Conservation Evidence: Evidence Data

Collected Evidence: Collected Evidence: Plant grass buffer strips/margins around arable or pasture fields Twenty-six studies evaluated the effects on butterflies and moths of planting grass margins around arable or pasture fields. Seventeen were in the UK, two were in each of Sweden, the Netherlands and the USA, and one was in each of China, France and Italy. COMMUNITY RESPONSE (15 STUDIES) Richness/diversity (15 studies): One of two replicated, controlled studies in the UK found that 2-m grass margins had a greater species richness of butterflies than cropped field edges, but 6-m grass margins did not. The other study found that the species richness of butterflies was similar in grass margins and cropped field edges. Five replicated, site comparison studies (including one paired study) in the USA, the UK and Italy found that wider grass margins (up to 6 m wide) had a greater species richness or diversity of butterflies, macro-moths and micro-moths than narrower or conventional width margins, although one of these studies found that the species richness of macro-moths was similar in wide and conventional grass margins. Three of five replicated studies (including three randomized, controlled studies, one controlled study, and one site comparison study) in the UK and Sweden found that floristically enhanced grass buffers or wildflower strips had a greater species richness of butterflies than standard grass margins. The other two studies found that farms with floristically enhanced margins (along with other enhanced agri-environment scheme (AES) options) had a similar species richness of butterflies and moths to farms with standard grass margins (along with basic AES options) and farms with no grass margins or other AES options. One site comparison study in Sweden found that grass margins sown with legumes or a clover and grass ley had a higher species richness of butterflies and moths than uncultivated margins, but less than a species-rich pasture. One replicated study in the Netherlands found that the species richness of butterflies increased over time after the establishment of grass margins. One replicated, randomized, controlled, before-and-after study in the USA found that disking or burning grass margins did not affect the species richness of butterflies. POPULATION RESPONSE (22 STUDIES) Abundance (21 studies): Three of four replicated, controlled studies in the UK found that grass margins had a higher abundance of butterflies than cropped field edges. The other study found that the abundance of gatekeepers on grass margins increased over four years after they were sown, but was only higher than cropped field edges at one of three farms after 2–4 years. Three of seven replicated, site comparison studies (including two paired studies) in the USA and the UK found that wider grass margins (up to 6 m wide) had a higher abundance of habitat-sensitive butterflies, macro-moths and micro-moths than narrower or conventional width margins. Two of these studies, and the other four studies, found that the abundance of disturbance-tolerant butterflies, macro-moths generally, and pale shining brown moths specifically, was similar in wide and conventional grass margins. Four replicated studies (including two randomized, controlled studies, one controlled study, and one site comparison study) in the UK and Sweden found that floristically enhanced grass buffers or wildflower strips had a higher abundance of butterflies than standard grass margins, uncultivated margins or margins sown with cereal crop. Two replicated, randomized, controlled studies in the UK found that farms with floristically enhanced margins (along with other enhanced agri-environment scheme (AES) options) had a higher abundance of some butterflies and micro-moths, a similar abundance of macro-moths, but a lower abundance of other butterflies, than farms with standard grass margins (along with basic AES options) and farms with no grass margins or other AES options. One site comparison study in Sweden found that grass margins sown with legumes or a clover and grass ley had a higher abundance of butterflies and moths than uncultivated margins or a species-rich pasture. Two replicated, before-and-after studies (including one randomized, controlled study) in the Netherlands and the USA found that mowing, disking or burning grass margins did not affect the abundance of butterflies and moths generally, or diamondback moths specifically, but that disking increased the abundance of disturbance-tolerant butterflies. One replicated, paired, site comparison study in the UK found that field margins had a similar abundance of butterfly and moth caterpillars to beetle banks established in the middle of fields. Survival (1 study): One site comparison study in China found that the survival of marsh fritillary caterpillars in grass margins around lightly cultivated fields was lower, but survival of egg clusters similar, to in uncultivated, grazed meadows. BEHAVIOUR (2 STUDIES) Use (2 studies): One replicated, site comparison study in China found that grass margins around lightly cultivated fields were more likely to be occupied by marsh fritillary eggs and caterpillars than uncultivated, grazed meadows. One replicated, paired, site comparison study in France found that meadow brown butterflies used grass margins in a similar way to meadows. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3982https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3982Thu, 18 Aug 2022 11:38:08 +0100Collected Evidence: Collected Evidence: Plant more than one crop per field (intercropping) One study evaluated the effects on butterflies and moths of planting more than one crop per field. The study was in Malaysia. COMMUNITY RESPONSE (1 STUDY) Community composition (1 study): One replicated, site comparison study in Malaysia found that smallholdings planted with oil palm and other crops did not differ in butterfly community composition from those planted with oil palm alone. Richness/diversity (1 study): One replicated, site comparison study in Malaysia found that smallholdings planted with oil palm and other crops did not have greater butterfly species richness than those planted with oil palm alone. POPULATION RESPONSE (1 STUDY) Abundance (1 study): One replicated, site comparison study in Malaysia found that smallholdings planted with oil palm and other crops did not have higher overall butterfly abundance than those planted with oil palm alone. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3983https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3983Sat, 20 Aug 2022 19:18:11 +0100