Large-mouthed Valve Snail Valvata macrostoma

The Large-mouthed Valve Snail (Valvata macrostoma) is a scarce aquatic snail of shallow, clean, well-vegetated ditches and grazing marsh drainage systems, associated with good water quality and stable, undisturbed hydrology. It has declined across Britain due to drainage improvements and deteriorating water quality, and is now largely confined to a small number of areas with traditionally managed coastal and riverside grazing marsh. Suffolk’s coastal levels and grazing marsh systems – particularly those associated with the estuarine river valleys – provide potential habitat. It is a good indicator of high-quality ditch systems with long management continuity and is associated with other scarce aquatic invertebrates. Image: Francisco Welter Schultes, public domain, iNaturalist.

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