Sky Islands

Sky Islands are mountains located within ranges that are isolated by valleys in which other ecosystems are located. As a result, mountain ecosystems are isolated from each other, and species can develop separately, as occurs on island groups such as the Galápagos Islands. The best known example of sky islands are the northern end of the Sierra Madre Occidental in New Mexico, Arizona, Chihuahua and Sonora on the U.S.-Mexico border.

Other sky islands of note in the U.S. are the Great Basin mountain forests, the White Mountains, Mt. San Jacinto in California, the Spring Mountains near Las Vegas, and numerous other Nevada mountain ranges. The Tepuis of Venezuela, Brazil, and Guyana, are also good examples of sky islands. Sky islands can be found elsewhere in Africa, New Guinea, Myanmar, Vietnam, Taiwan. Many of these mountains hold isolated outposts of Palearctic flora in otherwise tropical flora regions.

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