| Coastal Group Plan - Dorset |
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| Extent/Distribution Coastal Sand Dunes Sand dunes are entirely a coastal phenomenon in Dorset. They comprise of windblown sand formations that are both stable and shifting, and their associated slacks, grassland and scrub. The only significant sand dunes in Dorset occur at Studland in Purbeck, which comprise of approximately 204 hectares of dune and associated habitat. This acidic dune system supports a large area of dune heath and is also the only dune system in south central England to support any dune wetland (i.e. open water, mire, swamp, wet heath and wet woodland. The habitats importance for invertebrates, reptiles (e.g. sand lizard, smooth snake) and vegetation is reflected in its designations as National Nature Reserve and candidate Special Area of Conservation. Relict dunes occur at Sandbanks, Hengistbury and Mudeford. Coastal Saltmarsh Coastal saltmarshes comprise the upper, vegetated portions of intertidal mudflats, lying approximately between mean high water neap tides and mean high water spring tides. Saltmarshes are restricted to sheltered locations in estuaries, and the development of saltmarsh vegetation is dependent on the presence of intertidal mudflats. They are an important resource for wading birds and wildfowl. In Dorset by far the largest area of saltmarsh is found around Poole Harbour, with small stands present by the Fleet, at Lodmoor and in Christchurch Harbour. Dorset has suffered less from saltmarsh reclamation than other southern counties, and the upper saltmarsh zone with transitions to reedbed, woodland, mire and grassland is well represented. Coastal Vegetated Shingle Shingle is defined as sediment with particle sizes in the range 2 - 200 mm It is a globally restricted coastal sediment type with few occurrences outside North West Europe, Japan and New Zealand. Coastal vegetated shingle occurs widely around England’s coast, however, large shingle beaches where areas of shingle become stabilised and support vegetation are relatively few. Chesil Bank is one such exceptional shingle structure. It is an internationally important breeding ground for Little Terns, and shingle deposited above high water mark may become colonised by specialist vegetation. Small areas of vegetated shingle also occur in Poole Harbour. Littoral Chalk Littoral and sublittoral chalk is a geological habitat. It is relatively friable (crumbly) and easily eroded. In Dorset this habitat occurs on coastlines formed of calcareous rock, including those areas of chalk subject to inundation by the tide. In general littoral rock tends to be colonised by algae in wave-sheltered conditions, and by limpets, barnacles and mussels as wave-exposure increases. Chalk and limestone can support boring species. There is a distinct zonation of species down the shore that principally reflects the degree of immersion by the tide. Littoral rock areas in the south west also tend to be richer in species than similar habitat in the north and east of Britain. Littoral rock habitats are widespread around the UK, but vary in species richness depending on geology and wave exposure. Littoral and sublittoral chalk is represented by one UK Habitat Action Plan Maritime Cliffs & Slopes The cliffs and undercliffs of Dorset’s coastline comprise soft and hard cliffs. They vary between massive vegetated land slips, high chalk cliffs and pinnacles, grey shales and clays, and sheer limestone faces and ledges. The habitats that develop on the cliffs and slopes are varied, and some of the most natural anywhere in the county. Cliff ledges provide important nesting sites for breeding colonies of birds; of particular note are the guillemot and puffin colonies on Durlston ledges. There is a high proportion of bare ground compared with other habitats, which is utilised by many specialised plant and invertebrate species. Other habitats include maritime grassland, flushes, scrub and supralittoral rock. The coastal cliffs expose a complete section through the upper Jurassic to Cretaceous rock succession, which has earned the site World Heritage status. Mudflats Mudflats are intertidal, soft sediment habitats created by deposition of silts and clays in low energy coastal environments, such as estuaries. Characterised by high biological productivity and abundance of organisms, they provide important feeding and resting areas for migrant and wintering wildfowl. Extensive intertidal mudflats occur in Poole Harbour, an internationally important site for wildfowl and waders. Sea level rise presents a major threat to mudflats Sabellaria alveolata reefs Sabellaria alveolata reefs are formed by the honeycomb worm Sabellaria alveolata, a polychaete which constructs tubes in tightly packed masses with a distinctive honeycomb –like appearance. Reefs are mainly found on the bottom third of the shore attached to a variety of hard or mixed substrates, with an adjacent area of sand for reef building. The reefs bind the underlying substrate, stabilising previously mobile boulders and may increase the diversity of the site. The worm may form large reefs up to several metres across and a metre deep Sheltered Muddy Gravels A coastal/marine habitat that can be subtidal and/or intertidal in nature and found in a variety of salinities. It consists of a variety of mixed sediments ranging from fine silt and mud to pebbles and cobbles.
