SALINE LAGOONS

 

In Cumbria this habitat is found in man-made locations, such as docks, gravel and mine workings. They support a range of wildfowl, waders and sea birds and provide excellent bird watching opportunities.

 

Download statement

 

 

UK Priority Habitats covered by this statement:
Saline lagoons

 

Cumbria Biodiversity Action Plan habitats covered by this statement:
Coastal habitats

 

 

Contents

Description
Distribution and Extent
Conservation Issues
Planning Considerations
Enhancement Opportunities

Habitat Targets
Key Species
Further Information
Contacts
Current Action in Cumbria

Description

Saline lagoons are bodies of saline water, natural or artificial, partially separated from the adjacent sea. They retain a proportion of their sea water at low tide and may be either brackish, full saline or hyper-saline. Sea water exchange in lagoons takes place through natural or man-modified channels or by percolation through or overtopping of the barrier between the lagoon and the sea. The salinity of the system is determined by the level of fresh water input from ground or surface waters. In Cumbria all saline lagoons are man-made; they have a variety of origins, including docks, gravel extraction, mine workings and marine recreational lakes.

Lagoons usually contain soft sediments which often support tasselweeds, stoneworts (algae) and filamentous green and brown algae.

They provide important habitat for wildfowl, waders and sea birds, including Teal, Curlew, Knot, Redshank, shelduck, Mute Swan, Wigeon and Cormorant. They also support unique invertebrate groupings.

Distribution and Extent

This is a very rare habitat, restricted to a small number of sites, including the gravel pits on Walney Island (SPA and SAC), Hodbarrow Lagoon (SPA and SAC), Cavendish Dock (SPA) and docks at Whitehaven, Workington, Maryport and Silloth.

Conservation Issues

One of the main threats to saline lagoons comes from changes to water quality. A deterioration in water quality, including changes in temperature and a high biological oxygen deficit, can reduce biodiversity interest and increase algal growth. Similarly disruption of either freshwater or seawater inputs can have detrimental effects on the ecology and hence biodiversity interest of these lagoons.

High recreational pressure can damage biodiversity interests through both disturbance to wildlife and via changes in water quality due to pollution, or increased turbidity and wave action on shorelines. Dogs in particular can disturb birds and recreational pressure can damage shoreline
vegetation.

Another threat to saline lagoon ecosystems is the introduction of non-native species, which can radically change the ecosystem balance and result in the loss of rare species.

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Planning considerations

• PPS9 states that local authorities should conserve important natural habitat types (priority habitats and habitats of principal importance in England), and identify opportunities to enhance and add to them.
• Any development that may impact upon this habitat, and its species interests, would require an assessment of the likely effects on the habitat/species and, as necessary, appropriate protection and mitigation measures.
• Saline lagoons are highly sensitive to changes in water quality, both in the form of changes in the balance of sea and fresh waters they receive and in the form of pollution impacts from adjacent developments.
• Birds using the lagoons can also be highly sensitive to disturbance.
• The lagoons at Walney Island, Cavendish Dock and Hodbarrow are of international importance as European Marine Sites, designated as Special Areas of Conservation and/ or Special Protection Areas, as well as SSSIs. Other sites are not designated.
• Any development that may have a significant effect, directly or indirectly, on the European Sites would need to be assessed under the Habitats Regulations.
  

Enhancement Opportunities

• Any opportunities to reduce pollution and other impacts resulting from existing developments, through new development and design opportunities, will benefit saline lagoon habitat.
  

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Habitat Targets

• Habitat targets for Cumbria can be found in a separate document “Habitat Targets, Planning Considerations and Enhancement Opportunities” available from www.lakelandwildlife.co.uk or by clicking here

Key Species

The following Key Species could benefit from enhancement of this habitat, or be negatively impacted upon by inappropriate developments on or near this habitat:

 

Curlew	Little Tern

 

Go to Full Key Species List for further information on these species.

Further Information

UK BAP saline lagoons
Habitats of principal importance in England Section 41 NERC Act list
Cumbria BAP coastal habitats
Cumbria Wildlife Trust South Walney Reserve
RSPB Hodbarrow reserve information
RSPB: managing saline lagoons for birds
RSPB: creating saline lagoons for invertebrates and plants
Buglife: habitat management advice: saline lagoons
Environmental Stewardship and HLS handbook

Contacts

Current Action in Cumbria

The Environmental Stewardship Scheme run by Natural England provides financial incentives to manage land in a way that is sympathetic to its nature conservation interest with specific inter-tidal and coastal options applicable to this habitat.