Saltfleetby-Theddlethorpe Dunes NNR
Parish: Saltfleetby and Theddlethorpe
OS: 113 GR: TF 467917 (Rimac entrance) Map ref: 41
Part freehold, part leasehold, part management agreement 1968
Habitat type: Coastland
Also OS 122
Trust: 43 hectares (106.5 acres)
NNR: 556 hectares (1377 acres)
The larger part, 556 hectares, is a statutory National Nature Reserve managed by Natural England. Approximately 38 hectares (95 acres) are managed by the Trust on a licence agreement with the Ministry of Defence. Another 4 hectares (9.8 acres) are leased from Lincolnshire County Council, and the Trust owns about 3 hectares (7.5 acres) comprising the Sea View Field and Rimac Bridge. The total area within the SSSI is 951 hectares. The whole area is managed in close cooperation between the Trust and Natural England.
Location and Access
The Saltfleetby-Theddlethorpe reserve occupies 8.2 km (5 miles) of coast between Mablethorpe North End in the south and Saltfleet Haven in the north. There are six main access points from the A1031 coast road at (from north to south): Paradise (GR: TF 456934), Sea View (GR: TF 465924), Rimac (GR: TF 467917), Coastguard Cottages (GR: TF 478901), Brickyard (GR: TF 483893) and Crook Bank (GR: TF 489882). There are parking places at each of these entrances. Although most of the reserve is open to the public, visitors are requested to keep out of the signed sanctuary areas.
An easy access trail, with display boards, has been constructed at Rimac to allow people of less mobility to see much of the habitat described.
Description and Management
This important reserve contains tidal sand and mudflats, salt and freshwater marshes and sand dunes. On the foreshore, accreting mud and silt flats and saltmarsh in the north give way to a narrower sandy beach at the southern end. The sand dunes are also much wider in the north and there is an extensive freshwater marsh between two dune ridges, which converge into a narrower ridge south of Churchill Lane at Theddlethorpe. The much older landward dunes developed on a storm beach formed in the 13th century. The second ridge on the northern half of the reserve, enclosing the freshwater marsh, developed in the mid-1800s following the diversion of the Great Eau. New dunes are now forming along the southern half of the reserve.
In July and August, the saltmarsh is striking as it is covered with an abundance of sea-lavender. Other plants include thrift, sea aster and the silver-grey-leaved sea-purslane. Extensive samphire beds occur at the seaward accreting side of the marsh. In places at the top of the marsh freshwater species are beginning to colonise. Visitors are advised to be aware of the large creeks in the northern saltmarsh and the danger of rising tides flooding up the creeks; for your safety it is important to check the local tide table.
The old sand dunes support a rich flora, especially where grazing keeps a short turf. A wide range of grasses occur with sand and glaucous sedge, and there are many colourful flowers, including autumnal hawkbit, bird's-foot trefoil, common centaury, field mouse-ear, viper's-bugloss and calcicolous plants such as felwort, fairy flax, carline thistle, and pyramidal and bee orchids. On a few slopes there are patches of the rare sand-dune form of lesser meadow-rue. In the absence of grazing, false oat-grass followed by scrub of sea-buckthorn, elder and hawthorn become dominant. The foredunes are colonised by sand couch and stabilised by marram, sea lyme-grass and red fescue.
The freshwater marsh is of an unusual kind, termed 'maritime fen'. Greater pond-sedge, sea club-rush and common reed are the dominant plants. However, in more open areas and along edges where the vegetation is shorter, there is a great variety of plants, including kingcup, lesser spearwort and yellow flag among the more colourful, with rare or localised species, such as marsh arrowgrass, lesser water-plantain, bog pimpernel, skullcap, great water-parsnip and marsh pea. Marsh helleborine also occurs. In many years a spectacular display of early and southern marsh-orchids and their hybrids can be seen in June.
The commoner grassland butterflies are all found on the reserve, and green hairstreaks are a notable feature of early summer. Moths include a range of marsh and saltmarsh species, some of which are scarce. Dykes and ponds support a variety of aquatic creatures, including dragonflies, beetles, boatmen, skaters and the water spider. Frogs, toads and smooth newts all abound, but the most notable of the amphibians is the rare nocturnal natterjack toad for which this is one of only two Lincolnshire localities. A variety of birds breed, including shelduck, redshank and nine types of warbler. The greatest variety of birds occurs at migration, while in winter birds of prey are attracted by the large numbers of waders feeding on the open shore and berry- and seed-eaters flocking to the shrublands and saltmarsh.
Management has concentrated on re-establishing traditional grazing and hay-cutting regimes to much of the dunes and freshwater marsh. Most of the old dyke and pond network has also been re-habilitated and some new ponds have been dug. This work has been essential in order to maintain the abundant wildlife of the open grasslands and the freshwater marsh. Several acres of sea-buckthorn have been removed from the old dune ridge to allow the rich grass sward to recolonise.