Coastal Saltmarsh Coastal Vegetated Shingle Maritime Cliffs & Slopes 1. Maintain the extent and quality of the existing resource. 2. Increase the extent of eroding cliffs over time, by allowing natural processes of cliff mobility to continue. 3. Restore natural vegetation where possible, i.e. through removal of non-native species 4. Increase and link areas of clifftop semi-natural habitats. 5. Continue to survey and monitor to improve our knowledge of the habitat. 6. Raise awareness of the wildlife value of the habitat. Littoral Chalk 1. Seek to retain and where possible increase the existing extent of littoral (and sublittoral) chalk habitats unaffected by coastal defence and other engineering works. 2. Continue to survey and monitor to improve our knowledge of the habitat. 3. Raise awareness of the wildlife value of the habitat. Mudflats 1. Maintain the extent and quality of the existing resource. 2. Ensure water quality is sufficient to maintain habitat. 3. Continue to survey and monitor to improve our knowledge of the habitat. 4. Raise awareness of the wildlife value of the habitat. Sabellaria alveolata reefs 1. Maintain the extent and quality of the existing resource 2. Survey to determine the full extent of the habitat 3. Ensure water quality is sufficient to maintain habitat 4. Re-establish/ restore sabellaria alveolata reefs where they were formerly present. 5. Continue to survey and monitor to improve our knowledge of the habitat. 6. Raise awareness of the wildlife value of the habitat. Sheltered Muddy Gravels 1. Maintain the extent and quality of the existing resource 2. Continue to survey and monitor to improve our knowledge of the habitat. 3. Raise awareness of the wildlife value of the habitat. [no information currently available] Losing habitat due to coastal squeeze Impact of recreational activities Fencing off areas of sand dune at Studland. Fleet European Marine Sites (EMS) Steering Group to implement measures to reduce trampling effects. Sea cliff and slope – working with local clubs, e.g. rock climbing guidance, and signs requesting walkers to stick to paths. Debris from human activities (e.g. pleasure craft) Waste disposal facilities provided at ports and harbours. Annual beach clean e.g. Earthkind beach cleans at Poole Harbour. Dredging – may remove important sediment source
from the system Identifying and progressing sites for habitat re-creation Poole Bay coastal strategy identified possible sites in Poole bay for saltmarsh recreation. Monitoring changes in the extent and quality of coastal habitats Poole Harbour study group project on saltmarsh extent and Christchurch Bay strategy studies of Christchurch Harbour. Sabellaria alveolata survey. The effect of estuary dynamics Extent, quality and loss/change of mudflat resource Lack of understanding of sediment exchange processes Input into coastal engineering strategies by English Nature. Awareness of value of coastal habitats – flood defence, fisheries etc Coastal engineering strategies and groups. Chesil and the Fleet SAC Management Plan aims to raise awareness. Policy and legislation Ensure land behind saltmarsh habitat is included in designated site consultation areas.PARTNERS: EN Prepare a Coastal Habitat Management Plan (CHaMPS) for Poole Harbour. Management
{Management}Review how recreational activities may be affecting priority habitats. PARTNERS: Harbour Groups Promote biodegradable products through a publicity campaign and posters at key sites. LEAD: JDMC Develop a clearer understanding of sediment process cells through coastal strategies and CHaMPS. LEAD: EN, coastal engineers Investigate the potential and need to create new mudflats using dredging material. Identify new sites for freshwater habitat re-creation before implementing
saltmarsh creation programme through CHaMPs. Utilise agri-environment schemes for restoration and re-creation
of eligible coastal habitats. Research and monitoring
Extend monitoring of saltmarsh to other areas LEAD: EN Repeat survey of Sabellaria alveolata survey in 5 years time. JDMC Monitor impact of current grazing practises on saltmarsh e.g.
Christchurch Harbour Increase understanding of the effect of estuary dynamics through
coastal engineering studies. Encourage further studies of extent, quality and loss of mudflat
resource to be commissioned through coastal engineering studies.
Education and awareness raising
Increase understanding of sediment exchange processes through further studies. PARTNERS: Coastal engineering groups Biodiversity factsheets of location of habitats and sensitivities to be sent to local planning authorities and coastal groups etc. PARTNERS: JDMC no information currently available |
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