Ecosystems of the Lesser Antilles
The archetypal image of a Caribbean island is one of volcanic mountains clad in forest growing right down to the seashore, the Pitons of St Lucia being a prime example. There is, however, a huge variety of ecosystems on the islands, despite their small size. An island such as St Lucia or Martinique may contain rainforest, cloud forest, elfin forest, dry tropical forest, thorn scrub, coastal wetlands, swamps, and mangroves. Even the Pitons have several different vegetation zones, depending on altitude.
Little primary rainforest can be found on the islands as it has been cleared by man or destroyed by hurricanes or lava flows. However, many islands have good secondary rainforest, much of it protected, and an invaluable water catchment resource. What is often referred to as rainforest is in fact montane forest, found on the middle slopes of the mountains of the Caribbean. Trees here reach a height of 32–40ft (10–12 meters) and are covered with mosses, lichens, and epiphytes (sometimes known as air plants; they live on other plants but use them only for support, and
are not parisitic). Elfin woodland is found on the highest peaks, such as on Saba’s Mount Scenery, almost permanently in cloud with low temperatures and lots of wind. Trees here are dwarf versions of what grows on lower slopes, more spreading in habit and contorted by the wind. They are often covered with epiphytes, mosses, and lichens, which thrive in the moist atmosphere and high rainfall.
Areas with a more moderate rainfall have a semi-evergreen forest, where many trees shed their leaves in the dry season and burst into flower, so that their seeds are ready for the next rainy season. Dry woodland areas are less rich in species, the trees are shorter, and there are fewer lianas and epiphytes. Most trees shed their leaves in the dry season and their bark is thick, helping them to retain moisture.
Drier still are the areas of thorn scrub, usually found near the coasts, where the ground might have been cleared at some stage, followed by the grazing of goats, sheep, and cattle. The tallest plants here are usually no more than 12ft (3 meters) and they have adapted to dry conditions by growing very small leaves, or no leaves at all in the case of cactus, and the most successful have thorns or spines to ward off grazing animals. Closer to the beach are sea grape, manchineel, and coconut, which can tolerate a higher salt content in the soil.
Protecting the mangroves
Mangroves grow on the coast in shallow bays, lagoons, estuaries, and deltas where the soil is permanently waterlogged and the mud is disturbed daily by the tides. There are many different types of mangroves, but they are an important breeding ground for fish, and home to crabs, molluscs, and many birds.
In Barbuda an enormous colony of frigate birds, who are unable to walk on land, and a number of other birds have taken over a huge area of mangroves in Codrington Lagoon, while in Trinidad, the Caroni swamp is the night-time roosting place of the scarlet ibis and egrets, and both areas have become major tourist attractions. Mangroves can be cut back to make charcoal and they will regenerate within a few years, but if they are cleared completely for a marina or resort hotel, valuable nurseries are lost forever.
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