Action Plan: Saltmarsh & Mudflat

Mudflats are sedimentary intertidal habitats created by deposition in low energy coastal environments, particularly estuaries and other sheltered areas. Their sediment consists mostly of silts and clays with a high organic content. Mudflats are characterised by high biological productivity supporting an abundance of invertebrates, such as lugworms, sand mason worms and bivalves. These habitats are important breeding sites for wading birds and winter feeding areas for waders and wildfowl, including wigeon, teal and redshank. They also provide sheltered nursery sites for several species of fish.

Coastal saltmarsh is defined as the upper, vegetated portions of intertidal mudflats occupying the area approximately between mean high water neap tides and mean high water spring tides. Saltmarshes occur on soft, shallow shores in sheltered coastal areas and estuaries. Saltmarsh vegetation consists of a limited number of salt tolerant species adapted to regular immersion by the tides, with a clear zonation of vegetation according to frequency of inundation. Characteristic species include glassworts Salicornia spp, sea aster Aster tripolium and common saltmarsh grass Puccinella maritima. Saltmarsh areas with a high structural and plant diversity, particularly where freshwater seepages provide a transition from fresh to brackish conditions, are particularly important for invertebrates.