CYNGOR CEFN GWLAD CYMRU
COUNTRYSIDE COUNCIL FOR WALES
Views About Management/ Management Statement
A statement of English Nature’s and Countryside Council for Wales’s views about the
management of Dee Estuary/Aber Afon Dyfrdwy Site of Special Scientific Interest (SSSI).
1. Introduction
This statement represents English Nature and Countryside Council for Wales’s views about the
management of this SSSI for nature conservation. This statement sets out, in principle, our views on
how the site’s special conservation interest can be conserved and enhanced. English Nature and
Countryside Council for Wales have a duty to notify the owners and occupiers of the SSSI of their
views about the management of the land.
The document sets out a vision for the features of interest; it describes the key issues affecting the
features of interest and outlines any management considered necessary to safeguard these features.
Not all of the management principles will be equally appropriate to all parts of the SSSI. Also, there
may be other management activities, additional to our current views, which can be beneficial to the
conservation and enhancement of the features of interest.
It is very important to recognise that management may need to change with time. Problems that we
are aware of today may be resolved, or completely removed, and new, unforeseen problems may
arise. New improved management techniques may also become available. The process for agreeing
any necessary changes in management will be through our ongoing and regular discussions with
individual landowners and managers, and through the existing notice and consent mechanism.
The management views set out below do not constitute consent for any operation. English Nature and
Countryside Council for Wales’s written consent is still required before carrying out any operation
likely to damage the features of special interest (see your SSSI notification papers for a list of these
operations). English Nature and Countryside Council for Wales welcomes consultation with owners,
occupiers and users of the SSSI to ensure that the management of this site conserves and enhances the
features of interest, and to ensure that all necessary prior consents are obtained.
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2. What is ‘special’ about Dee Estuary/Aber Afon Dyfrdwy SSSI?
The Dee Estuary/Aber Afon Dyfrdwy supports many special features:
i. Estuary including its habitats and processes
The present geomorphology of the Dee Estuary is a product of the interplay of a variety of factors
including its recent geological history and deposits laid down by the most recent glaciation, its large
tidal range, a tidal cycle characterised by a short flood tide and a much longer ebb tide and its
freshwater inflows especially from the River Dee together with anthropogenic factors such as the
historical land claim in the upper estuary towards Chester and along the Welsh shoreline. The many
inter-tidal habitats and species found in the Dee Estuary are all dependant on these processes.
The Estuary contains a variety of habitats including mud and sand flats, salt marshes, swamps, reed
beds, sub-tidal creeks and channels, rocky shores particularly around Hilbre Island and sand
dunes/shingle features notably at Point of Ayr.
ii. Inter-tidal mud and sand flats
These make up the largest area of habitat in the Dee Estuary. The estuary currently contains extensive
areas of inter-tidal mud and sand flats including a range of generally muddy or sandy low-gradient
shores that are exposed to air during low tide and submerged during the higher tides. Those flats
exposed to high energy are generally sandy in nature whilst more sheltered, low energy flats are
muddier. The flats support a wide variety of marine invertebrates with the muddier flats supporting
particularly large numbers. These provide an important food source for fish and feeding sites for
breeding, wintering and passage birds within the estuary. The mud and sand flats in the estuary can be
highly mobile, such as around Flint Point, but generally appear relatively stable.
The nationally scarce thumbnail crab, Thia scutellata, and nationally rare worm, Ophelia bicornis,
have been recorded on the outer flats of the estuary.
iii. Salt marsh
Salt marsh forms in sheltered locations where mud and sand is sufficiently stable to be colonised by
plants. The Dee Estuary salt marshes are extensive in area and support a range of plants specially
adapted to being regularly submerged by salt water called halophytes. A complete range of salt marsh
vegetation types are present, ranging from ‘pioneer’ salt marsh dominated by glassworts and annual
sea-blite through to more mature salt marsh at a higher elevation on the shoreline with salt marsh
grass, sea aster and sea-purslane with red fescue, creeping bent and sea couch typically higher still.
Transitional vegetation to more terrestrial vegetation types occur at the very top of the shoreline
including swamp vegetation usually dominated by common reed or sea club-rush and marshy
grassland. Such a gradation is well represented on the English shoreline of the Estuary.
iv. Reeds and swamp/other freshwater transitions
Swamp and common reed beds can be found at the top of the shoreline where transitions to more
terrestrial habitats occasionally occur such as where freshwater inflows enter the estuary. Reed beds
provide cover, food and breeding areas for many species of bird including locally uncommon species
such as reed warbler. Several swamp species do occur although sea club-rush is by far the
commonest.
v. Maritime cliff with its associated heath land and grassland vegetation on Hilbre Island
Small areas of maritime cliff, heath and grassland occur on the sandstone islands of Hilbre and Little
Hilbre Islands where they are found in association with the hard sandstone rocks that form them.
