Trends and Threats [top]
lagoons are a rare habitat in Britain and Europe and are also highly
transient features, at least in geological terms. Barnes (1980)
considered that most natural lagoons would last for less than 1
000 years. Due to coastal processes, the shingle beach and sand
dune barriers tend to move inland, gradually encroaching on the
lagoon behind them. Over time this will result in the infilling
of the lagoon, hence their geologically short lifespan. If there
is development on the landward side of the lagoon then this process
may be accelerated as there is no room for any landward extension
of the lagoon. Lagoons may also be destroyed by severe storms breaching
the natural barrier and creating a bay. However, the lagoons in
Sussex do not appear to be under immediate threat from this process
as the natural barriers are quite extensive and are also monitored
and maintained by the Environment Agency as part of their coastal
defence work. Many lagoons are very shallow and if they are only
slightly saline, natural succession ~vi]l ultimately coIlvert them
to fen carr or reed swamp. Thus there is a natural tendency for
saline lagoons to be destroyed over time. Under natural conditions,
this loss would be compensated for by the formation of lagoons in
other areas. However, along the heavily built up Sussex coastline
the scope for natural creation of lagoons is extremely limited.
Therefore the long term trend will be for saline lagoons to gradually
disappear from the Sussex coastline.
However, saline lagoons can be created artificially with good examples
in Sussex being the 'scrape' on the eastern side of the Cuckmere
Haven and the wader pool at Rye Harbour. The 'scrape' in the Cuckmere
was specifically created as a lagoon and could be used as an example
of how lagoons can be created in the area to compensate for the
artificial and natural losses that are occurring. There is considerable
potential for the creation of further artificial lagoons at Rye
lagoons have a tendency to become eutrophic over time, primarily
due to pollution (as at Widewater), and this will disrupt the delicate
ecosystem of the habitat. Pollution may be carried in the water
supply to the lagoon (for example leaching of agricultural runoff)
or be inputted directly (for example sewage and rubbish). The problem
is compounded at Widewater as there is no outflow and pollutants
therefore accumulate in the lagoon.
and development are the main threats to the saline lagoons occurring
in Sussex. Most of the information on pollution has come from Widewater,
but much of it is applicable to other Sussex lagoons. At Widewater,
heavy metals have entered the lagoon as a result of sewage from
nearby sea outfalls percolating through the shingle bank in the
seawater, and also directly from the dumping of refuse such as old
paint tins (Everett 1993). It is thought that some of the pollution
here may be from coal waste used to build up the sea defence in
the post-war period. Runoff of pesticides from adjacent gardens
and dog-fouling along the shore are two other sources of pollution
at Widewater. Pollution of Widewater has been estimated as moderate
with the most serious threat coming from direct dumping of items
such as oil and paint cans; even minute quantities of contaminants
such as oil and paint, directly inputted, may prove lethal to the
flora and fauna of lagoons as they are quite enclosed ecosystems
with limited and slow water exchange. The number of specialist lagoon
species at Widewater declined by 50% between 1931 and 1993 (Everett
Development is a threat to some of Sussex's lagoons. Although many
of them lie within protected sites such as the Rye Harbour and Pagham
Harbour Local Nature Reserves, the Newhaven Tide Mills are under
continuing threat from development along the northern shore. Widewater
has been a LNR since 1997, but designation as a SSSI (once conditions
there are appropriate) would add further protection to this site.
Slipper Mill Pond and Peter Pond at Emsworth have been threatened
by development schemes to drain surface water from nearby housing
estates through them. One such attempt has been resisted, but another
is now in progress. These are not protected sites (they are SNCIs)
and legal protection would help to prevent such schemes from being
Sea defence works often interrupt the natural process of longshore
drift, upon which the natural formation of lagoons in Sussex is
dependent. Ironically, sea defences may therefore also protect some
natural lagoons by preventing this same natural process which would
ultimately destroy them.
Sea level rise is also a potential quite serious threat to lagoons.
Relative sea level rise is currently estimated to be at least 6mm
per year along this stretch of coast (3 mm due to sea level rise
and 3 mm due to land sinking) and as it is estimated that about
120 ha (or 10%) of England s saline lagoons will be lost to sea
level rise in the next 20 years or so (figures from the National
Saline Lagoon HAP), this has serious implications for those in Sussex.
