In 2011 the national park was added to the Wadden Sea World Heritage Site, highlighting its intact intertidal ecosystem, importance as a breeding area for many species of birds, and uniquely high biodiversity.

The Zone 1 areas are under special protection, limiting mudflat hiking and horse and carriage rides to designated routes.

Within the national park there are about 2,000 animal species, of which about 250 are endemic to the salt marshes of the Wadden Sea.

Due to the natural influx of sediment, there is a high concentration of food for young fish and seabirds at the mouth of the Elbe.

The approximately 180,000 birds of the north-western shelduck population spends also their moulting period from July to September in the Wadden Sea, which is protected by the three national parks in the states of Lower Saxony, Schleswig-Holstein and Hamburg.