The tidal range results in the estuary having one of the most extensive intertidal wildlife habitats in the UK, comprising mudflats, sandflats, rocky platforms and islands. These form a basis for plant and animal communities typical of extreme physical conditions of liquid mud and tide-swept sand and rock. The estuary is recognised as a wetland area of international importance and is designated as a Ramsar site. The estuary is recognised as a Special Protection Area (SPA) under the EC Directive on the conservation of Wild Birds. The estuary is recognised as a Special Area of Conservation (SAC) under the EU Habitats Directive.