 A rich invertebrate fauna is also associated with the rhynes and ditches including aquatic beetles including populations of two
nationally rare species, "Hydacticus transversalis" and Britain's largest water beetle, the Great Silver Water Beetle "(Hydrophilus piceus)".A number of dragonflies and damselflies are also found in the watercourses including the nationally scarce Variable Damselfly "(Coenagrion pulchellum)".Strong populations of the Common Freshwater Mussel occur as does the nationally rare Pea Mussel "(Pisidium pseudosphaerium)".