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January 31, 2019. Life / Islands

Madagascar and Western Indian Ocean Islands

Nicholas D. Holmes, Olivier Langrand, Russell A. Mittermeier, Anthony B. Rylands, Thomas Brooks, Dena R. Spatz, James C. Russell, Wes Sechrest, Federico Mendez Sanchez

South of the Equator, off the coast of East Africa, lie Madagascar, the Comoros, the Seychelles, the Mascarenes, and the Scattered Islands that constitute the Madagascar and Indian Ocean Islands Biodiversity Hotspot. They constitute an emerged area of 600,461 square kilometers, of which 99% are accounted for by Madagascar alone.

Madagascar is the world’s fourth largest island and the largest oceanic island. It was part of the massive supercontinent called Gondwana. When Madagascar split from Africa 165 million years ago, a large proportion of plants and animals had yet to evolve, and this was still the case when it separated from India 90 million years ago. Of over 15,000 vascular plant species found in Madagascar, more than 85% are endemic, and the same is true for most of the vertebrates.

The Mascarene Archipelago is made up of three islands: Réunion (2,512 km2), Mauritius (1,865 km2) and Rodrigues (109 km2).

The islands of the Seychelles cover only 455 square kilometers but are scattered over an extensive area.

The Comoros are made up of four volcanic islands (2,035 km2) anchored on oceanic basaltic bedrock.

The Scattered Islands—five islands of volcanic origin and coralline nature—are located west of the island of Madagascar, and include the Glorioso Islands, Europa, Juan de Nova, Bassas da India, and Tromelin, together totaling 44 square kilometers. They are important breeding sites for green turtles and many seabird species.


This is an excerpt from the CEMEX Nature Series Book “Islands” (2018)

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