Lymington and Keyhaven Marshes Local Nature Reserve

Coastal marshes, lagoons and former salt marshes particularly important for wintering birds

lymington and keyhaven marshes

About the site

Lymington and Keyhaven Marshes Local Nature Reserve is an area of coastal grazing marsh. It lies between the town of Lymington and the coastal village of Keyhaven.

Hampshire County Council began purchasing the area in 1974 when it bought Normandy Farm. Pennington Marshes were bought in 1979 followed in 1984 by Keyhaven Marshes. This far-sighted policy was a response to the rapid rate of development and loss of habitat in previous decades.

Bringing this area into public ownership was the only way to protect it for future generations to enjoy. By 2006 the reserve extended from the mouth of the Lymington River almost to the village of Keyhaven and covered over 500 acres.

The Hampshire & Isle of Wight Wildlife Trust’s involvement in the Lymington area started in 1961, its first year of existence. It entered into an agreement with the Ministry of Public Buildings and Works, to warden an area at the end of Hurst Spit. In the same year 20 acres of salterns at Lymington became a private nature reserve. The Wildlife Trust’s reserve started to expand in 1980 and now encompasses over 700 ha.

Today the combined area of the two reserves covers well over 1200 hectares. It incorporates mudflats, salt marshes, shingle banks, coastal grazing marshes, and saline lagoons. The reserve supports important populations of birds and rare and specialist plants and invertebrates.

Since the construction of the new seawall in the early 1990s the number of visitors to the reserves has increased. Despite this the reserves continue to offer people a great opportunity to enjoy this unique area and its wildlife.

The saline lagoons

Coastal lagoons are bodies of salt or brackish water that are partially connected to the sea through narrow openings or permeable barriers. On the Lymington-Keyhaven marshes the lagoons lie just inside the seawall. They are connected to the sea by sluices. Salt water also percolates through the sands and gravel below. The lagoons vary in size from less that 2m to over 200m in width. For most of their length the lagoons are relatively narrow ditches about 50 cm deep with muddy bottoms.

As well as sea water the lagoons receive freshwater as rainwater, runoff from adjacent land and from nearby streams. The amount of freshwater dilutes the sea water reducing the salinity. In hot weather salinity levels can rise as evaporation removes freshwater. Lagoons show a great fluctuation in salinity and temperature making them a hostile environment for most marine species. Some highly specialised organisms have evolved to take advantage of these conditions. These lagoonal specialists have restricted distributions and are rare. Some species that occur on the reserve are the lagoon shrimp, starlet anemone, lagoon cockle and foxtail stonewort. More obvious residents of the lagoons are birds which use them throughout the year. Species including little egret, teal and little tern feed in the lagoons. Waders such as curlew, sandpiper, dunlin and little stint stop off on their long migratory journeys.

The history of salt making

Archaeological finds show that a sea salt industry has operated in the Solent for at least 2000 years. The industry flourished and by medieval times was firmly established at Lymington. Salt was obtained by impounding sea water in shallow lagoons known as salterns, and allowing evaporation during the summer months to remove the water. This activity was undertaken on land that had been reclaimed from the sea through the construction of a series of sea walls.

The first reference to a medieval salt industry in the Lymington area comes from the Domesday Book of 1086. Salt remained the principle economic asset of the area throughout the middles ages. By the 17th century records show a flourishing economy in the area.

The industry reached its peak early in the 18th century when 163 saltpans were in use at Lymington. Many people were employed during the short late summer/autumn salt making period. The smoke and steam from the boiling houses must have given the marshes the appearance of an industrial landscape. During this period sea salt from Lymington was exported as far as Norway, Newfoundland and the USA.

The 19th century saw the decline of the industry. New rail links to the salt mines of Cheshire meant it was cheaper to dig salt from the ground and transport it around the country than extract it from sea water. The final Lymington saltern closed in 1865.

Today the reserve features the best preserved example of medieval and later salt workings in southern England including Moses, Maiden and Pennington ‘salt docks’. These docks were used for the importation of coal for the boiling houses and export of salt on barges.

Following the demise of the salt industry landowners looked for other sources of income. Most drained their holdings to produce the grazing marshes that exist today. The marshes have been grazed ever since. Parts have had other uses including a short-lived golf course, a rubbish tip and a rifle range.

Habitats on the reserve

Much of the reserve consists of rough grazing marsh. These areas are often flooded and become dominated by rush. They are important for wintering birds and also support populations of breeding waders in the summer months.

On higher ground scrub has developed. This habitat supports many specialist breeding birds including linnet and Dartford warbler.

There is a small area of vegetated shingle at Iley Point which supports a diverse flora. The land here was a former shingle spit connected to the seawall to form Keyhaven Lagoon. There are several small areas of reed bed on the reserve which have developed where the water is not too saline. These support populations of reed warbler and reed bunting.

Contact us

Central New Forest, The Old Courthouse, Avenue Road, Lymington, Hampshire, SO41 9YB

Phone 01590 674656

Email [email protected]