| Estuaries- SW |
|
||
| LBAP Home | Habitats | Common themes |
|
||
| LBAP involvement | 20% | |||
|
SW Resource Breakdown:2
1Action for biodiversity 2SW Biodiversity Audit (1996) |
||||||||||||||||||||
|
Definition1 Estuaries, including harbours and rias, are partially enclosed water bodies which are open to the sea but usually have reduced salinity as a result of freshwater inputs. Rias are drowned river valleys created by land subsidence, a rise in sea level, or a combination of both, forming deep narrow, well defined channels which have a large marine influence i.e. high salinity. Rias are characteristic of the South West, with the Region accounting for approximately 90% of the UK resource. The high salinity and shelter of rias supports a very high biodiversity compared with normal estuaries of lower salinity regime. Major estuarine habitats include intertidal mudflats and saltmarshes, rocky and sandy substrates, subtidal habitats and the water column and surface. Estuarine habitats and organisms covered in this plan are those occurring below Extreme High Water Springs tidal level between the mouth and the upper limit of seawater incursion or tidal influence. There will be complementary coverage within other Habitat Action Plans for the region, including those seagrass beds, rocky seabed, sand dunes, rivers and streams, coastal and floodplain grazing marsh, reedbeds, and urban. Current Extent1 The South West is estimated to contain c16,700 ha of mud and sandflats, representing 8% of the UK total (c200,000 ha) and c2,900 of salt marsh, representing 6% of the UK total (c40-45 000 ha)Examples of important sites in the South West1
Habitat Loss1 Notable historic losses of habitat have occurred in Poole Harbour (harbour construction mid 1980's, marinas in 1980s-1990s) and on the Exe (loss of intertidal mud and salt marsh, and grazing marsh due to construction of the railways in mid 19th Century), Tamar (naval dockyards and other developments over several centuries), Plym (reclamation in 1800s and 1970s), Camel (flood defence), Taw Torridge (agriculture over last 200 years, marinas and flood defence in 1980s and 1990's) Hayle (post 1945 infilling of Copperhouse, land-claim south of causeway) and the Severn (Avonmouth and Portbury docks, Cardiff Bay barrage on the Welsh shore in 1990s). Trends in habitat quality are difficult to assess. Water quality is
generally improving, although nutrient enrichment and heavy metals in
sediments, particularly from old mine workings present problems in some
sites e.g. Fal, Hayle, Tamar. Associated Species1 Mammals
Birds
Fish
Invertebrates
Plants
Current
factors affecting the habitat in the SW
UK biodiversity objectives and proposed targets Conservation direction: Maintain and enhance the extent and quality of estuarine habitats in the UK, including the full biodiversity of estuarine communities.South-west biodiversity objectives and proposed targets OBJECTIVE 1: Protect, maintain and enhance the extent and quality of estuarine
habitats in the South West OBJECTIVE 2 To recreate new fringing habitats through managed retreat where feasible. TARGET: By 2000 A number of planning processes are occurring in parallel with biodiversity plans and set out policies and actions to be delivered by a variety of agencies and organisations: Estuary management plans are in various stages of development on most key sites (Poole, Exe, Salcombe/Kingsbridge, Tamar, Dart, Fal, Camel, Taw Torridge, Severn). Local Environment Agency Plans (formerly catchment management plans) are being developed for catchments and incorporating biodiversity targets. Shoreline management plans, produced by groups of local authorities and agencies (MAFF, EA) set out options for coastal defence; most are in the early stage of development. These should identify areas where there is potential for habitat restoration through, for example, managed retreat. Development plans produced by local planning authorities generally
have protective policies for important wildlife sites and for the coastal
zone, reflecting national guidance and European directives. Saltmarsh creation may be grant aided through the MAFF Habitats Scheme. Many estuarine sites receive some protection through statutory and non-statutory designations and through sympathetic ownership and management. Reserves managed for conservation purposes cover part of many sites
e.g. the RSPB reserves on the Exe, Torridge, Poole, hayle; Local Nature
Reserves e.g. on the Exe; Wildlife Trust Reserves e.g. Exe; National
Trust landholdings - NT is currently targeting estuaries in the Enterprise
Neptune programme; Voluntary Marine Conservation Areas on the Helford
and at Polzeath, St. Mawes, Looe. Policy and legislation
Complete SSSI notification programmes (by 2000) LEAD: EN PARTNERS: NGOs, LAs Designate all sites qualifying as SPAs, and submit list of pSACs to European Commission (By 1998) LEAD: EN, DoE PARTNERS: NGOs, LAs
Ensure that development plan policies do not compromise future opportunities for managed retreat (ongoing) LEAD: MAFF,EN, DoE, LAs, HAs PARTNERS: NGOs, MAFF, EA Management
Ensure that there is minimal reduction in habitat area, and
no decrease in habitat quality, due to development or other activities
(ongoing) Ensure the formulation and adoption of management plans for all
SACs/SPAs (by 2004)
Ensure that agencies with a responsibility for estuarine habitat
management have environmental powers and duties (by 2000) Ensure that coastal management plans (SMPs, LEAPs, CZM) promote 'no net loss' of habitat and identify areas where intertidal habitat creation may be feasible and include re-creation targets (by 2001) LEAD: EN, LAs, MAFF PARTNERS: RIs, NGOs, EA Establish grazing management of saltmarsh habitats where
necessary and feasible (by 1998) Advisory Research and monitoring
Initiate a 5-yearly General Quality Assessment of macro-invertebrates
(By 1998) Continue WeBS counts and provide 5-yearly assessment of trends
for each key site (ongoing) Initiate a rolling programme of marine survey of estuaries (by 2001) LEAD: DWT, EA PARTNERS: MNCRs, RIs Research methods to secure improvements in water quality that maintain the diversity typical of estuarine habitats (by 2010) LEAD: EA PARTNERS: Water plcs Develop technologies to ensure that shellfisheries are managed in a sustainable manner and do not adversely affect biodiversity (2010) LEAD: MAFF, SFCs PARTNERS: ITE,EN, EA, NGOs Undertake research into activities potentially damaging to estuarine habitats and species and means of management to minimise impacts (ongoing) LEAD: DoE, EN PARTNERS: MAFF, ITE, NGOs, LAs
Undertake research into the effects of sea-level rise on estuarine
habitats and species and use results to inform management (ongoing)
Education and awareness raising
Promote appropriate interpretative facilities events and tourism in appropriate plans, e.g. estuary plans, development plans (ongoing) LEAD: LAs PARTNER: EN, NGOs
|
| Home page |
