Conservation Evidence: Evidence Data

Collected Evidence: Collected Evidence: Use prescribed fire to maintain or restore disturbance in forests Five studies evaluated the effects on butterflies and moths of using prescribed fire to maintain or restore disturbance in forests. Four studies were in the USA and one was in Australia. COMMUNITY RESPONSE (4 STUDIES) Richness/diversity (4 studies): Three of four studies (including one replicated study, one paired study, two controlled studies, two before-and-after studies, and one site comparison study) in the USA found that coniferous forest restored 1–2 years ago by burning (in combination with thinning) or burned once within the last 20 years, had a higher species richness of butterflies than unburned forest. The fourth study found that mixed forest and shrubland sites which had been burned the year before had similar butterfly species richness to unburned sites. POPULATION RESPONSE (3 STUDIES) Abundance (3 studies): Two studies (including one controlled, before-and-after study and one site comparison study) in the USA found that pine forest restored 1–2 years ago by burning (in combination with thinning) had a higher abundance of butterflies than unburned forest. One replicated, before-and-after study in Australia reported that in the spring after selective burning of eucalyptus forest there were fewer Eltham copper caterpillars than before. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3877https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3877Wed, 20 Jul 2022 18:19:12 +0100Collected Evidence: Collected Evidence: Change season/timing of prescribed burning Two studies evaluated the effects on butterflies and moths of changing the season or timing of prescribed burning. One study was in each of Australia and the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Abundance (2 studies): One replicated, controlled, before-and-after study in Australia found that management of a tropical savanna and floodplain with early season burning or no burning for 2–5 years increased the abundance of caterpillars, but management with late season burning did not. One replicated, paired, controlled study in the USA found that Karner blue butterfly abundance was similar on grasslands managed by burning in summer or autumn, and on unmanaged grasslands. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3878https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3878Thu, 21 Jul 2022 16:32:42 +0100Collected Evidence: Collected Evidence: Leave some areas unburned during prescribed burning Two studies evaluated the effects on butterflies and moths of leaving some areas unburned during prescribed burning. Both studies were in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Abundance (2 studies): One replicated study in the USA reported that the abundance of Karner blue butterflies increased over 2–3 years in oak savannas and prairies where unburned patches were left during prescribed burning. One replicated, site comparison study in the USA found that six out of nine specialist butterfly species were more abundant, one was less abundant, and two had similar abundance in pine barrens and prairies where unburned areas were left during prescribed burning compared to at sites without unburned areas. BEHAVIOUR (1 STUDY) Use (1 study): One replicated study in the USA reported that Karner blue butterflies were recorded using all 11 unburned patches which were surveyed within oak savannas and prairies managed by burning. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3879https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3879Thu, 21 Jul 2022 16:45:55 +0100Collected Evidence: Collected Evidence: Use fire suppression/control We found no studies that evaluated the effects of using fire suppression or control on butterflies and moths. ‘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%2F3880https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3880Thu, 21 Jul 2022 16:55:51 +0100Collected Evidence: Collected Evidence: Mechanically remove mid-storey or ground vegetation to create fire breaks Two studies evaluated the effects on butterflies and moths of mechanically removing mid-storey or ground vegetation to create fire breaks. One study was in Portugal and the other was in France. COMMUNITY RESPONSE (2 STUDIES) Richness/diversity (2 studies): One replicated, site comparison study in Portugal found that cork oak woodlands with more recent or more regular mechanical clearance of woody understorey vegetation had a greater species richness of butterflies than woodlands cleared less frequently or longer ago. One replicated, paired, controlled study in France reported that shrublands where trees and/or bushes were mechanically cleared to create firebreaks had a similar species richness of butterflies to a shrubland where grazing was used to suppress vegetation. POPULATION RESPONSE (1 STUDY) Abundance (1 study): One replicated, site comparison study in Portugal found that cork oak woodlands with more recent or more regular mechanical clearance of woody understorey vegetation had a higher abundance of butterflies than woodlands cleared less frequently or longer ago. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3881https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3881Thu, 21 Jul 2022 17:04:10 +0100Collected Evidence: Collected Evidence: Use prescribed fire to maintain or restore disturbance in grasslands or other open habitats Thirteen studies evaluated the effects on butterflies and moths of using prescribed fire to maintain or restore disturbance in grasslands or other open habitats. Eight studies were in the USA, three were in the UK, one was in South Africa and one was a review across Europe. COMMUNITY RESPONSE (3 STUDIES) Community composition (1 study): One replicated, site comparison study in the USA found that pastures managed by patch-burning had a similar butterfly community to rotationally or continuously grazed pastures. Richness/diversity (3 studies): Two replicated, before-and-after studies (including one randomized, controlled study and one paired sites, site comparison study) in the USA found that shrubland plots and grass field margins managed by burning had a similar species richness of butterflies to those which were unburned. One replicated, site comparison study in the USA reported that pastures managed by patch-burning had a lower species richness of butterflies than rotationally grazed pastures, a similar richness to rotationally grazed and mown pastures, and a higher species richness than continuously grazed pastures. POPULATION RESPONSE (12 STUDIES) Abundance (12 studies): Four of nine studies (including six replicated studies, two randomized studies, two paired sites studies, three controlled studies, two before-and-after studies, and five site comparison studies) in the UK, South Africa and the USA found that the abundance of heath fritillary adults, marsh fritillary caterpillar webs and Fender’s blue caterpillars and eggs was higher (sometimes after initial reductions in abundance) on heathland, fen meadows