NEWBOROUGH WARREN -YNYS LLANDDWYN SITE OF SPECIAL SCIENTIFIC INTEREST
Oblique aerial photograph of dune system (J B Ratcliffe 1991)
What is ‘special’ about Newborough Warren - Ynys Llanddwyn SSSI?
Newborough Warren - Ynys Llanddwyn has 32 special features:
Coastal landforms and the processes controlling beach and dune development.
Precambrian rocks exposed in coastal cliffs, foreshore exposures and inland outcrops.
Intertidal rocky shore communities and rock pools
Intertidal sandflat and mudflat communities.
Saltmarsh communities from the lower to the upper zones including glasswort (Salicornia spp).
Strandline, foredune and mobile dune communities.
Semi-fixed/fixed dune grassland communities.
Dune slack / mire communities.
Heathland and dune heath communities.
Shore dock.
Fir clubmoss,
Yellow bird’s nest,
Crowberry,
Dune heleborine
Welsh marsh orchid
Narrow leaved marsh dandelion
An assemblage of nationally rare and nationally scarce vascular plant species.
Petalwort (a liverwort).
Nail fungus.
An assemblage of nationally rare and nationally scarce lower plants (mosses, liverworts, fungi).
Baltic stonewort.
An assemblage of nationally rare and nationally scarce stoneworts (large freshwater algae).
Golden hair lichen.
An assemblage of nationally rare and nationally scarce lichens.
Medicinal leech.
Sandhill rustic (a moth).
A marine polychaete worm Ophelia bicornis.
An assemblage of dune invertebrate species.
An assemblage of amphibians including great crested newt.
Over-wintering waders/wildfowl including pintail.
A non-breeding population of raven
Breeding cormorant.
As well as the features listed above, Newborough Warren - Ynys Llanddwyn has other habitats or earth science features that contribute to the special interest. These include woodland, scrub, lakes and pools. This mixture of habitats is important for much of the other wildlife such as chough and red squirrel, and these too are components of the special interest of the site. Unless specified below, management of this site should aim to look after these habitats and species as well as the listed features of interest
The Precambrian bedrock geology at Ynys Llanddwyn should continue to be one of the best localities in Great Britain for the study of rocks of this age by maintaining their current level and continuity of exposure.
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© CCW Precambrian rocks are well-exposed on Llanddwyn Island, for example at Porth y Tŵr (above) and the famous pillow lavas (right) are particularly well exposed around Gwddw Llanddwyn. |
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The coastal landforms should demonstrate the natural processes of sediment transfer and deposition within the local coastal system. These geomorphological processes (which move sand and mud to create beaches, dunes, slacks and estuarine flats) also create the physical template upon which biological features develop. This will be achieved by minimizing activities or structures that would interrupt the natural movement of sediment, and that would directly or indirectly cause damage to the coastal landform assemblage.
The site should exhibit typical rocky shore, shingle, dune and estuarine communities, normally including mudflats and sandy foreshore, strandline, foredunes, mobile and fixed dunes, humid dune slacks and saltmarsh. These will vary in their proportion and location in response to naturally changing landforms. There should normally be a strandline with embryonic dunes at some location on the shore each summer, areas of mobile dune “blowout” and areas of newly formed wet slack to provide early successional phases of these habitats. Dune woodland and scrub, composed largely of native species, may be encouraged to develop on inland parts of the fixed dunes where forest soils have formed. Dune heath should be maintained and encouraged wherever it occurs.
The site should support viable populations of shore dock and petalwort along with other rare and uncommon native species (both plants and animals) typical of these habitats. Viable populations of great crested newt and medicinal leech should occur in numerous pools. The estuaries should contribute to the support of wintering populations of wildfowl and waders, particularly pintail, and there should be breeding populations of, notably, cormorant, lapwing and skylark. The dune woodland should support roosting ravens and, where compatible with other objectives, red squirrels.
