Mudflats and saltmarsh
Sand, mud and gravels are the most common habitat found at the intertidal zone around the coasts of the UK. They occur in a wide range of coastal environments, from sheltered bays and estuaries to exposed open coast. These habitats support a diversity of marine life including mollusks, polychaete worms, and crustaceans. They are also important breeding grounds for species of tern.
There are 38m of coastline forming the eastern boundary of the Tees Valley area. Some of this consists of coastal cliffs. However, a large proportion of this is shingle beaches with areas of sand and mud flats. These provide important nesting sites for little tern and ringed plover and important feeding grounds for sanderling, ringed plover and oystercatcher.
Saltmarsh occurs on soft, shallow shores in sheltered coastal areas and estuaries. It generally occupies the upper, vegetated portions of intertidal mudflats, lying approximately between the mean high water neap tides and mean high water spring tides. Characteristic species include glasswort, sea aster and common saltmarsh grass. The plant species found in saltmarsh show a clear zonation according to the frequency of inundation by tidal waters. Saltmarshes are important feeding ground for migrating and wintering bird species, including widgeon, redshank and teal. Saltmarshes support a specialized invertebrate community, many of which are confined to saltmarshes and are nationally scarce.
Saltmarshes are widely distributed around the UK coastline, with an estimated 45,500 ha. However just over 10 sites account for 60% of this total area.
In the Tees Valley Saltmarsh is a rare habitat, occurring in fragmented areas around Teesmouth. The extent of land reclamation on the Tees Estuary has reduced this habitat to a narrow belt in most areas. Key sites include patches along Greatham Creek, Seal Sands and Greenabella Marsh.
