Prescribed fire management of Karner blue butterfly habitat at Indiana Dunes National Lakeshire

Published source details Kwilosz J.R. & Knutson R.L. (1999) Prescribed fire management of Karner blue butterfly habitat at Indiana Dunes National Lakeshire. Natural Areas Journal, 19, 98-108.
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This study is summarised as evidence for the following.

	Action	Category
	Leave some areas unburned during prescribed burning Action Link
	Use rotational burning Action Link

Leave some areas unburned during prescribed burning

A replicated study in 1993–1997 in two oak savanna and prairie sites in Indiana, USA (Kwilosz & Knutson 1999) reported that Karner blue butterfly Lycaeides melissa samuelis populations increased where unburned patches were left during prescribed burning, and Karner blues were recorded within the unburned patches. Results were not tested for statistical significance. Over 2–3 years, at two sites managed by rotational burning with unburned patches left within the burn area, the maximum number of Karner blue adults recorded increased from 159–288 to 296–725. Karner blues were recorded in nine of 11 unburned patches within burned units during the first brood after burning, and in all 11 patches during the second brood. Within a 6,000-ha reserve, two sites were each divided into four units. At a 177-ha site, one unit was burned annually in autumn or spring from 1993–1996, and adjacent units were not burned in consecutive years. At a 59-ha site, one unit/year was burned in autumn 1995–1996. Within the burned units, multiple 50–300-m² patches with high Karner blue and wild lupine Lupinus perennis densities were left unburned. Butterflies were surveyed along a fixed 1.5–6.5-km transect/site, passing through all units and 11 unburned patches. The highest number recorded at each site was taken as an annual population estimate. In July 1994, two surveys were conducted at the larger site. In June–August 1995–1997, six–nine surveys/year were conducted 1–10 days apart at each site.

(Summarised by: Andrew Bladon)
Use rotational burning

A replicated, site comparison study in 1993–1997 in five oak savannas and prairies in Indiana, USA (Kwilosz & Knutson 1999) reported that sites burned on rotation had a similar abundance of Karner blue butterfly Lycaeides melissa samuelis to unburned sites. Results were not tested for statistical significance. Over 2–3 years, at two sites managed by rotational burning, the maximum number of Karner blue adults recorded increased from 159–288 to 296–725. Over 1–2 years, at two unburned sites, the abundance increased from 45–103 to 71–184. At a third unburned site, there were 104 adults in 1994 and 103 in 1997. Within a 6,000-ha reserve, two sites were each divided into four units. At a 177-ha site, one unit was burned annually in autumn or spring from 1993–1996, and adjacent units were not burned in consecutive years. At a 59-ha site, one unit/year was burned in autumn 1995–1996. Within the burned units, multiple 50–300-m² patches with high Karner blue and wild lupine Lupinus perennis densities were left unburned. Three sites (areas not given) were not burned during the study. Butterflies were surveyed along a fixed 1.5–6.5-km transect/site, passing through all units. The highest number recorded at each site was taken as an annual population estimate. In July 1994, two surveys were conducted at each of two sites (one burned and one unburned). In June–August 1995–1997, three–nine surveys were conducted at each of 4–5 sites/year. Surveys were conducted 1–10 days apart.

(Summarised by: Andrew Bladon)