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Issue 42 August '13

Wednesday 28th August 2013

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Plants and Animals

The West Wight supports a rich and varied range of habitats. The most significant of which are identified below. Click on the links below to learn more.

Maritime cliffs

Calcareous grassland

Estuaries

Woodland

Farmland


Maritime cliffs - The maritime cliffs provide some of the most spectacular landscape features in the West Wight. They support a rich diversity of wildlife, much of which is highly specialised and adapted to the extreme coastal environment.
The structure of the cliffs reflect the underlying geology. Those comprised of hard rocks tend to produce sheer cliff faces, for example around the Needles headland. Slumped cliffs have developed from softer substrates, for example around Compton Bay.
The vegetation of the cliffs is variable. It is dependent upon soil chemistry, cliff stability and water availability. They range from open pioneer groups consisting of a small number of plants, through to species-rich maritime grassland communities. Scrub and woodland are also common components of the cliff habitat in suitable situations, and fen-like vegetation develops around springs and within depressions upon the uneven slumped terraces.
On the southern coast under-cliff is a distinctive feature where land-slip has occurred. These give rise to their own micro-climate and specialist flora and fauna between the inner-cliff and the sea-washed outer-cliff.
In recognition of their high wildlife importance the majority of the maritime cliff is designated under European and UK wildlife legislation. On the south coast the South Wight Maritime SAC covers the majority of the coastline. The majority of the key sites on the north coast are designated as SSSI.


Calcareous grassland - The ridge of chalk which stretches across the West Wight from the Needles in the west to Culver in the east supports some of the richest calcareous grassland communities under maritime influence in south-east England.
The best downland swards are sheep grazed. Typically these comprise grasses such as sheep’s fescue and meadow oat-grass, together with a large number of colourful herbs. These include Salad burnet and wild thyme.
Ungrazed stands tend to be less diverse and dominated by the grass Upright brome. Less extensive, occupying steep drought-prone soils, are more open communities. These are characterised by the presence of Carline thistle, and support a number of nationally scarce and rare species, that include Early gentian and Dwarf mouse-ear.
Other communities of note are the chalk grassland lichen communities at Afton Down and Tennyson Down, the latter believed to be the richest of their type in Britain. In addition to their inherent botanical diversity these grasslands also provide important habitat for a host of other wildlife in particular invertebrates such as butterflies, moths and crickets.
The key chalk grassland sites, such as Tennyson Down, Compton Down and Mottistone Down, are designated under the Isle of Wight Downs SAC.

Estuaries - All of the main rivers within the West Wight discharge into the Solent via the Yar or Newtown estuaries. The Newtown estuary represents one of the best examples in south-east England of a relatively unmodified estuary network containing a diverse range of semi-natural habitats.
The estuary approaches are guarded by shingle and sand spits. Norton Spit at the mouth of the Yar and Hamstead Spit at the approaches of the Newtown estuary are both rich sites and support many specialist plants. These are characterised by Yellow horned poppy, and sea kale, together with a number of nationally scarce species such as Bulbous meadow-grass and Dune fescue. Sea heath, is also found in transitions between shingle and saltmarsh vegetation at Hamstead Spit.
In terms of fauna the shingle support specialist groups of nationally rare beetles whilst birds such as Ringed plover and Oystercatcher use the areas as breeding and roosting sites.
Where sediment from the rivers discharge into the Solent important areas of saltmarsh and inter-tidal mudflat have developed. The two estuaries account for approximately 80% of the Isle of Wight’s total resource of saltmarsh. They tend to be dominated by Common cord-grass, but richer examples displaying the full range of lower, middle and upper marsh plant communities occur around the western Yar and within Newtown Harbour. In these situations nationally scarce species such as Small cord-grass and Lax-flowered sea lavender occur frequently in the lower and middle marshes.
The upper marshes are generally well developed. Having escaped being disturbed by sea walls as is common elsewhere in south-east England, they support other nationally scarce species that include Golden samphire, Marsh mallow, and divided sedge. These areas are also valuable as sites of refuge and a source of food for wildfowl, waders, gulls, and passerine birds, such as Wigeon, Redshank and Skylark. In addition specialist groups of invertebrates are commonly associated with transitions between freshwater and brackish water.
The two estuaries are of international importance for the large number of wildfowl and waders they support. The key feeding ground for many of the birds are the inter- tidal muds which support three species of Eel grass, all of which are nationally scarce.
Saline lagoons are another valuable wildlife habitat associated with the Solent estuarine system and two key sites occur at Yar Bridge and Newtown Quay. Only a limited number of specialist plants and animals can tolerate the extreme saline conditions within lagoons. As a result many are nationally important and protected under the Wildlife and Countryside Act 1981. Theses include Starlet sea anemone and the Foxtail stonewort.
Wetland habitats, including fen marsh, swamp and reedbed, are, with the exception of the latter, a scarce habitat type within the West Wight. The most extensive example occur along the Yar River, and include brackish reedbeds in transitions with saltmarsh, as well as freshwater reedbeds dominated by Common reed, with a range of fen species such as Purple loosestrife, Water dock and Greater pond-sedge. Relatively rich stands of reedbed of this type occur at Freshwater Marshes. The habitat here supports characteristic wetland wildlife that includes species such as Sedge warbler, Reed bunting, and Water vole. In addition the rare Desmoulins whorl snail has been found.
Grazing marsh is an agricultural land type that provides a link between estuary and terrestrial habitats. It is similar in character to wet tussock grassland and represents upper saltmarsh that has been reclaimed to provide grazing for stock on coastal farms. It is confined to an area of land that once formed part of the original Yar meanders surrounding the Thorley and Barnfield streams. The site contains two nationally scarce plants Marsh mallow, and Bulbous foxtail. It also provides important winter roosting and feeding for wildfowl and waders.
The rivers that feed into the estuary systems, despite rising from the chalk, run for much of their length through heavily cultivated farmland on sand soils. As a result of drainage, engineering, poor water quality, low flows, and the geographic isolation of the island, they tend to be poor in aquatic wildlife. However, geographic isolation means the Isle of Wight is the only county in England without a feral mink population. As result water voles are frequent in suitable locations for example Afton Marshes on the Yar River.
The importance of the north coast estuaries for wildfowl and wading birds, and the general high wildlife value of the semi-natural habitats present, is reflected in the raft of international and national designations that cover the area. These include the Solent and Southampton Water RAMSAR and SPA, the Solent Maritime SAC, and the Newtown Harbour NNR.

