NatureScot Commissioned Report 617: Geyer’s whorl snail (Vertigo geyeri) surveillance on Islay 2012

This work aimed to monitor and report on the condition of V. geyeri populations and their habitats on Islay. Surveying was therefore undertaken at sites on the north (near Bunnahabain, on the margins of Loch Lossit and at a series of sites to the west of Loch Finnlagan) and on the south Islay (Loch Ard Achadh on The Oa). Presence of Vertigo geyeri was confirmed at five of the former sites: Loch Smigedail, Margadale River, Loch Lossit, Loch Finnlagan and Loch Ard Achadh. The snail was not found at the Ballachlaven sites, although habitat conditions at the main calcareous flushes did not seem to have changed since surveyed in 1996 and indeed appeared to be still ideal. Some habitat deterioration was observed at Loch Ard Achadh and half of the Finlaggan sites; fen or flush habitat had been very closely grazed by cattle and ‘poached’ by hooves, which created large areas of bare ground. Lower flush water flows at both sites were considered to have contributed to this problem. Measures to address habitat damage at Loch Ard Achadh and some of the Finlaggan sites are discussed, including the suggestion of a temporary electric fence around flush areas. For all sites, there should be clear and recorded communication with landowners/ tenants to inform them of the presence of this vulnerable species on their land and measures to conserve it.

Pages: 41
Published: 2013

NatureScot Commissioned Report 617