Global warming and climite change is also likely to have an effect
on this delicate ecosystem, although it is not fully known what
this might be.
The creation of the scrape at Cuckmere Haven and the wader pool
at Rye Harbour has shown that there is potential for creating artificial
saline lagoons along the Sussex coast. Maximum use should be made
of this potential, especially considering that there is little chance
of saline lagoons forming naturally along the Sussex coast, due
to the various coastal defence schemes and heavy development. Suitable
areas for lagoons should be identified with a view to creating as
much of this habitat as possible, providing that doing so does not
threaten or compromise other important natural habitats.
There is also potential for improving the quality of existing lagoons,
for example by ensuring that suitable water levels are maintained
and pollution affecting the sites is dealt with and eliminated.
The current situation at Widewater has shown that minimising pollution
and ensuring adequate water levels are essential in maintaining
saline lagoons in a healthy state.
Current Action [top]
8.1 Site Protection
Most of the saline lagoons in Sussex are protected by their SSSI
and/or LNR status. Newhaven Tide Mills, Brighton Marina, Birdham
Pool, Slipper Mill Pond/Peter Pond at Emsworth and some of the gravel
pits in the Camber area are the only lagoons which currently have
no protection. Although it has been a LNR since 1997 and despite
being the county's most important lagoon (at least historically),
Widewater is currently not in a good enough condition to qualify
for designation as a SSSI. The problems at Widewater are being addressed
(the water levels are currently significantly higher than they were
in the drought years of the late 1980s) but it may still be some
time before Widewater improves sufficiently to meet the criteria
for designation as a SSSI. Peter Brett Associates have recently
completed a hydrological investigation of Widewater, on behalf of
the Environment Agency and English Nature, which has resulted in
several recommendations for improving the state of the lagoon. The
most suitable of these are currently the subject of a feasibility
study by the Environment Agency.
8.2 Site Management
A management plan for Widewater was produced in 1993, but it has
only been partly implemented. This has recently been updated however.
The lagoons within Pagham Harbour and Rye Harbour should have specific
management guidelines drawn up as part of the LNR management plans
if this has not been done already. Site Management Statements produced
for landowners by English Nature may also be used to guide management
for any lagoons within SSSIs which are under private ownership.
Existing Agri-environment Schemes [top]
No agri-environment schemes are available for this habitat. However,
such schemes are available for scrape creation, which can be used
to create new lagoons.
The national objectives, taken from the National Saline Lagoon HAP,
are as follows:
current number, area and distribution of coastal lagoons should
be maintained and enhanced. There are at present some 5200 ha of
known saline lagoonal habitats in the UK.
by the year 2010, sufficient lagoonal habitat to offset losses over
the last 50 years. It is considered that even with a great deal
of effort it will be possible to produce only very indicative figures
of losses over the last 50 years. Instead it should he accepted
that there has been some loss during this period and to focus on
creating new habitat, using the target of 120 ha referred to herein
(the amount of habitat which it is estimated will be lost from 1992-2022
as a result of sea level rise). If any figures were to be obtained
there should be an attempt to distinguish between losses due to
natural processes and due to human activities.
evaluations estimated that 38 English lagoons were lost in the latter
half of the 1980s (this is an estimate which should be taken as
an indication of the fact that saline lagoon habitat has been lost
over the last 50 years). In 1992 the creation of at least 120 ha
of lagoon habitat over the following 20 years was considered attainable
and necessary within England just to keep pace with projected losses.
It is considered that this figure should be used as the target for
creation of new saline lagoon habitat to offset previous losses.
Future losses should be compensated for where feasible as and when
they arise, creating new habitat as near to the original site as
key Sussex objectives are:
prevent net loss of lagoon habitats caused by development or land
allow natural formation/evolution of lagoons wherever possible.
maintain water quality and quantity and eliminate pollution from
all sources, and to maintain the biodiversity interest in all
determine the hydrology of all the lagoons of Sussex, to enable
appropriate management techniques to be applied.
identify areas for lagoon creation and restoration, including
during flood defence projects.
manage the recreational use of lagoons. including the use of zoning.
to minimise disturbance to wildlife.
increase public awareness and appreciation of this important habitat,
for example through interpretation boards at targeted lagoons
and the involvement of local people in managing lagoons.