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Their extent is comparatively small but their importance is enhanced by the lack of rocky coast in this
part of Wales and North West England.
vi. Hard inter-tidal habitat including rocky shores
The natural rocky sandstone shore areas around the Hilbre Islands provide one of the few localities
along this stretch of coastline. They support a variety of different habitats including rock pools,
bedrock ledges, gullies and crevices. Honeycomb worm, Sabellaria alveolata, reefs are a particular
feature of the lower shore on Hilbre Island.
Additionally Holocene sediments including peat deposits are found within the estuary most notably on
Salisbury Bank, which supports the nationally important community, mussel, Mytilus edulis and
piddocks.
vii. A range of strandline, fore dune and mobile sand dune communities and the presence of
sand hill rustic moth
This type of dune habitat is restricted to both sides of the estuary around its mouth, although there are
more extensive dune systems immediately adjacent. The sand-hill rustic moth is found in young sand
dunes where its food plant, the sand couch, grows.
viii. Coastal grazing marsh
Coastal grazing marsh, much of which has been historically reclaimed from the estuary and in which
former tidal creeks are still evident, occur behind the flood defences in the Estuary. They may be
lower lying than the foreshore areas of the estuary and can flood in winter. They are important
feeding and roosting areas for waterfowl, especially during high tides.
ix. Birds
The Dee Estuary supports nationally and internationally important numbers of waterfowl bird species,
which include both wildfowl and wader species. Important over wintering species include shelduck,
teal, pintail, wigeon, knot, black-tailed godwit, bar-tailed godwit, oystercatcher, dunlin, redshank,
grey plover, curlew and great crested grebe. The total over-wintering wader and wildfowl population
of the Dee Estuary is regularly over 130,000 individuals. These birds can potentially use all parts of
the Estuary including inter-tidal flats, coastal fields and salt marshes for feeding, roosting and loafing
purposes; shingle spits, the Hilbre Islands and other elevated ground for roosting at high tide and the
sub-tidal channels for feeding and loafing. Many other wintering waterfowl species utilise the estuary
but not in significant numbers. The populations of these species also help to maintain the overall total
population of waterfowl species at internationally significant levels within the Dee Estuary site as a
whole.
Many other birds use the estuary as a stopping off point during their spring and autumn migrations to
and from their Arctic breeding grounds. Key passage species include ringed plover, redshank and
Sandwich tern.
These bird populations also utilise adjacent SSSIs including Inner Marsh Farm; Shotton Lagoons and
Reed beds; Gronant Dunes and Talacre Warren and North Wirral Foreshore for feeding, loafing and
roosting purposes.
In the summer important populations of birds also occur. The common terns nesting at the nearby
Shotton Lagoons and Reed beds SSSI utilise the estuary for feeding purposes; non-breeding sub-adult
black-tailed godwit summer in the estuary; cormorant feed and roost in the estuary and redshank
breed on the salt marshes.
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Formatted: Indent: Hanging: 54 pt,
Numbered + Level: 1 + Numbering
Style: i, ii, iii, … + Start at: 6 +
Alignment: Left + Aligned at: 18 pt +
Tab after: 54 pt + Indent at: 54 pt,
Tab stops: Not at 54 pt
x. Fish
Of the migratory fish species present within the Dee Estuary, the two lamprey species, sea lamprey
and river lamprey, are of particular importance. Lampreys use the estuary, which also provides a route
to and from their spawning sites in the River Dee and its tributaries.
xi. Assemblage of higher plants
Five nationally scarce species of plant occur. These are Portland spurge; dune fescue; slender hare’sear; the endemic rock sea lavender Limonium britannicum celticum; and white mullein. Four of these
are only associated with coastal habitats and all occur locally within the Estuary. Portland spurge and
dune fescue occur on the dunes at Point of Ayr; slender hare’s-ear very locally on the salt marshes in
the upper estuary on the Welsh shoreline and the rare endemic rock sea lavender in its cliff top habitat
on Hilbre Island.
