Grazing intensity and the diversity of grasshoppers, butterflies, and trap-nesting bees and wasps
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Published source details
Kruess A. & Tscharntke T. (2002) Grazing intensity and the diversity of grasshoppers, butterflies, and trap-nesting bees and wasps. Conservation Biology, 16, 1570-1580.
Published source details Kruess A. & Tscharntke T. (2002) Grazing intensity and the diversity of grasshoppers, butterflies, and trap-nesting bees and wasps. Conservation Biology, 16, 1570-1580.
Actions
This study is summarised as evidence for the following.
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Reduce grazing intensity on pastures Action Link |
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Reduce grazing intensity on grassland (including seasonal removal of livestock) Action Link |
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Reduce grazing intensity on pastures
In a comparison of six intensively (5.5 cattle/ha) and six lightly (1.5 cattle/ha) cattle-grazed meadows with six ungrazed meadows in Germany, meadows with light grazing had a greater number of individual cavity-nesting bees, wasps and their brood parasites than meadows with intensive grazing (Kruess & Tscharntke 2002). There was an average of 47 emerging individuals/lightly grazed site, compared to 27 emerging individuals/intensively grazed site. Reduced intensity of grazing did not significantly increase the number of bee and wasp species.
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Reduce grazing intensity on grassland (including seasonal removal of livestock)
A replicated comparison of six intensively (5.5 cattle/ha) and six lightly (1.5 cattle/ha) cattle-grazed meadows with six ungrazed meadows in Germany (Kruess & Tscharntke 2002) found that meadows with light grazing had a greater number of individual cavity-nesting bees, wasps (Hymenoptera) and their brood parasites than meadows with intensive grazing. There was an average of 47 emerging individuals/lightly grazed site, compared to 27 emerging individuals/intensively grazed site. Reduced intensity of grazing did not significantly increase the number of bee and wasp species. Both abundance and total species richness of these insects were significantly higher on ungrazed grassland (11.5 species) than on intensively (4.7 species) or lightly (6.2 species) grazed pastures. These results were linked to an increase in vegetation height as grazing intensity is reduced.
