Field meeting to Llandudno – the Limestone Pavements

The pavements examined on the Great Orme were divided into five discrete segments, three of which are in SH7583 and a further two in SH7584. The combined total of species found within the five areas of limestone pavement came to 19.

The limestone pavements on the Great Orme are free of tree cover and thus exposed to both the heat of the sun, winds and even salt spray during violent winter storms, even though they are situated at a height of over 170 metres. In contrast the limestone pavement examined at Bryn Pydew is situated within a wooded glade part of which had been covered by scrub, as evidenced by the recent clearance of part of the site. The pavement at this site produced a total of 20 species.

The combined list of 26 species occurred within the two contrasting sites (see summary table). Some of the differences can be explained by the hot dry conditions. If, for example, we remove the three species of Arion found in the more shaded site at Bryn Pydew in SH8179, all three of which would probably occur on the pavements on the Great Orme in wetter conditions, the two sites have very similar numbers of species. However, it is more difficult to explain the absence of Clausilia bidentata, Deroceras reticulatum and Nesovitrea hammonis in the more protected site at Bryn Pydew.

345 records of 54 species were accumulated over the period both at the meeting itself, as well both before and after the official dates, and by members travelling to and from the venue.

I would like to take this opportunity to thank the various staff at the Countryside Council for Wales for all their help in supplying maps and other practical details and for expediting our request for permits.

figure 2: Bryn Pydew limestone pavement.

figure 3: Cecilioides acicula at Bryn Pydew. (photo: Peter Topley)