Roman snails are the largest terrestrial land snail in north-west Europe. In the UK they have a limited distribution and are mainly found in southern England with particular hotspots associated with the Chilterns, North Downs and Cotswolds.
Roman Snail Identification
Roman snails have a large shell (up to 5cm across) with a ridged texture, it may be striped but never has a zigzag pattern. They always have a narrow umbilicus (hole) visible and this can be useful feature for smaller specimens. Shells can be variable in colour and some can have more prominent markings than others. Roman snails are the only species that form a calcified white structure over the mouth of the shell during the winter called an epiphragm.
Roman snails are known to live up to 8 years in captivity so in the wild can be much less.
Roman snail ecology
Roman snails are active from late April – May until October each year. Over the winter they hibernate and form a rigid calcium carbonate lid over the mouth of their shell. This is known as an epiphragm and it prevents the snail from desiccating over winter. Come spring this epiphragm is discarded when the snail emerges and their annual cycle of mating and laying eggs begins again.
Romans snails require calcareous soils as they need to consume calcium carbonate to form their shell and it is for this reason that they have probably persisted in areas with an underlying calcareous geology such as the Chilterns etc. They need rough vegetation to provide shelter from predators and food (no particular plant species is required). Loose, friable soil is needed for egg-laying in sunny and open areas.
They are found on a wide range of habitats which include;
Grassland with scrub / shelter
Woodland (edges/open sunny glades)
Hedgerows
Scrub
Occasionally;
Field margins
Former allotments
Rail/road embankments
Quarries
Legal protection
Since 2008 Roman snail (Helix pomatia) has been listed on Schedule 5 of The Wildlife and Countryside Act 1981 (as amended) and is protected in relation to Section 9 (1), (2) & (5) in England and Wales. This legislation makes it an offence to;
Intentionally kill, injure or take (handle) the species
Possess a live or dead Roman snail if it was taken from the wild.
It is not an offence to disturb Roman snail or to damage or destroy breeding places or resting places of this species, however they are known to often move no more than 50m in their life so a licence is often needed to handle Roman snails as part of the mitigation.
When should I get an ecologist to conduct a survey for roman snail?
If records indicate that the species is present in the local area;
Roman snail should be considered if your site is in the Chilterns (particularly Hertfordshire), North Downs and Cotswolds;
If field signs (live snails, empty shells etc) are present;
If the proposed works may kill or injure the species or require them to be moved from the development footprint; and
‘Any intentional moving’ of the species must be licenced. (Natural England Technical Information Note 103).
What do surveys involve?
Normally surveys will involve a walkover of site or a detailed hand search of particular areas to gauge the population size. Survey guidance is not prescriptive but normally surveys include:
Systematic search of vegetation during the day;
Night survey - torching, one hour after sunset.
To maximise the chances of finding active snails surveys should be conducted between late April and September in warm, humid conditions with night time temperatures above 8 degrees.
We will work with you to design a mitigation plan which protects the population whilst allowing your development to proceed. Ecology by Design have worked on a number of projects where Roman snails are present and have successfully secured multiple licences to move the species where necessary. Get in touch if you require advice!