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Providing evidence to improve practice

Individual study: Trials of management options to benefit insects on permanent pasture in Devon and Somerset, England: extensive management benefits butterflies, sown legumes benefit bees

Published source details

Potts S.G., Woodcock B.A., Roberts S.P.M., Tscheulin T., Pilgrim E.S., Brown V.K. & Tallowin J.R. (2009) Enhancing pollinator biodiversity in intensive grasslands. Journal of Applied Ecology, 46, 369-379


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Reduce the intensity of farmland meadow management Bee Conservation

A randomised, replicated, controlled trial on four farms in southwest England (Potts et al. 2009) found that 50 x 10 m plots of permanent pasture managed more extensively without fertilizer or without grazing, and/or with a higher cutting height or reduced cutting frequency did not support more common bumblebees Bombus spp. than control plots conventionally managed for silage. There were twelve replicates of each management type, monitored over four years. No more than 2.2 bumblebees/transect were recorded on average on any grassy plot in any year.

Raise mowing height on grasslands to benefit farmland wildlife Farmland Conservation

A randomised, replicated, controlled trial from 2003 to 2006 in southwest England (Potts et al. 2009) (same study as (Defra 2007, Woodcock et al. 2007)) found plots of permanent pasture cut to 10 cm in May and July did not attract more butterflies (Lepidoptera), butterfly larvae or common bumblebees Bombus spp. than control plots cut to 5 cm. Experimental plots 50 x 10 m were established on permanent pastures (more than five-years-old) on four farms. There were nine different management types, with three replicates/farm, monitored over four years. Bumblebees and butterflies were surveyed along a 50 m transect line in the centre of each experimental plot, once a month from June to September annually. Butterfly larvae were sampled on two 10 m transects using a sweep net in April and June-September annually.

 

Undersow spring cereals, with clover for example Farmland Conservation

A randomized, replicated, controlled trial from 2003 to 2006 in southwest England (Potts et al. 2009) (same study as (Defra 2007, Holt et al. 2010)) found plots on permanent pasture annually sown with a mix of legumes, or grass and legumes, supported more common bumblebees Bombus spp. (individuals and species) than seven grass management options. In the first two years, numbers of common butterflies (Lepidoptera) and common butterfly species were higher in plots sown with legumes than in five intensively managed grassland treatments. No more than 2.2 bumblebees/transect were recorded on average on any grass-only plot in any year, compared to over 15 bumblebees/transect in both sown treatments in 2003. Plots sown with legumes generally had fewer butterfly larvae than all grass-only treatments, including conventional silage and six different management treatments. Experimental plots 50 x 10 m were established on permanent pastures (more than five-years-old) on four farms. There were nine different management types, with three replicates/farm, monitored over four years. The two legume-sown treatments comprised either spring barley Hordeum vulgare undersown with a grass and legume mix (white clover Trifolium repens, red clover T. pratense, common vetch Vicia sativa, bird’s‐foot trefoil Lotus corniculatus and black medick Medicago lupulina) cut once in July, or a mix of crops including linseed Linum usitatissimum and legumes, uncut. Seven management types involved different management options for grass-only plots, including mowing and fertilizer addition. Bumblebees and butterflies were surveyed along a 50 m transect line in the centre of each experimental plot, once a month from June to September annually. Butterfly larvae were sampled on two 10 m transects using a sweep net in April and June-September annually.

 

Plant dedicated floral resources on farmland Bee Conservation

A randomised, replicated, controlled trial on four farms in southwest England (Potts et al. 2009) found that 50 x 10 m plots of permanent pasture annually sown with a mix of legumes, or grass and legumes, supported more common bumblebees (individuals and species) than seven grass management options. There were twelve replicates of each management, monitored over four years. No more than 2.2 bumblebees/transect were recorded on average on any grassy plot in any year, compared to over 15 bumblebees/transect in both sown treatments in one year. The legumes sown included white clover Trifolium repens, red clover T. pratense, common vetch Vicia sativa and bird's-foot trefoil Lotus corniculatus.

Reduce chemical inputs in grassland management Farmland Conservation

A randomized, replicated, controlled trial from 2003 to 2006 in southwest England (Potts et al. 2009) (same study as (Defra 2007, Woodcock et al. 2007)) found plots of unfertilized permanent pasture cut just once in July or not cut at all during the summer attracted more adult butterflies (Lepidoptera), but not more butterfly species or common bumblebees Bombus spp. than control fertilized plots cut in May and July (managed for silage). Plots cut just once in May, plots cut twice either unfertilized or ungrazed, and plots with a higher cutting height did not support more adult butterflies than control plots. Caterpillars were more abundant in unfertilized plots cut just once in May or July, or not at all in summer, than in other treatments. None of the grass treatments supported more common bumblebee species or individuals than control plots. Experimental plots 50 x 10 m were established on permanent pastures (more than five-years-old) on four farms. There were nine different management types, with three replicates/farm, monitored over four years. Seven management types involved different management options for grass-only plots, including conventional silage practices, no cutting in summer, early summer cut (May), late summer cut (July), raised mowing height. Bumblebees and butterflies were surveyed along a 50 m transect line in the centre of each experimental plot, once a month from June to September annually. Butterfly larvae were sampled on two 10 m transects using a sweep net in April and June-September annually.

