Tamar–Tavy Estuary
Encyclopedia
The Tamar–Tavy Estuary is a Site of Special Scientific Interest
(SSSI) covering the tidal estuaries
of the River Tamar
and the River Tavy
on the border between Cornwall
and Devon
in England, UK. Part of the Tamar estuary also forms the Tamar Estuary Nature Reserve, owned by the Cornwall Wildlife Trust
. The site was designated in 1991 for its biodiversity and varying habitats that support a large number of wader
and wildfowl species, as well as the special interest of its marine biology.
down to the Tamar Bridge
in the south, where it forms the Hamoaze
, and the River Tavy from Lopwell
to its discharge in the Tamar. The site also includes Kingsmill Lake, Tamerton Lake and a few other tributary streams of the Tamar, as well as the marshes around Morwellham Quay
.
The site forms part of the Tamar Estuaries Complex Special Protection Area
(SPA), along with the estuary of the River Lynher
and St John's Lake
, as well as forming part of the Plymouth Sound
and Estuaries Special Area of Conservation
(SAC).
The Cornwall Wildlife Trust owns the 109 hectares (269.3 acre) Tamar Estuary nature reserve
around Kingsmill Lake, below Landulph
, and Lopwell Dam is a Local Nature Reserve
, covering the dam and surrounding woodlands.
for wildfowl and wader birds.
Mudflat
s form the lower reaches of the estuary system and are bordered by salt marsh
, inundation grassland
and rocky shoreline habitats. These mainly contain common saltmarsh-grass (Puccinellia maritima
), Red Fescue and Sea Couch, as well as two nationally scarce species of grass: Stiff Saltmarsh-grass (Puccinellia rupestris) and Bulbous Foxtail. The upstream part of the system supports freshwater marsh
, fen
, rush pasture and reedmarsh
habitats, along with wooded valleys in places. Species include the Common Reed and the only known population in the British Isles
of Triangular Club-rush, part of the Schoenoplectus
genus.
The mudflats attract more than 20% of the British wintering population of the uncommon Pied Avocet
. They additionally support Black-tailed Godwit
, Common Redshank
, Dunlin
, Whimbrel
, Greenshank
, Spotted Redshank
and Green Sandpiper
during the wintering period, with the first birds arriving in October and leaving again throughout March.
The highly variable salinity along the transition from marine estuary to river allows for a diverse marine culture. Seaweeds, green algae
and communities of polychaete worm
s are all found in the estuary system; near Calstock
is found the shrimp Palaemon longirostris, which has been recorded in only two other estuaries in Britain. The estuary is also one of only two sites in the UK where the fish, allis shad
, spawn.
Other larger animals found in undisturbed parts of the SSSI include the European Otter
, the Common Kingfisher and dormice
.
Site of Special Scientific Interest
A Site of Special Scientific Interest is a conservation designation denoting a protected area in the United Kingdom. SSSIs are the basic building block of site-based nature conservation legislation and most other legal nature/geological conservation designations in Great Britain are based upon...
(SSSI) covering the tidal estuaries
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
of the River Tamar
River Tamar
The Tamar is a river in South West England, that forms most of the border between Devon and Cornwall . It is one of several British rivers whose ancient name is assumed to be derived from a prehistoric river word apparently meaning "dark flowing" and which it shares with the River Thames.The...
and the River Tavy
River Tavy
The Tavy is a river on Dartmoor, Devon, England. The name derives from the Brythonic root "Taff", the original meaning of which has now been lost...
on the border between Cornwall
Cornwall
Cornwall is a unitary authority and ceremonial county of England, within the United Kingdom. It is bordered to the north and west by the Celtic Sea, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Cornwall has a population of , and covers an area of...
and Devon
Devon
Devon is a large county in southwestern England. The county is sometimes referred to as Devonshire, although the term is rarely used inside the county itself as the county has never been officially "shired", it often indicates a traditional or historical context.The county shares borders with...
in England, UK. Part of the Tamar estuary also forms the Tamar Estuary Nature Reserve, owned by the Cornwall Wildlife Trust
Cornwall Wildlife Trust
The Cornwall Wildlife Trust is a charitable organisation founded in 1962 that is concerned solely with Cornwall, United Kingdom.It deals with the conservation and preservation of Cornwall's wildlife and habitats managing over 50 nature reserves covering approximately , amongst them Looe...
. The site was designated in 1991 for its biodiversity and varying habitats that support a large number of wader
Wader
Waders, called shorebirds in North America , are members of the order Charadriiformes, excluding the more marine web-footed seabird groups. The latter are the skuas , gulls , terns , skimmers , and auks...
and wildfowl species, as well as the special interest of its marine biology.
