Study

Enhanced diversity of cavity-nesting solitary bees on naturally regenerated set-aside in the Kraichgau, Baden-Württemberg, Germany

  • Published source details Gathmann A., Greiler H.J. & Tscharntke T. (1994) Trap-nesting bees and wasps colonizing set-aside fields: succession and body size, management by cutting and sowing. Oecologia, 98, 8-14

Actions

This study is summarised as evidence for the following.

Action Category

Provide set-aside areas in farmland

Action Link
Bee Conservation

Increase the use of clover leys on farmland

Action Link
Bee Conservation

Plant dedicated floral resources on farmland

Action Link
Bee Conservation

Provide artificial nest sites for solitary bees

Action Link
Bee Conservation

Provide nest boxes for bees (solitary bees or bumblebees)

Action Link
Farmland Conservation

Provide or retain set-aside areas in farmland

Action Link
Farmland Conservation

Plant nectar flower mixture/wildflower strips

Action Link
Farmland Conservation

Provide artificial nest sites for solitary bees

Action Link
Bee Conservation
  1. Provide set-aside areas in farmland

    A replicated, controlled trial with four replicates of each treatment (Gathmann et al.1994) compared cavity-nesting bees and wasps nesting on set-aside arable land managed in six different ways with crop fields and old meadows in Kraichgau, southwest Germany. The study used reed Phragmites australis stem nest boxes (described in 'Provide artificial nest sites for solitary bees'), and recorded nesting only, not foraging activity. Set-aside fields were either sown in the year of study, with a grass-clover mix or phacelia Phacelia tanacetifolia (also known as scorpion weed, lacy phacelia or tansy phacelia)or were in their first or second year of natural regeneration, with or without mowing. Overall, naturally regenerated fields had significantly more nests, and more nesting species than fields sown with fallow or arable crops. Of the six set-aside treatments, the most species were found on two-year-old set-aside, mown in late June or early July, with a total of eight nesting bee species. This compares with four bee species found on 1-year-old unmown set-aside, and none on set-aside sown with phacelia. Twelve bee species were found on old meadows (>30 years old, with old fruit trees). Amongst 2-year-old, naturally regenerated set-aside fields, mown fields had more than twice as many species (bees and wasps) as unmown fields (average 4.8 species/field vs. 1.8).

  2. Increase the use of clover leys on farmland

    As part of a larger study with 10 field types, Gathmann et al. (1994) placed bundles of reed stems Phragmites australis for cavity-nesting bees (and wasps) in four set-aside fields newly sown with a clover-grass mix. The mix was mostly white clover Trifolium repens, perennial rye grass Lolium perenne and alfalfa Medicago sativa. Four species of bee made nests in the reed stems in these fields, including one endangered species Megachile alpicola. However, in the same study, three of those four species also nested in reed stems placed in barley Hordeum vulgare fields. By contrast, 12 bee species nested in reed stems placed in 2-year-old set-aside fields mown in late June, and 16 species nested in reed stems in old meadows.

  3. Plant dedicated floral resources on farmland

    As part of a larger study with 10 field types, Gathmann et al. (1994) placed bundles of reed Phragmites australis stems for cavity-nesting bees (and wasps) in four set-aside fields newly sown with phacelia in Kraichgau, southwest Germany. The phacelia fields attracted many honey bees Apis mellifera (foraging bees not quantified), but no cavity-nesting solitary bees made nests in reed stems in these fields. By comparison, in the same study, 12 bee species nested in reed stems placed in 2-year-old naturally regenerated set-aside fields mown in late June.

  4. Provide artificial nest sites for solitary bees

    In April 1990, in Kraichgau, southwest Germany, 240 bundles of reed stems Phragmites australis in tins were put out, six in each of 40 fields of 10 management types, including various types of set-aside, crop fields and old meadows (Gathmann et al. 1994, also referred to by Tscharntke et al. 1998). Of 43,200 available stems, 292 were occupied by a total of 14 bee species and nine wasp species. Five species of bee considered to be endangered in Germany occupied the reed stem nests: Anthidium lituratum, Heriades crenulatus, Megachile alipcola, Osmia gallarum and Osmia leaiana. The two endangered Osmia species were exclusively found in nests in old meadows (more than 30 years old with several old fruit trees). The other three also nested in stems provided in 2-year-old mown set-aside, and two species (A. lituratum and M. alpicola) used reed stems in a variety of field types, including cereal crops.

     

  5. Provide nest boxes for bees (solitary bees or bumblebees)

    A replicated study in April 1990 of 240 bundles of reed Phragmites australis stems in 40 fields of 10 management types, in Kraichgau, southwest Germany (Gathmann et al. 1994) (same study as (Gathmann & Tscharntke 1993)) found of 43,200 available reed stems, 292 were occupied by a total of 14 bee (Apidae) species and nine wasp species (Hymenoptera). Five species of bee considered to be endangered in Germany occupied the reed stem nests: Anthidium lituratum, Heriades crenulatus, Megachile alpicola, Osmia gallarum and Osmia leaiana. The two endangered Osmia species were exclusively found in nests in old meadows (more than 30 years old with several old fruit trees). The other three also nested in stems provided in 2-year-old mown set-aside, and two species (A. lituratum and M. alpicola) used reed stems in a variety of field types, including cereal crops. The proportion of larvae in the nests that died from disease or failed parasitism was 13%; 2% were successfully parasitized. Two-hundred-and-forty bundles of reed stems in tins were put out, six in each of 40 fields of 10 management types, including various types of set-aside, crop fields and old meadows. This study is also referred to by (Tscharntke et al. 1998).

  6. Provide or retain set-aside areas in farmland

    A replicated, controlled site comparison study with four replicates of each treatment (Gathmann et al. 1994) - the same study as (Gathmann & Tscharntke 1993) - found that naturally regenerated set-aside fields had significantly more cavity-nesting bee and wasp nests, and more nesting species than fields sown with fallow or arable crops. The study compared bees and wasps nesting on set-aside land managed in six different ways with crop fields and old meadows in Kraichgau, southwest Germany. It used reed Phragmites australis stem nest boxes and recorded nesting only, not foraging activity. Set-aside fields were either sown in the year of study, with a grass-clover mix or phacelia Phacelia tanacetifolia, or were in their first or second year of natural regeneration, with or without mowing.

     

  7. Plant nectar flower mixture/wildflower strips

    A replicated, controlled, site-comparison study in 1990 in the Kraichgau region, Germany (Gathmann et al. 1994) found set-aside fields newly sown with phacelia Phacelia tanacetifolia attracted many honey bees Apis mellifera (foraging bees not quantified), but no cavity-nesting solitary bees (Apidae) made nests in bundles of reed stems Phragmites australis placed in the phacelia-sown fields. In contrast, 12 bee species nested in reed stems placed in 2-year-old naturally regenerated set-aside fields mown in late June in the same study. Four set-aside fields were sown with phacelia. Bundles of reed stems for cavity-nesting bees (and wasps Sphecidae, Eumenidae) were placed in the four newly sown phacelia set-aside fields in April 1990 and sampled in October 1990. This trial was part of a larger study (Greiler 1994).

  8. Provide artificial nest sites for solitary bees

    In April 1990, in Kraichgau, southwest Germany, 240 bundles of reed stems in tins were put out, six in each of 40 fields of 10 management types, including various types of set-aside, crops fields and old meadows (Gathmann et al. 1994). The proportion of larvae in the nests that died from disease or failed parasitism was 13%; 2% were successfully parasitized.

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