Geography - The Coastal Zone - Delicate Coastal Ecosystem - Keyhaven Saltmarsh CASE STUDY

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Keyhaven Marsh CASE STUDY

Background

Salt marshes are areas of periodically flooded low lying coastal wetland

Keyhaven saltmarsh is formed in the lee of the Hurst Castle Spit in Hampshire on the south coast of England

Silt and mud is deposited in sheltered areas behind the spit

Deposition continues until mud breaks through the surface forming mud-flats - at this point plants start to colonise the area.

Vegetation Success

Pioneer plants such as cord grass, which are salt tolerant, colonise frequently flooded areas. It has very long roots which prevent it being washed away and help to further trap sediment

As the level of mud rises, rain water can flush out some salt, and decomposing plants can help soli fertility.

Colourful sea lavenders and sea asters can now grow which help to attract more wildlife

In marsh uplands, improved fertility and reduced salinity of soil means scrub and trees can grow.

Wildlife

Saltmarshes are an important habitat for wading birds such as the Oyster Catcher and the Red Shank, and insects such as the Wold Spider

Vital feeding ground for migratory birds such as Brent geese, Dunlin and Grey Plover

Threats

Different users want different things which can cause conflict and damage to the ecosystem.

Management

Education boards and information centres to help people understand the delicate ecosystem.

Parking and sites to concentrate tourists in certain areas which are easier to manage

Monitor grazing to prevent invasive species overgrazing which could damage the area

Footpaths and boardwalks designed to keep tourists on less delicate areas and to protect vegetation

Allow for some areas of managed retreat, allowing areas of farmland to flood by removing walls to reduce pressure on other areas.

Coastal protection with rock barriers and beach nourishment to prevent the spit being overcome by the sea