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Threatened Species - Ram's Horn Snail

Ram's Horn snails are all shaped like a flat coil, or the horn of ram. They tend to live in unpolluted, usually calcareous water in the ponds and drains of grazing marshes and are often associated with a rich variety of freshwater molluscs, including other rare species. It favours shallow ditches often choked with a rich, diverse flora. Low intensity management and preservation of traditional grazing marshes may be keys to the survival of the species. It is often associated with a rich variety of freshwater molluscs.

It can be found locally throughout Europe, northwards to southern Scandinavia but are now in serious decline in the UK. A national survey in 1996 found good populations in Norfolk, Sussex and east Kent. The reasons for decline are not clearly understood but the main threats are believed to be: over-frequent ditch clearance, eutrophication due to fertiliser run-off, and conversion of grazing levels to arable farming with associated water table lowering.

Protection of the species requires a change in farm management practices. Total ditch clearance should be avoided. Ditch management on a 7 year rotation, partial ditch clearance by dredging only one side and not clearing adjacent ditches in the same year are recommended.

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