Cropping and year effects on the availability of invertebrate groups important in the diet of nestling farmland birds

Plant wild bird seed or cover mixture

A replicated, site comparison study in 1995–1999 on an arable farm in Leicestershire, UK (Moreby & Southway 2002, same experimental set-up as 1 -Moreby 2002) found that the abundance of moth and butterfly caterpillars was similar in non-crop strips (wild bird cover or grass beetle banks) and crop fields in most years. The abundance of moth and butterfly caterpillars was similar in non-crop strips (0–1 individuals/sample) and crop fields (0–1 individuals/sample) in four out of five years. In 1996, the abundance of caterpillars was lower in non-crop strips (0.4 individuals/sample) than in crop fields (0–2.2 individuals/sample). However, a composite group of key ‘chick food insects’ (including caterpillars) had higher densities in non-crop strips (65 individuals/sample) than in crop fields (2–10 individuals/sample) in all years. Wild bird cover was sown as 2–5-m-wide strips along field boundaries and re-sown every few years with a cereal or kale-based Brassica spp. mixture. Grass beetle banks (1 m wide) were sown onto a raised bank along edges or across the centre of fields. Invertebrates were sampled each year in the centre of 5–11 wild bird cover strips or grass beetle banks, and 3-m into 3–4 pasture, 8–12 wheat, 6–8 barley, 3–6 oilseed rape and 4 field bean fields. Two samples of 0.5 m² were taken in each habitat using a D-Vac suction sampler in June 1995–1999.

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

Create beetle banks

A replicated, site comparison study in 1995–1999 on an arable farm in Leicestershire, UK (Moreby & Southway 2002, same experimental set-up as Moreby 2002) found that the abundance of moth and butterfly caterpillars was similar in non-crop strips (grass beetle banks or wild bird cover) and crop fields in most years. The abundance of moth and butterfly caterpillars was similar in non-crop strips (0–1 individuals/sample) and crop fields (0–1 individuals/sample) in four out of five years. In 1996, the abundance of caterpillars was lower in non-crop strips (0.4 individuals/sample) than in crop fields (0–2.2 individuals/sample). However, a composite group of key ‘chick food insects’ (including caterpillars) had higher densities in non-crop strips (65 individuals/sample) than in crop fields (2–10 individuals/sample) in all years. Grass beetle banks (1 m wide) were sown onto a raised bank along edges or across the centre of fields. Wild bird cover was sown as 2–5-m-wide strips along field boundaries and re-sown every few years with a cereal or kale-based Brassica spp. mixture. Caterpillars were sampled each year in the centre of 5–11 grass beetle banks or wild bird cover strips, and 3-m into 3–4 pasture, 8–12 wheat, 6–8 barley, 3–6 oilseed rape and 4 field bean fields. Two samples of 0.5 m² were taken in each habitat using a D-Vac suction sampler in June 1995–1999.

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

Plant wild bird seed or cover mixture

A replicated study from 1995 to 1999 of arable habitats on a farm in Leicestershire, UK (Moreby & Southway 2002) found that the abundance of some invertebrate groups was higher in non-crop strips (wild bird cover or grass beetle banks), whereas other groups were more abundant in crops. Four invertebrate groups tended to have significantly higher densities in non-crop strips than crops in all years spiders (Araneae) 7 vs 1-5 individuals/sample, true bugs (Homoptera) 29 vs 1-4, typical bugs (Heteroptera) 10-58 vs 0-9, and key ‘chick food insects’ 65 vs 2-10. In three of the years, true weevils (Curculionidae) were found at significantly higher densities in non-crop strips and beans (0-11) than other crops (0-2). In contrast, in three or four of the years, densities in crops were significantly higher than non-crops for: true flies (Diptera) 20-230 vs 25-100 individuals and aphids (Aphididae). Moth and butterfly larvae (Lepidoptera) and ground beetles (Carabidae) differed significantly in only one or two years, when density was higher in crops than non-crops. Total beetles (Coleoptera) varied between years and habitats. Sawfly larvae (Symphyta), leaf beetles (Chrysomelidae) and soldier beetles (Cantharidae) showed no significant differences. Wild bird cover was sown as 2-5 m-wide strips along field boundaries and re-sown every few years with a cereal or kale-based Brassica spp. mixture. Grass strips (1 m-wide) were sown onto a raised bank along edges or across the centre of fields. Invertebrates were sampled each year in the centre of 5-11 grass/wild bird cover strips and 3 m into 3-4 pasture, 8-12 wheat, 6-8 barley, 3-6 oilseed rape and four field bean fields. Two samples of 0.5 m² were taken in each habitat using a D-Vac suction sampler in June 1995-1999. This study was part of the same experimental set-up as Moreby (2002), Murray et al. (2002).

Create beetle banks

A study in 1995-1999 in arable land in Leicestershire, UK (Moreby & Southway 2002) found that spiders (Araneae) and some groups of bugs (Homoptera) were consistently more abundant in uncropped strips than in four crop types or in grazed pasture. Other bug groups (Heteroptera) were most abundant in uncropped strips in four out of five years. Abundance of other groups in different crop types varied between years. The experiment sampled insects from six habitats: wheat Triticum aestivum, barley Hordeum vulgare, oilseed rape Brassica napus and field bean Vicia faba crop fields, grazed pasture fields and uncropped strips. The uncropped strips included both beetle banks and strips sown with wild bird cover mix, and the study did not differentiate results from these two habitats. Insect sampling used a "D-Vac" suction sampler. The study did not indicate whether insect groups were pests, natural enemies or neutral. This study was part of the same experimental set-up as Collins et al. 1996 and Collins et al. 2003.

Create beetle banks

A replicated study from 1995 to 1999 of arable habitats on a farm in Leicestershire, UK (Moreby & Southway 2002) found that the abundance of some invertebrate groups was higher in non-crop strips (grass beetle banks or wild bird cover), whereas other groups were more abundant in crops. Four invertebrate groups tended to have significantly higher densities in non-crop strips than crops in all years: spiders (Araneae) 7 vs 1-5 individuals/sample, true bugs (Homoptera) 29 vs 1-4, typical bugs (Heteroptera) 10-58 vs 0-9, and key ‘chick food insects’ 65 vs 2-10. In three of the years, true weevils (Curculionidae) were found at significantly higher densities in non-crop strips and beans (0-11) than other crops (0-2). In contrast, in three or four of the years, densities in crops were significantly higher than non-crops for: true flies (Diptera) 20-230 vs 25-100 individuals and aphids (Aphididae). Moth and butterfly larvae (Lepidoptera) and ground beetles (Carabidae) differed significantly in only one or two years, when density was higher in crops than non-crops. Total beetles (Coleoptera) varied between years and habitats. Sawfly larvae (Symphyta), leaf beetles (Chrysomelidae) and soldier beetles (Cantharidae) showed no significant differences. Grass strips (1 m-wide) planted as beetle banks were sown onto a raised bank along edges or across the centre of fields. Wild bird cover was sown as 2-5 m-wide strips along field boundaries and re-sown every few years with a cereal or kale-based mixture. Invertebrates were sampled each year in the centre of 5-11 grass/wild bird cover strips and 3 m into 3-4 pasture, 8-12 wheat, 6-8 barley, 3-6 oilseed rape and four field bean fields. Two samples of 0.5 m² were taken in each habitat using a D-Vac suction sampler in June 1995-1999. This study was part of the same experimental set-up as (Collins et al. 1996, Murray et al. 2002, Bence et al. 2003, Collins et al. 2003).