommatus bellargus) had better population trends in protected areas assessed as being in “Favourable” condition than in protected areas assessed as “Unfavourable No Change” or “Unfavourable Declining”. Three species had similar population trends in protected areas assessed as being in each condition. Data presented as model results. The habitat condition (“Favourable”, “Unfavourable Recovering”, “Unfavourable No Change” or “Unfavourable Declining”) of each protected area where a species occurred was assessed by English Nature from 1997–2005. Changes in the abundance of eight threatened or declining grassland butterfly species within protected areas between 1994–2003 were obtained from the UK Butterfly Monitoring Scheme, which surveys >1,000 sites/year.

    Study and other actions tested
  6. A replicated, site comparison study in 1991–2000 in 152 grassland sites across southern England, UK (Brereton et al. 2008) found that chalkhill blue Polyommatus coridon abundance changes were not different in statutory protected sites and sites without statutory protection. There was no difference in the abundance change of chalkhill blues at 111 sites with statutory protected status (Site of Special Scientific Interest or National Nature Reserve) and 41 sites without statutory protection (data not reported). Chalkhill blues were counted annually from 1991 to 2000, at 152 sites across its entire UK range. This was part of the UK Butterfly Monitoring Scheme, which takes weekly transect counts along a set route at each site and follows standardized weather conditions.

    Study and other actions tested
  7. A replicated, site comparison study in 2006–2011 in 850 sites across England, UK (Oliver 2014) found that sites surrounded by more habitat legally protected as Sites of Special Scientific Interest had a higher population density of butterflies than sites surrounded by no protected areas in one of two analyses. One analysis, using data from 399 randomly placed transects, found that there were more butterflies on sites with more protected habitat in the surrounding 1 or 3 km than on sites surrounded by no protected areas (data presented as model results). A second analysis, using data from 451 transects that were less likely to pass through farmland, found no difference in the number of butterflies on sites surrounded by protected areas or with no protected areas nearby (data presented as model results). The area of land protected by a Site of Special Scientific Interest designation within 1- or 3-km around each survey site was calculated. From 2006–2011, butterflies were surveyed once/week throughout the flight season (up to 26 weeks) along fixed transects at 451 sites as part of the UK Butterfly Monitoring Scheme. In July–August 2010–2011, butterflies were surveyed at least twice/year on two parallel transects within 399 1-km squares as part of the Wider Countryside Butterfly Monitoring Scheme.

    Study and other actions tested
  8. A replicated, site comparison study in 1995–2010 across the UK (Gillingham et al 2015) found that areas legally protected as Sites of Special Scientific Interest had a higher abundance of 53% of butterfly species than areas without legal protection. Thirty out of 57 species of butterfly were more abundant in protected areas than at unprotected sites. No species were significantly less abundant in protected areas than at unprotected sites. See paper for individual species results. Protected areas were defined as Sites of Special Scientific Interest, representing IUCN category IV protection for target species or habitats. From 1995–2010, butterflies were recorded by volunteers on a national recording scheme (“Butterflies for the New Millennium”). Only records with abundance information, recorded at 100 × 100-m resolution or finer, were included. Records were counted as inside a protected area if any part of the 100 × 100 m square was within a protected area.

    Study and other actions tested
  9. A replicated, paired, site comparison study in 2011 in 12 bogs in County Offaly, Ireland (Flynn et al. 2016) found that bogs legally protected as Special Areas of Conservation had a similar total abundance and species richness of moths to unprotected bogs, but individual species showed mixed preferences. The total number of moths recorded on protected bogs was 951 individuals of 67 species, compared to 865 individuals of 73 species on unprotected bogs (statistical significance not assessed). Of the 14 most common species, three were more abundant on protected bogs (dark arches Apamea monoglypha, large yellow underwing Noctua pronuba, dark tussock Dicallomera fascelina), three were more abundant on unprotected bogs (map-winged swift Pharmacis fusconebulosa, narrow-winged pug Eupithecia nanata, spruce carpet Thera britannica), and eight showed no difference (data presented as model results). Of 15 bog-associated species of conservation concern, only three (dark tussock, bordered grey Selidosema brunnearia, garden tiger Arctia caja) were recorded in higher numbers on protected sites than on unprotected sites (statistical significance not assessed). Six raised bogs (74–246 ha) designated as Special Areas of Conservation, and six nearby (1.5–5 km away), highly modified but vegetated undesignated raised bogs (40–578 ha) were selected. At four of the protected sites, restoration work (mostly drain blocking) had taken place. From July–October 2011, moths were sampled five times using a Heath-type actinic 15 W light trap left overnight at each site. Paired sites were sampled on the same night, and all sites were sampled over two nights/visit.

    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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