Population dynamics and future persistence of the clouded Apollo butterfly in southern Scandinavia: The importance of low intensity grazing and creation of habitat patches

Published source details Johansson V. & Franzen M. (2017) Population dynamics and future persistence of the clouded Apollo butterfly in southern Scandinavia: The importance of low intensity grazing and creation of habitat patches. Biological Conservation, 206, 120-131.
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This study is summarised as evidence for the following.

	Action	Category
	Delay cutting or first grazing date on grasslands to create variation in sward height Action Link
	Reduce grazing intensity on grassland by reducing stocking density Action Link
	Cease grazing on grassland to allow early succession Action Link

Delay cutting or first grazing date on grasslands to create variation in sward height

A replicated, site comparison study in 1984–2015 in 24 grasslands in Blekinge province, Sweden (Johansson et al. 2017) found that grasslands grazed lightly, later in the year or with fewer animals, had a higher abundance of clouded Apollo Parnassius mnemosyne than grasslands grazed heavily, earlier in the summer or with more animals. In grasslands managed by light grazing, the abundance of clouded Apollo (1–169 individuals/grassland/year) was higher than in heavily grazed grasslands (2–22 individuals/grassland/year) or ungrazed grasslands (0–109 individuals/grassland/year). In addition, abundance was higher on larger grasslands, and grasslands which were close together were more likely to be colonized (data presented as model results). From 1984–2015, twenty-four open grasslands (>150 m apart) with >0.5 m² cover of the host plant Corydalis spp. and the presence of a major nectar plant Lychnis viscaria were assigned annually to one of three management categories: light grazing (grazing commenced after 15 June with 1–9 animals/hectare); heavy grazing (grazing commenced before 15 June or with ≥10 animals/hectare for ≥8 weeks); no grazing. Grazing animals were cattle and sheep. In 1984–1987, 1991 and 2003–2015, butterflies were surveyed ≥6 times/year on each site, by marking and recapturing individuals along irregular routes through each grassland. In 1988–1989 and 1992–2002, grasslands were visited more irregularly and their presence recorded. Surveys were used to estimate the local population size on each grassland each year.

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

A replicated, site comparison study in 1984–2015 in 24 grasslands in Blekinge province, Sweden (Johansson et al. 2017) found that grasslands grazed lightly, with fewer animals or later in the year, had a higher abundance of clouded Apollo Parnassius mnemosyne than grasslands grazed heavily, with more animals or earlier in the summer. In grasslands managed by light grazing, the abundance of clouded Apollo (1–169 individuals/grassland/year) was higher than in heavily grazed grasslands (2–22 individuals/grassland/year) or ungrazed grasslands (0–109 individuals/grassland/year). In addition, abundance was higher on larger grasslands, and grasslands which were close together were more likely to be colonized (data presented as model results). From 1984–2015, twenty-four open grasslands (>150 m apart) with >0.5 m² cover of the host plant Corydalis spp. and the presence of a major nectar plant Lychnis viscaria were assigned annually to one of three management categories: light grazing (grazing with 1–9 animals/hectare commenced after 15 June); heavy grazing (grazing with ≥10 animals/hectare for ≥8 weeks or commenced before 15 June); no grazing. Grazing animals were cattle and sheep. In 1984–1987, 1991 and 2003–2015, butterflies were surveyed ≥6 times/year on each site, by marking and recapturing individuals along irregular routes through each grassland. In 1988–1989 and 1992–2002, grasslands were visited more irregularly and their presence recorded. Surveys were used to estimate the local population size on each grassland each year.

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

A replicated, site comparison study in 1984–2015 in 24 grasslands in Blekinge province, Sweden (Johansson et al. 2017) found that ungrazed grasslands had a lower abundance of clouded Apollo Parnassius mnemosyne than lightly grazed grasslands, but a higher abundance than heavily grazed grasslands. In ungrazed grasslands, the abundance of clouded Apollo (0–109 individuals/grassland/year) was lower than in lightly grazed grasslands (1–169 individuals/grassland/year), but higher than in heavily grazed grasslands (2–22 individuals/grassland/year). In addition, abundance was higher on larger grasslands, and grasslands which were close together were more likely to be colonized (data presented as model results). From 1984–2015, twenty-four open grasslands (>150 m apart) with >0.5 m² cover of the host plant Corydalis spp. and the presence of a major nectar plant Lychnis viscaria were assigned annually to one of three management categories: no grazing; light grazing (grazing commenced after 15 June with 1–9 animals/hectare); heavy grazing (grazing commenced before 15 June or with ≥10 animals/hectare for ≥8 weeks). Grazing animals were cattle and sheep. In 1984–1987, 1991 and 2003–2015, butterflies were surveyed ≥6 times/year on each site, by marking and recapturing individuals along irregular routes through each grassland. In 1988–1989 and 1992–2002, grasslands were visited more irregularly and their presence recorded. Surveys were used to estimate the local population size on each grassland each year.

(Summarised by: Andrew Bladon)