and prairies one or more years after management by burning than before burning, or compared to unburned or grazed land, although the total population of Fender’s blue declined in adjacent burned and unburned areas. Three studies found that the abundance of Brenton blue butterfly eggs and adults, rosy marsh moth caterpillars and regal fritillary adults was lower on a bog and prairies managed by burning than on unburned land, at least one and five years after burning. One study found that grass field margins managed by burning had a similar abundance of butterflies to unburned field margins. The seventh study found that abundance of Powershiek skipperling to burning, along with haying and idling, depended on the site’s vegetation characteristics. Two replicated, site comparison studies in the USA found that two prairie specialists (regal fritillary and arogos skipper) and three out of nine butterfly species were less abundant in prairies or pastures managed by burning than in prairies managed by haying or grazed pastures. These studies also found that the abundance of generalist and migrant species, and of purplish copper, was higher in burned prairies or pastures than hayed prairies or grazed pastures. One review across Europe reported that occasional burning on grassland benefitted 10 out of 67 butterfly species of conservation concern. Survival (1 study): One replicated, paired sites, controlled study in the USA found that in prairie plots burned one year before, Fender’s blue butterfly caterpillars had lower survival than in unburned plots. BEHAVIOUR (1 STUDY) Use (1 study): One replicated, site comparison study in the UK found that a similar proportion of fen meadows were occupied by marsh fritillary caterpillars whether they were managed by burning, grazing or were unmanaged. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3882https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3882Mon, 25 Jul 2022 12:37:11 +0100Collected Evidence: Collected Evidence: Use rotational burning Seventeen studies evaluated the effects on butterflies and moths of using rotational burning. Twelve studies were in the USA, one was in South Africa and one was in Japan. COMMUNITY RESPONSE (5 STUDIES) Community composition (1 study): One replicated, site comparison study in the USA found that prairies managed by rotational burning (every 1–6 years) and grazing had a different community composition of butterflies to prairies managed by rotational burning or grazing alone. Richness/diversity (5 studies): Two replicated, site comparison studies in the USA and Japan found that pine-oak barrens and semi-natural grasslands managed by rotational burning every 2 years or 2–5 years (sometimes combined with rotational mowing) had a higher species richness of butterflies than unmanaged sites or sites managed by annual burning or mowing. However, one of these studies also found that the species richness of grassland butterflies was lower in prairies managed by rotational burning than in unmanaged prairies in one of two regions. Two replicated, site comparison studies in the USA found that the species richness of butterflies was higher on prairies burned more than one or four years ago than on prairies burned in the last one or two years under rotational burning management. One replicated, site comparison study in the USA found that prairies managed by rotational burning (every 1–6 years) and grazing had a similar species richness of butterflies to prairies managed by rotational burning or grazing alone, but a lower diversity of butterflies than sites managed by rotational burning only. One replicated, randomized, controlled study in the USA found that species richness of butterflies did not differ between prairies managed with annual rotational burning or complete burning. POPULATION RESPONSE (15 STUDIES) Abundance (15 studies): Four replicated studies (including one paired, controlled study and three site comparison studies) in the USA found that under rotational burning management the total abundance of prairie specialist, grassland and all butterflies, and of most insects including butterflies and moths, was higher on prairies burned more than one, two or four years ago, or longer ago, than on prairies burned in the last one or two years, or recently. One of these studies also found that the abundance of grassland and generalist butterflies was highest in the third year after burning, and migrant butterflies in the first year after burning. Two of these studies6,8, and an additional replicated, site comparison study in the USA found that the total abundance of butterflies, and of most insects including butterflies and moths, was higher in pine-oak barrens and prairies managed by rotational burning every 2–5 years, 2–3 years or 1–6 years than at unmanaged sites or sites managed by rotational burning or grazing alone. One of these studies also found that the abundance of butterflies was lower in prairies managed by rotational burning than in unmanaged prairies in one of two regions. Four of six replicated studies in the USA (including five site comparison studies and one randomized, controlled study) found that rotational burning in prairies, pine barrens and grasslands had mixed effects on butterflies, compared to unmanaged, hayed, grazed, mowed or completely burned sites. The fifth study found that prairies managed by rotational burning had more strongly declining populations of grass-skipper butterflies than unmanaged pine barrens or lightly managed fields. The sixth study found that for three fritillary species rotational burning in prairies did not affect abundance, but for three others, in at least one region surveyed, abundance was lower in prairies managed by rotational burning, sometimes in combination with haying, grazing and/or mowing, than in prairies managed with only haying or grazing, or in unmanaged prairies. One replicated, site comparison study in the USA reported that Karner blue butterfly abundance was similar in rotationally burned and unmanaged oak savannas and prairies. One site comparison study in the USA reported that regal fritillary abundance was higher in grasslands and oak barrens managed by rotational burning every three years (following restoration by seeding) than on unmanaged sites or remnant prairies. One replicated, site comparison study in the USA found that the abundance of regal fritillary was higher in rotationally burned prairies four years after the last burn than one or eight years after the last burn. One replicated, randomized, paired, controlled study in the USA found that, in June, the abundance of regal fritillaries in prairies burned on rotation that spring was lower than in prairies burned 1–2 years ago, but in July the abundance was higher in recently burned prairies. Survival (1 study): One replicated study in South Africa found that populations of Karkloof blue persisted for at least a year following rotational burning. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3883https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3883Mon, 25 Jul 2022 15:05:14 +0100