A quantitative conservation approach for the endangered butterfly, Maculinea alcon

Published source details Wallis-DeVries M. (2004) A quantitative conservation approach for the endangered butterfly, Maculinea alcon. Conservation Biology, 18, 489-499.
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This study is summarised as evidence for the following.

	Action	Category
	Restore or create peatland Action Link
	Retain connectivity between habitat patches Action Link
	Maintain or create bare ground Action Link
	Employ areas of semi-natural habitat for rough grazing (includes salt marsh, lowland heath, bog, fen) Action Link

Restore or create peatland

A replicated, site comparison study in 1998–1999 on 68 wet heathland sites in the Netherlands (WallisDeVries 2004) found that raising water levels reduced occupancy by Alcon large blue Maculinea alcon. Fewer recently flooded sites were occupied by Alcon large blue (48%) than non-flooded sites (85% occupancy), and sites where measures had been taken to raise the water level were more likely to be flooded (68%) than sites without such measures (35%). Sixty-eight wet heathland sites in the Netherlands where Alcon large blue was known to have occurred since 1990 were selected. Management information for the last five years was obtained by sending questionnaires to land managers. Changes in management designed to raise water levels had been used at 31% of sites (further details not provided). From mid-July–early September 1998–1999, Alcon large blue eggs were counted in each of three 10 × 10 m plots/site to determine butterfly presence in the plot.

(Summarised by: Andew Bladon)
Retain connectivity between habitat patches

A replicated, site comparison study in 1998–1999 on 114 wet heathland sites in the Netherlands (WallisDeVries 2004) found that well connected, lower quality habitat patches were more likely to retain Alcon large blue Maculinea alcon populations than less well connected lower quality patches, but connectivity did not affect occupancy of high quality patches. Alcon large blue were more likely to be found in low quality patches if they were well connected to other patches, but connectivity did not affect occupancy of higher quality patches (data presented as model results). A total of 114 wet heathland sites in the Netherlands where Alcon large blue was known to have occurred since 1990 were selected. From mid-July–early September 1998–1999, the size of each habitat patch, area of gentian Gentiana pneumonanthe, and number of reproductive gentians were recorded as measures of patch quality. In each of three 10 × 10 m plots/site, all gentians were counted, 15-minute searches were conducted for host ant Myrmica spp. nests (also for patch quality), and Alcon large blue eggs were counted to determine butterfly presence.

(Summarised by: Andrew Bladon)
Maintain or create bare ground

A replicated, site comparison study in 1998–1999 on 68 wet heathland sites in the Netherlands (WallisDeVries 2004) found that sod cutting to create bare ground did not increase occupancy by Alcon large blue Maculinea alcon. Alcon large blue occupancy at sites with sod cutting (47%) was similar to sites with no management (41%), but was lower when sod cutting and grazing were applied together (26%). Sixty-eight wet heathland sites in the Netherlands where Alcon large blue was known to have occurred since 1990 were selected. Management information for the last five years was obtained by sending questionnaires to land managers. Sod cutting had been used at 57% of sites, normally covering >100 m²/site (range: 10 m² to 2 ha). From mid-July–early September 1998–1999, Alcon large blue eggs were counted in each of three 10 × 10 m plots/site to determine butterfly presence in the plot.

(Summarised by: Andew Bladon)
Employ areas of semi-natural habitat for rough grazing (includes salt marsh, lowland heath, bog, fen)

A replicated, site comparison study in 1998–1999 on 68 wet heathland sites in the Netherlands (WallisDeVries 2004) found that sites grazed year-round by horses and sheep had higher Alcon large blue Maculinea alcon occupancy than sites under other grazing regimes or ungrazed sites. Alcon large blue occupancy was higher in grazed plots (68%) than in ungrazed plots (41%), but was lowest in plots where grazing was combined with sod cutting (26%). Among grazed plots, occupancy was highest under year-round grazing by horses and sheep (77%), intermediate under year-round grazing by horses or sheep with summer grazing by cattle (56%), and lowest under summer grazing by cattle and sheep (29%). Sixty-eight wet heathland sites in the Netherlands where Alcon large blue was known to have occurred since 1990 were selected. Management information for the last five years was obtained by sending questionnaires to land managers. Grazing had been used at 44% of sites, with different livestock and regimes, but always equivalent to about 50 kg/ha/year (further details not provided). From mid-July–early September 1998–1999, Alcon large blue eggs were counted in each of three 10 × 10 m plots/site to determine butterfly presence in the plot.

(Summarised by: Andrew Bladon)