Nature Reserve Habitats
There are several important aspects which increase the diversity of habitats within the area.
Across the site there is a wide range of;
- WATER LEVEL
- LAND MANAGEMENT
- FLOODING BY THE SEA
- EXPOSURE TO SALT-LADEN WINDS
The main habitats of the SSSI can be broadly divided into ten types.
- Reclaimed Saltmarsh
- Drainage Ditches
- Shingle Ridges
At low tide there is an extensive area of sand and mud with shallow pools that is continually changing in structure and form, depending on tides and weather. The area varies with the tidal cycle, with about 105 hectares at mean low water. This is an important feeding and roosting site for waders, terns and gulls. The exposed nature of the foreshore means that few plants can maintain a foothold and there are few signs of invertebrates at the surface, except for the casts of Lugworm and the tubes of the Mason worm. However, there is a rich invertebrate fauna living below the surface, for example, Sea Mouse, Baltic Tellin and Lugworm. The latter is abundant in the intertidal mud of the open shore and provides a source of bait for fishermen, with bait digging providing several people with an income. The shrimps are common in the shallow water over sand just offshore and during the spring and summer several people use wide nets to catch shrimps for food. At the River Mouth the sea defences provide a hard substrate for some rocky shore species, for example, the Beadlet Anemone, Serrated Wrack and Channelled Wrack, a regionally rare species. The commercial fish stocks of Rye Bay have declined during the last 50 years following the more efficient methods employed by fishing boats, but there is still a small fishing fleet based in Rye and some shore fishing by rod and keddle netting.[ Back to top ]
Along the River Rother, at the higher part of the intertidal zone there has developed a saltmarsh habitat that is dominated by Borrer's Saltmarsh-grass, Stiff Saltmarsh-grass, Sea Purslane and Sea Aster. On the highest part of the saltmarsh, only occasionally covered by the sea, grows Sea Heath and Sea Wormwood and on the lowest part, in the mud that is covered by most tides, grow several species of Glasswort. These specialised plants are the food of some scarce invertebrates, including Crescent Striped Moth, many micro-moths and beetles. This type of habitat was once extensive, covering much of the river levels and Romney Marsh, but due to flood defences is now restricted to a very narrow strip along the river. Now 13 hecatares lies within the Nature Reserve, including the Wader Pool where a further hectare was created in 1991 by controlling the access of the sea into a prepared scrape and now a further 6.4 hectares beyond on the Flat Beach where the sea water flows from the Wader Pool (since 2003). This has been successfully colonised by many saltmarsh species including Glassworts, Annual Sea Blite, Sea Aster and Corophium volutator, a small shrimp that is the favoured food of Redshank.[ Back to top ]
Where the water table is close to the ground level there is the potential for the development of a marsh habitat. The vegetation is dependent upon the salinity, soil type and the degree of grazing, so within the Nature Reserve and SSSI there is a wide variety of marsh habitats: rushes tolerate grazing, whereas reeds grow where there is none. Reedbed is important for several species of bird – Reed Warbler, Bearded Tit, Water Rail and Bittern – as well as many rare species of invertebrates (the moths include, Chilo phragmitella, Schoenobius gigantella, Donacaula mucronellus, Reed Dagger, Southern Wainscot, Obscure Wainscot, Flame Wainscot, Twin-spotted Wainscot, Brown-veined Wainscot, Fen Wainscot and Silky Wainscot).[ Back to top ]
By the construction of embankments and the digging of drainage ditches it has been possible to exclude the sea and cultivate the alluvial deposits of the old saltmarsh. The major form of agriculture was and remains sheep grazing, although large areas have been cultivated in the past, especially during the 1939−45 war. Since the 1970's there has been an increase in arable agriculture with some ditches filled in and field drainage installed. Although these areas are generally species poor, they provide valuable areas for some species: in winter large flocks of Lapwing, Curlew and Golden Plover feed on the invertebrates of the pasture, while Grey Partridge, Corn Bunting, Tree Sparrow and Mute Swan spend much of their time on the arable areas.[ Back to top ]
The reclaimed saltmarsh areas are drained by a network of ditches, some of which follow the line of the old saltmarsh creeks. Most are regularly cleaned mechanically, but still contain an interesting variety of the wetland flora and fauna, including the Water Vole. Although there has been some infilling of ditches in the SSSI during the last twenty years there is about 22 kilometres remaining. Some ditches are dominated by Reed, some by Branched Bur-reed and other, more saline ditches by Sea Club-rush. Many ditches dry out in some summers and this keeps the fish population low, which in turn enables a high population of amphibians and aquatic invertebrates to survive, for example more than 100 species of water beetle, including the largest, the Great Silver Diving Beetle.[ Back to top ]
There are three types of shingle ridges within the SSSI:
i) Natural, bare ridges
Where the form and structure of the ridges are natural there is very little soil and it is only possible for a very few, highly specialised, plant species to colonise, for example, Sea Kale , Sea Pea, Sea Campion and Curled Dock. Similarly the invertebrate fauna is highly specialised, for example, the rare flea beetle Dibolia cynoglossum is found only on Red Hemp-nettle. The ridges are also the preferred habitat of nesting Little Tern, Oystercatcher and Ringed Plover. These natural ridges are characterised by a smooth rounded form, a grading of stone size with little material between the stones. Over very many years material accumulates (by exceptionally high tides and wind blown debris), especially at the base of ridges and more species become established, for example, Vipers Bugloss, Yellow-horned Poppy and the maritime sub-species of Herb Robert. The Viper's Bugloss is an important plant for several rare invertebrates, the micro-moths Ethmia bipunctella, E.terminella and Cynaeda dentalis and the weevil Ceutorhynchus geographicus. Where the shingle is not disturbed, a rich Lichen community develops which builds up the soil for other plants to grow in the shingle. This Lichen community is home to many invertebrates including a rare moth, the Pygmy Footman.
