Habitat management in calcareous grasslands: effects on the insect community developing in flower heads of Cynarea

Published source details Völkl W., Zwölfer H., Romstöck-Völkl M. & Schmelzer C. (1993) Habitat management in calcareous grasslands: effects on the insect community developing in flower heads of Cynarea. Journal of Applied Ecology, 30, 307-315.
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This study is summarised as evidence for the following.

	Action	Category
	Maintain species-rich, semi-natural grassland Action Link
	Cease mowing on grassland to allow early succession Action Link
	Cease grazing on grassland to allow early succession Action Link

Maintain species-rich, semi-natural grassland

A replicated, paired, site comparison study in 1990–1991 in 35 calcareous grasslands in Northern Bavaria, Germany (Völkl et al. 1993) reported that semi-natural grasslands maintained by sheep grazing had a higher density of meadow neb moth Metzneria metzneriella caterpillars, and a similar occurrence of hoary bell moth Eucosma cana caterpillars, compared to mown grasslands. Results were not tested for statistical significance. In grazed grasslands, 2.9–3.3% of greater knapweed Centaurea scabiosa flowerheads contained meadow neb caterpillars, compared to 0–0.3% of flowerheads in mown grasslands, and 2.2–2.5% of flowerheads in abandoned grasslands. The occurrence of hoary bell was similar in mown, grazed and abandoned grasslands (data not presented). Thirty-five grasslands (0.5–2 ha) were managed by either light sheep grazing in early autumn (7 sites, vegetation <10 cm) or annual mowing (usually in midsummer, 7 sites, vegetation ~25 cm before cutting), or had been abandoned for at least five years (21 sites, vegetation >25 cm with shrubs). In September–October 1990 and 1991, samples of 100–350 greater knapweed flowerheads/site were collected from seven pairs of grazed-abandoned and mown-abandoned grasslands, and seven (1990) and four (1991) unpaired, abandoned grasslands. Flowerheads were dissected in the laboratory to identify caterpillars.

(Summarised by: Andrew Bladon)
Cease mowing on grassland to allow early succession

A replicated, paired, site comparison study in 1990–1991 in 21 calcareous grasslands in Northern Bavaria, Germany (Völkl et al. 1993) reported that abandoned grasslands had a higher density of meadow neb moth Metzneria metzneriella caterpillars, and a similar occurrence of hoary bell moth Eucosma cana caterpillars, compared to mown grasslands. Results were not tested for statistical significance. In abandoned grasslands, 2.2–2.5% of greater knapweed Centaurea scabiosa flowerheads contained meadow neb caterpillars, compared to 0–0.3% of flowerheads in mown grasslands. The occurrence of hoary bell was similar in abandoned and mown grasslands (data not presented). Twenty-one grasslands (0.5–2 ha) were either abandoned for at least five years (14 sites, vegetation >25 cm with shrubs) or managed by annual mowing (usually in midsummer, 7 sites, vegetation ~25 cm before cutting). In September–October 1990 and 1991, samples of 100–350 greater knapweed flowerheads/site were collected from seven pairs of mown-abandoned grasslands, and seven (1990) and four (1991) unpaired, abandoned grasslands. Flowerheads were dissected in the laboratory to identify caterpillars.

(Summarised by: Andrew Bladon)
Cease grazing on grassland to allow early succession

A replicated, paired, site comparison study in 1990–1991 in 21 calcareous grasslands in Northern Bavaria, Germany (Völkl et al. 1993) reported that abandoned grasslands had a similar density of meadow neb moth Metzneria metzneriella caterpillars, and a similar occurrence of hoary bell moth Eucosma cana caterpillars, to grazed grasslands. Results were not tested for statistical significance. In abandoned grasslands, 2.2–2.5% of greater knapweed Centaurea scabiosa flowerheads contained meadow neb caterpillars, compared to 2.9–3.3% of flowerheads in grazed grasslands. The occurrence of hoary bell was similar in abandoned and grazed grasslands (data not presented). Twenty-one grasslands (0.5–2 ha) were either abandoned for at least five years (14 sites, vegetation >25 cm with shrubs) or managed by light sheep grazing in early autumn (7 sites, vegetation <10 cm). In September–October 1990 and 1991, samples of 100–350 greater knapweed flowerheads/site were collected from seven pairs of grazed-abandoned grasslands, and seven (1990) and four (1991) unpaired, abandoned grasslands. Flowerheads were dissected in the laboratory to identify caterpillars.

(Summarised by: Andrew Bladon)