Teän
Encyclopedia
Teän
is one of the uninhabited islands to the north of the Isles of Scilly
archipelago between Tresco
, 1.5 km to the west and St Martin's
300 m to the east.
Approximately 16 ha in area the island consists of a series of granite tors with the highest point, Great Hill, rising to 40 m at the eastern end. The low lying land is overlain with glacial till and outwash gravels with glacial erratics abundant on the north coast beaches which indicates the southern limit of outwash from an ice sheet.
There is evidence of occupation from the Bronze Age
to the early 19th century and the island was still being grazed in 1945. An early Christian chapel exists on the island, it is possibly named after a Saint Theon.
The island lies within the Isles of Scilly Heritage Coast
, and is in the Isles of Scilly Area of Outstanding Natural Beauty
and managed by the Isles of Scilly Wildlife Trust
which has an Higher Level Stewardship (HLS) agreement
period can be seen at extreme low tides. One of the carns, Old Man, has an early structure, a Bronze Age
entrance grave
, as does Great Hill in the east of the island. Roman type brooches have been found in a grave on Old Man. Sixteen early Christian graves have been found under the east wall of St Theona's chapel which was built later on top of the graves. There was probably an earlier wooden chapel.
A Parliamentary survey of 1652 reported one man living in a ruined house on the island and, in 1684, there was a thatched cottage between East Porth and West Porth which belonged to a Mr Nance who introduced kelp
burning to Scilly. His family continued to live on Teän for several more generations and by 1717 there were ten people living on the island, but in 1752 William Borlase
only saw fields of corn and ruined buildings. In the 19th century Woodley reported occasional occupation, a few acres of cultivation and sheep grazing. Cattle were still being grazed in 1945.
in 1971 and re-notified in 1986 under the 1981 Act. The SSSI was last assessed on 8 September 2009 and was found to be favourable. The assessment found that the vascular plant assemblage was all recorded apart from four-leaved allseed Polycarpon tetraphyllum
. A key issue was lack of management for orange bird’s-foot (Ornithopus pinnatus
) which needs short turf, and can be addressed with the HLS agreement held by the Isles of Scilly Wildlife Trust.
) and still has relic pasture plants such as rye grass (Lolium perenne
), red clover (Trifolium pratense), hop trefoil (Trifolium campestre) and black knapweed (Centaurea nigra
). The maritime grassland around St Helen's Porth, and on the south coast, has abundant thrift (Armeria maritima
) and sea campion (Silene maritime
), and near Clodgie Point orange bird’s-foot occurs. The dune
grassland area behind East and West Porth is important for the very rare dwarf pansy (Viola kitaibeliana). The summit of Great Hill has a small area of lowland heath
.
A pair of Marsh Harrier (Circus aeruginosus) bred on Teän in 2008 with two juveniles seen.
, due to isolation.
Recent visits have not found the Common Blue to be significantly different on Teän so Ford’s remarkable form no longer seems to exist; unusual female colour forms and aberrations may just occur more frequently on Scilly than elsewhere.
Red Barbed Ant (Formica rufibarbis)
The Red Barbed Ant
has been described as ″...perhaps the rarest resident animal in mainland Britain″ with only four nests in Surrey
and extinct in Cornwall (last recorded in 1907). Found on St Martin's, the Eastern Isles and also Teän where it was recorded in 2008. It's favoured habitat is open heathland with plenty of bare ground. Queens from St Martin's are captured and taken to Surrey to maintain those colonies.
is one of the uninhabited islands to the north of the Isles of Scilly
Isles of Scilly
The Isles of Scilly form an archipelago off the southwestern tip of the Cornish peninsula of Great Britain. The islands have had a unitary authority council since 1890, and are separate from the Cornwall unitary authority, but some services are combined with Cornwall and the islands are still part...
archipelago between Tresco
Tresco
Tresco is the second-biggest island of the Isles of Scilly, Cornwall, United Kingdom. It is in size, measuring about by .-History:In early times one group of islands was in the possession of a confederacy of hermits. King Henry I gave it to Tavistock Abbey which established a priory on Tresco;...