This should be achieved through a holistic approach to management, which recognises that critical processes, such as sediment supply and deposition, groundwater movement, plant and animal dispersion, occur on a landscape scale.
What management is needed on Newborough Warren - Ynys Llanddwyn SSSI and why?
Although Newborough Warren Ynys Llanddwyn is an excellent place for wildlife and geology it will only remain so if the necessary management continues. CCW will work with you to ensure that this management is carried out.
What does this mean in practice?
There are many factors that could damage the special features at Newborough Warren - Ynys Llanddwyn if they are not properly managed. These are the ones we regard as most important:
Mineral specimen collecting: Mineral and specimen collecting is a major threat to the geological interest on Ynys Llanddwyn, and there should be a presumption against collecting geological specimens. Visiting geologists should not be allowed to use hammers on the island and, as many universities already have specimens/thin sections from the site, no specimens should be collected unless demonstrably for new research.
Erosion: Beaches and sand dune systems experience natural fluctuations of erosion and deposition and these, particularly the cyclical erosion and redevelopment of the frontal dunes, should be welcomed. Nothing should be done to significantly hinder this process. Structures such as groynes, slipways or other coastal defences, which impede natural sediment movement, should be resisted. The dune systems are becoming increasing stable with the development of soils on the vegetated areas. The consequent loss of mobile sand removes an important invertebrate habitat. In the absence of natural events that increase mobility management measures may be required to ensure that significant areas of bare sand are present on the dune system. Conifers planted on the mobile dunes should be removed (including where possible the root plates) to restore natural profiles. Whilst minor erosion by people can be beneficial in maintaining bare areas, concentrated erosion at entrances etc. is not able to redevelop naturally and may require appropriate intervention. The processes of wind scouring, accumulation of sand around marram grass and gradual movement of dunes create new dune slacks in their wake and provide important new habitat.
Natural erosion of the bedrock on Ynys Llanddwyn is slow and its effect on the site interest negligible. Natural movement of sand in the vicinity of the island, leading to the covering of rock, will be tolerated. Movement of sand by coastal processes may reveal new exposures around Gwddw Llanddwyn and further inland. Such new exposures will need to be mapped and may reveal fresh examples of minerals which are depleted elsewhere.
Tourism infrastructure: This site is visited by thousands of people each year who access the site across the dunes and along the beach. Close liaison between site managers should ensure that footpath maintenance and development of other tourist infrastructure does not impact adversely upon the site interest.
Afforestation: The conifer forest was planted to stabilise the dunes. The trees prevent natural sand movement and pine litter smothers most of the natural dune vegetation. The trees also intercept and transpire significant quantities of water, depleting the dune groundwater (see below). Part of the forest may need to be removed to restore the groundwater to dune slacks and the pattern of mobile and fixed dunes. Where distinct forest soils have developed there should be a presumption in favour of retaining native trees to establish semi-natural dune woodland.
Scrub:The development of
scrub (blackthorn, willow, birch) on the dunes shades underlying dune
vegetation, increases soil nutrients and the loss of groundwater. A
limited area of scrub can be valuable for its associated fauna and
its potential for development of woodland and copses, but should not
be at the expense of more diverse dune vegetation. The invasive
spread of sea buckthorn (not native to this area) should be resisted
in particular.