xii. Other non-qualifying habitats and species
The Dee Estuary/Aber Afon Dyfrdwy SSSI has other habitats that are essential to the maintenance of
the special wildlife interest. These include neutral and damp grassland, pools, ditches, vegetated
margins to watercourses, scrub and wet woodland, all of which can add considerably to the diversity
of the habitats and species present. This diversity of habitats similarly supports a wide range of
species and these too are a key component of the special interest of the site. Other notable species
include grey seals with their haul-out on West Hoyle Bank; red blysmus, a salt marsh plant species, at
its southern limit in Britain; the fern, sea spleenwort, occurring on the cliffs of Hilbre Island; various
migratory fish species including Atlantic salmon, twaite shad, smelt and sea trout which use the
estuary in their migration upstream to spawn in the River Dee and rockpools dominated by sea firs
(hydroids), ephemeral seaweeds and edible periwinkle Littorina littorea. The estuary is also a
designated bass nursery area.
Unless it is specified below, management of this site should aim to look after these habitats as well as
the formally listed features of interest.
Most of this site falls within the existing and proposed The Dee Estuary Special Protection Area
(SPA) and Ramsar Site and much within the proposed Dee Estuary/Aber Dyfrdwy Special Area of
Conservation (pSAC). This site is contiguous with the River Dee/Afon Dyfrdwy SSSI and SAC.
3. What do we want Dee Estuary/Aber Afon Dyfrdwy SSSI to look like?
Our long-term vision for the Dee Estuary is for all its special features to be maintained and enhanced
whilst allowing natural dynamic coastal processes to continue. Many of the habitats and species found
in the Dee Estuary are dependant on them.
Whilst it is desirable for the extent and distribution of the salt marsh and other important estuarine
habitats to be maintained, it is accepted that there will be a degree of natural fluctuation in their
temporal and spatial extent as estuaries are dynamic environments, which is fundamental to their
interest. Additionally the Dee Estuary is an accreting system that has an annual net inflow of
sediment. Consequently change will occur with a predicted increase in the extent of salt marsh
habitats.
The estuary currently contains extensive areas of inter-tidal mud and sand flats. These habitats need to
remain sufficiently large and disturbance free to allow the population of breeding, summering,
passage and over-wintering birds to be sustained in the long term.
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The estuary contains large inter-tidal banks of sand in the more mobile middle parts of the estuary
with banks of finer silts and sands in more sheltered areas. The diversity and richness of the
invertebrate fauna associated with these banks should remain intact. In certain locations the banks
contain Holocene clay deposits which being less prone to erosion tend to delineate the location of
channels within the Estuary. If such harder deposits are ever lost the whole morphology of the estuary
will change. The nationally important community, mussel and piddocks, would also be lost.
The salt marshes within the Dee Estuary are extensive and will change over time as a consequence of
natural processes and other changes such as sea level rise. A range of salt marsh vegetation types
should be present, ranging from ‘pioneer’ salt marsh to freshwater/dune transitions. The existing
variation in vegetation height and structure should also be maintained. Redshanks breed on the salt
marshes, where the vegetation is structured and provides cover for nesting.
Some areas of bare mud have been colonised by the invasive cord grass Spartina anglica at the
expense of glasswort and other ‘pioneer’ species. The occurrence of Spartina is symptomatic of the
fact that the estuary is accreting. Its presence will therefore be tolerated particularly as it does not
persist once the pioneer phase has passed.
Transitional vegetation to more terrestrial vegetation types, including marshy grassland, swamp and
reed beds, which typically occur at the top of the shoreline, will be retained and allowed to further
develop. Scrub encroachment of these swamp areas should however be resisted. At Point of Ayr, the
salt marsh is transitional to other habitats including sand dunes and shingle, which should be
maintained.
The small areas of maritime cliff, heath and grassland on the sandstone islands of Hilbre and Little
Hilbre Islands will be maintained and enhanced by appropriate management. The extent of these
habitats should not be reduced in size and where practicable encouraged to expand. Within the
maritime grasslands thrift and Danish scurvy grass should be common whilst the maritime heath will
be dominated by heather with bell heather. Sand sedge should also be numerous in this heath.
Structurally the grassland and heath will be variable in height.
Sand dune habitats are susceptible to natural erosion by storms and to recreational damage from
trampling by visitors and vehicles. Conditions suitable for dune formation should be maintained
including young sand dunes where sand couch grows, the food plant of the sand hill rustic moth. This
will assist in maintaining existing populations of this restricted species. Conservation management
should be aimed at ensuring the habitat can sustain populations of sand hill rustic moth in the long
term. However the Dee Estuary populations need to be managed in conjunction with adjoining
populations in the Gronant Dunes and Talacre Warren SSSI.
