1441 Shore dock Rumex rupestris
Description and ecological characteristics
Shore dock Rumex rupestris grows on rocky, sandy and raised beaches, shore platforms and the lower slopes of cliffs, and rarely in dune slacks. Plants can be found growing in isolation on the strand-line, through to tall-herb perennial communities at the base of flushed cliffs. However, it occurs only where a constant source of freshwater, running or static, is available. It is most commonly found growing by the side of streams entering beaches, on oozing soft-rock cliffs, and in rock clefts where flushing occurs. Populations of shore dock are known to fluctuate according to the severity of winter storms.
Culverting of streams, coastal defence, and boat-ramp construction on beaches have altered many of the shore dock’s former localities, making them unsuitable for its survival by separating perennial vegetation at the bases of cliffs from the strand-line community and interfering with the natural geomorphological processes of slumping cliffs and streams entering beaches. Visitor pressure appears to be a significant factor in the decline of shore dock at several sites. A high proportion of the UK localities for this plant are owned by conservation bodies or public authorities, so favouring the maintenance and enhancement of populations at these localities. Other measures to promote species recovery have also been undertaken, including its attempted reintroduction at three sites in Devon and Cornwall.
European status and distribution
Rumex rupestris is one of Europe’s most threatened endemic vascular plants. Outside the UK, it is restricted to the coastal margins of Normandy and Brittany in France and Galicia in Spain, where it is declining and in low numbers. The UK is the world stronghold for this species.
UK status and distribution
In the UK, Rumex rupestris is currently known from about 40 locations in south-west England and Wales. The species is extinct in the former easternmost part of its range in Dorset. Several new colonies have been found in recent years as a result of systematic surveys of coastlines with suitable habitat in south-west England and south and west Wales. Population size varies greatly between sites, with the largest colonies supporting 50-100 individuals, most others (especially those on rocky shores) generally holding fewer than ten individuals, and several sites comprising single plants. The total UK population is estimated to comprise <650 plants
Site selection rationale
Sites with the largest extant populations have been selected to take account of the species’ rarity and the UK’s special responsibilities for its conservation. Sites have been selected from all parts of the geographical range (including outlying Welsh localities as well as sites from the species’ stronghold in south-west England). Special effort has been made to encompass the full range of habitats in which the species occurs, including sea cliffs, rocky shores, and sand dunes. In order to allow for future movement or expansion of populations, any sizeable adjoining areas of suitable habitat have been included in sites where possible.
This small site supports the largest known extant population of shore dock Rumex rupestris in Devon, and one of the largest concentrations of this species on rocky sea-cliffs in south-west England. In 1999 there were five discrete colonies totalling at least 29 plants, including one large ‘clump’ (7 x 4 metres) which could have been made up of several individual plants.
The 20 or so plants of shore dock Rumex rupestris growing here on damp coastal limestone are the only remnant of the species’ former Bristol Channel range. The species has disappeared through loss of damp dune-slacks and shingle banks from other sites at Merthyr Mawr, Kenfig, Braunton Burrows and Pennard but is relatively secure on this steep, inaccessible site. The Dunraven Bay population is a significant seed-source for recolonisation of Bristol Channel dunes and beach-heads when future management restores these habitats to favourable condition.
Fal and Helford
Cornwall and Isles of Scilly, Extra-Regio
A rocky-shore site supporting a large, dispersed population of shore dock Rumex rupestris near to the centre of its distribution in south-west England. Three sections of open coastline are included within the site, which when last surveyed (in 1999) supported 12 colonies and at least 34 plants. The site also holds extensive additional areas of suitable habitat.
Isles of Scilly Complex
Cornwall and Isles of Scilly
There are historical records of shore dock Rumex rupestris from seven of the larger islands, as well as from several small rocky outcrops and the eastern isles. Recent surveys suggest that it may now be restricted to just four islands (Tresco, Annet, Samson, Tean). Despite recent losses (and possibly earlier over-estimates of its abundance), the Isles of Scilly remain an important stronghold of the species at the south-western limit of its UK range. It is thought likely that the species is in long-term decline here, probably due to sea-level rise, increased storminess and ‘coastal squeeze’. Recent population data are lacking for some colonies, but it is thought that the total population, estimated in 1994 to be 165 plants, may now be rather less than this, perhaps fewer than 100 plants.
Pembrokeshire Marine/ Sir Benfro Forol
Extra-Regio, West Wales and The Valleys
Species occurrence description not yet available.
Cornwall and Isles of Scilly
Penhale Dunes is an important sand-dune site for shore dock Rumex rupestris, with possibly the largest concentration of plants on the UK mainland. More than 50 plants were recorded at this site in the late 1980s; in 1994 the number had apparently declined to 33 fruiting plants but, following the discovery in the late 1990s of new plants away from the previously-known colonies, the total population is now thought to comprise >70 plants.
Plymouth Sound and Estuaries
Cornwall and Isles of Scilly, Devon, Extra-Regio
One of the chief rocky-shore strongholds for shore dock Rumex rupestris on the UK mainland, in 1999 comprising 15 colonies and 42 plants. The site also holds a sizeable area of additional suitable habitat.
Polruan to Polperro
Cornwall and Isles of Scilly
An important rocky-shore site for shore dock Rumex rupestris, near to the centre of its UK distribution. In 1999 the site supported 13 widely scattered colonies and at least 30 plants, along with numerous small pockets of additional suitable habitat.
South Devon Shore Dock
This important rocky-shore site for shore dock Rumex rupestris lies at the eastern limit of its current UK range. In 1999 a thorough survey of the site located 16 colonies and a total of at least 62 plants. The site also has some very extensive areas of additional suitable habitat.
Y Twyni o Abermenai i Aberffraw/ Abermenai to Aberffraw Dunes
West Wales and The Valleys
Abermenai to Aberffraw Dunes in north Wales is important as it represents shore dock Rumex rupestris at the far north-west of its geographical range. It is remote from other known sites for this species, and shore dock occurs in an unusual situation: along a small stream bed and on damp pond edges, formerly in duneland, now in a clearing in a conifer plantation. There are two small colonies, which held 21 flowering plants in 1994, 26 in 1995 and 53 in 1996.
Many designated sites are on private land: the listing of a site in these pages does not imply any right of public access.