The successful conservation of an endangered species, the heath fritillary butterfly Mellicta athalia, in Britain

Published source details Warren M.S. (1991) The successful conservation of an endangered species, the heath fritillary butterfly Mellicta athalia, in Britain. Biological Conservation, 55, 37-56.
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This study is summarised as evidence for the following.

	Action	Category
	Use rotational mowing Action Link
	Legally protect habitat Action Link
	Use prescribed fire to maintain or restore disturbance in grasslands or other open habitats Action Link
	Translocate to re-establish populations in known or believed former range Action Link
	Coppice woodland Action Link
	Release captive-bred individuals to the wild Action Link

Use rotational mowing

A replicated, site comparison study in 1980–1989 on eight grasslands in Cornwall, UK (Warren 1991) reported that grasslands managed by rotational mowing supported populations of heath fritillary Mellicta athalia while populations on unmanaged grasslands went extinct. Results were not tested for statistical significance. Two grasslands managed by rotational mowing maintained heath fritillary populations of 1,300–2,700 adults/year (5-ha site) and 200–600 adults/year (0.25-ha site), compared to six unmanaged grasslands where the heath fritillary populations went extinct (data not presented). From 1981–1989, the flatter areas of a 5-ha grassland were mown annually in autumn using a tractor-drawn ‘bush-hog’ cutter, while the steeper areas were cut every two or four years using hand-held brush cutters. A second 0.25-ha grassland was managed by cutting half of the site each year. Six other grasslands were unmanaged throughout this period. From 1980–1989, butterflies were surveyed annually on timed counts along a zig-zag route covering the known flight areas at each site. The total yearly population at a site was estimated by multiplying the peak population count by three.

(Summarised by: Andrew Bladon)
Legally protect habitat

A before-and-after, site comparison study in 1980–1989 in two woodlands in Kent, UK (Warren 1991) reported that a woodland legally protected as a National Nature Reserve and managed by coppicing established a large population of heath fritillary Mellicta athalia, while over half of the colonies in a privately owned, unmanaged wood went extinct. Results were not tested for statistical significance. After four years of coppicing in one protected wood, the number of heath fritillaries peaked at 2,000 adults, and stabilized at around 800 adults after nine years, compared to “just a few individuals” when management began. In an unmanaged, unprotected wood, there were 800 adults across nine colonies in 1989, compared to over 10,000 adults across 20 colonies in 1980. From 1980–1989, a woodland protected as a National Nature Reserve was managed by coppicing one or two plots (1–5 ha) each year on a 15–20-year rotation. Plots were connected by wide rides and permanent glades. A nearby, privately owned woodland was not managed. From 1980–1989, butterflies were surveyed most years on timed counts along a zig-zag route covering the known flight areas at each site. The total yearly population at a site was estimated by multiplying the peak population count by three.

(Summarised by: Andrew Bladon)
Use prescribed fire to maintain or restore disturbance in grasslands or other open habitats

A before-and-after study in 1980–1989 on a heathland on Exmoor, UK (Warren 1991) reported that prescribed burning increased the number of heath fritillary Mellicta athalia. Results were not tested for statistical significance. Seven years after burning, over 5,500 adult heath fritillary were recorded at the site, compared to 280 adults two years before burning. However, in the summer after burning, no heath fritillaries were seen, and only 17 were recorded the following year. The author noted that these adults may have recolonized from a neighbouring site 500 m away. In March 1982, most of a 9-ha heathland was burned. In 1980, and from 1982–1989, butterflies were surveyed annually on timed counts along a zig-zag route covering the known flight area.

(Summarised by: Andrew Bladon)
Translocate to re-establish populations in known or believed former range

A study in 1987–1989 in a woodland in Essex, UK (Warren 1991) reported that translocated heath fritillary Mellicta athalia released into a coppiced woodland survived and the population increased. Results were not tested for statistical significance. Two years after the release of 38 adult heath fritillaries, the population was around 200 adults. In 1987, a total of 38 adult heath fritillaries (20 females, 18 males) were translocated from a nearby population (which had been established from captive-bred butterflies in 1984), and released into a 30-ha wood with 0.5 ha of coppicing. In 1988–1989, butterflies were surveyed annually on timed counts along a zig-zag route covering the known flight area. The total yearly population was estimated by multiplying the peak population count by three.

(Summarised by: Andrew Bladon)
Coppice woodland

A before-and-after, site comparison study in 1980–1989 in two woodlands in Kent, UK (Warren 1991, same experimental set-up as Warren 1987) reported that a protected woodland managed by coppicing established a large population of heath fritillary Mellicta athalia, while over half of the colonies in a privately owned, unmanaged wood went extinct. Results were not tested for statistical significance. After four years of coppicing in one protected wood, the number of heath fritillaries peaked at 2,000 adults, and stabilized at around 800 adults after nine years, compared to “just a few individuals” when management began. In an unmanaged, unprotected wood, there were 800 adults across nine colonies in 1989, compared to over 10,000 adults across 20 colonies in 1980. From 1980–1989, a woodland protected as a National Nature Reserve was managed by coppicing one or two plots (1–5 ha) each year on a 15–20-year rotation. Plots were connected by wide rides and permanent glades. A nearby, privately owned woodland was not managed. From 1980–1989, butterflies were surveyed most years on timed counts along a zig-zag route covering the known flight areas at each site. The total yearly population at a site was estimated by multiplying the peak population count by three.

(Summarised by: Andrew Bladon)
Release captive-bred individuals to the wild

A study in 1984–1989 in a woodland in Essex, UK (Warren 1991) reported that captive-bred heath fritillary Mellicta athalia released into a coppiced woodland survived and the population increased. Results were not tested for statistical significance. Two years after the release of 53 adult heath fritillaries, the population was nearly 3,000 adults (when the extent of breeding habitat was at its maximum), but stabilized at around 500 adults after five years. In 1984, a total of 53 captive-bred adult heath fritillaries (31 females, 22 males) were released into a coppiced woodland (coppicing commenced in 1980) containing around 4 ha of hostplant (common cow-wheat Melampyrum pratense). From 1985–1989, butterflies were surveyed annually on timed counts along a zig-zag route covering the known flight areas. The total yearly population was estimated by multiplying the peak population count by three.

(Summarised by: Andrew Bladon)