Creation and management of pollen and nectar habitats on farmland: Annual report 2007/8

Plant wild bird seed or cover mixture

A replicated, randomized, controlled study in 2006–2007 on a farm in Warwickshire, UK (Pywell et al. 2008) found that butterfly abundance and species richness differed between 10 plant species commonly sown in wild bird seed mixtures. In 2006, more butterflies were found in plots sown with lucerne Medicago sativa (6.3 individuals/plot) than plots sown with borage Borago officinalis (0.3 individuals/plot), chicory Cichorium intybus (0.8 individuals/plot) and sainfoin Onobrychis viciifolia (0.8 individuals/plot). More butterfly species were found in lucerne plots (3.5 species/plot) than in borage, chicory, sainfoin and fodder radish Raphanus sativus (0.3–0.5 species/plot). There was no significant difference in abundance (1.0–3.3 individuals/plot) or species richness (1.0–2.8 species/plot) between the other plant species. In 2007, red clover Trifolium pratense had a higher abundance of butterflies (3.3 individuals/plot) than chicory (0.0 individuals/plot), but the abundance on all other plant species was similar (0.3–2.3 individuals/plot) and there were no significant differences in species richness (0.0–1.8 species/plot). In May 2006, ten small-seeded crop species commonly sown in wild bird seed mixtures (borage, buckwheat Fagopyrum esculentum, crimson clover Trifolium incarnatum, fodder radish, linseed Linum usitatissimum, lucerne, mustard Brassica juncea, phacelia Phacelia tanacetifolia, sunflower Helianthus annuus and sweet clover Melilotus officinalis) and three perennial species sown in pollen and nectar mixtures (chicory, red clover, sainfoin) were sown individually in 6 × 4 m plots, replicated four times. Annual species were re-sown May 2007. Butterflies were surveyed six times/year, from July–September 2006 and May–September 2007.

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

Plant nectar flower mixture/wildflower strips

A replicated, randomized, controlled study in 2006–2007 on a farm in Warwickshire, UK (Pywell et al. 2008) found that butterfly abundance and species richness differed between three plant species commonly sown in nectar flower mixtures. In 2006, more butterflies were found in plots sown with lucerne Medicago sativa (6.3 individuals/plot) than plots sown with borage Borago officinalis (0.3 individuals/plot), chicory Cichorium intybus (0.8 individuals/plot) and sainfoin Onobrychis viciifolia (0.8 individuals/plot). More butterfly species were found in lucerne plots (3.5 species/plot) than in borage, chicory, sainfoin and fodder radish Raphanus sativus (0.3–0.5 species/plot). There was no significant difference in abundance (1.0–3.3 individuals/plot) or species richness (1.0–2.8 species/plot) between the other plant species. In 2007, red clover Trifolium pratense had more butterflies (3.3 individuals/plot) than chicory (0.0 individuals/plot), but the abundance on all other plant species was similar (0.3–2.3 individuals/plot) and there were no significant differences in species richness (0.0–1.8 species/plot). In May 2006, three perennial species sown in pollen and nectar mixtures (chicory, red clover, sainfoin) and 10 small-seeded crop species commonly sown in wild bird seed mixtures (borage, buckwheat Fagopyrum esculentum, crimson clover Trifolium incarnatum, fodder radish, linseed Linum usitatissimum, lucerne, mustard Brassica juncea, phacelia Phacelia tanacetifolia, sunflower Helianthus annuus and sweet clover Melilotus officinalis) were sown individually in 6 × 4 m plots, replicated four times. Annual species were re-sown May 2007. Butterflies were surveyed six times/year, from July–September 2006 and May–September 2007.