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Hilbre Island showing sandstone sea cliffs with maritime grassland above and
stands of rock sea lavender (P Day, July 2004)
The coastal grazing marsh/fields around the Welsh shoreline should be managed as permanent pasture
and able to flood on a regular basis in order to provide wintering feeding and roosting areas for
waterfowl. Ideally disturbance from agricultural, recreational and other activities should be minimal.
The total number of waterfowl and seabirds using the Estuary (and adjacent SSSIs) should remain
stable or increase in number and all populations of individual species mentioned above should ideally
have stable or increasing populations. For this to occur wintering and passage bird species require a
plentiful food supply with the opportunity to feed without disturbance and safe disturbance free
roosting/loafing sites over the high tide period. Breeding species also need sites free from disturbance
and suitable for nesting.
Fish populations should be sustainable in the long term and be able to use the estuary for feeding. The
estuary also forms an important nursery area for fish such as bass. Migratory species should be able to
use the estuary as a route to and from spawning sites unimpeded by physical barriers, poor water
quality or other factors.
All the nationally scarce higher plant populations should have at least stable populations and the
specific localities where they occur will be managed for them.
4. What management is needed on Dee Estuary/Aber Afon Dyfrdwy SSSI and why?
Although the Dee Estuary/Aber Afon Dyfrdwy is an excellent place for wildlife it will only remain so
if the necessary management continues. We 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 the Dee Estuary/Aber Afon Dyfrdwy
if they are not properly managed. These are the ones we regard as most important:
i.
Coastal processes including sedimentation and erosion/coastal defence and sea level changes
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Formatted: Indent: Hanging: 72 pt,
Numbered + Level: 1 + Numbering
Style: i, ii, iii, … + Start at: 1 +
Alignment: Left + Aligned at: 36 pt +
Tab after: 72 pt + Indent at: 72 pt,
Tab stops: 18 pt, List tab + Not at
72 pt
Estuaries are dynamic systems whereby tidal channels move naturally over time with consequential
changes in the spatial extent of other inter-tidal habitats including salt marshes and inter-tidal mud and
sand flats. Consequently there will be coastal process changes occurring over time, which is
acceptable. The Dee Estuary is a naturally accreting system with an annual net inflow of sediment
from Liverpool Bay and salt marshes are likely to continue to increase at the expense of inter-tidal
flats. Such processes may be modified by sea level rise and may cause erosion of inter-tidal habitat
including salt marshes. However there may be other activities occurring within the estuary such as
dredging or coastal defence works, which could affect these natural process changes. Any such
activities need to be considered on their individual merits and their impact fully assessed. The change
from inter-tidal flats to salt marsh could have consequential impacts on the extent of the feeding
habitat for passage and wintering waterfowl bird populations, as these open, often invertebrate rich
flats are lost. However such changes are acceptable provided they have occurred naturally. Cord
grass, Spartina an invasive non-native species is one of the earliest colonists of the mud and sand flats
as sediment accretes, although more typical native colonists such as glasswort and annual sea-blite are
also widespread. Cord grass causes the rate of sediment accretion to increase so that salt marsh forms
more quickly than with other pioneer species. It is not considered necessary to control Spartina as its
occurrence is symptomatic of sediment accretion. The occurrence and extent of Spartina within the
estuary appears to have declined recently.
The three sandstone islands at Hilbre Island are threatened by erosion by the waves and tides.
Historically defence works have been implemented particularly on the main island to provide erosion
protection. Any further works should be resisted as these rocky shores, with their range of species,
should remain undisturbed, developing at their present locations as the tidal movement allows. The
honeycomb worm should be present ideally in a range of reef types from newly settled worms
through to older hummocks.
Additional works to existing soft coastlines should also be resisted to allow the coast to evolve/regress
when subject to wave attack such as the boulder clay cliffs at Thursaston, which are designated as Dee
Cliffs SSSI in their own right.
The sand hill rustic moth’s habitat is newly formed sand dunes with sand couch grass growing on
them. The main threats to the moth come from the erosion of these dunes, through wind and sea
erosion or from trampling from people and vehicles. Vehicle access to these dunes should be
restricted and dunes particularly those supporting the food plant, that are being damaged by human
activity, fenced. However, the long-term survival of this moth requires a succession of new dunes to
regularly form and be colonised by sand couch grass.
