Relative contributions of local and regional factors to species richness and total density of butterflies and moths in semi-natural grasslands

Published source details Poyry J., Paukkunen J., Heliölä J. & Kuussaari M. (2009) Relative contributions of local and regional factors to species richness and total density of butterflies and moths in semi-natural grasslands. Oecologia, 160, 577-587.
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This study is summarised as evidence for the following.

	Action	Category
	Cease grazing on grassland to allow early succession Action Link

Cease grazing on grassland to allow early succession

A replicated, site comparison study in 2000 in 48 grassland sites in Uusimaa and Pirkanmaa, Finland (Pöyry et al 2009) found that at sites where grazing had recently ceased, butterfly density and species richness was higher, compared to sites where it had ceased a decade before or sites currently grazed. Butterfly species richness and density were higher on grasslands where grazing was stopped two to nine years before (richness: 22–34 species, density: 201–688 butterflies/0.25 ha), than on sites where grazing stopped ≥10 years before (richness: 19–30 species, density: 130–876 butterflies/0.25 ha) or on currently grazed pastures (richness: 7–28 species, density: 36–489 butterflies/0.25 ha). Seven surveys were carried out in May–August 2000, at 48 unforested 0.25–6 ha grassland sites (10 grazed two to nine years before, 15 grazed ≥10 years before, 23 currently grazed). Butterflies and day-flying moths were surveyed along a 350 m transect within a 0.25 ha study plot at each site to calculate density, and then along a transect outside the plot which was proportionate to the size of the site to record all species. Butterfly density was measured as the number of individuals seen within the study plot transect.

(Summarised by: Eleanor Bladon)