Individual study: Bees on set-aside fields: Impact of flower abundance, vegetation and field-age
Steffan-Dewenter I. & Tscharntke T. (1995) Bees on set-aside fields: Impact of flower abundance, vegetation and field-age. Mitteilungen Der Deutschen Gesellschaft Fur Allgemeine Und Angewandte Entomologie, 10, 319-322
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Provide or retain set-aside areas in farmland
A replicated site comparison study from April to August 1993 at 21 farmland sites in Kraichgau, Germany (Steffan-Dewenter & Tscharntke 1995) (same study as Gathmann & Tscharntke 1993) found that naturally regenerated set-asides and orchard meadows held more wild bee species and more individual bees than set-aside fields sown with phacelia Phacelia tanacetifolia (averages of 27, 28 and 10 bee species; 120, 100 and 75 bees, respectively). Also the numbers of Red-listed bee species and specialist species were higher in naturally developed than in Phacelia-sown set-asides. Seven field types (four replicates each) were investigated: one, two, three, four and five-year-old naturally regenerated set-asides, 1-year-old set-asides sown with phacelia and orchard meadows. Wild bees were monitored for 30 minutes on each of six visits to each site. Along one 100 m long transect in the field centre, bees were caught using sweep nets (100 sweeps/transect). In addition, flower-visiting bees were caught.
Plant nectar flower mixture/wildflower strips
A replicated, controlled study from April to August 1993 in the Kraichgau region, Germany (Steffan-Dewenter & Tscharntke 1995) found that wild bee (Apidae) species richness was lower on set-asides sown with phacelia Phacelia tanacetifolia (around 10 species) than on two-year-old naturally developed set-asides (around 27 spp.) and orchard meadows (around 28 spp.). The number of red-listed bee species and specialist species were lower on phacelia-sown set-asides than on orchard meadows and naturally developed set-asides. Wild bee abundance in phacelia-sown set-asides (around 75 individuals) was lower than in orchard meadows (around 120 ind.) and two-year-old naturally developed set-asides (around 100 ind.), but higher than in naturally developed set-asides of different ages. Seven field types (four replicates each) were investigated in 21 farmland sites: one, two, three, four and five-year-old naturally developed set-asides, one-year-old set-asides sown with phacelia, and orchard meadows. Wild bees were monitored on six 30 minute visits at each site. Bees were caught using sweep nets (100 sweeps/transect) along one 100 m transect in the field centre. Plant species richness and the abundance of flowering plants was recorded at each visit. Additional plant surveys on a 49 m2 quadrat were performed in July and August.