General characteristics

Marine areas, Sea inlets (60%)

Tidal rivers, Estuaries, Mud flats, Sand flats, Lagoons (including saltwork basins) (35%)

Salt marshes, Salt pastures, Salt steppes (3%)

Coastal sand dunes, Sand beaches, Machair (1%)

Shingle, Sea cliffs, Islets (1%)

Habitats that are a primary reason for selection of this site

Sandbanks which are slightly covered by sea water all the time

This is a sheltered site on the south-west coast of England, with a low tidal range and a wide range of substrates resulting in biologically one of the richest examples of sandbanks in the UK. Sublittoral sandbanks are present throughout much of the ria system and Falmouth Bay. There are particularly rich sublittoral sand invertebrate communities with eelgrass Zostera marina beds near the mouth of both the Fal and Helford and in some channels of the rias, such as the Percuil River and Passage Cove. Of particular importance are the maerl (Phymatolithon calcareum and Lithothamnion corallioides) beds that occur in the lower Fal on St Mawes Bank, and the extensive areas of maerl gravel which extend throughout the Carrick Roads and Falmouth Bay. These are the largest beds in southwest Britain and harbour a rich variety of both epifaunal and infaunal species, including some which are rarely encountered, such as Couch’s goby Gobius couchi.

Mudflats and sandflats not covered by seawater at low tide

This area supports examples of sheltered intertidal mudflats and sandflats representative of south-west England, and is particularly recognised for the importance of the species living in the sediments, including amphipods, polychaete worms, the sea cucumber Leptopentacta elongata and bivalve molluscs. Most of the shores of the Fal and Helford rias, and their upper reaches, are fringed by sandflats and mudflats. Owing to the sheltered nature of the site, the sediments are stable as well as being diverse, and include muds, muddy sand and clean sand. These support particularly rich and nationally important sediment communities in the Fal/Ruan estuary, Percuil River and in Passage Cove, including beds of dwarf eelgrass Zostera noltei and diverse invertebrate communities.

Large shallow inlets and bays

This site is a ria system in south-west England that supports a wide range of communities representative of marine inlets and shallow bays. The rias of the Fal and Helford have only a low freshwater input and as a result the area contains a range of fully marine habitats from extremely sheltered in the inlets to the wave-exposed, tide-swept open coast. There is a particularly diverse algal flora and a number of warm-water species are present. The area supports extensive and rich sediment communities, which include the largest and most south-westerly maerl Phymatolithon calcareum bed in the UK.

Atlantic salt meadows (Glauco-Puccinellietalia maritimae)

The Fal and Helford is an example of saltmarsh vegetation in a ria (drowned river valley), a physiographic type restricted to south-west England and west Wales. There is a narrow saltmarsh zonation typical of rias, from pioneer to upper marsh, and transitions to woodland where the fringing trees overhang the tidal river, an unusual juxtaposition of vegetation in the UK.

Habitats present as a qualifying feature, but not a primary reason for selection of this site



Species that are a primary reason for selection of this site

Shore dock  Rumex rupestris

A rocky-shore site supporting a large, dispersed population of shore dock Rumex rupestris near to the centre of its distribution in south-west England. Three sections of open coastline are included within the site, which when last surveyed (in 1999) supported 12 colonies and at least 34 plants. The site also holds extensive additional areas of suitable habitat.

© Crown copyright. All rights reserved. Natural England [2015].