St. Pierre Island

__NOTOC__:"For the French island off the coast of Canada see Saint-Pierre and Miquelon.":"For the island in Maryland see St. Pierre Island (Manokin River)"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 at (coord|9|17|S|50|44|E|), 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. The island is nearly circular, 1.6 km (1 mile) east-west by 1.4 km (0.87 mi) north-south, with a land area of 1.68 km² (0.65 sq mi)Piggott (1961)] . 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 and 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)Verify source|date=April 2008 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 blowholes worn out of the coral, depositing dunes 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.

The climate is dominated by the southeast trade winds which are most pronounced between April and November, during which time little if any rain falls. Temperatures during that time are around 28 °C (83°F) in what little shade the casuarina forest provides. During the northwest monsoon season, rains are more frequent, sometimes accompanying tropical cyclones, but even so St Pierre is a rather arid place altogether.

History and ecology

In former times, much of the island was overed with a "Pisonia grandis" forest, in which large numbers of seabirds 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 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 bananas ("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.

Footnotes

References

* (1961): Notes on some of the Seychelles Islands, Indian Ocean. "Atoll Research Bulletin" 83: 1-10. [http://www.botany.hawaii.edu/faculty/duffy/ARB/076-84/83.pdf PDF fulltext]