Sky island
Sky islands are mountains in ranges isolated by valleys in which other ecosystems are located. As a result, the mountain ecosystems are isolated from each other, and species can develop in parallel, as on island groups such as the Galápagos Islands.
The best known examples of sky islands are at the Madrean sky islands 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 are the Great Basin montane forests of the United States' Great Basin, such as the White Mountains, Mt. San Jacinto, in California, and the Spring Mountains near Las Vegas, Nevada, and numerous other Nevada mountain ranges. The Tepuis of Venezuela, Brazil, and Guyana, Mt. Kilimanjaro in Africa and Mt. Wilhelm in New Guinea are also considered examples.
Some Asian examples of sky islands include Nat Ma Taung or Mt. Victoria (3050 m) in western Myanmar, Fan Si Pan (3140 m) in northernmost Vietnam, and the mountains of central Taiwan; these mountains all hold isolated outposts of Palearctic flora in the otherwise tropical Indomalayan flora region.