St. Pierre Island
Encyclopedia
St Pierre Island is a raised reef
island west of Providence Atoll
and part of Farquhar Group
, which belongs to the Outer Islands
of the Seychelles
. The island is located 35 km (19 nautical miles) west of Cerf Island of Providence Atoll
, 704 km (380 nmi) from Mahé
and 500 km (270 nmi) ENE of Aldabra
. This uninhabited island is nearly circular, 1.6 km (0.994196378639691 mi) east-west by 1.4 km (0.869921831309729 mi) north-south, with a land area of 1.68 km² (0.648651626435459 sq mi). St. Pierre has a gently sloping seabed on the exposed southeastern coast and a steep drop off on the northwest, where the fringing reef
is all but absent. It is uninhabited, and indeed in modern times all but uninhabitable. There is a derelict jetty at the ruined settlement on the north west shore, which is accessible by boat in the calmest weather only.
s worn out of the coral, depositing dune
s of sand and coral debris up to 10 m (30 ft) inland. At the southeast shore of the island, the wearing-away has caused the formation of flat shelves, and the entire island is honeycombed by caverns washed out by the sea. Due to this, no source of fresh water
exists on St Pierre.
forest, in which large numbers of seabird
s nested. The coral rock was thus covered with guano
. The guano, and since the 1950s also the rock and sand into which the phosphate
had been leached
, were mined away between 1906 and 1972 converting an island once densely forested to the current barren, pitted landscape. During that time, a small workers' settlement existed in the NW of St Pierre, which depended on supplies shipped in from abroads.
Today the island is barren except for a clump of Casuarina equisetifolia
trees up 12 m (40 ft) high on its northwestern part, covering a third of the land area. The trees were originally planted as windbreak
for the mining camp, and have unexpectedly thrived and spread. Most of the plant
species
once found on St Pierre are now gone, including the Pisonia, Suicide Tree
(Cerbera odollam) and rosemallow (Hibiscus tiliaceus). Some Pemphis acidula might persist.
By about 1960, it was noted that the most common herbaceous plant
was Stachytarpheta indica, while the introduced Indian Blanketflower (Gaillardia pulchella) had established itself widely. Sisal
(Agave sisalana), Chinese Violet (Asystasia gangetica), Papaya
(Carica papaya), Jimsonweed (Datura stramonium) and banana
s (Musa) were found around the mining camp. Whether any of these has survived is not known, though the dropseed grass
Sporobolus virginicus
which was found in abundance on the dunes probably has.
Raised coral atoll
A raised coral atoll is a typical atoll which has been lifted high enough above sea level by tectonic forces to protect it from scouring by storms and enable soils and diverse – often endemic – species of flora and fauna to develop...
island west of Providence Atoll
Providence Atoll
The Providence Atoll is part of the Seychelles, in the Farquhar Group. The islands in the group are small, coraline and inhospitable. The atoll has a more than 30 km long north-south axis, and is up to 10 km wide. The total area covered by the atoll is approximating 200 km². The aggregate land...
and part of Farquhar Group
Farquhar Group
The Farquhar Group belong to the Outer Islands of the Seychelles, lying in the southwest of the island nation, more than 700 kilometres southwest the capital, Victoria, on Mahé Island. The total land area of all islands in the group is less than 11 km², but the total area of the atolls measures...
, which belongs to the Outer Islands
Outer Islands (Seychelles)
The Outer Islands or Coralline Seychelles is a collective term for those islands of the Seychelles that are not on the shallow Seychelles Bank which defines the location of the Inner Islands. They are located at distances of 230 to 1150 km from the main Seychelles island of Mahé, and are all...
of the Seychelles
Seychelles
Seychelles , officially the Republic of Seychelles , is an island country spanning an archipelago of 115 islands in the Indian Ocean, some east of mainland Africa, northeast of the island of Madagascar....
. The island is located 35 km (19 nautical miles) west of Cerf Island of Providence Atoll
Providence Atoll
The Providence Atoll is part of the Seychelles, in the Farquhar Group. The islands in the group are small, coraline and inhospitable. The atoll has a more than 30 km long north-south axis, and is up to 10 km wide. The total area covered by the atoll is approximating 200 km². The aggregate land...
, 704 km (380 nmi) from Mahé
Mahé, Seychelles
Mahé is the largest island of the Seychelles, lying in the north east of the nation. The population of Mahé is 80,000. It contains the capital city of Victoria and accommodates 90% of the country's total population...
and 500 km (270 nmi) ENE of Aldabra
Aldabra
Aldabra, the world's second largest coral atoll, is in the Aldabra Group of islands in the Indian Ocean that form part of the Seychelles. Uninhabited and extremely isolated, Aldabra is virtually untouched by humans, has distinctive island fauna including the Aldabra Giant Tortoise, and is...
. This uninhabited island is nearly circular, 1.6 km (0.994196378639691 mi) east-west by 1.4 km (0.869921831309729 mi) north-south, with a land area of 1.68 km² (0.648651626435459 sq mi). St. Pierre has a gently sloping seabed on the exposed southeastern coast and a steep drop off on the northwest, where the fringing reef
Fringing reef
A fringing reef is one of the three main types of coral reefs recognized by most coral reef scientists. It is distinguished from the other two main types in that it has either an entirely shallow backreef zone or none at all...
is all but absent. It is uninhabited, and indeed in modern times all but uninhabitable. There is a derelict jetty at the ruined settlement on the north west shore, which is accessible by boat in the calmest weather only.
