Grass-skipper (Hesperiinae) trends in midwestern USA grasslands during 1988-2013

Published source details Swengel A.B. & Swengel S.R. (2015) Grass-skipper (Hesperiinae) trends in midwestern USA grasslands during 1988-2013. Journal of Insect Conservation, 19, 279-292.
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This study is summarised as evidence for the following.

	Action	Category
	Use rotational burning Action Link

Use rotational burning

A replicated, site comparison study in 1988–2013 in 24 prairies, pine-oak barrens and fields in Wisconsin, USA (Swengel & Swengel 2015) found that prairies managed by rotational burning had more strongly declining populations of grass-skipper butterflies (Hesperiinae) than unmanaged pine barrens or lightly managed fields. In prairies managed by rotational burning, specialist and grassland skipper butterflies had more strongly declining population trends than in pine-oak barrens (specialist and grassland species) or old fields (grassland species only) (data presented as model results). Ten native prairies were managed by cool-season burning, typically on a 2–5-year rotation, with some mowing, cutting and spot herbicide application. Eight pine-oak barrens were last burned by wildfires in 1977 or 1988. Six fields reverting from agriculture were managed by burning, grazing, haying, cutting, herbicide or tilling, but with no more than 10% of a site managed each year. In spring and summer 1988–2013, butterflies were surveyed along transects (2–3 km/hour) at each site, generally at least twice/year and in at least two years/site. Skippers were classified as eight “specialist” (restricted to native grassland habitat) or five “grassland” (occurring widely in open habitat) species.

(Summarised by: Andrew Bladon)