Geography
The 1422 hectares (3,513.8 acre) SSSI encompasses the entirety of the tidal regions of the Tamar; from GunnislakeGunnislake
Gunnislake is a large village in east Cornwall, United Kingdom. It is situated in the Tamar Valley approximately ten miles north of Plymouth...
down to the Tamar Bridge
Tamar Bridge
The Tamar Bridge is a major road bridge at Saltash in southwest England carrying traffic between Cornwall and Devon. When it opened in 1961 it was the longest suspension bridge in the United Kingdom...
in the south, where it forms the Hamoaze
Hamoaze
The Hamoaze is an estuarine stretch of the tidal River Tamar, between the River Lynher and Plymouth Sound, England.The Hamoaze flows past Devonport Dockyard, which belongs to the Royal Navy...
, and the River Tavy from Lopwell
Lopwell
Lopwell is a site of natural beauty situated at the upper tidal mark on the River Tavy, 3 miles from north Plymouth and 7 miles from Tavistock, Devon, England....
to its discharge in the Tamar. The site also includes Kingsmill Lake, Tamerton Lake and a few other tributary streams of the Tamar, as well as the marshes around Morwellham Quay
Morwellham Quay
Morwellham Quay is a historic river port in Devon, England that developed to support the local mines. The port had its peak in the Victorian era and is now run as a tourist attraction and museum...
.
The site forms part of the Tamar Estuaries Complex Special Protection Area
Special Protection Area
A Special Protection Area or SPA is a designation under the European Union Directive on the Conservation of Wild Birds.Under the Directive, Member States of the European Union have a duty to safeguard the habitats of migratory birds and certain particularly threatened birds.Together with Special...
(SPA), along with the estuary of the River Lynher
River Lynher
The River Lynher flows through east Cornwall, UK, passing St Germans and enters the River Tamar at the Hamoaze, which in turn flows into Plymouth Sound.-Geography:...
and St John's Lake
St John, Cornwall
St John is a coastal civil parish and a village in south-east Cornwall, United Kingdom south of Saltash and south-east of Torpoint.-Geography:...
, as well as forming part of the Plymouth Sound
Plymouth Sound
Plymouth Sound, or locally just The Sound, is a bay at Plymouth in England.Its southwest and southeast corners are Penlee Point in Cornwall and Wembury Point on Devon, a distance of about 3 nautical miles . Its northern limit is Plymouth Hoe giving a north-south distance of nearly 3 nautical miles...
and Estuaries Special Area of Conservation
Special Area of Conservation
A Special Area of Conservation is defined in the European Union's Habitats Directive , also known as the Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora...
(SAC).
The Cornwall Wildlife Trust owns the 109 hectares (269.3 acre) Tamar Estuary nature reserve
Nature reserve
A nature reserve is a protected area of importance for wildlife, flora, fauna or features of geological or other special interest, which is reserved and managed for conservation and to provide special opportunities for study or research...
around Kingsmill Lake, below Landulph
Landulph
Landulph is a hamlet and a rural civil parish in south-east Cornwall, United Kingdom. It is situated about 3 miles north of Saltash in the St Germans Registration District....
, and Lopwell Dam is a Local Nature Reserve
Local Nature Reserve
Local nature reserve or LNR is a designation for nature reserves in the United Kingdom. The designation has its origin in the recommendations of the Wild Life Conservation Special Committee which established the framework for nature conservation in the United Kingdom and suggested a national suite...
, covering the dam and surrounding woodlands.
Wildlife and ecology
The SSSI, due to its habitats, is of international importance for nature conservation, in particular as a wintering siteBird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
for wildfowl and wader birds.
Mudflat
Mudflat
Mudflats or mud flats, also known as tidal flats, are coastal wetlands that form when mud is deposited by tides or rivers. They are found in sheltered areas such as bays, bayous, lagoons, and estuaries. Mudflats may be viewed geologically as exposed layers of bay mud, resulting from deposition of...
s form the lower reaches of the estuary system and are bordered by salt marsh
Salt marsh
A salt marsh is an environment in the upper coastal intertidal zone between land and salt water or brackish water, it is dominated by dense stands of halophytic plants such as herbs, grasses, or low shrubs. These plants are terrestrial in origin and are essential to the stability of the salt marsh...
, inundation grassland
British NVC community MG11
British NVC community MG11 is one of the mesotrophic grassland communities in the British National Vegetation Classification system. It is one of three types of mesotrophic grassland classified as grass-dominated inundation communities.It is a quite localised community...
and rocky shoreline habitats. These mainly contain common saltmarsh-grass (Puccinellia maritima
Puccinellia maritima
Puccinellia maritima is a species of grass known by the common names including seaside alkali grass, common saltmarsh-grass or sea poa grass. It is native to Western Europe and it is present in most of North East North America. It grows in moist, usually saline soils. It can reach a height of...
