Has anyone noticed unusual mortality among Roman Snails, Helix pomatia in the past couple of years? A report of the death of large numbers in the Chilterns, prior to mid-May 2008 by someone (whom we have been unable to contact, and who was carrying out a risk assessment for National Trails) was followed in July 2009 by a report from the mid-Cotswolds of the death of at least 40 out of a population in a cottage garden. In this case the owner was put in touch with me by the Gloucestershire Wildlife Trust; she had been studying the snails for at least 10 years.
It has not been easy to locate reports of deaths of large numbers of these snails. The best (i.e. only) summary I have found was on the Web site for the Animal Diversity Web (ADW) of the University of Michigan, Museum of Zoology: “Nematodes, trematodes, fungi and other parasites are capable of infecting dense snail populations, causing high mortality (“Helix Pomatia”, 2007; U.S. Department of Agriculture, 1998)”
With many thanks to Joan Oakley for the 2009 report, to Alice Paling of the Gloucestershire Wildlife Trust for putting me into touch with Joan, to Alisa Swanson of English Nature for drawing my attention to the 2008 report, and to Martin Willing for suggesting this note.