The future location and extent of inter-tidal habitats including mud or sand flats is also dependent on
the extent to which the estuary or coast is constrained from responding to sea level rise and changing
sediment regimes. Management needs to create space to enable landward roll-back to take place in
response to sea-level rise, and should also allow the system to be dynamic and retain the flexibility to
respond to associated changes such as the movement of physical features within the system, e.g.
migrating sub tidal channels and sandbanks.
In low-lying areas without sea defences, sea level rise would naturally cause the seaward edge of
inter-tidal habitats, such as mud or sand flats, to be permanently lost under water. The inter-tidal
habitat would naturally move inland, following the new, higher coastline. However, in areas where
there are fixed barriers, such as coastal defences, this movement is prevented, and inter-tidal habitats
may become ‘squeezed’ between the coastal defences and the deepening estuary. Existing and new
coastal defences have to be carefully considered to ensure they do not result in the loss of inter-tidal
habitats. This may require novel approaches to how we defend land from flooding and/or
consideration of areas where retreat of defences to allow the estuary to adapt might be possible.
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Sand dunes develop where sand is blown landwards from the adjacent beach and is deposited above
the high water mark. This is then colonised by dune building grasses, which can continue to grow up
as new layers of sand are deposited. A process of succession takes place as sand dunes develop first
into embryo dunes, which can be ephemeral, then into semi-fixed dunes dominated by marram grass,
and eventually into fixed dunes. Within the estuary there are areas at the mouth of the estuary where a
range of strandline, fore-dune and mobile sand dune communities have developed which need to have
a supply of sand to keep them invigorated.
ii. Water Quantity
The major freshwater input into the estuary is from the River Dee. This input has been subject to
historical changes starting with the installation of Chester Weir, followed by the introduction of river
regulation by Thomas Telford in the early 19 th Century. More recently the Bala Lake Schemes in the
1950s enhanced water available for summer abstraction, whilst mitigating the impact of flood events
at Bala and further down the catchment.
The scale of river regulation was further enhanced in the 1960s and 1970s with the construction of
Celyn and Brenig Reservoirs, primarily for supplying potable water to parts of Wales and England.
This regulation ensures that low freshwater flows into the tideway be maintained above a level that
would occur naturally during hot dry periods. The residual flow limits the saline intrusion upstream of
Chester weir during spring tide sequences and protects fish migrating through the inner estuary. A
bank of water is available to mitigate for adverse water quality and temperature in the estuary even
during severe drought. This freshwater flow is also a major factor in controlling the salinity levels at
the head of the estuary.
A consequence of this is that summer inputs into the estuary have increased, whilst the frequency of
flood peak flows may be reduced. However, the embankments upstream and downstream of Chester
tend to contain higher flows within the river channel and lead to enhanced rates of discharge through
the canalised section during the earlier and later periods of a significant flood event, maintaining
sediment transport through to the estuary.
Consequently any future flow regulation and abstraction schemes within the River Dee catchment
needs to carefully consider the implications for the estuary and its wildlife. Water quantity also has
direct implications for water quality, because pollutants become more concentrated during low flows.
iii. Pollution and water quality
Urban areas, industrial sites and agricultural land surround the Dee Estuary. These uses can impact
on the estuary through changes to water and sediment quality. Water quality is a key intrinsic factor
in maintaining the nature conservation interests and particularly those organisms such as salmonid
fish, which are sensitive to poor water quality.
The Dee Estuary receives discharges directly from a number of manufacturing industries, power
stations, wastewater treatment works and combined sewage outfalls and from other discharges in the
catchment, including agricultural runoff and associated nutrients and chemicals. These discharges if
not properly controlled will impact on the organisms and habitats present in a variety of ways
including direct toxic effect such as from oil spills or sewage discharges. Other discharges might
favour certain organisms, for instance around sewage outfalls, where there is high organic loading,
large populations of worms might develop, which provide opportunities for feeding birds such as
redshank. This maintains an artificially higher density of birds than might be expected in a natural
system, although bird populations might be artificially raised, there could be consequential impacts on
their long-term survival as feeding on contaminated organisms could impact on their future health and
survival. Additionally in such situations there is a total loss of bivalve molluscs and large worms,
which are important structural and stabilising influences on mudflats. Pollutants in the estuarine
environment may also affect the survival of migrating salmon and other fish.
