Andohahela National Park, in southeast
Madagascar, is remarkable for the extremes of habitats that are represented within it. The park covers 760 square kilometers of the
Anosy mountain range, the southernmost spur of the Malagasy Highlands. These mountains form a natural barrier to the moist
trade winds that blow from the east, causing a rainfall of 1500 to 2000mm per year on their eastern side that supports one of the few rainforests south of the tropic of Capricorn. At the western edge of the park, the rainfall is just 600 to 700mm per year and the resulting vegetation is a dry
spiny forest characteristic of southern Madagascar. In the area between these two climatic extremes is a unique transitional forest known as the Ranopiso transition, which is characterised by the locally
endemic triangular palm,
Dypsis decaryi.