Woodland - Woodland covers around 10% of the West Wight, a figure close to the national average. A significant proportion of the resource is of planted origin often occurring as copses or plantation among farmland. However, there are a number of semi-natural stands of both recent and ancient origin.
The character of these stands is strongly influenced by the underlying geology, with woodland on calcareous soils tending to be dominated by a canopy of Ash, and a shrub layer comprising abundant hazel coppice. The herb layer typically comprises plants such as Nettle leaved bellflower and Columbine. The parasitic plant Toothwort is particularly associated with calcareous woods.
Woods on the sandy acid soils of the south comprise English oak and birch over bracken. Neutral soils tend to support English oak, Maple, and Ash over a shrub layer of Hazel. Plantations of non-native conifers and broad-leaved species consist of a variety of commercial trees. They have often replaced former ancient woodland, or have been created in grassland and heathland habitats.
Wet woodland is present within the Yar and Newtown estuaries. Alder and Willow species are typically dominant, and often extend down to the edge of tidal marshes. These stands are of high national importance and represent some of the best examples of succession from coastal vegetation to woodland in southern England. Another characteristic woodland type found within the West Wight are those located in suitable locations on the soft cliffs, for example the cliff woods at Bouldnor.
Woodlands of great antiquity (1600AD) are largely confined to the northern half of the West Wight and often contain vernal herbs such as Bluebell, and Wood anemone, together with a number of indicator plants that rarely occur outside of ancient stands, such as Narrow-leaved lungwort, Wild service tree, and Sessile oak.
The woodland resource supports a variety of wildlife of national importance. Particularly characteristic of Isle of Wight woodland is the presence of both red squirrel and dormouse, not found together in any other county in Britain. Other species of importance include Nightingales, Pearl bordered fritillary, Red necked footman, and Wood cricket.
The most important woodland sites in the West Wight are designated as SSSI. These include a number of copses in the Newtown Harbour SSSI, cliff woods at Bouldnor and Hamstead SSSI, and Thorness Bay SSSI, as well individual stands at Northpark Copse SSSI. In addition a series of wet woodland sites are included within the Yar Estuary and Newton Harbour SSSIs.

Farmland - The farmland of West Wight is a mix of arable and pasture, and despite modern agricultural practices being commonplace, supports a great deal of wildlife typically associated with traditional methods of farming. For example the presence of both chalk and dry sandy soils in close proximity has produced a rich arable weed flora that contains many uncommon species of plant.
There is also an extensive network of hedgerows running throughout the farmland landscape. While many older hedgerows have been grubbed out or replaced by ones dominated by Hawthorn, or Blackthorn, some ancient species-rich hedgerow habitat remains. These are particularly well conserved on the clay soils of the north, for example Hart’s Farm near Newtown.
Hedgerows act as a connective corridor for a great deal of wildlife. For example, linking larger blocks of semi-natural woodland together, or as a refuge in otherwise barren landscapes. As a result they are important for a number of farmland birds such as Corn bunting, Linnet and Bullfinch. They also provide key habitat for small mammals such as dormouse, bats and red squirrel. Where a rough grassland strip is left as a buffer between crop and hedge, woodland edge flowers and invertebrates can also flourish.
Another common component of the farmed landscape is improved grassland, managed as pasture for livestock, horses or ponies. It is typically dominated by Perennial rye-grass, and botanically is inherently species-poor. However over wintering birds such as Lapwing, and Song thrush, are often associated with this habitat, and where grasslands of this type form part a network with other farmland habitats, mammals such as badger, brown hare and bats are likely to be found.