), Red Fescue and Sea Couch, as well as two nationally scarce species of grass: Stiff Saltmarsh-grass (Puccinellia rupestris) and Bulbous Foxtail. The upstream part of the system supports freshwater marsh
Freshwater marsh
A freshwater marsh is a marsh that contains fresh water. They are usually found near the mouths of rivers and are present in areas with low drainage. The Florida Everglades, the largest freshwater marsh in the United States, are an example of this type of marsh....
, fen
Fen
A fen is a type of wetland fed by mineral-rich surface water or groundwater. Fens are characterised by their water chemistry, which is neutral or alkaline, with relatively high dissolved mineral levels but few other plant nutrients...
, rush pasture and reedmarsh
Reed bed
Reed beds are natural habitats found in floodplains, waterlogged depressions andestuaries. Reed beds are part of a succession from young reed colonising open water or wet ground through a gradation of increasingly dry ground...
habitats, along with wooded valleys in places. Species include the Common Reed and the only known population in the British Isles
British Isles
The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...
of Triangular Club-rush, part of the Schoenoplectus
Schoenoplectus
Schoenoplectus is a genus of about 80 species of sedges with a cosmopolitan distribution. Note that the name bulrush is also applied to species in the unrelated genus Typha...
genus.
The mudflats attract more than 20% of the British wintering population of the uncommon Pied Avocet
Pied Avocet
The Pied Avocet, Recurvirostra avosetta, is a large black and white wader in the avocet and stilt family, Recurvirostridae. They breed in temperate Europe and western and Central Asia. It is a migratory species and most winter in Africa or southern Asia...
. They additionally support Black-tailed Godwit
Black-tailed Godwit
The Black-tailed Godwit, Limosa limosa, is a large, long-legged, long-billed shorebird first described by Carolus Linnaeus in 1758. It is a member of the Limosa genus, the godwits...
, Common Redshank
Common Redshank
The Common Redshank or simply Redshank is an Eurasian wader in the large family Scolopacidae.- Description and systematics :...
, Dunlin
Dunlin
The Dunlin, Calidris alpina, is a small wader, sometimes separated with the other "stints" in Erolia. It is a circumpolar breeder in Arctic or subarctic regions. Birds that breed in northern Europe and Asia are long-distance migrants, wintering south to Africa, southeast Asia and the Middle East...
, Whimbrel
Whimbrel
The Whimbrel Numenius phaeopus, is a wader in the large family Scolopacidae. It is one of the mostwidespread of the curlews, breeding across much of subarctic North America, Europe and Asia as far south as Scotland....
, Greenshank
Greenshank
The Common Greenshank is a wader in the large family Scolopacidae, the typical waders. Its closest relative is the Greater Yellowlegs, together with which and the Spotted Redshank it forms a close-knit group...
, Spotted Redshank
Spotted Redshank
The Spotted Redshank, Tringa erythropus, is a wader in the large bird family Scolopacidae. It breeds across northern Scandinavia and northern Asia and migrates south to the Mediterranean, the southern British Isles, France, tropical Africa, and tropical Asia for the winter...
and Green Sandpiper
Green Sandpiper
The Green Sandpiper is a small wader of the Old World. It represents an ancient lineage of the genus Tringa; its only close living relative is the Solitary Sandpiper . They both have brown wings with little light dots and a delicate but contrasting neck and chest pattern...
during the wintering period, with the first birds arriving in October and leaving again throughout March.
The highly variable salinity along the transition from marine estuary to river allows for a diverse marine culture. Seaweeds, green algae
Green algae
The green algae are the large group of algae from which the embryophytes emerged. As such, they form a paraphyletic group, although the group including both green algae and embryophytes is monophyletic...
and communities of polychaete worm
Polychaete
The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. More than 10,000...
s are all found in the estuary system; near Calstock
Calstock
Calstock is civil parish and a large village in south east Cornwall, England, United Kingdom, on the border with Devon. The village is situated on the River Tamar south west of Tavistock and north of Plymouth....
is found the shrimp Palaemon longirostris, which has been recorded in only two other estuaries in Britain. The estuary is also one of only two sites in the UK where the fish, allis shad
Allis shad
The allis shad is a species of fish in the Clupeidae family.-Location:It is found in Algeria, Belgium, Bulgaria, Denmark, France, Germany, Greece, Ireland, Italy, Morocco, the Netherlands, Norway, Poland, Portugal, Spain, Sweden, Switzerland, Turkey, and the United Kingdom.-Biology and...
, spawn.
Other larger animals found in undisturbed parts of the SSSI include the European Otter
European Otter
The European Otter , also known as the Eurasian otter, Eurasian river otter, common otter and Old World otter, is a European and Asian member of the Lutrinae or otter subfamily, and is typical of freshwater otters....
, the Common Kingfisher and dormice
Dormouse
Dormice are rodents of the family Gliridae. Dormice are mostly found in Europe, although some live in Africa and Asia. They are particularly known for their long periods of hibernation...
.