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

Plant wild bird seed or cover mixture

A randomized, replicated study in 2006 and 2007 in Warwickshire, UK (Pywell et al. 2008) (same study as (Pywell et al. 2010)) found that butterflies (Lepidoptera) and bumblebees Bombus spp. displayed different preferences for 13 annual and perennial plant species, 10 of which were typical components of wild bird seed mixtures. In 2006, more butterflies were found in plots sown with lucerne Medicago sativa (6.3 butterflies/plot) than plots sown with borage Borago officinalis (0.3), chicory Cichorium intybus (0.8) and sainfoin Onobrychis viciifolia (0.8). More butterfly species were found in lucerne plots (3.5 species/plot) than in borage, chicory, sainfoin and fodder radish Raphanus sativus (0.3-0.5). In 2007, red clover Trifolium pratense plots had the largest number of butterflies, significantly more than chicory (3.3 vs 0.0 butterflies/plot), whilst all other plant species ranged between 0.3-2.3. In both years, bumblebees were most abundant in phacelia Phacelia tanacetifolia plots (134 and 38.5 bumblebees/plot in 2006 and 2007), followed by borage (100 and 32). Crimson clover T. incarnatum and sunflower Helianthus annuus (37 and 26 respectively) had more bumblebees than other plant species (0-6) in 2006. Red clover plots had more bumblebees (21) than buckwheat Fagopyrum esculentum, chicory, linseed Linum usitatissimum, lucerne, mustard Brassica juncea or sweet clover Melilotus officinalis in 2007. The number of bumblebee species recorded in crimson clover, phacelia, borage and sunflower was significantly higher than all other plant species (2.8-4.0 vs 0-1.3 species/plot) in 2006. In 2007, red clover in addition to the four species from 2006 had significantly more bumblebee species than mustard (3.0-3.3 vs 0.5 species/plot). Short-tongued bees showed a significant preference for phacelia and borage compared with all other treatments in both years. Long-tongued bees showed a significant preference for crimson clover over all other species apart from borage and phacelia in 2006, and red clover in 2007 (although they also showed a strong preference for crimson clover and sainfoin in 2007). Peak flowering of many important bee forage species was in late July, including phacelia, borage, red clover and sweet clover. Thirteen species were sown in single species stands in 6 x 4 m plots with four replicates in May 2006. Annual species were re-established in the same plots in May 2007. Abundance and diversity of butterflies and bumblebees were recorded on transects in each plot six times between July and September 2006 and May and September 2007. On each visit the percentage cover of flowers of all dicot species/plot was estimated.

Plant nectar flower mixture/wildflower strips

Two randomized replicated studies from 2005 to 2007 in Yorkshire and Warwickshire, UK (Pywell et al. 2008) studied different ‘pollen and nectar’ seed mixes. The Yorkshire study (2005-2007) looked at six different seed mixes and found two agricultural varieties of red clover Trifolium pratense had the highest cover. There were more flowers of sown plant species in an agricultural clover mix in 2005 and in wild Somerset red clover in 2006. There were more red clover flowers in an agricultural mix in all three years. Bird's-foot trefoil Lotus corniculatus flowers were more abundant in the first and third years in wild Somerset red clover mix than in agricultural mixes. Plots measured 48 x 6 m and were replicated twice. The Warwickshire study (2006-2007) (same study as (Pywell et al. 2010b)) found butterfly (Lepidoptera) abundance and species richness were highest in plots sown with lucerne Medicago sativa or red clover (3-6 butterflies/plot, 2-3.5 species vs 0-3 butterflies and 0-3 species for all other plots). Phacelia Phacelia tanacetifolia plots had the highest number of bumblebees Bombus spp. (39-134 bumblebees/plot), followed by borage Borago officinalis (32-100). Phacelia, crimson clover Trifolium incarnatum, borage, sunflower Helianthus annuus and red clover (2007 only) plots had significantly more bumblebee species than all other plots in 2006 (3-4 vs 0-1 species/plot). Short-tongued bees preferred phacelia and borage in both years. Long-tongued bees preferred crimson clover, borage, phacelia or red clover. In the first year there were more annual than perennial flowers. Flowering of many important bee forage species peaked in late July. Thirteen annual and perennial plant species were sown individually in 6 x 4 m plots, replicated four times in May 2006, annual species were re-sown May 2007. Butterflies and bumblebees were surveyed six times in each plot (July-September 2006 and May-September 2007). On each visit the percentage cover of all flowers was estimated.