Estuaries are highly productive ecosystems that form where rivers enter the sea: in Wales, this is often signified by the Welsh place name having the pre-fix ‘Aber’ and followed by the name of the river, e.g. Aberystwyth, Aberdyfi etc. The larger, fully developed, saltmarsh systems, e.g. the Severn Estuary, the Dee Estuary and the Burry Inlet can host a wide range of saltmarsh habitats, including the ‘Atlantic salt meadows’ and ‘Salicornia and other annuals’ Annex I habitats on the EC Habitats Directive. These and the other major saltmarsh habitats are described in the sections below.