Surveys of aquatic invertebrate surveys on estates across England

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Surveys of the aquatic invertebrate communities in freshwater habitats across a wide variety of National Trust properties were undertaken over several years, ranging from large lakes, ponds, rivers, streams, springs and small pools in valley mires and marshes. The surveys identified particular species and communities of conservation interest and helped to inform the future management of the various properties.

Surveys were carried out at: Petworth House, Sussex, notable for its large ornamental lake and several ponds; Clumber Park, Nottinghamshire, also notable for its large lake, the lower section of which overlies extensive coal workings and the River Poulter; Cothele House, Cornwall, which contains several small stream catchments draining into the tidal River Tamar; Arlington Court, North Devon, which includes ponds, streams and reaches of the River Yeo; Winkworth Arboretum, in Surrey, which contains two large lakes within the landscape; Killerton House in Devon, which includes a variety of ponds, streams, springs, ditches and stretches of the river Culm across the estate, Langham’s Pond SSSI in Surrey, designated on the basis of its highly diverse aquatic fauna and flora; and Penare Farm, Cornwall, which includes several small stream catchments and valley mires.

More extensive surveys were also undertaken at Loe Pool and along the Wey-Godalming Navigation.  Loe Pool the only natural lowland lake in Cornwall is fed by several stream catchments and has experienced considerable eutrophication in recent decades, leading to a marked decline in the abundance and diversity of its aquatic flora and fauna. In addition to a conservation evaluation, the invertebrate survey at this property was also undertaken to assess the impact of diffuse organic pollution and eutrophication from the surrounding agricultural landscape and treatment works below the town of Helston and at the nearby Culdrose air base. An aquatic invertebrate survey was carried out along the length of the Wey-Godalming Navigation in Surrey, with a boat used for transport between sites and to support sampling within some of the deeper sections. The survey identified some important Odonata and mussel populations along the length of the navigation, as well as alerting the Trust to problems with encroaching invasive species at the lower end, where the navigation joins the River Wey.