Madagascar – October 19th, 2008
Madagascar, or Republic of Madagascar (older name Malagasy Republic), is an island nation in the Indian Ocean off the southeastern coast of Africa. The main island, also called Madagascar, is the fourth-largest island in the world, and is home to 5% of the world’s plant and animal species, of which more than 80% are endemic to Madagascar. They include the lemur infraorder of primates, the carnivorous fossa, three bird families and six baobab species.
Madagascar, as part of East Gondwana, split from Africa approximately 160 million years ago; the island of Madagascar was created when it separated from India 80 to 100 million years ago. Most archaeologists estimate that the human settlement of Madagascar happened between 200 and 500 A.D., when seafarers from southeast Asia (probably from Borneo or the southern Celebes) arrived in outrigger sailing canoes. Bantu settlers probably crossed the Mozambique Channel to Madagascar at about the same time or shortly afterwards. However, Malagasy tradition and ethnographic evidence suggests that they may have been preceded by the Mikea hunter gatherers.
At 587,041 km² (226,657.8 sq mi), Madagascar is the world’s 46th-largest country and the fourth largest island. It is slightly larger than France, and is one of 11 distinct physiographic provinces of the South African Platform physiographic division.
Towards the east, a steep escarpment leads from the central highlands down into a ribbon of rain forest with a narrow coastal further east. The Canal des Pangalanes is a chain of natural and man-made lakes connected by canals that runs parallel to the east coast for some 460 km (about two-thirds of the island). The descent from the central highlands toward the west is more gradual, with remnants of deciduous forest and savanna-like plains (which in the south and southwest, are quite dry and host spiny desert and baobabs). On the west coast are many protected harbours, but silting is a major problem caused by sediment from the high levels of erosion inland.
Along the crest of this ridge lie the central highlands, a plateau region ranging in altitude from 2,450 to 4,400 ft (750 to 1350m) above sea level. The central highlands are characterised by terraced, rice-growing valleys lying between barren hills. Here, the red laterite soil that covers much of the island has been exposed by erosion, showing clearly why the country is often referred to as the “Red Island”.
The island’s highest peak, Maromokotro, at 2,876 m (9,436 ft), is found in the Tsaratanana Massif, located in the far north of the country. The Ankaratra Massif is in the central area south of the capital Antananarivo and hosts the third highest mountain on the island, Tsiafajavona, with an altitude of 2,642 m (8,668 ft). Further south is the Andringitra massif which has several peaks over 2400 m (about 8,000 ft) including the second and fourth highest peaks, Pic Imarivolanitra, more widely known as Pic Boby (8,720 ft, 2,658 m), and Pic Bory (8,626 ft, 2,630 m). Other peaks in the massif include Pic Soaindra (8,594 ft, 2,620 m) and Pic Ivangomena (8,385 ft, 2,556 m). This massif also contains the Andringitra Reserve. On very rare occasions, this region experiences snow in winter due to its high altitude.
There are two seasons: a hot, rainy season from November to April, and a cooler, dry season from May to October. South-eastern trade winds predominate, and the island occasionally experiences cyclones.
Madagascar’s long isolation from the neighboring continents has resulted in a unique mix of plants and animals, many found nowhere else in the world; some ecologists refer to Madagascar as the “eighth continent”. Of the 10,000 plants native to Madagascar, 90% are found nowhere else in the world.
Madagascar’s varied fauna and flora are endangered by human activity, as a third of its native vegetation has disappeared since the 1970s, and only 18% remains intact.
The eastern, or windward side of the island is home to tropical rainforests, while the western and southern sides, which lie in the rain shadow of the central highlands, are home to tropical dry forests, thorn forests, and deserts and xeric shrublands. Madagascar’s dry deciduous rain forest has been preserved generally better than the eastern rainforests or the high central plateau, presumably due to historically low population densities.
Extensive deforestation has taken place in parts of the country. Slash-and-burn activity, locally called tavy, has occurred in the eastern and western dry forests as well as on the central high plateau, reducing certain forest habitat and applying pressure to some endangered species. Slash-and-burn is a method sometimes used by shifting cultivators to create short-term yields from marginal soils. When practiced repeatedly without intervening fallow periods, the nutrient-poor soils may be exhausted or eroded to an unproductive state. The resulting increased surface runoff from burned lands has caused significant erosion and resulting high sedimentation to western rivers.