The Island has a particularly rich and varied sea cliff resource. It is of national geological and ecological significance for its chalk cliffs and landslips. The coastline is characterised by a wide variety of erosional processes.

Maritime Cliffs and Slopes

The seacliff habitat extends inland along the inner greensand cliff above the Undercliff, which is itself a large, ancient preexisting landslide complex. The inner cliffs supports some of the best Island examples of maritime hard cliff vegetation, principally at the western end of this exposure. The habitats which develop on the cliffs and slopes are particularly varied, dependent upon soil type, ground stability and water source. There is generally a high proportion of bare ground compared with other semi-natural habitats. The vegetation forms a transition from maritime species to terrestrial communities further inland. In addition, soft cliffs on sheltered parts of the coast can develop undercliff vegetation of woodland, scrub, tall herb and rank grassland. There is an unusual example of a perched dune on the clifftop at Chale.

Maritime cliffs are formed at the junction between the land and the sea where a break in slope is formed by slippage and/or erosion by the sea. The slopes formed range from shallow to vertical and vary in height and geology. Soft rock cliffs are characterised by slips, seepages and areas of slumped cliff face that gradually become vegetated. Chalk cliffs are characterised by sheer faces with small, but important, plant communities and ledges that can provide important nesting sites for seabirds. Exposure to wind and salt spray, together with geology, is one of the key determinants of the vegetation type which develops along maritime cliffs.

The seacliffs and slopes frequently support rich and specialised plant and animal communities, many on the northern limit of their range. The combination of friable soils, hot substrates and open conditions maintained by cliff slippages offer a continuity of otherwise very restricted microhabitats and these support many rare invertebrates which are confined to such sites..

Seepages, springs and pools provide the wet muds required by many species of solitary bees and wasps for nest building, and also provide suitable conditions for a rich assemblage of other invertebrates and rare plants. Ponds, which can be transient in nature, are important for breeding amphibia. Chalk cliffs at the eastern and western extremities hold significant populations of breeding seabirds. Cliffs are also important as geomorphological features and for their geological exposures.

Saltmarsh

Saltmarshes are distributed along the Solent coastline within comparatively small estuaries. They form a key component of the Solent and Southampton Waters SPA and candidate Maritime SAC. 80% of the Island resource is concentrated in two sites, at the estuary of the Western Yar and at Newtown. The Medina and East Yar estuaries in contrast have lost much of their semi-natural saltmarshes to reclamation, increasing demand for recreational boating facilities, development of water-side industries and homes, and the natural processes of erosion leading to coastal squeeze.

Mixed saltmarsh is a particularly valuable resource and those in the Solent are notable for their concentration of nationally scarce flowering plant species. Although saltmarshes in the Solent are considered to be generally of recent origin (less than 120 years old), some on the Island, principally in parts of the Newtown estuary, are believed to be much older, and they are not dominated by cord grass. However, the 17 hectares which have developed at Newtown since the breach of the sea wall in 1954 are more typical of the cord grass swards of the Solent coast. The Island’s saltmarshes contribute to the international importance of the Solent as an important resource for wading birds and wildfowl. They act as high tide refuges for birds feeding on adjacent mudflats, as breeding sites for waders and gulls and as a source of food for passerine birds particularly in autumn and winter. In winter they may also be used as feeding grounds for Brent goose, teal and wigeon. Areas with high structural and plant diversity, particularly where freshwater seepages provide a transition from fresh to brackish conditions, can be important for invertebrates. The intimate relationship between saltmarsh vegetation and other coastal habitats such as shingle structures, sand dunes and intertidal flats means that they need to be considered as a functional unit.

Sand Dunes
Sand dunes provide a unique habitat for a rich community of highly specialised plant and animal species. St Helen’s Duver is the best local example; it supports the richest concentration of flowering plants per area of anywhere on the Island. Plant species associated with sandy soils are currently (2000) showing increases in numbers and distribution. Sea buckthorn dune scrub is present on the spit dunes at the entrance to Bembridge Harbour.

Coastal Saline Lagoons

Saline lagoons are a nationally rare habitat, largely confined to the south and east coasts of England, where they are relatively transient features. There are only a limited number of species able to tolerate the extreme conditions found within them; but they include a significant number of specialists which are not, or rarely, found elsewhere. Lagoons possess a characteristic invertebrate fauna that shows little regional variation, even within Europe. In Britain, several of these species are very rare and are protected under the Wildlife & Countryside Act 1981. These include the starlet sea anemone in its type locality, Bembridge Harbour lagoon, and a lagoonal worm.