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Other aqueous discharges include thermal/salinity plumes from power stations and leachate from
landfill sites including historical sites where containment measures were never included. Maintaining
water quality is important to conserve the habitats and species in the Estuary.
Better control and regulation of pollution and waste disposal, changes in industry and industrial
practices, and remedial works such as improvements of infrastructure such as wastewater treatment
works and changes to the content and timing of discharges to the estuary, have improved water quality
in more recent years and should continue.
However, many of the existing landfill sites on the Welsh shoreline of the Estuary are vulnerable to
erosion by wave attack and/or by anthropogenically/naturally induced morphological change. It is
important to ensure that appropriate remediation is put in place to avoid the risk of this contamination
migrating into the Estuary.
Aerial discharges from power stations and industrial developments could also damage the site through
dry deposition and contaminated rain.
Estuarine sediments particularly the finer muddier ones contain a legacy of historical contamination,
given the nature of the heavy industries around the Welsh shoreline and care needs to be taken if such
sediments are disturbed in the future
iv. Development
The Dee Estuary has been historically subject to significant land claim and about 30% of its original
area particularly at its head is now used for other purposes including agriculture, residential and
industrial development. This reclamation was prompted by a need to maintain a navigable channel to
Chester, which in the seventeenth century was a major port and at this time a new channel on the
Welsh shoreline was developed. In spite of this it was difficult to maintain this channel and the port of
Chester ceased operating. The land claim within the estuary occurred progressively over 200 years.
The estuary is still responding to these changes.
The Welsh shoreline has been used for a variety of purposes including heavy manufacturing industry,
mining for coal and the smelting of ores such as lead from its immediate hinterland. This has resulted
in a legacy of tipped land around the estuary much of which is contaminated and in need of
remediation. Whilst some historical landfill sites have been subject to at least some remediation, other
sites have received none. Some of these sites are vulnerable to erosion by waves and tides and become
increasingly so as sea levels rise.
There remain development pressures on the estuary especially along the Welsh shoreline and
particularly around the head of the estuary where new industrial users are being encouraged to
develop. All developments whether they are large or small may have the potential to impact on the
estuary and need to be carefully considered. For example, developments outside the site may directly
impact on the estuary by increasing discharges and the demand for water or raising levels of
disturbance to estuarine bird populations. Because this land has been historically reclaimed from
estuary it is particularly susceptible to sea level rise.
Most of the towns along the Welsh shoreline had their own shipping docks/wharves, which were
maintained free of silt by the operation of a series of dock flushing lagoons. These are no longer used
for this purpose and have silted up and now often support salt marsh.
The estuary has seen an increase in energy generating capacity in recent years with the construction of
two gas–fired power stations at the head of the estuary, which utilise estuarine water for cooling
purposes. This has lead to the building of further power lines in this vicinity with an inherent risk of
bird collisions particularly where there are waterfowl flight paths in the estuary.
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Additionally new technological developments such as renewable energy generation from off-shore
wind turbines in Liverpool Bay may have considerable impacts on birds particularly if located in
critical flight lines and migration routes. There needs to be an integrated approach to such
developments.
It is essential that the potential impacts of development on the estuaries wildlife are fully considered
v. Port facilities including navigational/operational requirements
Operational port facilities are confined to the Port of Mostyn and there is a requirement to maintain
the navigation channel from the sea to the port by dredging. The sand material dredged for this
purpose is deposited at a specific disposal site within the estuary in Mostyn Deep. Careful
consideration needs to be given to the disposal of dredged sediments to ensure that it is not ‘lost’ from
the system. Dredging should not affect key features of the estuary including Holocene deposits
Other wharves/facilities for commercial shipping exist in the upper estuary and adjacent canalised
sections of the River Dee, although the only regular use currently is the transhipment of aircraft wings
from Broughton.
vi. Recreation/Human Disturbance
The Dee Estuary is used by a large number of people for recreational purposes and is close to areas of
significant human populations particularly Merseyside including the Wirral.
