Impact of grazing management on hibernating caterpillars of the butterfly Melitaea cinxia in calcareous grasslands

Published source details van Noordwijk C.G.E., Flierman D.E., Remke E., Wallis-DeVries M.F. & Berg M.P. (2012) Impact of grazing management on hibernating caterpillars of the butterfly Melitaea cinxia in calcareous grasslands. Journal of Insect Conservation, 16, 909-920.
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This study is summarised as evidence for the following.

	Action	Category
	Remove, control or exclude vertebrate herbivores Action Link
	Reduce grazing intensity on grassland by reducing stocking density Action Link
	Translocate to re-establish populations in known or believed former range Action Link

Remove, control or exclude vertebrate herbivores

A paired, controlled study in 2009–2010 on a calcareous grassland in the Netherlands (van Noordwijk et al. 2012) found that fewer Glanville fritillary Melitaea cinxia caterpillar nests were damaged in a fenced, ungrazed area than in a grazed area. After 10 days of autumn grazing, fewer caterpillar nests had signs of damage in a fenced area (2/24 nests damaged) than nests in a grazed area (15/25 nests damaged). Two months later, the number of nests with signs of damage was similar in fenced (6/24 nests damaged) and grazed areas (6/25). All 24 nests in the fenced area survived until spring, compared to 22/25 surviving in the grazed area (statistical significance not assessed). In July–August 2009, a grazed 4-ha grassland was searched three times for caterpillar nests. Half of the area with the highest density of nests was fenced to create a 0.15-ha ungrazed area. Twenty-four pairs of the largest, equally sized nests (>1 m apart) in each area were selected, and their location marked on GPS. In September 2009, the unfenced area was grazed by 114 sheep over 1.23 ha for 10 days, after which an expanded 1.76-ha area was grazed by 15 sheep for 50 days. In October and December 2009, nests were checked for damage, and in March 2010 the survival of each nest was recorded.

(Summarised by: Andrew Bladon)
Reduce grazing intensity on grassland by reducing stocking density

A site comparison study in 2009–2010 in two calcareous grasslands in Belgium and the Netherlands (van Noordwijk et al. 2012) found that fewer Glanville fritillary Melitaea cinxia caterpillar nests were damaged at less intensively grazed and ungrazed sites than at a more intensively grazed site. After 6–10 days of autumn grazing, fewer caterpillar nests had signs of damage in a lightly grazed (2/25 nests damaged) and ungrazed (2/24 nests damaged) site than nests in a heavily grazed site (15/25 nests damaged). Two months later, the number of nests with signs of damage was similar in lightly grazed (3/25 nests damaged), ungrazed (6/24 nests damaged) and heavily grazed (6/25 nests damaged) areas. All 24 nests in the ungrazed area, and 24/25 nests in the lightly grazed area, survived until spring, compared to 22/25 surviving in the heavily grazed area (statistical significance not assessed). In July–August 2009, a lightly grazed 0.52-ha grassland and a heavily grazed 4-ha grassland were searched three times for caterpillar nests. At the larger site, half of the area with the most nests was fenced to create a 0.15-ha ungrazed site. The 24–25 largest nests (>1 m apart) in each site were selected, and their location marked on GPS. In September 2009, the 0.52-ha grassland was grazed by 26 sheep for six days, and a 1.23-ha area of the larger site was grazed by 114 sheep for 10 days, after which an expanded 1.76-ha area was grazed by 15 sheep for 50 days. In October and December 2009, nests were checked for damage, and in March 2010 the survival of each nest was recorded.

(Summarised by: Andrew Bladon)
Translocate to re-establish populations in known or believed former range

A study in 1997–2009 in two calcareous grasslands in Belgium and the Netherlands (van Noordwijk et al. 2012) reported that two introduced populations of Glanville fritillary Melitaea cinxia survived for two and 12 years. At one site, 41 caterpillar nests were present 12 years after reintroduction, and at a second site 120 nests were present two years after the reintroduction of 14 nests (no further details provided). In 1997, Glanville fritillaries were reintroduced to a 4-ha grassland in Belgium, managed by low density rotational sheep grazing from April to October. In 2007, fourteen caterpillar nests from that site were reintroduced to a network of grasslands 10 km away in the Netherlands, managed by high density sheep grazing in spring and autumn, and lower density grazing over winter. In the first year after introduction, part of the grassland containing the most caterpillar nests was fenced off during autumn grazing. No further details were provided. In July–August 2009, both grasslands were searched three times for caterpillar nests.

(Summarised by: Andrew Bladon)