Habitat account - Marine, coastal and halophytic habitats


1210 Annual vegetation of drift lines 

Background to selection

Distribution of SACs/SCIs/cSACs with habitat 1210 Annual vegetation of drift lines.  Click image for enlarged map.
Distribution of SACs/SCIs/cSACs with habitat 1210 Annual vegetation of drift lines. Click image for enlarged map.

Description and ecological characteristics

 

This habitat type occurs on deposits of shingle lying at or above mean high-water spring tides. The types of deposits involved are generally at the lower end of the size range of shingle (2-200 mm diameter), with varying amounts of sand interspersed in the shingle matrix. These shingle deposits occur as fringing beaches that are subject to periodic displacement or overtopping by high tides and storms. The distinctive vegetation, which may form only sparse cover, is therefore ephemeral and composed of annual or short-lived perennial species.

 

In the UK this Annex I type is not always easy to classify using the NVC because it is highly variable between sites and from year to year at the same site. It can include NVC types SD2 Honkenya peploides – Cakile maritima strandline community and SD3 Matricaria maritima – Galium aparine strandline community on stony substrates. MC6 Atriplex prostrata – Beta vulgaris ssp. maritima sea-bird cliff community and other vegetation with abundant orache Atriplex spp. may also occur on shingle shores. Drift-lines on essentially sandy beaches are assessed as sand dune communities (see 2110 Embryonic shifting dunes), and are not included in this Annex I type. However, where drift line vegetation develops on other coarse clastic sediments, such as shell-banks (cheniers), it can be considered as part of Annual vegetation of drift lines.

 

The mobility of shingle foreshores is an overriding consideration, and colonising species are able to tolerate periodic disturbance, which may involve the total removal of the surface and subsequent recolonisation with vegetation. Species are also tolerant of saltwater inundation, as the beaches are often over-topped by the tide or subject to spray from waves breaking over the beach. Level or gently-sloping, high-level mobile beaches, with limited human disturbance, support the best examples of this vegetation.

European status and distribution

 

Annual vegetation of drift lines has a wide distribution in the EU, and has been recorded from Mediterranean coastlines in southern Europe north to the coasts of Sweden and Finland.

UK status and distribution Click to view UK distribution of this habitat

 

Approximately one-third of the UK coastline is fringed by a shingle or sand/shingle beach, but much of this is too dynamic to sustain drift-line vegetation. Many of the fringing beaches with drift-line vegetation are small, and annual vegetation may exist in one location in one year but not another. Therefore, although widespread around the UK, sites where this Annex I type is persistent are rare, and even the largest sites probably support less than 10 ha of this habitat. At most sites the habitat is naturally species-poor, and there is a limited range of ecological variation.

Site selection rationale

 

The ephemeral nature of this habitat type has been taken into account during site selection. Sites have been selected to reflect the more constant occurrences of drift-line vegetation found in association with larger, more stable areas of shingle structures. The selected sites represent the majority of the more persistent examples of this habitat type in the UK. They all exhibit good conservation of structure and function (i.e. they are relatively unmodified and are less prone to human disturbance) and represent the range of variation in substrate type and physical structure.


Site accounts

Chesil and the Fleet Dorset and Somerset
Chesil Beach is a large (28 km-long), relatively undisturbed shingle bar, and is one of two representatives of Annual vegetation of drift lines on the south coast of England. The inner shore of the beach supports extensive drift-line vegetation dominated by sea beet Beta vulgaris ssp. maritima and orache Atriplex spp. This community exists in a dynamic equilibrium with the perennial shrubby sea-blite Suaeda vera community typical of 1420 Mediterranean and thermo-Atlantic halophilous scrubs (Sarcocornetea fruticosi), for which this site has also been selected.
Dungeness Kent, Surrey, East and West Sussex
The Dungeness foreland has a very extensive and well-developed shoreline, although with sparse vegetation and in places some human disturbance. It is one of two representatives of Annual vegetation of drift lines on the south coast of England. The strandline community on this site comprises Babington’s orache Atriplex glabriuscula, which occurs mostly on the accreting eastern shoreline, although it is also present on the eroding southern shoreline.
Minsmere to Walberswick Heaths and Marshes East Anglia
This site is one of two representatives of Annual vegetation of drift lines on the east coast of England. It occurs on a well-developed beach strandline of mixed sand and shingle and is the best and most extensive example of this restricted geographical type. Species include those typical of sandy shores, such as sea sandwort Honckenya peploides and shingle plants such as sea beet Beta vulgaris ssp. maritima.
Orfordness - Shingle Street East Anglia
Orfordness is an extensive shingle spit some 15 km in length and is one of two sites representing Annual vegetation of drift lines on the east coast of England. In contrast to Minsmere to Walberswick Heaths and Marshes, drift-line vegetation occurs on the sheltered, western side of the spit, at the transition from shingle to saltmarsh, as well as on the exposed eastern coast. The drift-line community is widespread on the site and comprises sea beet Beta vulgaris ssp. maritima and orache Atriplex spp. in a strip 2-5 m wide.

SACs/SCIs/cSACs where this Annex I habitat is a qualifying feature, but not a primary reason for site selection

Dee Estuary/ Aber Dyfrdwy Cheshire, East Wales, Extra-Regio, Merseyside, West Wales and The Valleys
Isle of Portland to Studland Cliffs Dorset and Somerset
North Antrim Coast Northern Ireland
North Uist Machair Highlands and Islands
Rathlin Island Northern Ireland
Sidmouth to West Bay Devon, Dorset and Somerset
Solent Maritime Extra-Regio, Hampshire and Isle of Wight, Surrey, East and West Sussex
South Uist Machair Highlands and Islands
Strangford Lough Northern Ireland
 

Many designated sites are on private land: the listing of a site in these pages does not imply any right of public access.