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Desmoulins Whorl Snails

Volume 451: debated on Monday 6 November 2006

To ask the Secretary of State for Environment, Food and Rural Affairs (1) what assessment he has made of the state of the Desmoulins Whorl snail population in sites of special scientific interest in the UK; (99489)

(2) what estimate he has made of Desmoulins Whorl snail populations at sites of special scientific interest in each year to 2010; and if he will make a statement;

(3) what representations he has received on the effect on the Desmoulins Whorl snail population of the completion of the A34 Newbury bypass;

(4) what the Desmoulins Whorl snail population was in the sites of special scientific interest at (a) Rack Marsh, (b) Boxford, (c) Hunts Green and (d) Bagnor Island in each year since 1997; and if he will make a statement.

Since the public inquiry over the A34 Newbury bypass, knowledge of the Desmoulins Whorl snail distribution, ecology and conservation status has improved considerably. This has been achieved both through research and surveys (contracted by the former English Nature) and work undertaken by members of the Conchological Society of Great Britain and Ireland, including work undertaken in Europe.

The species is much more widespread in the UK than it was formerly thought to be and has been found in new areas of some other European countries. This is likely to be a result of under-recording in the past rather than an increase in its population. It is also less fastidious in its habitat requirements and less restricted to riparian areas than was previously thought.

Its populations fluctuate considerably at individual sites, depending on the wetness of the season and, consequently, its numbers on some parts of some sites of special scientific interest (SSSIs) have been reduced in recent drought years.

Rack Marsh, Hunts Green and Bagnor Island all form part of the Kennet and Lambourn SSSI and Boxford Watermeadow is a separate SSSI. Both sites are assessed as being in favourable condition. Whilst there have been population fluctuations of the snail, including absence on some of the drier areas, healthy populations remain elsewhere in the Kennet and Lambourn confluence floodplain both inside and outside the SSSIs.

This variation is to be expected, given the species' response to the humidity of its environment. Precise numbers are not recorded each year as this would be highly resource-intensive and unlikely to give meaningful results. However the Environment Agency and the Department for Transport have undertaken monitoring in a number of areas in the Kennet and Lambourn confluence floodplain.

This Department has not received any representations concerning the Desmoulins Whorl snail following the completion of the A34 Newbury bypass.