, 1.5 km to the west and St Martin's
St Martin's, Isles of Scilly
St Martin's is the northernmost populated island of the Isles of Scilly, United Kingdom. It has an area of .-Description:There are three main settlements on the island - Higher Town, Middle Town and Lower Town - in addition to a number of scattered farms and cottages, with a total population of...
300 m to the east.
Approximately 16 ha in area the island consists of a series of granite tors with the highest point, Great Hill, rising to 40 m at the eastern end. The low lying land is overlain with glacial till and outwash gravels with glacial erratics abundant on the north coast beaches which indicates the southern limit of outwash from an ice sheet.
There is evidence of occupation from the Bronze Age
Bronze Age Britain
Bronze Age Britain refers to the period of British history that spanned from c. 2,500 until c. 800 BC. Lasting for approximately 1700 years, it was preceded by the era of Neolithic Britain and was in turn followed by the era of Iron Age Britain...
to the early 19th century and the island was still being grazed in 1945. An early Christian chapel exists on the island, it is possibly named after a Saint Theon.
The island lies within the Isles of Scilly Heritage Coast
Heritage Coast
A Heritage Coast is a strip of UK coastline designated by the Countryside Agency in England and the Countryside Council for Wales as having notable natural beauty or scientific significance.- Designated coastline :...
, and is in the Isles of Scilly Area of Outstanding Natural Beauty
Area of Outstanding Natural Beauty
An Area of Outstanding Natural Beauty is an area of countryside considered to have significant landscape value in England, Wales or Northern Ireland, that has been specially designated by the Countryside Agency on behalf of the United Kingdom government; the Countryside Council for Wales on...
and managed by the Isles of Scilly Wildlife Trust
Isles of Scilly Wildlife Trust
The Isles of Scilly Wildlife Trust is a wildlife trust covering the Isles of Scilly off the coast of Cornwall, England, UK.The trust works in conjunction with the Cornwall Wildlife Trust, and jointly produces a thrice yearly magazine called Wild Cornwall & Wild Scilly.It is dedicated to ensuring...
which has an Higher Level Stewardship (HLS) agreement
History
The coastline of Teän consists of a number of bays and sandy beaches which link to offshore rocks and carns at low tide. The western part of the island has low lying ground linking granite carns, and field boundaries from the Romano-BritishRomano-British
Romano-British culture describes the culture that arose in Britain under the Roman Empire following the Roman conquest of AD 43 and the creation of the province of Britannia. It arose as a fusion of the imported Roman culture with that of the indigenous Britons, a people of Celtic language and...
period can be seen at extreme low tides. One of the carns, Old Man, has an early structure, a Bronze Age
Bronze Age Britain
Bronze Age Britain refers to the period of British history that spanned from c. 2,500 until c. 800 BC. Lasting for approximately 1700 years, it was preceded by the era of Neolithic Britain and was in turn followed by the era of Iron Age Britain...
entrance grave
Scillonian entrance grave
The entrance graves of Cornwall and the Isles of Scilly, and south east Ireland are megalithic chamber tombs of the Neolithic and early Bronze Age in the British Isles. Comparable sites are also known in Brittany and the Channel Islands...
, as does Great Hill in the east of the island. Roman type brooches have been found in a grave on Old Man. Sixteen early Christian graves have been found under the east wall of St Theona's chapel which was built later on top of the graves. There was probably an earlier wooden chapel.
A Parliamentary survey of 1652 reported one man living in a ruined house on the island and, in 1684, there was a thatched cottage between East Porth and West Porth which belonged to a Mr Nance who introduced kelp
Kelp
Kelps are large seaweeds belonging to the brown algae in the order Laminariales. There are about 30 different genera....
burning to Scilly. His family continued to live on Teän for several more generations and by 1717 there were ten people living on the island, but in 1752 William Borlase
William Borlase
William Borlase , Cornish antiquary, geologist and naturalist, was born at Pendeen in Cornwall, of an ancient family . From 1722 he was Rector of Ludgvan and died there in 1772.-Life and works:...
only saw fields of corn and ruined buildings. In the 19th century Woodley reported occasional occupation, a few acres of cultivation and sheep grazing. Cattle were still being grazed in 1945.
