Invasive alien species
Besides the native vegetation, Seychelles supports an estimated 850 introduced exotic (alien) species. Many of these were introduced in the early years of human settlement for the production of food, fodder, spices, medicines, essential oils and other natural products. At the same time, all the good native timber trees were exploited and vast areas were cleared to make way for plantations and other forms of development. Even in the present, plant introductions continue as horticulture establishes itself as a real industry.
As a result, an estimated 90% of the primary vegetation has been destroyed, with the remaining 10% surviving in small inaccessible areas. Since the 1970’s many of the plantations have been abandoned, creating excellent breeding stock for the further invasion of the few remaining fragmented habitats. Today there is not a single habitat that has not been profoundly altered or invaded by invasive exotic species. Glacis vegetation has, fortunately, been least affected.