Submitted by AJ Cann on Sat, 03/02/2024 - 16:05

Molluscs

Flood debris provides a rare opportunity to find evidence of snails that can be difficult to find. This small pot-full collected from Watermead South revealed 22 different species! More...

Snails are often easier to record from their shells than from the live animals and flood debris can offer a treasure trove of shells. The heavy flow and recent floods that have affected nearly all our waterways pick up shells of aquatic snails and deposit these on land amongst other collected debris. At the same time, the flooding drowns many terrestrial snails and adds their shells to the haul. Look for areas around flooded waterways where branches, vegetation and litter has collected – these accumulations nearly always include a range of snail shells providing a convenient opportunity to identify a range of species from the area.

David Nicholls scooped up a small pot of such flood debris from Watermead South recently and a careful sort through revealed 22 different snail species (plus a few beetles and other invertebrates). The snails included a few unusual species plus a few surprises. Bithynia leachii was new to NatureSpot and with only two previous VC55 records. Two shells of the diminutive Ribbed Grass Snail (Vallonia costata) were found unexpectedly as the books say this is a species of calcareous grassland – a habitat not found in the area! While it is possible that a few shells have been carried there from upstream areas, it is highly likely that most were living in the immediate area. If you do record snails from shells, just add a note to say where you you found them. If you want any help identifying shells, just contact dnicholls@naturespot.org.uk