Reduce grazing intensity on grassland (including seasonal removal of livestock) Farmland Conservation

A randomized, replicated, controlled trial from 2003 to 2006 in southwest England (Potts et al. 2009) (same study as (Defra 2007, Woodcock et al. 2007)) found plots of permanent pasture managed without autumn/winter grazing did not attract more butterflies (Lepidoptera), butterfly larvae or common bumblebees Bombus spp. than control grazed plots. All plots were cut for silage in May and July. Grazed plots were grazed with cattle from September until the grass height was 5-7 cm. Experimental plots 50 x 10 m were established on permanent pastures (more than five years-old) on four farms. There were nine different management types, with three replicates/farm, monitored over four years. Bumblebees and butterflies were surveyed along a 50 m transect line in the centre of each experimental plot, once a month from June to September annually. Butterfly larvae were sampled on two 10 m transects using a sweep net in April and June-September annually.

 

Reduce management intensity on permanent grasslands (several interventions at once) Farmland Conservation

In the same randomized, replicated, controlled trial as (Defra 2007) from 2003 to 2006 on four farms in southwest England, (Potts et al. 2009) found plots of unfertilized permanent pasture cut just once in July or not cut at all during the summer attracted more adult butterflies (Lepidoptera) (but not more butterfly species or common bumblebees Bombus spp.) than control fertilized plots cut in May and July, managed as in conventional silage management. Plots cut just once in May, plots cut twice either unfertilized or ungrazed, and plots with a higher cutting height did not support more adult butterflies than control plots. Butterfly larvae were more abundant in unfertilized plots cut just once in May or July, or not at all in summer, than in other treatments. None of the grass treatments supported more common bumblebee species or individuals than control plots. No more than 2 bumblebees/transect were recorded on average on any grassy plot in any year. Experimental plots 50 x 10 m were established on permanent pastures (more than five-years-old) on four farms. There were nine different management types, with three replicates/farm, monitored over four years. Seven management types involved different management options for grass-only plots, including conventional silage practices, no cutting in summer, early summer cut (May), late summer cut (July), raised mowing height. Bumblebees and butterflies were surveyed along a 50 m transect line in the centre of each experimental plot, once a month from June to September annually. Butterfly larvae were sampled on two 10 m transects using a sweep net in April and June-September annually. This study was also part of the same study as (Pilgrim et al. 2007, Woodcock et al. 2007).

Plant wild bird seed or cover mixture Farmland Conservation

A randomized, replicated, controlled trial from 2003 to 2006 in southwest England (Potts et al. 2009) found plots on permanent pasture annually sown with a mix of legumes, or grass and legumes, supported more common bumblebees Bombus spp. (individuals and species) than seven grass management options. In the first two years, the numbers of common butterflies (Lepidoptera) and common butterfly species were higher in plots sown with legumes than in five intensively managed grassland treatments. No more than 2.2 bumblebees/transect were recorded on average on any grass-only plot in any year, compared to over 15 bumblebees/transect in both sown treatments in 2003. The plots sown with legumes generally had fewer butterfly larvae than all grass-only treatments, including conventional silage and six different management treatments. Experimental plots 50 x 10 m were established on permanent pastures (more than five-years-old) on four farms. There were nine different management types, with three replicates/farm, monitored over four years. Seven management types involved different management options for grass-only plots, including mowing and fertilizer addition. The two legume-sown treatments comprised either a mix of crops sown partly for wild birds, including linseed Linum usitatissimum and legumes, uncut, or spring barley Hordeum vulgare undersown with a grass and legume mix (white clover Trifolium repens, red clover T. pratense, common vetch Vicia sativa, bird’s?foot trefoil Lotus corniculatus and black medick Medicago lupulina) cut once in July. Bumblebees and butterflies were surveyed along a 50 m transect line in the centre of each experimental plot, once a month from June to September annually. Butterfly larvae were sampled on two 10 m transects using a sweep net in April and June-September annually. This study was part of the same experimental set-up as (Defra 2007, Pilgrim et al. 2007, Holt et al. 2010).

Plant nectar flower mixture/wildflower strips Farmland Conservation

A randomized, replicated, controlled trial from 2003 to 2006 in southwest England (Potts et al. 2009) (same experimental set up as Pilgrim et al. 2007) found plots on permanent pasture annually sown with a mix of legumes, or grass and legumes, supported more common bumblebees Bombus spp. (individuals and species) than seven grass management options. In the first two years, there were more common butterflies (Lepidoptera) and common butterfly species in plots sown with legumes than in five intensively managed grassland treatments. No more than 2.2 bumblebees/transect were recorded on average on any grass-only plot in any year, compared to over 15 bumblebees/transect in both sown treatments in 2003. Plots sown with legumes generally had fewer butterfly larvae than all grass-only treatments, including conventional silage and six different management treatments. Experimental plots 50 x 10 m were established on permanent pastures (more than five-years-old) on four farms. There were nine different management types, with three replicates/farm, monitored over four years. Seven management types involved different management options for grass-only plots, including mowing and fertilizer addition. The two legume-sown treatments comprised either barley Hordeum vulgare undersown with a grass and legume mix (including white clover Trifolium repens, red clover T. pratense, and common vetch Vicia sativa) cut once in July, or a mix of crops (including linseed Linum usitatissimum) and legumes, uncut. Bumblebees and butterflies were surveyed along a 50 m transect line in the centre of each experimental plot, once a month from June to September annually. Butterfly larvae were sampled on two 10 m transects using a sweep net in April and June-September annually.