The combination of southeastern trade winds and northwestern monsoons produces a hot rainy season (November–April) with frequently destructive cyclones, and a relatively cooler dry season (May–October).
Rain clouds originating over the Indian Ocean discharge much of their moisture over the island’s eastern coast; the heavy precipitation supports the area’s rainforest ecosystem.
The central highlands are both drier and cooler while the west is drier still, and a semi-arid climate prevails in the southwest and southern interior of the island.
Tropical cyclones annually cause damage to infrastructure and local economies as well as loss of life. In 2004 Cyclone Gafilo became the strongest cyclone ever recorded to hit Madagascar.
The storm killed 172 people, left 214,260 homeless and caused more than US$250 million in damage.
Ecology
As a result of the island’s long isolation from neighboring continents, Madagascar is home to an abundance of plants and animals found nowhere else on Earth.
Approximately 90% of all plant and animal species found in Madagascar are endemic, including the lemurs (a type of strepsirrhine primate), the carnivorous fossa and many birds.
This distinctive ecology has led some ecologists to refer to Madagascar as the “eighth continent”, and the island has been classified by Conservation International as a biodiversity hotspot.
More than 80 percent of Madagascar’s 14,883 plant species are found nowhere else in the world, including five plant families. The family Didiereaceae, composed of four genera and 11 species, is limited to the spiny forests of southwestern Madagascar.
Four-fifths of the world’s Pachypodium species are endemic to the island. Three-fourths of Madagascar’s 860 orchid species are found here alone, as are six of the world’s nine baobab species.
The island is home to around 170 palm species, three times as many as on all of mainland Africa; 165 of them are endemic. Many native plant species are used as herbal remedies for a variety of afflictions.
The drugs vinblastine and vincristine are vinca alkaloids, used to treat Hodgkin’s disease, leukemia, and other cancers, were derived from the Madagascar periwinkle.
The traveler’s palm, known locally as ravinala and endemic to the eastern rain forests, is highly iconic of Madagascar and is featured in the national emblem as well as the Air Madagascar logo.
Flora and Fauna
Like its flora, Madagascar’s fauna is diverse and exhibits a high rate of endemism. Lemurs have been characterized as “Madagascar’s flagship mammal species” by Conservation International.
In the absence of monkeys and other competitors, these primates have adapted to a wide range of habitats and diversified into numerous species. As of 2012, there were officially 103 species and subspecies of lemur, 39 of which were described by zoologists between 2000 and 2008.
They are almost all classified as rare, vulnerable, or endangered. At least 17 species of lemur have become extinct since humans arrived on Madagascar, all of which were larger than the surviving lemur species.
A number of other mammals, including the cat-like fossa, are endemic to Madagascar. Over 300 species of birds have been recorded on the island, of which over 60 percent (including four families and 42 genera) are endemic.
The few families and genera of reptile that have reached Madagascar have diversified into more than 260 species, with over 90 percent of these being endemic (including one endemic family).
The island is home to two-thirds of the world’s chameleon species, including the smallest known, and researchers have proposed that Madagascar may be the origin of all chameleons.
Endemic fish of Madagascar include two families, 15 genera and over 100 species, primarily inhabiting the island’s freshwater lakes and rivers. Although invertebrates remain poorly studied on Madagascar, researchers have found high rates of endemism among the known species.
All 651 species of terrestrial snail are endemic, as are a majority of the island’s butterflies, scarab beetles, lacewings, spiders and dragonflies.
Environmental issues
Deforestation in Madagascar and Illegal logging in Madagascar
Madagascar’s varied fauna and flora are endangered by human activity. Since the arrival of humans around 2,350 years ago, Madagascar has lost more than 90 percent of its original forest.
This forest loss is largely fueled by tavy (“fat”), a traditional slash-and-burn agricultural practice imported to Madagascar by the earliest settlers.
Malagasy farmers embrace and perpetuate the practice not only for its practical benefits as an agricultural technique, but for its cultural associations with prosperity, health and venerated ancestral custom (fomba Malagasy).
As human population density rose on the island, deforestation accelerated beginning around 1400 years ago. By the 16th century, the central highlands had been largely cleared of their original forests.
More recent contributors to the loss of forest cover include the growth in cattle herd size since their introduction around 1000 years ago, a continued reliance on charcoal as a fuel for cooking, and the increased prominence of coffee as a cash crop over the past century.
According to a conservative estimate, about 40 percent of the island’s original forest cover was lost from the 1950s to 2000, with a thinning of remaining forest areas by 80 percent.
In addition to traditional agricultural practice, wildlife conservation is challenged by the illicit harvesting of protected forests, as well as the state-sanctioned harvesting of precious woods within national parks.
Although banned by then-President Marc Ravalomanana from 2000 to 2009, the collection of small quantities of precious timber from national parks was re-authorized in January 2009 and dramatically intensified under the administration of Andry Rajoelina as a key source of state revenues to offset cuts in donor support following Ravalomanana’s ousting.
It is anticipated that all the island’s rainforests, excluding those in protected areas and the steepest eastern mountain slopes, will have been deforested by 2025. Invasive species have likewise been introduced by human populations.
Following the 2014 discovery in Madagascar of the Asian common toad, a relative of a toad species that has severely harmed wildlife in Australia since the 1930s, researchers warned the toad could “wreak havoc on the country’s unique fauna.” Habitat destruction and hunting have threatened many of Madagascar’s endemic species or driven them to extinction.
The island’s elephant birds, a family of endemic giant ratites, became extinct in the 17th century or earlier, most probably due to human hunting of adult birds and poaching of their large eggs for food.
Numerous giant lemur species vanished with the arrival of human settlers to the island, while others became extinct over the course of the centuries as a growing human population put greater pressures on lemur habitats and, among some populations, increased the rate of lemur hunting for food.
A July 2012 assessment found that the exploitation of natural resources since 2009 has had dire consequences for the island’s wildlife: 90 percent of lemur species were found to be threatened with extinction, the highest proportion of any mammalian group.
Of these, 23 species were classified as critically endangered. By contrast, a previous study in 2008 had found only 38 percent of lemur species were at risk of extinction.
In 2003 Ravalomanana announced the Durban Vision, an initiative to more than triple the island’s protected natural areas to over 60,000 km2 (23,000 sq mi) or 10 percent of Madagascar’s land surface.
As of 2011, areas protected by the state included five Strict Nature Reserves (Réserves Naturelles Intégrales), 21 Wildlife Reserves (Réserves Spéciales) and 21 National Parks (Parcs Nationaux).
In 2007 six of the national parks were declared a joint World Heritage Site under the name Rainforests of the Atsinanana. These parks are Marojejy, Masoala, Ranomafana, Zahamena, Andohahela and Andringitra. Local timber merchants are harvesting scarce species of rosewood trees from protected rainforests within Marojejy National Park and exporting the wood to China for the production of luxury furniture and musical instruments.
To raise public awareness of Madagascar’s environmental challenges, the Wildlife Conservation Society opened an exhibit entitled “Madagascar!” in June 2008 at the Bronx Zoo in New York.
