Evaluation of ecological measures: spiders and butterflies

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

A replicated, site comparison study in 1998 in two agricultural regions in the Swiss Plateau, Switzerland (Jeanneret et al. 2000, same experimental set-up as 2 and partially the same as 4) found that grasslands managed with reduced intensity had a similar species richness of butterflies to conventional grasslands. Butterfly species richness was similar on low intensity meadows, extensively managed meadows and intensively managed meadows. However, butterfly species richness was higher in extensively managed meadows (but not in low intensity meadows) than in cereal fields. See paper for details. Across two arable regions, 109 sites were composed of eight habitat types: Ecological Compensation Areas including 19 extensively managed meadows, 16 low intensity meadows, eight orchard meadows, five hedgerows and eleven wildflower strips on set-aside land, along with seven intensively managed meadows, 20 winter wheat fields, and 23 forest edges. From May–September 1998, butterflies were observed for 10 minutes on each of six visits to each site (0.25 ha/site).

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

Plant nectar flower mixture/wildflower strips

A replicated, site comparison study in 1998 in two agricultural regions in the Swiss Plateau, Switzerland (Jeanneret et al. 2000, same study as Jeanneret et al. 2003) found that the species richness of butterflies in wildflower strips sown on set-aside areas was similar to winter wheat fields. Butterfly species richness in the wildflower strips (more than 6 species) differed significantly only from forest edges (fewer than 4 species). However, wildflower strips attracted some species of butterfly that were never or only rarely found in other habitats. Across two arable regions, 109 sites were composed of eight habitat types: Ecological Compensation Areas including eleven wildflower strips on set-aside land, five hedgerows, 19 extensively managed meadows, 16 low intensity meadows and eight orchard meadows, along with 20 winter wheat fields,  seven intensively managed meadows and 23 forest edges. From May–September 1998, butterflies were observed for 10 minutes on each of six visits to each site (0.25 ha/site).

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

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

A replicated, controlled study in summer 1997 and 1998 in 109 sites of two arable regions in Switzerland (Jeanneret et al. 2000) found mixed effects of reduced management intensity on grasslands on butterflies (Lepidoptera) and spiders (Araneae). For butterflies, species richness did not differ significantly between low-intensity or extensively managed meadows and intensively managed meadows, however butterfly species richness was higher in extensively managed meadows (but not in low-intensity meadows) than in cereal fields. The number of spider species was found to be higher in low-intensity meadows (but not in extensively managed meadows) than in cereal fields, but no difference was detected between extensive, low- and high-intensively managed meadows. Spider community composition differed between the intensively managed meadows and the two meadow types with reduced management intensity. The investigated habitat types were forest edges, arable fields (winter wheat and intensively managed meadow) and ecological compensation areas including hedgerows, extensively managed and low-intensity meadows, wildflower strips on set-aside land and orchard meadows. Spiders were collected in pitfall traps in May and June 1997. Butterflies were observed during six visits (10 minutes, covering 0.25 ha) in each site in 1998. This was part of the same study as (Jeanneret et al. 2003a, Jeanneret et al. 2003b).

Plant nectar flower mixture/wildflower strips

A replicated, controlled study in summer 1997 and 1998 in Switzerland (Jeanneret et al. 2000) found that the number of spider (Araneae) and butterfly (Lepidoptera) species in wildflower strips sown on set-aside areas did not differ significantly from winter wheat fields. The number of spider species in wildflower strips was among the lowest reported (average 20 species), significantly lower than in low-intensity meadows (more than 25 species) and forest edges (more than 35 species). Butterfly species richness in the wildflower strips (more than 6 species) differed significantly only from forest edges (less than 4 species). However, for both taxa, wildflower strips attracted some species that were never or only rarely found in other habitats. The investigated habitat types were forest edges, arable fields (winter wheat and intensively managed meadow) and ecological compensation areas including hedgerows, extensively managed and low-intensity meadows, wildflower strips on set-aside land and orchard meadows. There were 109 sites in two arable regions. Spiders were collected in pitfall traps in May and June 1997. Butterflies were observed during six visits (10 minutes, covering 0.25 ha) in each site in 1998. This was part of the same study as Jeanneret et al. 2003.