Natural history
The island was first notified as a Site of Special Scientific InterestSite 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...
in 1971 and re-notified in 1986 under the 1981 Act. The SSSI was last assessed on 8 September 2009 and was found to be favourable. The assessment found that the vascular plant assemblage was all recorded apart from four-leaved allseed Polycarpon tetraphyllum
Polycarpon tetraphyllum
Polycarpon tetraphyllum, commonly known as Four-leaved Allseed , is a plant of the family Caryophyllaceae . An annual herb growing to 15 cm in height, it is found on sandy soils, in coastal areas and on wasteland. Native to Europe, it is also naturalised in parts of North America, Australia and...
. A key issue was lack of management for orange bird’s-foot (Ornithopus pinnatus
Ornithopus
Ornithopus is a genus of flowering plants in the family Fabaceae.Selected species:*Ornithopus compressus—yellow serradella*Ornithopus micranthus*Ornithopus perpusillus—little white bird's foot*Ornithopus pinnatus—orange bird's foot...
) which needs short turf, and can be addressed with the HLS agreement held by the Isles of Scilly Wildlife Trust.
Flora
Human activity is relatively recent and evident with 8 ha of the island surrounded by hedges and once cultivated. This area is dominated by bracken (Pteridium aquilinumPteridium aquilinum
Pteridium aquilinum is a species of fern occurring in temperate and subtropical regions throughout much of the northern hemisphere....
) and still has relic pasture plants such as rye grass (Lolium perenne
Lolium perenne
Lolium perenne, common name Perennial Ryegrass, is a grass from the family Poaceae. It is native to Europe, Asia and northern Africa, but is widely cultivated and naturalised around the world.-Description:...
), red clover (Trifolium pratense), hop trefoil (Trifolium campestre) and black knapweed (Centaurea nigra
Centaurea nigra
Centaurea nigra is a species of flowering plant in the daisy family known by the common names Lesser Knapweed, Common Knapweed and Black Knapweed...
). The maritime grassland around St Helen's Porth, and on the south coast, has abundant thrift (Armeria maritima
Armeria maritima
Armeria maritima is the botanical name for a species of flowering plant.It is a popular garden flower, known by several common names, including thrift, sea thrift, and sea pink. The plant has been distributed worldwide as a garden and cut flower...
) and sea campion (Silene maritime
Silene
Silene is a genus of flowering plants in the family Caryophyllaceae. Common names include campion and catchfly....
), and near Clodgie Point orange bird’s-foot occurs. The dune
Dune
In physical geography, a dune is a hill of sand built by wind. Dunes occur in different forms and sizes, formed by interaction with the wind. Most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter "slip face" in the lee of the wind...
grassland area behind East and West Porth is important for the very rare dwarf pansy (Viola kitaibeliana). The summit of Great Hill has a small area of lowland heath
Lowland heath
Lowland Heath is a Biodiversity Action Plan Habitat as it is an ancient wild landscape type. Natural England's Environmental Stewardship scheme describes it as containing dry heath, wet heath and valley mire communities, usually below 250 metres, on acidic soils and shallow peat, typically...
.
Rare plants
- Shore dock (Rumex rupestris) first recorded here in 1984 and still there in 2005; a BAPUnited Kingdom Biodiversity Action PlanThe United Kingdom Biodiversity Action Plan is the governmental response to the Convention on Biological Diversity signed in 1992. When the Biodiversity Action Plans were first published in 1994, the conservation of 391 species and 45 habitats was covered. 1,150 species and 65 habitats are...
species. - Four-leaved allseed (Polycarpon tetraphyllumPolycarpon tetraphyllumPolycarpon tetraphyllum, commonly known as Four-leaved Allseed , is a plant of the family Caryophyllaceae . An annual herb growing to 15 cm in height, it is found on sandy soils, in coastal areas and on wasteland. Native to Europe, it is also naturalised in parts of North America, Australia and...
) last recorded in 1990 - Saltwort (Salsola kaliSalsola kaliKali soda is an annual plant that grows in arid soils and in sandy coastal soils. Its original range is Eurasian, but it has become naturalized, and even invasive, in North America, Australia, and elsewhere...