Many activities regularly occur within or adjacent to the site including bird watching, angling, bait
digging, horse riding, sailing, water-skiing, wind surfing, wildfowling and walking/dog walking. A
coastal cycle-path is being developed on the Welsh shoreline of the estuary. All these activities have
the potential to disturb roosting and/or feeding birds. In severe weather conditions, any reduction in
the time spent feeding, or increase in the time spent flying as a response to disturbance is likely to
increase the mortality of these birds. Although stopping disturbance altogether will not be possible,
reducing it through voluntary agreements, education, and visitor management will be necessary,
especially at all key feeding and roosting sites including high tide roosts. There is historic evidence
that the high tide roost on the foreshore at West Kirby was adversely affected by recreational activities
occurring at high tide and eventually these birds relocated elsewhere outside of the estuary
Wildfowling can also have a direct effect on numbers of wild quarry species, and management of this
activity needs to continue to ensure a sustainable level of cropping of such species. During prolonged
periods of freezing weather, wildfowling is suspended through voluntary and statutory measures.
Disturbance from wildfowling is also reduced by managing areas as no-shooting sanctuary zones, of
which there are several in the Dee Estuary.
Unsuitable recreation activities including motorcycling on the salt marsh, which causes damage and
destruction of the vegetation as well as disturbing any breeding birds that are present should be
controlled.
The trampling of vegetation, where visitor pressure is high such as on and around the Hilbre Islands,
may damage important habitats such as maritime cliff heath land and heath land and efforts should be
made to limit visitor access to marked footpaths.
Many of the vegetation types supported by sand dunes are fragile and vulnerable to erosion from
heavy trampling and other recreational activities. Where recreational pressures result in the loss of
existing vegetation cover and prevent its recovery, it has been necessary to take steps to manage
access by putting boardwalks in and to control activities in vulnerable areas such as the fore-dunes at
Point of Ayr. However dune systems are mobile systems and ideally should be allowed to evolve as
tides and winds dictate
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The demands of maintaining an attractive coastline for recreational usage places additional pressure
on the habitats and species that occur in areas at the mouth of the estuary particularly sand dunes and
their associated fauna. Where the high tide reaches, it is common to find a ‘strandline’, consisting of
pieces of driftwood and vegetation dislodged from salt marshes by tidal and wave action together with
unsightly plastic and other rubbish. Beach cleaning has tended to remove all such litter. However
such ‘strandlines’ are often important in the formation of new sand dunes in areas of accretion. Any
cleaning therefore needs to fully consider its impact on these processes and methods should be
adopted to remove unsightly litter without impacting on sediment accretion
The trampling of the foreshore on the rocky coastline around Hilbre Island will lead to damage to
Sabellaria reefs
Foreshore, strandline, embryo dunes at Point of Ayr (P Day, 2005)
vii.
Fishing
The estuary has traditionally been fished commercially for shellfish such as cockles and shrimps and
fish species such as flounder, bass and salmon. Certain fish of particular interest within the estuary
such as lampreys are not of commercial interest to fishermen
Currently, the most important commercial shellfish fishery is that for cockles, which can involve very
substantial numbers of people hand raking the beds, when they are open. The fishery can potentially
impact estuary features in several ways. These include direct impact on estuary habitats by trampling
or direct damage through raking; adverse impact on bird feeding through reduced populations of
cockles and other invertebrates preyed upon by estuarial bird species; and by disturbing birds from
their feeding areas. Over-exploitation of cockle stocks is a particular threat to birds like oystercatcher
and knot, which feed on them. The disturbance of waterfowl feeding on the beds, can reduce the time
these birds spend feeding, and displace birds to areas with a poorer food supply or increase energy
expenditure, which in turn can lead to increased mortality at times when bird populations may be
stressed, such as during severe winter weather.
Management of the fishery should aim to avoid over-exploitation, ensuring a sustainable fishery and
adequate escapement to cater for natural predation and stock regeneration. Fishing seasons should be
regulated to manage impact on birds from disturbance, and particularly to minimise it during the
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autumn and winter periods when estuarial bird populations are highest and most prone to adverse
impact. The currently proposed Fishery Regulating Order should ensure such an appropriate fishery
management regime.
Traditionally, salmon were an important commercial fishery too. However, this has reduced with the
decline in the number of salmon returning from the open sea and a consequent reduction in net
licensees engaged in their capture, which is hoped will aid their conservation.
Recreational shore fishing occurs within the site but is relatively localised to a small number of
locations.
Fishing can result indirectly in disturbance to wintering birds and to damage by trampling of salt
marsh vegetation.
The fish and shellfish stocks within the site need to be managed sustainably to benefit the commercial
fishermen and to ensure that sufficient food resources are available for its waterfowl populations.
viii. Agricultural land management
a. Grazing and mowing of salt marshes and swamps
Sheep (and historically cattle) have grazed parts of the salt marsh, although some areas have never
been grazed particularly the recently accreted salt marshes on the English side of the estuary.