Groundwater:
Dune slacks indicate the groundwater-table at the time of
formation (wind does not scour wet sand) and they should flood in
normal winters to provide conditions necessary for species such as
petalwort and other rarities. The forest (and drainage ditches
associated with it) has caused lowered water levels across much of
the site, leaving many slacks dry. Management of the forest to reduce
interception and evapo-transpiration by conifers and infilling of
drainage ditches are required to restore groundwater. The shore dock
occupies water seepages from higher ground as well as the banks of
pools and slacks where it appears to benefit from the minor
disturbance associated with land-slips and light trampling
Grazing:
Grazing on the dune grassland and slacks removes excess herbage
and reduces competition from coarse grasses or scrub, allowing
typical sand dune species to flourish. Grazing with (preferably)
ponies or with cattle or sheep also enables rabbits to establish
sustainable colonies (they cannot maintain a viable population in the
absence of larger grazing animals) and create a patchwork of grazing
patterns and sward height. The warm bare sand associated with hoofed
animals and with rabbits is important for many invertebrates and
their predators and creates opportunities for renewed dune movement. The
saltmarshes are mostly ungrazed by larger animals, having developed
distinctive vegetation under that regime. Any grazing allowed on
these areas should be very light and occasional if this vegetation is
not to be altered. Grazing
animals within the forest and glades can reduce bramble thickets but
should not be at a level which impedes native tree regeneration in
the longer term. The
dung from grazing animals is an important resource for invertebrates
(and thereby for insectivorous birds including chough) and for fungi.
The use of parasite drenches should be avoided or minimised. Grazing
stock also provide blood for medicinal leeches in some pools,
apparently without significant harm to the host animals.
Soil
nutrients: These dune
soils are characterised by low levels of nutrients (N,P,K,) and high
levels of calcium. Fertilisers, including atmospheric Nitrogen (NOx)
pollution, encourage the growth of coarse grasses at the expense of
the desired species. The use of any form of artificial fertiliser
should therefore be avoided. Wind erosion
and rabbit burrowing ensures that calcareous (shelly) sand is
regularly brought to the surface to replace acid soil layers.
Cord
grass: Common Cord-grass (which developed from the
hybridisation of American and British precursors) colonises mudflats.
However, it often exploits sedimentary changes within the estuary –
in the case of the Cefni, the halving of the estuary size by the
Malltraeth Cob and the canalisation of the Afon Cefni, which reduces
tidal scour and permits the increased accumulation of sediment.
Common Cord-grass will be succeeded by conventional saltmarsh
vegetation. Its control is thus a short term and unsustainable
action.
Wildfowling:
There is no evidence that the levels of wildfowling occurring in
Britain directly affect the populations of the quarry species.
However, at a local scale the disturbance caused by shooting may deny
feeding opportunities to wintering populations of waders and wildfowl
at a critical stage in their survival. Controlled shooting occurs on
Traeth Cefni (and Y Foryd) whilst Traeth Melynog is a sanctuary zone.
Disturbance:
Nesting
birds require undisturbed conditions. Beach recreation (particularly
with dogs) threatens nesting ringed plover, boating threatens nesting
cormorant. Codes of conduct and zoning of activities can alleviate
some of these problems. Uncontrolled cockling remains a problem on
the estuaries leading to disturbance of wintering birds. Fishing
activity: Bait collection and cockle collection are legitimate
activities but poor practice can reduce the diversity of the
communities and continued survival of the populations. Fishermen
should follow codes of good practice such as infilling pits, putting
boulders in their original position, avoiding areas of seagrass beds
and returning undersized shellfish
Invasive
Species: Several non-native species such as cotoneaster,
montbretia and tor-grass threaten to smother areas of interest and
may need to be controlled or eradicated. An alien seaweed, wireweed
has also been recorded. Although currently not a problem, its
presence should be monitored. Finally Our
knowledge and understanding of wildlife is continually improving. It
is possible that new issues may arise in the future, whilst other
issues may disappear. This statement is written with the best
information we have now, but may have to change in the future as our
understanding improves, in particular, of the possible/probable
impact of climate change. Any information you can provide on the
wildlife of your site, its management and its conservation would be
much appreciated.
If
you would like to discuss any aspect of your SSSI, or have any
concerns about your SSSI, please contact your local CCW office. Your
local office is: Cyngor
Cefn Gwlad Cymru North
Wales Region Llys
y Bont Ffordd
y Parc
Parc
Menai Bangor
Gwynedd LL57
4BN Fax:
01248 679259
Telephone: 01248
672500