Targets and Costs [top]
significant areas of saline lagoon should be formally protected
by the end of 2001.
protected areas of saline lagoon should have a written management
statement/management plan by 2003 (including any that only have
hydrological survey of Widewater should be completed by April
2000, with a view to providing recommendations on how to maintain
appropriate water levels at the site. (This has now been completed).
lagoon should meet the criteria for designation as a SSSI by2003.
10 ha of saline lagoon habitat in Sussex by 2010.
that all significant lagoons in Sussex have been mapped and surveyed
for lagoon specialist species by 2003.
survey of Widewater (already done) £4000
implement the recommendations of the Widewater hydrological survey
5 ha of saline lagoon by 2010 £10,000
and map lagoons £13,000
All these are rough estimates and will no doubt be modified as the
HAP is implemented.
Action Plan [top]
Species Action Plan for Ivell's sea anenome, drawn up by the UK
Biodiversity Group, recommended surveying Widewater by 1998 to determine
whether this species still survives there. This was done, with negative
results, but the surveys were not very intensive (the main one was
over two days in September 1997) and it is felt that ongoing survey/monitoring
work should take place over the next five years to give a clearer
picture of this species' status.
Monitoring and Review [top]
Habitat Action Plan will be monitored annually by English Nature
(Sussex & Surrey Team) in conjunction with the Sussex Biodiversity
Partnership, with a full review carried out at five year intervals.
Monitoring will include checking up on the implementation by the
relevant Lead Agency of the Action points identified in the Action
Folkestone to Selsey Bill Natural Area Profile, 1998 English Nature.
Coastal Vegetated Shingle Habitat Action Plan, 1999 Sussex Biodiversiry
UK Biodiversity Group Tranche 2 Action Plans ,Vol. V maritime species
and habitats, 1999
Bamber, R.N., Batten, S.D., Sheader, M. & Bridgewaer, N .D.
(1992) On the ecology of brackish water lagoons in Great Britain.
Aquatic Conservation 2: 63-94
Barnes, R.S.K. (1980) Coastal Lagoons. Cambridge University Press,
Barnes, R.S.K. (1988) The coastal lagoons of Britain: an overview.
Nature Conservancy Council CSD report No 933
Bratton, J.H. (1991) British Red Data Books: 3. Invertebrates other
than insects. Joint Nature Conservation Committee
Downie, A.J. (1996) Saline Lagoons and Lagoon-like Saline Ponds
in England. English Nature Science No 29
Everett, S. (1993) Widewater Lagoon Management Plan. Eiiglish Nature
Science No 16
Irving, R.A. (1997) Survey of Widewater Lagoon, Lancing, West Sussex,
16 & 17
September 1997. WorldWide Fund for Nature, UK
Shirt, D.B. (1987) Red Data Books: 2. Insects. Nature Conservancy
Smith, B.P. & Laffoley, D. (1992) A directory of saline lagoons
and lagoon like habitats in England, 1st edition. English Nature
Science No 6
following were consulted during the preparation of this Habitat
Action Plan: Phil Griffiths (Environment Agency), Sarah Dawkins
(RSPB), Graham Roberts & Neil
(West Sussex County Council), Alex Tait (East Sussex County Council),
Matthew Thomas (Brighton & Hove Unitary Authority), Barry Yates
(Rye Harbour LNR, http://www.yates.clara.net/
), Rob Carver (Pagham Harbour LNR), Henri Brocklebank & Don
Baker (Sussex Wildlife Trust), Paul Gilliland (EN Maritime Team),
Anne de Potier (Chichester Harbour Conservancy), Robert Irving,
Vic Howard (Friends of Widewater Lagoon), Dr. Y.R. Fares (University
of Surrey), Martin Sheader (University of Southampton), Brian Banks
(EN Kent Team), Ian Pearson (EN Hampshire team).