Flora of St Helena

From Infogalactic: the planetary knowledge core
(Redirected from Flora of Saint Helena)
Jump to: navigation, search

The flora of Saint Helena, an isolated island in the South Atlantic Ocean, is exceptional in its high level of endemism and the severe threats facing the survival of the flora. [1] In phytogeography, it is in the phytochorion St. Helena and Ascension Region of the African Subkingdom, in the Paleotropical Kingdom.

Endemic and introduced flora

The endemic plants of Saint Helena include many notable "insular arborescent Asteraceae", that is, members of the daisy family which have evolved a shrubby or tree-like habit on islands. Other notable endemics include the closely related St Helena redwood (Trochetiopsis erythroxylon) and St Helena dwarf ebony (Trochetiopsis ebenus). These are unrelated to the redwood trees of California or to the ebony trees of commerce, being instead in the Mallow family (Malvaceae).

Vegetation

Today there are three major vegetation zones: the tree-fern thicket of the highest parts of the central ridge; the pastures of middle elevations and the dry, eroded "crown wastes" of lower elevations. Of these only the tree-fern thicket is a natural vegetation type. The middle elevations were formerly covered with native woodland of gumwoods (Commidendrum) and other trees, now largely destroyed. The "Crown wastes" or coastal zones were formerly covered with native scrub, of which a major component was probably St Helena dwarf ebony (Trochetiopsis ebenus and St Helena tree ebony Trochetiopsis melanoxylon).

Human impact and conservation

The destruction of the native vegetation began soon after the discovery of the island by the Portuguese in 1502, with the introduction of goats. As there were no native herbivorous mammals, the flora was unadapted to such threats. Later with the establishment of permanent settlement on the island by the English East India Company in 1659, many introduced plants became established which created new vegetation types. Furthermore the native trees were subject to catastrophic cutting for such purposes as housebuilding and to fuel stills for the distillation of arrack. As a result of this legacy many endemic plant species are extinct or critically endangered.

Endemic vascular plants of St Helena

Monocotyledons

<templatestyles src="Div col/styles.css"/>

Dicotyledons

<templatestyles src="Div col/styles.css"/>

Pteridophytes (Ferns and fern-allies)

<templatestyles src="Div col/styles.css"/>

Endemic genera

<templatestyles src="Div col/styles.css"/>

See also

External links

References

  1. ↑ Lua error in package.lua at line 80: module 'strict' not found.

Sources

  • Lua error in package.lua at line 80: module 'strict' not found.

Further reading

  • Lua error in package.lua at line 80: module 'strict' not found.
  • Lua error in package.lua at line 80: module 'strict' not found.
Retrieved from "https://infogalactic.com/w/index.php?title=Flora_of_St_Helena&oldid=3471329"