Collected Evidence: Collected Evidence: Design the route of roads to maximize habitat block size We found no studies that evaluated the effects on butterflies and moths of designing the route of roads to maximize habitat block size. ‘We found no studies’ means that we have not yet found any studies that have directly evaluated this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3851https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3851Tue, 05 Jul 2022 11:33:46 +0100Collected Evidence: Collected Evidence: Minimize road lighting to reduce insect attraction We found no studies that evaluated the effects on butterflies and moths of minimizing road lighting to reduce insect attraction. ‘We found no studies’ means that we have not yet found any studies that have directly evaluated this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3852https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3852Tue, 05 Jul 2022 11:34:54 +0100Collected Evidence: Collected Evidence: Use infrastructure to reduce vehicle collision risk along roads One study evaluated the effects on butterflies and moths of using infrastructure to reduce vehicle collision risk along roads. This study was in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (1 STUDY) Behaviour change (1 study): One controlled study in the USA reported that “altitude guide” netting, and poles topped with bright colours or flowers (attractive features), did not alter the behaviour of Oregon silverspot around roads. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3853https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3853Tue, 05 Jul 2022 11:41:12 +0100Collected Evidence: Collected Evidence: Restore or maintain species-rich grassland along road/railway verges Eight studies evaluated the effects on butterflies and moths of restoring or maintaining species-rich grassland along road or railway verges. Three studies were in the USA and one was in each of Germany, the UK, Finland, Poland, and Canada. COMMUNITY RESPONSE (6 STUDIES) Richness/diversity (6 studies): Four replicated, site comparison studies (including one paired study) in Germany, the UK, the USA and Finland found that restored roadside prairies, verges sown with native wildflowers, with more butterfly species’ larval food plants, with more species of plants and with more plants in flower had a higher species richness and diversity of butterflies, day-flying moths, burnet moths and meadow-specialist moths than verges dominated by non-native vegetation or with fewer butterfly species’ larval food plants, fewer plant species, and fewer plants in flower. However, one of these studies also found that verges sown with more plant species did not have higher species richness of meadow-specialist butterflies. One replicated, site comparison study in Canada found that road verges and land under power lines managed by mowing once or twice a year, or not at all, had a similar species richness of butterflies to remnant prairies. One replicated, site comparison study in Poland found that wide road verges had a higher species richness of butterflies than narrow road verges. POPULATION RESPONSE (7 STUDIES) Abundance (5 studies): Two of three replicated, site comparison studies (including one paired study) in the UK, the USA and Finland found that restored roadside prairies and verges sown with more butterfly species’ larval food plants had a greater abundance of butterflies and burnet moths than verges dominated by non-native vegetation or with fewer butterfly species’ larval food plants. However, one of these studies also found that verges with more plants in flower did not have a greater abundance of butterflies and burnet moths than verges with fewer plants in flower. The other study found that verges sown with more plant species did not have a greater abundance of meadow-specialist butterflies or moths. One replicated, site comparison study in Canada found that road verges and land under power lines managed by mowing once or twice a year, or not at all, had a similar abundance of butterflies to remnant prairies. One replicated, site comparison study in Poland found that wide road verges had a greater abundance of butterflies than narrow road verges. Survival (3 studies): One of two replicated, site comparison studies (including one paired study) in the USA found that restored prairie road verges had a lower mortality risk for butterflies than verges dominated by non-native grasses. The other study found more dead butterflies and moths on roads with tall meadow verges than on roads with frequently mown, non-native, short grass verges or wooded verges. This study also found more dead butterflies and moths on roads with habitat in the central reservation than on roads without habitat in the central reservation. One replicated, site comparison study in Poland found that less frequently mown road verges, and verges mown later in the summer, had fewer dead butterflies than verges which were mown more frequently or earlier in the summer. Condition (1 study): One replicated, site comparison study in the USA found that monarch caterpillars living on road verges mown once or twice a year had a similar number of parasites to caterpillars living in mown and unmown prairies. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3854https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3854Tue, 05 Jul 2022 12:03:30 +0100Collected Evidence: Collected Evidence: Manage land under power lines for butterflies and moths Six studies evaluated the effects on butterflies and moths of managing land under power lines for butterflies and moths. Two studies were in each of the USA and Finland, and one was in each of the UK and Canada. COMMUNITY RESPONSE (3 STUDIES) Richness/diversity (3 studies): Two replicated, site comparison studies (including one paired study) in Finland found that land under power lines managed by mechanical cutting had a higher species richness of butterflies than unmanaged land, and butterfly species richness was highest 2–4 years after scrub and trees were cleared. One replicated, site comparison study in Canada found that the species richness of butterflies was similar under power lines and on road verges mown once or twice a year, or left unmown. POPULATION RESPONSE (6 STUDIES) Abundance (6 studies): One of two replicated, site comparison studies (including one paired study) in Finland and Canada found that land under power lines managed by mechanical cutting had a higher abundance of butterflies than unmanaged land. The other study found that land under power lines and on road verges managed by mowing had a lower abundance of pearl crescent and northern pearl crescent butterflies, and a similar abundance of other butterflies, to those left unmown. Two of three site comparison studies (including two replicated studies) in the USA, the UK and Finland found that the time since management under power lines did not affect the abundance of Karner blue butterflies or small pearl-bordered fritillaries, but chequered skipper abundance was higher in areas cleared ≤2 years ago than in areas cut ≥4 years earlier. The other study found that power lines cleared of trees and scrub 2–4 years earlier had a higher abundance of butterflies than power lines cleared 1 year or 6–8 years earlier. Two site comparison studies in the USA found that land under power lines managed by cutting or herbicide application, and by mowing or cutting, had a similar abundance of Karner blue butterflies and six other butterfly species, but the abundance of frosted elfin was higher under power lines managed by mowing than those managed by cutting. BEHAVIOUR (1 STUDY) Use (1 study): One replicated, site comparison study in the UK reported that pearl-bordered fritillaries used areas under power lines where scrub had been cleared one or two years earlier, but not under power lines cleared three or more years ago. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3855https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3855Tue, 05 Jul 2022 12:26:37 +0100
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What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

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