Nice weather for slugs…

On the 16th of June this year, despite a very poor weather forecast, a small group of hardy volunteers ventured out to WTSWW’s Coed Y Bedw reserve to carry out a survey of the snails and slugs living there. The survey was led by Dr Ben Rowson, a curator at the National Museum, and two members of the Conchological Society; Ron Boyce and Rosemary Hill. The Conchological Society of Great Britain and Ireland is dedicated to the study of molluscs, be it marine bivalves such as mussels, cephalopods such as octopus or the humble garden snail.

Tree slug

Tree slug

Located only 3km north of Cardiff, Coed Y Bedw is an ancient broadleaved woodland of over 16 hectares, spread across both acidic and calcareous soils. It consists of various woodland types ranging from dry beech woodland in the north and west to wet alder carr along the valley bottom.

Beneath the canopy, there is a diverse assemblage of shrubs and flowers, many of which are ancient woodland indicators such as spindle, ramsons (or wild garlic) and bluebells. The area has a rich terrestrial mollusc fauna including species characteristic of old woodlands. Woodlands are a good place to find slugs and snails as they provide the damp conditions that they require with plenty of cover and food.

Slugs and snails may not be the most glamorous of animals but anyone who attended WTSWW’s training course last year, also run by Ben, will attest that they are a fascinating and under-appreciated taxa. And the photo above shows that they can be very attractive too – this is the spotted form of the tree slug Lehmannia marginata, which was one of the species spotted at Coed Y Bedw.

In Britain, there are aaround 100 species of land snail and 35 slug species, but some of these are very restricted in range and others are very difficult to identify without expert help.  Surveying for terrestrial molluscs involves rooting through leaf litter and under stones and logs and amongst vegetation, so the pouring rain on the survey day made it a very damp undertaking!

Despite the poor visibility and wet vegetation and leaf litter, the intrepid surveyors managed to identify 19 species; 12 slugs and 7 snails. 3 of these, including the non-native worm slug Boettgerilla pallens, hadn’t been recorded in this square before so a very worthwhile excursion!