Phylica arborea
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Phylica arborea trees on the Amsterdam island |
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| Phylica arborea | ||||||||||||
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Phylica arborea is a rare tree-like, woody plants art from the family of the Buckthorn family (Rhamnaceae). It is located exclusively on the South Atlantic island of Gough and the Amsterdam island in the Indian Ocean .
distribution
While there is a second tree species in the Tristan da Cunha archipelago , to which Gough belongs, with Sophora cassioides , Phylica arborea is the only wood plant on the Amsterdam island and now only grows there on the eastern slope of the island. However, this has not always been the case. In 1726 Valentyn described a phylica forest in the form of a belt between 100 and 250 meters above sea level and an area of 1500 ha (about 27% of the surface of the island). This forest was so dense that it was practically impossible to get through. In 1875, Velain estimated that the forest covered no more than 250 hectares. The last volcanic eruption in 1792 and the resulting fires may have caused the forest on Amsterdam Island to disappear. In the mid-1980s, only a few remnants of the former forest remained. The extreme decline in the phylica population is primarily the result of human clearing, fires and cattle abandoned by Heurtin (a colonist from La Réunion ). Following the extermination of part of the herds in the south of the island in 1988 and the establishment of protective fences, a protection program allowed the replanting of 7,000 trees. The seeds of the remaining specimens were used. Today the Grand Bois - a protected area, the last dense phylica population on the eastern slope, covers an area of only 10 hectares (0.2% of the island's area).
relationship
Long it was believed that Phylica -Trees of Amsterdam Island belong to the species Phylica nitida . More recent phylogenetic studies, however, showed that the Phylica plants were not directly related to Phylica nitida from La Réunion or Mauritius . Accordingly, Phylica nitida is now considered an endemic species of the Mascarene . Even so, the Amsterdam Island phylica plants are referred to as Phylica nitida on many documents, including postage stamps from the French Southern and Antarctic Lands .
On the other hand, the Phylica -Trees of Amsterdam Island genetically very closely related to those of the 7200 km island remote Gough and form with them a kind. The transport of seeds by the Atlantic yellow-nosed albatross , the relationship could explain this long distance.
literature
- JE Richardson & al. (2003). Species Delimitation and the Origin of Populations in Island Representatives of Phylica (Rhamnaceae) . Evolution, Vol. 57, No. 4th