Where there has not been a history of grazing, the salt marsh will be able to maintain itself and
grazing-sensitive species will be present. Here grazing should not be introduced.
Where traditional grazing has occurred this can continue where this is at appropriate stocking density
and periodicity. The precise timing and intensity of grazing will vary according to local conditions
and requirements; for example the type or availability of stock and/or the need to avoid trampling
ground nesting birds. Redshank is an important breeding species, which needs taller vegetation in
which to breed so it would benefit from lower or no levels of grazing during the nesting period.
Grazing provides a variety of different habitats, particularly for wintering bird species, and if grazing
were to cease there may be a loss of botanical diversity. However on many sites, the aim will be to
create a short turf that can be attractive to over-wintering wildfowl, such as for feeding wigeon, with a
reduction in stock density in the early summer for the benefit of ground-nesting birds. Indeed, careful
reduction of grazing can increase the number of breeding birds, without significantly altering the plant
species composition.
Historically small areas of the salt marsh around flashes (salt marsh pools) have been mown on the
traditionally grazed Burton Marshes to promote usage by feeding wildfowl for shooting purposes.
The salt marsh should not be overgrazed, as this may reduce the diversity of animal and plant species
that the salt marsh is able to support, as well as potentially impacting the sediments supporting the salt
marsh by localised erosion and poaching.
On areas that are grazed, livestock may trample and eradicate swamp vegetation especially common
reeds. Swamp vegetation typically tends to occur at the top of the shore where there are freshwater
influences and ideally where it wants to develop it should be actively encouraged particularly along
the English shoreline. Such freshwater influences should be retained. As the litter build up occurs,
shrub species including sallow will invade; this needs to be controlled. Rotational cutting and removal
of the cut reeds during the winter period can invigorate the reeds themselves.
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Maritime cliff grasslands and heath lands on cliff tops are usually maintained by a combination of
grazing and natural factors, such as erosion and exposure to salt-spray and wind. Together these
maintain its characteristic open nature and the Hilbre Islands occur in an exposed situation. Today
there is no grazing on Hilbre Island and the former management for agricultural purposes has led to
parts of the tops of the Island supporting agricultural swards. Because of the scarcity of this habitat
regionally ideally expansion of these habitats is to be encouraged by appropriate management.
However reintroduction of grazing is considered impracticable.
b. Agricultural management of coastal fields
The coastal flat fields around the estuary are utilised by the Dee Estuary’s waterfowl bird populations
especially during the wintering period. Wading bird species, which particularly use such areas for
roosting and feeding, are curlew, black-tailed godwit, oystercatcher and redshank, although many
other waterfowl species occur including large numbers of lapwing. Such areas are generally dry in the
summer, but wet in winter with areas of standing water and have been traditionally managed as
permanent grassland with sheep/cattle grazing or cut for hay/silage with the aftermath grazed. Ideally
these grasslands should not be reseeded or it they are, they should be managed on a very long rotation.
Periodic dressings of well-rotted farmyard manure are acceptable. The sward height in early autumn
should be short to encourage usage by such bird species. The deepening of existing surface drains
should be avoided and incorporation of under-drainage resisted. Disturbance albeit from shooting or
other farming or recreational activities in winter should be minimised to encourage use by these
species. Hedges should be retained but managed so that they do not become overgrown. Tree planting
should be avoided and the land should not be re-profiled as fields containing former estuarine creeks
and channels provide wet conditions in winter suitable for feeding
The work undertaken at Warren Farm, Talacre should be seen as an exemplar for positive works to
benefit target wintering wading bird species. Pools have been created there for winter field irrigation
purposes to benefit wader feeding. Water abstraction for other purposes should be resisted.
5. Finally
Our knowledge of wildlife is far from complete. It is possible that new features of value may appear
and new management issues may arise in the future, whilst other issues may disappear. 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 and/or English Nature office.
Your local office is:
Countryside Council for Wales
Glan y Nant,
Unit 19,
Mold Business Park,
Mold,
Flintshire, CH7 1XP
English Nature
Cheshire to Lancashire Team
Pier House
Wallgate
Wigan
Lancashire WN3 4AL
Telephone:
Fax :
Telephone:
Fax :
Email:
Web site:
01352 706600
01352 752346
01942 820342
01942 614026
[email protected]
http://www.english-nature.org.uk/
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