Hurst Castle spit is a shingle spit located on the Hampshire coast close to the city of Southampton.
The Keyhaven Marshes are salt marshes formed in the lee of Hurst Castle Spit.
The landform has been actively shaped by longshore drift for hundreds of years.
Henry VIII built a castle near the tip of the spit to help defend England from possible invasions.
Vegetation and Wildlife Found at Keyhaven
Cordgrass
Spiky, untidy looking grass that grows fast on mudflats.
Sea Lavender
Has attractive, colourful flowers that attract wildlife.
Oystercatcher (bird)
Feeds and nests in salt marshes.
Ringed Plover (bird)
Feeds intertidally and nests on the salt marshes.
Common Blue Butterfly
Resident butterfly, commonly found on higher marshes.
Wold Spider
Clings for hours to submerged stems of cordgrass waiting for low tide and food.
Threats to the Marsh
The salt marsh is retreating by up to 6m a year. The reasons for this aren't fully understood, but further sea-level rise threatens a 'squeeze' of the salt marsh as it lies between a low sea wall built in the early 1990s and the encroaching sea.
The salt marsh has been under threat from the breaching of Hurst Castle spit during severe storms. In December 1989 storms pushed part of the shingle ridge over the top of the salt marsh, exposing 50-80m to the full fury of the sea, which was eroded in less than three months.
Increasing demand for leisure and tourism have meant that increasing numbers of people wish to visit the marshes. Careful management is required to prevent damage by trampling, parking and pollution. The area is popular with mariners who use the many creeks to moor their boats.
For the future, with sea levels expected to rise by 6mm per year, the big issue concerns the 'squeeze' between the low sea wall and the rising sea.
Sustainability
In 1996 rock armour and beach nourishment were used to increase the height and width of the spit in an attempt to stop breaching. Since the completetion of the £5 million defences, the spit has not been breached.
Keyhaven Marshes has been nationally recognised as an important site for wildfowl and wading birds, so is an SSI, and parts are a nature reserve. This means that the area is carefully monitored to manage and maintain its rich biodiversity. Access is limited and development restricted.