Individual study: A small population of New Forest burnet moth Zygaena viciae increases dramatically in response to the exclusion of sheep, in Western Argyll, Scotland
Young M.R. & Barbour D.A. (2004) Conserving the New Forest burnet moth (Zygaena viciae (Denis and Schiffermueller)) in Scotland; responses to grazing reduction and consequent vegetation changes. Journal of Insect Conservation, 8, 137-148
The New Forest burnet moth Zygaena viciae is restricted to one small site in the UK, in Western Scotland. Its numbers declined between 1980 and 1990, down to at most 20 adult moths, apparently due to over-grazing. The larvae feed mainly on meadow vetchling Lathyrus pratensis. This study documents the effects of excluding sheep from the site, the location of which is undisclosed.
The site, approximately 1 ha of sloping grassland beneath cliffs, was first fenced in late winter 1990/1991. Damage to fences by wind and rock falls led to some sheep entering the site in early 1994 and again in 1996. From 1997 to 2004, sheep were effectively excluded.
From 1990-1996, the number of New Forest burnet moths remained low, between 0.2 and 1.2 adults/transect on average, with an estimated population between 10 and 24 individuals. From 1997 onwards, numbers increased dramatically, rising to 264 moths/transect and an estimated population size of 8,500-10,200 adults in 2003.