Untangling the effects of fire, grazing, and land-use legacies on grassland butterfly communities

Published source details Moranz R.A., Debinski D.M., McGranahan D.A., Engle D.M. & Miller J.R. (2012) Untangling the effects of fire, grazing, and land-use legacies on grassland butterfly communities. Biodiversity and Conservation, 21, 2719-2746.
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This study is summarised as evidence for the following.

	Action	Category
	Use rotational burning Action Link
	Cease grazing on grassland to allow early succession Action Link

Use rotational burning

A replicated, randomized, controlled study in 2007–2009 in 13 tallgrass prairies in Iowa and Missouri, USA (Moranz et al 2012) found that butterfly species richness did not differ between pastures with rotational burning and grazing and pastures where the whole area was burned (with or without grazing), but the density of some species differed with management and year. There was no difference in species richness between pastures burned rotationally with grazing (6–7) and pastures with complete burning and grazing (6–7) or no grazing (7). Regal fritillary Speyeria idalia densities were lower with rotational burning with grazing and complete burning with grazing (both average: 0 individuals/ha) than with complete burning and no grazing (5–7 individuals/ha). The same was seen in the common wood-nymph Cercyonis pegala (rotational burning/grazing or complete burning/grazing = 2 individuals/ha; complete burning/no grazing = 21) and the monarch butterfly Danaus plexippus (rotational burning/grazing or complete burning/grazing = 1 individuals/ha; complete burning/no grazing = 2) but only in 2009 (the survey after the burn in non-rotational pastures, no difference in 2008). In 2008 only, eastern tailed-blue Cupido comyntas population densities were higher in rotational burning with grazing pastures (124 individuals/ha) than complete burning with (101) or without grazing (55) pastures (no difference in 2009). Other species analysed were not affected by management in either year. Pastures (15–31 ha) were managed in one of three ways: 1) rotational burning, with a third of each pasture burned annually in spring 2007–2009 and grazing May–October annually (five pastures), 2) complete burning in spring 2008 or 2009 and grazing May–October annually (four pastures), or 3) complete burning in spring 2008 or 2009 without grazing (four pastures). Butterflies were surveyed in June–July 2008–2009 along six 100-m transects/pasture.

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

A replicated, randomized, controlled study in 2007–2009 in 13 tallgrass prairies in Iowa and Missouri, USA (Moranz et al 2012) found that butterfly species richness did not differ between pastures with no grazing where the whole area was burned every three years and those with grazing and either complete burning or rotational burning, but the density of some species differed depending on management and year. There was no difference in species richness between pastures entirely burned once every three years without grazing (7) and those either burned entirely every three years (6–7) or rotationally (6–7) with grazing. Regal fritillary Speyeria idalia densities were higher in the pastures with no grazing (average: 5–7 individuals/ha) than those with grazing and complete burning (0 individuals/ha) or rotational burning (0 individuals/ha). The same trend was seen in the common wood-nymph Cercyonis pegala (complete burning/no grazing = 21 individuals/ha; complete burning/grazing = 2; rotational burning/grazing = 2) and the monarch Danaus plexippus (complete burning/no grazing = 2; complete burning/grazing = 1; rotational burning/grazing = 1) but only in 2009 (the survey after the burn in the non-rotational pastures, no difference in 2008). In 2008 only, eastern tailed-blue Cupido comyntas population densities were lower in pastures without grazing (55 individuals/ha) than those with grazing and complete burning (101 individuals/ha) or rotational burning (124 individuals/ha) (no difference in 2009). Other species analysed were not affected by management in either year. Pastures (15–31 ha) were managed in one of three ways: 1) rotational burning, with a third of each pasture burned annually in spring 2007–2009 and cattle grazing May–October annually (five pastures), 2) complete pasture burning in spring 2008 or 2009 and cattle grazing May–October annually (four pastures), or 3) complete pasture burning in spring 2008 or 2009 without grazing (four pastures). Butterflies were surveyed in June–July 2008–2009 along six 100-m transects/pasture.

(Summarised by: Eleanor Bladon)