Effect of field margins on moths depends on species mobility: field-based evidence for landscape-scale conservation

Manage hedgerows to benefit wildlife (e.g. no spray, gap-filling and laying)

A replicated, paired, site comparison study in 2007 in four arable fields in Oxfordshire, UK (Merckx et al. 2009a, same experimental set-up as Merckx et al. 2009b, 2010, 2012) found no difference in the abundance of common farmland larger moth species in margins adjacent to hedgerows with or without mature trees. Field margins with trees in the adjacent hedgerow had similar numbers of nine common moth species to margins with no trees in the adjacent hedgerow (data presented as model results). On the 32 nights (dusk till dawn) with suitable weather between 5 June and 14 July 2007, eight Heath pattern actinic light traps (6 W) were positioned in two arable fields/night, one in each field margin (1 m from the hedgerow). Four traps were within 5 m of a mature (>15 m high) hedgerow tree, and four were next to hedgerows with no trees. All traps were >100 m apart and >50 m from hedgerow intersections. Traps were alternated between two pairs of fields each night, one with 6-m-wide perennial grass margins and the other with standard 1-m-wide margins. Moths were identified on the morning after capture.

(Summarised by: Andrew Bladon, edited from Farmland synopsis)

Plant grass buffer strips/margins around arable or pasture fields

A replicated, paired, site comparison study in 2007 in four arable fields in Oxfordshire, UK (Merckx et al. 2009a, same experimental set-up as Merckx et al. 2009b, 2010a, 2010b, 2012) found a higher abundance of common farmland larger moth species in the margins and centres of fields with 6-m-wide perennial grass margins than in fields with standard 1-m margins, but this varied between species. Fields with 6-m-wide grass margins had 40% more moths of nine common species combined than fields with standard margins (data presented as model results). However, only two individual species (treble lines Charanyca trigrammica and brown-line bright-eye Mythimna conigera) were more abundant in fields with wide margins (data presented as model results). On the 32 nights (dusk till dawn) with suitable weather between 5 June and 14 July 2007, ten Heath pattern actinic light traps (6 W) were positioned in two arable fields/night: one in the centre of each field, and one in each field margin (1 m from hedgerow). All traps were >100 m apart and >50 m from hedgerow intersections. Traps were alternated between two pairs of fields each night, one with 6-m-wide perennial grass margins and the other with standard 1-m-wide margins. Moths were identified on the morning after capture.

(Summarised by: Andrew Bladon, edited from Farmland synopsis)

Pay farmers to cover the costs of conservation measures (as in agri-environment schemes or conservation incentives)

A replicated, paired, site comparison study in 2007 in four arable fields in Oxfordshire, UK (Merckx et al. 2009a, same experimental set-up as Merckx et al. 2009b, 2010a, 2010b, 2012) found a higher abundance of common farmland larger moth species in the margins and centres of fields with 6-m-wide perennial grass margins, which farmers were paid to maintain, than in fields with standard 1-m margins, but this varied between species. Fields with 6-m-wide agri-environment scheme grass margins had 40% more moths of nine common species combined than fields with standard margins (data presented as model results). However, only two individual species (treble lines Charanyca trigrammica and brown-line bright-eye Mythimna conigera) were more abundant in fields with wide margins (data presented as model results). On the 32 nights (dusk till dawn) with suitable weather between 5 June and 14 July 2007, ten Heath pattern actinic light traps (6 W) were positioned in two arable fields/night: one in the centre of each field, and one in each field margin (1 m from hedgerow). All traps were >100 m apart and >50 m from hedgerow intersections. Traps were alternated between two pairs of fields each night, one with 6-m-wide perennial grass margins maintained under agri-environment agreements, and the other with standard 1-m-wide margins. Moths were identified on the morning after capture.

(Summarised by: Andrew Bladon, edited from Farmland synopsis)

Plant grass buffer strips/margins around arable or pasture fields

A replicated mark-release-recapture study in summer 2007 in Oxfordshire, UK (Merckx et al. 2009a) found overall higher abundance of nine common larger farmland moth (Lepidoptera) species in the margins and centres of arable fields with 6 m-wide perennial grass margins than in fields with standard about 1 m margins, but this varied highly between species. Six moth species which contributed to the higher abundance of moths in wide field margins were less mobile; moving a shorter distance between captures and being more frequently recaptured at the site of first capture. Nectar availability (number of flowerheads) was higher in wide margins, both for overall nectar plant species and plant species known to be moth favourites. Plant species richness and diversity was similar in hedgerows surrounding fields bordered with wide margins and with standard margins. Five Heath pattern actinic light traps (6 W) were positioned in each of four arable fields: one in the centre and one in each field margin (1 m from hedgerow). All traps were >100 m apart and >50 m from hedgerow intersections. Traps were operated on the 32 nights (dusk till dawn) with suitable weather between 5 June and 14 July. Nectar availability was assessed at each trap site on 25 June by counting the number of flowerheads present on field margins 10 m either side of the trap locations. Percentage cover and species richness of woody plant species (excluding trees) was estimated in hedges bordering the fields.