True lagoons support only three types of aquatic vegetation – stands of green algae, sea-grasses and similar plants, and occasionally stoneworts. The foxtail stonewort, which occurs in the Bembridge Harbour lagoon, is protected under the Wildlife & Countryside Act 1981. However, much of the area of lagoon beds is bare sediment, devoid of vegetation.

Mudflats
Intertidal flats are extremely productive biologically and they can be characterised in terms of their benthic fauna and their ability to support internationally important populations of wildfowl and waders as winter feeding grounds. Typically, twelve species of wildfowl and twenty species of wader regularly use the Island’s estuaries.

Holme & Bishop (1980) split the sedimentary shore communities of the Solent and Southampton Water into five main types: crustacean-polychaete, sandmason worm, lugworm, carpet shell and furrow shell.

• Mudflats are characterised by high biological productivity and abundance of organisms, but low diversity with few rare species. They are also important nursery areas for flatfish.
• Sheltered muddy gravel habitats can be extremely species rich, especially in fully marine conditions, because the complex nature of the substratum supports a high diversity of both infauna and epifauna.
• Intertidal sediments along the north coast of the Island can also support beds of three species of eelgrass and these extend into the sublittoral. All three species are nationally scarce and, additionally, extensive seagrass beds are highly productive because organic material released from decaying grass provides an important nutrient source for marine ecosystems. The plants themselves provide attachment for invertebrates and algae and the stabilised substrate can support a rich infauna. Extensive beds can provide important nursery and feeding grounds for a variety of juvenile fish. Intertidal beds can be a vital food source for brent geese and wigeon.

Estuaries
Estuaries are complex and highly productive ecosystems supporting a wide range of habitats and species. They extend from the river’s upper tidal limit to the sea and form a constantly changing environment where freshwater and marine systems interact.

Traditionally places of human settlement, estuaries provided sheltered harbours, transport and trade routes and the natural resources for industry. Such history provides a backdrop of rich cultural and maritime heritage for today’s activities. Estuaries support a wide range of activities including recreation, transport and industry. This, together with their ecological importance, can often result in conflicting interests and the need for management. There are a range of organisations with statutory responsibilities on land, sea and across the intertidal zone and each has different priorities. In addition, an increasing number of national and international designations, policy and byelaws make management of the estuary as a whole very complicated.

The need to adopt a strategic approach to estuary and coastal management was formally recognised by the UK Government in 1992, following a report by the House of Commons Select Committee on coastal planning. The report highlighted the need for a holistic approach to the management of coastal areas and that coastal users and managers should be encouraged to work together to produce coastal and estuary management plans. On the Isle of Wight, such plans have so far been produced for the Medina Estuary and the Western Yar Estuary. The Isle of Wight Estuaries Project is a joint collaboration between Cowes Harbour Commissioners, Natural England, the Environment Agency, the Isle of Wight Council and Yarmouth Harbour Commissioners. The current focus of the project is the management of the Medina Estuary and the Western Yar Estuary.

The Medina Estuary Management Plan was published in 1997 and is an informal document that complements existing plans and provides supplementary advice and guidance for the Medina Estuary. The plan collated existing data, co-ordinated interest groups and agencies and provided a framework that addresses issues relating to the estuary as a whole. It also sets out agreed management objectives and recommendations and provides a clear statement about the sustainable use of the estuary in the future. Developed under the guidance of a Steering Committee the plan incorporates the work of Topic Groups consisting of representatives from key organisations and individuals with an interest in the estuary. The Plan was reviewed and updated in 2000.

The Western Yar Estuary Management Plan was published in 1998 after extensive consultation with the local community and interest groups. The plan aims to influence the policies and activities of the statutory authorities, provide a means of local input into decision-making and improve communication between statutory bodies, land managers and local interests. It sets out key policy areas, lists the bodies responsible in each policy area and suggests action to facilitate each policy. The Management Plan was initiated by the Yarmouth Harbour Commissioners and was prepared under the direction of the Western Yar Liaison Committee. This Committee is made up of a cross-section of interests including statutory authorities, land owners, local businesses and local people. The Plan was reviewed and updated in 2004.

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