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By Chris du Feu

The Conchological Society of Britain and Ireland organises monthly field meetings for members. One of the aims of these meetings is to add to our knowledge of the distributions of the country’s 200 or so species of land and freshwater mollusc. The known distributions of all our species are published in the 1999 Atlas of Land and Freshwater Molluscs of Britain and Ireland (ISBN 0 946589 48 8). The basis of recording is the 10 kilometre square. If a species has been recorded in that square, there is a dot in it, otherwise it is blank. Beckingham sits at the North-east corner of square SK78 with Retford at the South-west corner.

North Nottinghamshire is one of the least well recorded areas in England. The Conchological Society Field Meeting of September 2007 aimed to look at a variety of habitats within the parish. We managed to visit several habitats – the flood plain at Morton Tongue, the Old Willow Works, a garden in the village and two patches of woodland – Beckingham Wood and Dogs Hole Wood.

Molluscs are more active in damp conditions – as many gardeners have noticed during the long, wet summer. However, this meeting followed a very dry spell. After the wonderfully good mollusc hunting conditions which had prevailed over the summer, we were faced with very dry ground. Molluscs were very hard to find, many having hidden themselves deep in crevices or underground to avoid the heat and dryness. A measure of the difficulty of finding molluscs was the slug count in the garden – only 5 species of slug compared to the total of 20 I had recorded over the last decade.

Overall 44 species were recorded, some seen in several of the habitats. Of these, 12 will give new 10km records for the national distribution map. Two more species were listed in the atlas only as having been recorded here as fossil shells – not the living animals we found on the day. Looking at the known distributions of the species found, it seemed that we were filling gaps in a much under-recorded area, with most species we found being known in adjacent, better recorded 10km squares.

Perhaps the most interesting finds was the tiny Prickly Snail, Acanthinula aculeata. This one which had only previously been found in fossil form. Even full grown it is no more than 2 millimetres in diameter when full grown, the shell is covered in tiny spines.

These are only visible under a magnifying lens. No wonder it is not often seen except by the dedicated mollusc hunter. Ancient woodland should be a rich habitat for molluscs. On the day, Beckingham Wood was reluctant to reveal its mollusc fauna. There were large cracks in the clay soil and the molluscs were, no doubt, lurking out of sight in these chasms. On the other hand, the Willow Works – apparently less unpromising produced a good number of species. The apparent relative richness of the Willow Works is, perhaps, explained by the two habitats represented there – the nearby land drainage ditch and surrounds of the building, much influenced by human activity including extensive use of limestone hardcore in the past. The Willow Works also revealed a rather surprising heap of shells. This included a few large tropical land snails and and a number of tropical coral reef species. It would have been nice had it been the fossilised remains of some prehistoric tropical reef. Alas, it was less exciting – just a discarded shell collection. These records, of course, will not be included in the national map; not even as records of ‘shells only’.

Please click on the following images to view a larger image:-

Please click here for a short video clip of “Elvis” in motion!
Typically, after the long, dry spell the autumn rain began falling the next week.
Thanks are due to various landowners for permission to visit the sites: Paul Hemsley (Beckingham Wood), Mrs Tomlinson (Dogs Hole Wood), Andy Crawford of Environment Agency (Morton Tongue), Beckingham History Group (Willow Works).

Results of Conchological Society Field Meeting

Species Dogs Hole
Valvata piscinalis P P
Potamopyrgus antipodarum P
Bithynia tentaculata P
Carychium minimum N
Carychium tridentatum F
Galba truncatula N
Radix balthica P P
Anisus vortex P N
Gyraulus albus P
Succinea putris N P N
Oxyloma elegans P
Cochlicopa lubrica P P P P
Columella edentula N
Lauria cylindracea N P
Vallonia costata P
Vallonia excentrica P
Acanthinula aculeata F
Discus rotundatus P P P P P
Arion ater agg P P
Arion distinctus P P
Arion intermedium P P P
Vitrina pellucida P
Vitrea contracta P P
Aegopinella nitidula P P P P
Oxychilus cellarius P P
Oxychilus alliarius P P P P P
Oxychilus helveticus N
Zonitoides nitidus N
Tandonia budapestensis P
Limax maximus P
Limacus flavus P
Deroceras reticulatum P P P P
Deroceras panormitanum P
Clausilia bidentata P
Candidula intersecta N
Monacha cantiana P P
Ashfordia granulata N
Trochulus hispidus P P P
Arianta arbustorum P P
Cepaea nemoralus P P P P
Cepaea hortensis N P P
Cornu aspersum P P

Key to species table:
P – already known from 1999 Atlas
F – only fossil records in 1999 Atlas
N – new 10km square record

Note that the scientific names of species are given. Very few species have familiar English names – usually being regarded simply as ‘slugs’ or ‘snails’. The images show some of the more photogenic finds.

More information about the Conchological Society can be found at www.conchsoc.org

The Yellow Slug

The Yellow Slug (Limax flavus) is fairly common but not often seen as it is highly nocturnal. It feeds on lichen and algae and some other decaying matter. It is definitely not a pest. Individuals all have markings as individually identifiable as human finger prints. At this time of year they emerge at about 22:00. Those that feed on lichen on the roof take about an hour to climb the house walls. They then feed on the lichen on the roof tiles for about 3 hours before returning to ground level – another hour’s journey to be back lurking somewhere cool and dark before first light at around 04:00. The picture (right) shows what they can do – a trail of their tooth marks clearly visible in the green slime on a picnic table.

The image below was a rare daylight glimpse of the Yellow Slug that was found under a shrub in a domestic garden.

On 4th August 2008 BBC Nottingham local news featured Beckingham and its slugs – click here to be directed to the story on the BBC Nottingham web page.