) recorded in 2009, once found on most sandy beaches in Scilly and now a rare plant; previous record on Scilly was 2004 on SamsonSamson, Isles of ScillySamson is the largest uninhabited island of the Isles of Scilly. It is in size. The island consists of two hills, North Hill and South Hill, which are connected by an isthmus on which the former inhabitants built many of their sturdy stone cottages...
.
Fauna
The only mammals found on Teän are the Brown Rat (Rattus norvegicus) and the House Mouse (Mus musculus). Rabbit (Oryctolagus cuniculus) may be extinct, and with no grazing animals on the island, plants that prefer a short sward such as orange bird’s foot may become extinct. In 1850 J. W. North reported that Teän "is a preserve of white rabbits"! Scilly Shrew (Crocidura suaveolens) bones have been found in Roman or early medieval middens and it was last recorded in 1964. There are no recent records.Breeding birds
The SSSI citation lists five species of breeding birds on the island including the Puffin (Fratercula arctica). Other breeding seabirds are the Kittiwake (Rissa tridactyla), Herring Gull (Larus argentatus), Lesser Black-backed Gull (Larus fuscus) and a small number of Greater Black-backed Gull (Larus marinus). The seabird breeding colonies are in decline on the Isles of Scilly and in the years 2006–09 the Kittiwake has failed to breed on all the islands bar one chick raised on St Agnes in 2009. Of the species listed above, none have been recorded as breeding on Teän in 2009.A pair of Marsh Harrier (Circus aeruginosus) bred on Teän in 2008 with two juveniles seen.
Invertebrates
Teän was the site of ground breaking mark and re–capture population studies of the Common Blue (Polyommatus icarus) butterfly by entomologists E. B. Ford and Prof W. H. Dowdeswell who camped on the island from 26 August to 8 September 1938. They marked each insect with a dot of cellulose paint so that it was possible to tell the date of first capture and any subsequent recaptures. The Common Blue is not a migratory butterfly and no marked butterflies were captured on the west side of St Martin’s, so additions to the Teän population were likely to be mainly emergences and losses due to death. It was noted that the normal form of the butterfly was found on St Mary’s, Tresco and St Martin’s whilst on Teän a separate raceRace (biology)
In biology, races are distinct genetically divergent populations within the same species with relatively small morphological and genetic differences. The populations can be described as ecological races if they arise from adaptation to different local habitats or geographic races when they are...
, due to isolation.
Ford described them as "The females obtained in the summer (I have no knowledge of the spring form) have an extensive scattering of pale silvery-blue scales, so that they are most unlike those found elsewhere, which are neither blackish or else marked with a violet shade. Moreover, the form from Teän is associated with a characteristic variation on the under-side of the hind-wings, which affects both sexes; for in a large proportion of the specimens the two spots placed along the coastal margin are united, forming a short curved line, and other varieties in spotting are frequent. We seem to here a stage in the evolution of an independent sub-species".
Recent visits have not found the Common Blue to be significantly different on Teän so Ford’s remarkable form no longer seems to exist; unusual female colour forms and aberrations may just occur more frequently on Scilly than elsewhere.
Red Barbed Ant (Formica rufibarbis)
The Red Barbed Ant
Formica rufibarbis
Formica rufibarbis is a European formicine ant of the Formica fusca group. In the classification by Auguste Forel, it is treated in the subgenus Serviformica....
has been described as ″...perhaps the rarest resident animal in mainland Britain″ with only four nests in Surrey
Surrey
Surrey is a county in the South East of England and is one of the Home Counties. The county borders Greater London, Kent, East Sussex, West Sussex, Hampshire and Berkshire. The historic county town is Guildford. Surrey County Council sits at Kingston upon Thames, although this has been part of...
and extinct in Cornwall (last recorded in 1907). Found on St Martin's, the Eastern Isles and also Teän where it was recorded in 2008. It's favoured habitat is open heathland with plenty of bare ground. Queens from St Martin's are captured and taken to Surrey to maintain those colonies.