2010 04 The Severn Estuary European Marine Site – Christine Marsh

ASERAASSOCIATION OF SEVERN ESTUARY RELEVANT AUTHORITIES

The Severn Estuary European Marine Site

Christine Marsh ASERA Implementation Officer

Source of photo: Monmouthshire County Council

UK Marine Protected Areas

The Severn Estuary’s special featuresHabitats; Estuaries, Atlantic salt

meadows, intertidal mud and sand flats, reefs, saltmarsh, shingle and rocky shore

Fish species; Allis and Twaite Shad, Eel, River and Sea Lamprey,

Waterfowl; Bewicks Swan, Redshank, Dunlin, Shelduck, European white-

fronted Goose, Gadwall,

SAC Features• Estuaries• Subtidal

sandbanks• Mudflats &

sandflats• Atlantic

Saltmeadow• Reefs• River Lamprey• Sea Lamprey• Twaite Shad

SPA Features• Bewicks Swan• European White

Fronted Goose• Wintering Dunlin• Wintering

Redshank• Wintering Shelduck• Wintering Gadwall• Internationally

important assemblage of waterfowl

Ramsar Features• Estuaries• Assemblage of

migratory fish species• Bewicks Swan• European White

Fronted Goose• Dunlin• Redshank• Shelduck• Gadwall• Internationally

important assemblage of waterfowl

• Physical, chemical and biological processes (geomorphology and ecology)

• second largest tidal range in the world• millions of tonnes of sediment in

suspension and highly mobile sand and mud banks moved around the estuary by the tide and storms.

• Wide variety of habitats and species all dependant on and/or driven by these natural processes.

Estuaries

Source of photo: Natural England


Sub-tidal sandbanks(sand banks slightly covered by sea water all of the time)

• Permanently submerged soft sediments in shallow <20m water - both banks and channels

• Severn has gravelly & clean sands and muddy sands – 7 biotopes identified, in places up to 20m thick deposits

• Some are highly mobile and changing banks due to extreme tidal conditions

• Most mobile have restricted species due to dynamic nature of sediments

• Important in terms of representing this habitat across the UK and Europe – Severn is the only coastal plain estuary selected in the UK and one of only two sites with a variable and low salinity regime


Reefs

Reefs built by Sabellaria alveolata - the honeycomb worm

Make tubes from sand particles - large numbers produce distinctive honey comb colonies which can be ca 30cm high.

Each opening is a tube that contains one of these worms. The worms when covered by the tide will poke out their tentacled head to feed

In the Severn these occur both in the subtidal areas and intertidal areas - those in the subtidal are the designated “reef” feature


Intertidal mud and sand • These make up the largest area of

habitat in the Severn Estuary. The transition from sand, through muddy sand to mud, typical of coastal plain estuaries is only found in part of the Severn.

• The mud and sand in the estuary is generally highly mobile, although parts of the estuary are relatively stable.

• Movement of sediment is accompanied by the many specialised animals such as snails, shrimps and ragworms that live just beneath the surface

• Whilst the range of species in these habitats is often low in places some species can occur in large numbers and provide an important food source for fish and feeding sites for breeding, wintering and passage birds within the estuary.

• Intertidal zone plays an important role in protecting the shoreline by reducing wave energy.


Supporting cast Other habitats & species that areIntrinsic parts of the over-archingestuary feature:

• Atlantic saltmeadow• Rocky shores• Reedbeds & swamps• Transition grasslands • Invertebrates• Vascular plants• Fish

All are features of the underpinningSSSIs - we need to take account ofthem in defining the conservationrequirements of the estuary


Waterfowl; ducks, geese, swans, waders

Unless otherwise stated, photos sourced: Dominic Heard

Wigeon (Anas penelope)Gadwall (Anas strepera)

Shelduck (Tadorna tadorna)

Bewicks swan (Cygnus columbianus)

Source : Natural England

Ringed Plover (Charadrius hiaticula)

Tufted duck (Aythya fuligula)Redshank

Dunlin

Source : ASERA

Source : ASERA

Fish species

• 3 species of migratory fish for which the Severn is specifically designated as a Special Area of Conservation (SAC)– Twaite shad– River lamprey– Sea lamprey

• All use the estuary as a route to and from spawning sites

• All use neighbouring rivers, such as the Usk, Wye and Severn, to spawn

• Further 4 significant migratory species, Allis shad, salmon, sea trout and eel – important in context of the over arching estuary feature

• Wider community of over 100 species recorded in the Severn

• The estuary supports 36 of 41 British estuarine species


The object of the Association of Severn Estuary Relevant Authorities is to establish and maintain in being, a management scheme for the Severn Estuary European Marine Site under which the functions of the relevant authorities shall be exercised so as to secure in relation to that site compliance with the requirements of The Conservation of Habitats & Species Regulations 2010 (as amended) which transpose the Habitats and Birds Directives into law in Great Britain.


ASERA’s Progress so far with the management scheme…

• Finalising the new scheme of management

• Producing specific action plans for relevant authorities to implement the management scheme

• Producing guidance notes as required for certain activities

• Updating the reporting process for relevant authorities

• Establishing a monitoring programme for the activities and features in the European marine site

Relevant Authority activities in the Severn Estuary;

Recreation; Airborne sports, Land based recreation, Water based recreation,

Events/Festivals, Wildfowling . Angling; Angling (recreational), Bait digging, Eel and elver fishing, Fishing. Boating and shipping;

Anchoring , Boat repairs , Moorings, Navigation. Port activities; Commercial

shipping/cargo operations, Discharge/exchange of water ballast, Lock-

gate & dock water mgt, Maintenance dredging, Port waste management (inc ship

generated waste). Land management; Agricultural run-off, Beach cleaning,

Grazing, Habitat creation and restoration, Release of contamination through historic

industry, Barrage and sluice operation . Water management; Excavation, Water channel maintenance, Coastal protection

and flood defence improvement and maintenance works. Infrastructure; Estate

& Highways discharge, Cable laying & maintenance, Pipeline and Outfall maintenance, Property & estate

maintenance. Education; Collection of scientific data, Archaeology (studies &

protection), Educational field trips. Planning; Emergency planning , Managing

unauthorised waste. Misc; Low flying aircraft.

What next for ASERA….



Christine MarshASERA Implementation Officer

Email: [email protected] Web: http://www.severnestuary.net/asera

Ringed Plover

mailto:[email protected]

http://www.severnestuary.net/asera

http://www.severnestuary.net/asera

2010 04 The Severn Estuary European Marine Site – Christine Marsh

Environment