Geology and climate
The seaward faces of St. Pierre Island are abrupt and undercut fossil coral cliffs, 2.4-3 m (8-10 ft) high and broken at one point only by a 5 m (16 ft)-wide inlet to a cove with sandy bottom. Thus St Pierre Island is virtually inaccessible from the sea. In the center is a depression more or less of sea level. The ceaseless sea swell has undercut these faces; jets of water are thrown up in many places by each wave as it strikes blowholeBlowhole (geology)
In geology, a blowhole is formed as sea caves grow landwards and upwards into vertical shafts and expose themselves towards the surface, which can result in blasts of water from the top of the blowhole if the geometry of the cave and blowhole and state of the weather are appropriate.A blowhole is...
s worn out of the coral, depositing 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...
s of sand and coral debris up to 10 m (30 ft) inland. At the southeast shore of the island, the wearing-away has caused the formation of flat shelves, and the entire island is honeycombed by caverns washed out by the sea. Due to this, no source of fresh water
Fresh Water
Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...
exists on St Pierre.
History and ecology
In former times, much of the island was covered with a Pisonia grandisPisonia grandis
Pisonia grandis is a species of flowering tree in the Bougainvillea family, Nyctaginaceae.-Description:The tree has broad, thin leaves, smooth bark and bears clusters of green sweet-smelling flowers that mature into sticky barbed seeds....
forest, in which large numbers of seabird
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
s nested. The coral rock was thus covered with guano
Guano
Guano is the excrement of seabirds, cave dwelling bats, and seals. Guano manure is an effective fertilizer due to its high levels of phosphorus and nitrogen and also its lack of odor. It was an important source of nitrates for gunpowder...
. The guano, and since the 1950s also the rock and sand into which the phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
had been leached
Leaching (pedology)
In pedology, leaching is the loss of mineral and organic solutes due to percolation. It is a mechanism of soil formation. It is distinct from the soil forming process of eluviation, which is the loss of mineral and organic colloids. Leached and elluviated materials tend to be lost from topsoil and...
, were mined away between 1906 and 1972 converting an island once densely forested to the current barren, pitted landscape. During that time, a small workers' settlement existed in the NW of St Pierre, which depended on supplies shipped in from abroads.
Today the island is barren except for a clump of Casuarina equisetifolia
Casuarina equisetifolia
Casuarina equisetifolia is a she-oak species of the genus Casuarina. The native range extends from Burma and Vietnam throughout Malesia east to French Polynesia, New Caledonia, and Vanuatu, and south to Australia...
trees up 12 m (40 ft) high on its northwestern part, covering a third of the land area. The trees were originally planted as windbreak
Windbreak
A windbreak or shelterbelt is a plantation usually made up of one or more rows of trees or shrubs planted in such a manner as to provide shelter from the wind and to protect soil from erosion. They are commonly planted around the edges of fields on farms. If designed properly, windbreaks around a...
for the mining camp, and have unexpectedly thrived and spread. Most of the plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
once found on St Pierre are now gone, including the Pisonia, Suicide Tree
Cerbera odollam
Cerbera odollam, commonly known as the Suicide tree, Pong-pong, and Othalanga, is a species of tree native to India and other parts of Southern Asia. It grows preferentially in coastal salt swamps and in marshy areas. It grows wild along the coast in many parts of Kerala, India and has been grown...
(Cerbera odollam) and rosemallow (Hibiscus tiliaceus). Some Pemphis acidula might persist.
By about 1960, it was noted that the most common herbaceous plant
Herbaceous plant
A herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...
was Stachytarpheta indica, while the introduced Indian Blanketflower (Gaillardia pulchella) had established itself widely. Sisal
Sisal
Sisal is an agave that yields a stiff fibre traditionally used in making twine, rope and also dartboards. The term may refer either to the plant or the fibre, depending on context...
(Agave sisalana), Chinese Violet (Asystasia gangetica), Papaya
Papaya
The papaya , papaw, or pawpaw is the fruit of the plant Carica papaya, the sole species in the genus Carica of the plant family Caricaceae...
(Carica papaya), Jimsonweed (Datura stramonium) and banana
Banana
Banana is the common name for herbaceous plants of the genus Musa and for the fruit they produce. Bananas come in a variety of sizes and colors when ripe, including yellow, purple, and red....
s (Musa) were found around the mining camp. Whether any of these has survived is not known, though the dropseed grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...
Sporobolus virginicus
Sporobolus virginicus
Sporobolus virginicus, known by numerous common names including Marine Couch, Sand Couch, Coastal Rat-tail Grass, Salt Couch Grass, Saltwater Couch and Nioaka, is a coastal non-bunching tussock grass with a wide distribution.-Description:It is a perennial tussock grass from 10 to 50 centimetres in...
which was found in abundance on the dunes probably has.