Snails in Death's Dingle

By G H Green (identifications checked by J W Meiklejohn).

After a weary morning tramping some very uninteresting arable land in search of flowering plants as part of tetrad bashing for the Worcestershire Flora Project on 15th August, Roger Maskew thought we needed a sight of some unusual and important habitat to raise our spirits. So we went to Death's Dingle! Despite its sombre name the dingle is a beautiful and remarkable place. A stream cuts back into the steep side of the Teme valley and in so doing cuts through the calcareous bands of Psammosteus limestone. The waters that spring from this band are highly calcareous and deposit calcium carbonate on plants, stones and rock, in places forming a softish rock known as tufa. As is often the case limestone brings interesting rare plants and animals. Death's Dingle, other dingles along the Teme, and similar areas along part of the Sapey Brook are known to be important places for flowering plants, ferns and bryophytes, but we have little information on other taxa.

Parts of the dingles are clothed in ancient woodland , and, sadly, many others are wooded with secondary and plantation woodland of conifer, poplar and sycamore. It is likely that some areas were once open tufa marsh, an uncommon and scarce habitat on a European scale (Biron 1999). Nowadays, in some places, the woodland soils contain innumerable fragments of tufa derived from the original carbonate deposits on woodland debris and mosses.

During our visit in August I remarked to Terry Knight that we had recently thought it important to investigate the snails of west Worcestershire limestone areas as they were under-recorded, and the soil we were standing on at the time looked interesting in this context. Being a man of action Terry said something like - "Well, get on with it then!" so we filled a polybag with a few handfuls of soil and woodland leaf litter.

When I washed it out at home I was pleased and a little astonished to see dozens of snail shells, mostly in the 2 mm to 10mm size range. The majority were shells without living snails and must have accumulated over the years. I showed my harvest to John Meiklejohn and he took some to identify and eventually we keyed out the following species (the size and status note according to Kerney (1999):

Acicula fusca Point snail2.2-2.5 mm longIntolerant of human disturbance and declining
Carychium minimum Herald snail1.6-1.9mm longCommon
Carychium tridentatum. Slender Herald snail1.8-2mm longCommon
Lymnaea truncatula, Dwarf Pond snail7-12 mmCommon. Intermediate host of liver fluke
Ena obscura. Lesser Bulin8.5-9mmSomewhat restricted national distribution. Undisturbed shady places
Discus rotundatus. Rounded snail5.5-7mmUbiquitous in moist sheltered places
Vitrea crystallina. Crystal snail3-4mmWidespread
Vitrea contracta. Milky Crystal snail2.2-2.5Common in somewhat dried places than previous species
Nesovitrea hammonis. Rayed Glass snail3.5-4.2Common
Aegopinella pura Delicate glass snail3.5-4.2mmCommon in woodland leaf litter
Oxychilus draparnaudi. Draparnaud's Glass snail11-15mmOriginally Mediterranean. Spreading
Oxychilus cellarius. Cellar snail9-12mmCommon
Oxychilus alliarius. Garlic snail5.5-7mmCommon
Zonitoides excavatus. Hollowed Glass snail5.3-6mmRestricted national distribution, usually in old-established acid woodland!
Zonitoides nitidus. Shiny Glass snailTends to found in wetter areas. Probably declining nationally
Euconulus alderi2.3-2.8mmLocal. Nationally scarce
Clausilia bidentata. Common Door snail9-12mmCommon. Climbs. tree
Trichia striolata. Strawberry snail11-15mmCommon
Cepaea hortensis. White-lipped Hedge snail16-20mmCommon
Helix aspersa. Garden snail30-40mmCommon

Most of these species are fairly common if searched for in woodland litter. The most interesting are Acicula fuscus, a brown almost cylindrical snail with a horny operculum, and Zonitoides excavatus which, according the Kerney (1999) is scarce though probably unrecorded.

Bearing in mind that this list is derived from a few handfuls of soil and litter, and that many common or expected species are "missing" it is likely that the limy Teme valley areas are important for snails and need further study. I already have several bottles of snail shells awaiting identification!

Death's Dingle is near Eastham around grid reference SO670677. A public footpath goes through the wood which is otherwise private property.

References

BIRON L 1999 Tufa springs in Somerset. Nature in Somerset 1999, 32-36.
KERNEY, M 1999 Atlas of Land and Freshwater Molluscs of Britain and Ireland, published recently by Harley Books

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