Tomorrow morning we're taking the CalMac ferry to the Scottish inner hebridean island of Rùm in search of rare snails. We're looking for tiny whorl snails (Vertigo species), guided by maps of Schoenus nigricans (black bog-rush, often associated with alkaline flushes), geology, geomorphology, and vegetation cover.
We're looking forward to the challenge of finding these elusive invertebrates, inhabiting highly-localised and specialised niches. We'll be spending five days there from Monday to Friday in the coming week, staying at the bunkhouse in Kinloch, and working alongside ecologist Glenn Norris from Caledonian Conservation Ltd.
The aim of the game is to prospect for previously-unknown populations of rare whorl snail species. The familiar Desmoulins' whorl snail (Vertigo moulinsiana), of Newbury bypass fame, doesn't come this far north, but the other ones do. Narrow-mouthed whorl snail (Vertigo angustior) likes damp maritime grassland; Geyer's whorl snail (Vertigo geyeri) and round-mouthed whorl snail (Vertigo genesii) favours calcareous flushes and fens; Lilljeborg's whorl snail (Vertigo lilljeborgi) inhabits neutral loch edges; alpine whorl snail (Vertigo alpestris) is found in calcareous rubble; and 'cross vertigo' (Vertigo modesta) is an extremely-rare montane species.
With such a lot of ground to cover, it will be a big ask to find any new populations of these rare species. But we will take lots of samples for later analysis; we'll walk different parts of the island, watching for botanical clues to the groundwater chemistry; and here's hoping we see the odd otter or sea eagle too. We'll keep the website, Facebook and Twitter posted with progress and nice pics. Wish us luck!
(Maps courtesy of the NBN Gateway and the BGS).