Green Mountain

Green Mountain is a common name for "The Peak" on Ascension Island which has gained some fame for claims that it is one of very few large-scale artificial forests.

Many early 19th century accounts, including Charles Darwin's (July 1836), described the volcanic island as barren with very few plants, some of them endemic to the island, not to be found anywhere else. Scientists estimate the island's native vascular plants to be between 25 and 30 species, 10 of them endemic to Ascension (Ashmole 2000, Gray et al. 2005). This impoverished flora is a consequence of the age of the island (only 1 million years old) and isolation (over 1,000 miles - 1,600 km - from any major landmass). Then, in 1843, the British plant collector Joseph Dalton Hooker visited the island with Sir James Clark Ross's Antarctica expedition. Hooker proposed a plan to plant the island with vegetation to attempt to increase rainfall and make life more bearable for the garrison that was stationed there (see Duffey 1964). Crucially he saw the appointment of a farm superintendent as being the key to success.

From that time on many plants have been introduced and Hooker's plan can be seen from one angle as an overwhelming success. An 1865 Admiralty report stated on the subject of Green Mountain, "(the island) now possesses thickets of 40 kinds of trees, besides numerous shrubs; through the spreading of vegetation, the water supply is now excellent." By the early 1900s many crops such as bananas and guavas were growing naturally. It is unlikely that this success lead to an increase in rainfall, However it is likely that there has been increased capture of occult deposition (mist) by the greater amount of vegetation.

The result however is not a man-made tropical forest, or a cloud forest as is sometimes claimed (see Wilkinson 2004 and Gray 2004) but a mosaic of habitats including woodland, grassland and shrubland. It has also been claimed that this ecosystem has arrived without any coevolution among its constituent species and this has been ignored by recent writers on the ecology of St. Helena and Ascension because it is "a wholly artificial ecosystem" (Ashmole 2000, p 250). However, things are never as simple as they seem, some of the species imported to Green Mountain were imported because of their evolutionary relationships. For example, many legumes (members of the pea family) were introduced to Ascension, legumes are exploited the world over for their apparent nitrogen fixation qualities, this actually arises as a result of an evolutionary relationship with the micro-organisms that are directly responsible for the nitrogen fixation. Also co-evolutionary relationships have been directly exploited, for example, the control of the prickly pear cactus (Opuntia vulgaris) through the use of the cactus moth (Catoblastus sp.) Today's ecologists are concerned about the effect these alien species have on the endemic species of the island. At least four endemic species are extinct and the remaining in danger of being so. Because of this Green Mountain is now a national park where native and endemic species are actively conserved.

The mineral dalyite was first found at Green Mountain.^[1]

References

• P. Ashmole and M. Ashmole (2000). St. Helena and Ascension Island: a natural history
• E. Duffey (1964). The Terrestrial Ecology of Ascension Island. The Journal of Applied Ecology, 1, (2), pp. 219–251.
• A. Gray, T. Pelembe and S. Stroud (2005).The conservation of the endemic vascular flora of Ascension Island and threats from alien species. Oryx 39, (4), pp. 449–453.
• A. Gray (2004).The parable of Green Mountain: massaging the message. Journal of Biogeography, 31, (9), pp. 1549–1550.

See also

• Terraforming
• Coevolution

External links

• David M. Wilkinson, "The parable of Green Mountain: Ascension Island, ecosystem construction and ecological fitting" in Journal of Biogeography 2004 vol31, pp 1–4 (pdf file)
• Global Volcanism Program: Ascension Island