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Providing evidence to improve practice

Individual study: Bees and wasps in trap nests on sown crop fields and self-sown fallow fields (Hymenoptera Aculeata)

Published source details

Gathmann A. & Tscharntke T. (1993) Bees and wasps in trap nests on sown crop fields and self-sown fallow fields (Hymenoptera Aculeata). Verhandlungen Gesellschaft fur Okologie, 22, 53-56


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 Farmland Conservation

A replicated, controlled site comparison study from May to October 1990 in 40 farmland sites (10 field types, four replicates each) near Karlsruhe, south Germany (Gathmann & Tscharntke 1993) found significantly more species of solitary bee in artificial reed stem nests in unsown sites with naturally developed vegetation (average 7.9 species) than in sown fields, including crops and sown grass/clover fields (average 4.6 spp.). Bee species richness increased with increasing age of the unsown set-asides and with increasing plant diversity. Wasp diversity was similar in the different field types (1 to 4 spp./field type). Smaller bee and wasp species inhabited fields with high plant diversity but were absent in fields with low plant diversity. Foraging flights took twice as long in fields with low plant diversity (35 min) than in fields with high plant diversity (15 min) for two investigated bee species (leaf-cutter bee Megachile versicolor, blue carpenter bee Osmia caerulescens). No such effect was found for the European potter wasp Ancistrocerus gazella (ca. 21 min in both sites). Unsown sites with naturally developed vegetation included one- and two-year old mown and unmown set-asides and old meadow orchards. Crops on sown fields were peas, barley, rye, clover-grass mixture and Phacelia tanacetifolia. Mowing of set-asides took place in late June-early July. Three artificial nests (each with two 750 ml cans filled with 180 reed stems) were located in each field centre. Female body length of bees and wasps was measured. For Ancistrocerus gazella, Megachile versicolor and Osmia caerulescens, the time spent on foraging flights was measured on four one-year old set-asides and four old meadows. Plant surveys were conducted in May, July and October.

 

Provide nest boxes for bees (solitary bees or bumblebees) Farmland Conservation

A replicated, controlled study in May to October 1990 in 40 farmland sites (10 field types, four replicates each) near Karlsruhe, south Germany (Gathmann & Tscharntke 1993) (same study as (Gathmann et al. 1994)) found a significantly higher species richness of solitary bees (Apidae) in artificial reed Phragmites australis stem nests in unsown sites with naturally developed vegetation (approximately 7.9 species) than in sown fields (approximately 4.6 spp.). Unsown sites with naturally developed vegetation included one- and two-year old mown and unmown set-asides and old meadow orchards. Crops on sown fields were peas, barley, rye, clover Trifolium spp.-grass mixture and phacelia Phacelia tanacetifolia. Mowing of set-asides took place in late June-early July. Three artificial nests (each with two 750 ml cans filled with approximately 180 reed stems) were located in each field centre.