Population dynamics and the importance of habitat management for conservation of the butterfly Lopinga achine

Published source details Bergman K.O. (2001) Population dynamics and the importance of habitat management for conservation of the butterfly Lopinga achine. Journal of Applied Ecology, 38, 1303-1313.
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This study is summarised as evidence for the following.

	Action	Category
	Clear or open patches in forests Action Link

Clear or open patches in forests

A replicated, controlled, before-and-after study in 1992–1997 in 18 deciduous woods in Östergötland, Sweden (Bergman 2001) found that clearing new woodland glades increased the population size of woodland brown Lopinga achine butterflies in five out of six woods. Over 4–5 years after glades were created, the population of woodland brown increased by 93–97% in five woods where glades were created, but decreased by 19–25% in nine woods where no glades were created. However, in a sixth wood cleared later, the population decreased by 27% in the first two years after glades were created, compared to a 9% decrease over the same time period in three other woods where no glades were created. The authors noted that populations only occurred at sites with >60% canopy cover, but sites with 70–75% canopy cover had the highest population density. From 1992–1995, irregularly-shaped glades (10–30 m long) were created in six woodlands (20 in one wood, and 5–6 in each of the others). Where possible, the longest side had a south-west to north-east orientation to maximize sun exposure. In July 1992–1997, the adult population size of woodland brown butterflies was estimated in six woods where glades were created, and in 12 woods where no glades had been created.

(Summarised by: Andrew Bladon)