East-northeast of the Horn of Africa, at the eastern end of the Gulf of Aden, lies an island archipelago known as Socotra (or Soqotra). The largest member of this island chain bears the same name as the archipelago itself. The islands are all part of the Republic of Yemen, and lie some 320 kilometers (200 miles) south of the mainland. The islands have a tropical desert climate with generally sparse rainfall.
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite took this picture of Socotra Island on June 3, 2008. The island’s hues range from pale beige to brick red to green. Green hues concentrate in a mountainous area in the eastern half of the island—an area that enjoys more rain than the coastal lowlands. Along parts of the island’s coast, sandy beaches are nearly gleaming white.
Socotra is a landmass of continental, rather than volcanic, origin. It broke free from the ancient landmass of Gondwana and carried with it some unusual—and now rare—organisms. Dracaena cinnabari, or “dragon’s blood trees,” so named for their red sap, evolved on the ancient continent, and later thrived throughout the Mediterranean and Middle East. Although isolated stands remain elsewhere, the largest stands are now confined to Socotra. Suited to the long droughts that can strike this island, the trees are more vulnerable to introduced livestock species, such as grazing goats.
Although dragon’s blood trees may be the most striking, they are not the only unique species on Socotra. Some 37 percent of the island chain’s 825 plant species, 90 percent of its reptile species, and 95 percent of its land snail species occur nowhere else in the world. Socotra’s biodiversity prompted the United Nations Educational, Scientific and Cultural Organization (UNESCO) to inscribe the island archipelago as a Word Heritage site in 2008.
NASA image created by Jesse Allen, using data obtained from the Goddard Land Processes data archives (LAADS). Caption by Michon Scott.
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