ii) Natural, vegetated ridges
After hundreds of years a thin soil has developed on the old shingle ridges (although this may have been encouraged by past land management to increase the area for grazing) and a variety of grassland plants have established, Buck's-horn Plantain, Stemless Thistle, Stork's-bill, Smooth Cat's-ear, Sand Spurrey, Gorse and fifteen species of vetch and clover, including the rare Clustered Clover. A few bare areas do still exist, but in some cases this is due to more recent damage. The thin soil, overlying shingle, dries out very quickly and consequently the plants must be adapted to regular periods of drought. For the invertebrates, such as the Girdled and the Hairy Legged Mining Bees the thin, dry soils on the ridges warm up quickly and there is a good source of nectar.
iii) Damaged ridges
Where shingle has been disturbed or removed to a level above the water table, there is a succession of plants that is different to that of the natural ridges. Relatively quickly a wide variety of species colonise so that bare shingle remains in only a few areas where there is little sand between the stones. In several places sand has been added to flattened areas (along the old railway, the roadway and on the sites of fishing huts) and these are particularly rich in grassland species such as Danish Scurvy Grass, Bird's-foot Trefoil, Rue-leaved Saxifrage and the rare Least Lettuce.[ Back to top ]
Where shingle was extracted to a level below the water table there have developed important wetland habitats that partly replace the natural wetland that once occurred here. An important aspect of their interest is a very wide range of salinity within the SSSI. There is about 77 hectares of open water. New pits are rapidly colonised by a rich variety of aquatic flora and fauna but, as the vegetation develops around the margin, some of the pioneering species are lost, for example the three rare beetles Spangled Button Beetle, Cercyon bifenestratus and Heterocerus hispidulus are dependent on bare sand at the margin of still, fresh water. If left unmanaged the pit margins often develop a fringe of Reed or Reedmace, which in time may be shaded out by Grey Willows. The variety of water depth is attractive to many wildfowl throughout the year; diving duck prefer the deep water of the pits, while the dabbling duck prefer the shallows and margins. At Castle Water the Nature Reserve has modified the steep margins to create gentle gradients that favour some wetland wildlife. Some pits have islands which are a safe haven for nesting or roosting birds. At Ternery Pool the islands have been managed to provide suitable nesting sites for terns and gulls.[ Back to top ]
In a few areas the soil is sandy. On the Beach Reserve, near the River Mouth, there is a small dune of wind blown sand from Camber Dunes, just across the River Rother. At Castle Farm, near the farm buildings there is an extensive ridge of sand. Plants associated with this habitat include Thyme-leaved Sandwort, Sea Sandwort, Sand Sedge and Sand Couch Grass. At Castle Water the extensive sandy areas are mainly man-made, resulting from the large quantity of washings from the shingle extraction process. Here the grassland is particularly interesting and in some areas bare sand dominates with rosettes of Stork's-bill, this is the habitat of the rare weevil, Limobius mixtus – Castle Water is its only known British site.[ Back to top ]
The development of scrub is restricted by management, especially by grazing and cultivation. There are areas of Gorse, Hawthorn, Bramble, Elder, Blackthorn and Sea-buckthorn scrub at Castle Water, Castle Farm and the Beach Reserve. These are important sites for invertebrates and birds, including nesting Linnet and Whitethroat.[ Back to top ]
Trees would dominate much of the area if it were not for management, especially by grazing and cultivation. Where these activities have not taken place for very many years, for example, on some islands at Castle Water, there is a dense growth of several tree species, including White and Grey Willows and Birch. These are a favourite nest site for Cormorants and roosting site of Little Egrets and Long-eared Owl.[ Back to top ]