Madrean Sky Islands

The region east of the flatland Sonoran Desert with the sky islands of SE Arizona, SW New Mexico, and northern Sonora. The sky islands lie west and southwest of the Rio Grande Valley, in the northern Sierra Madre Occidental.

The Madrean sky islands are enclaves of Madrean pine-oak woodlands, found at higher elevations in a complex of small mountain ranges in southern and southeastern Arizona, southwestern New Mexico, and northwestern Mexico. The sky islands are surrounded at lower elevations by the Sonoran and Chihuahuan deserts. The northern west-east perimeter of the sky island region merges into the higher elevation eastern Mogollon Rim and the White Mountains of eastern Arizona (southern Anasazi region).

The sky islands are the northernmost of the Madrean pine-oak woodlands, and are classified as part of the Sierra Madre Occidental pine-oak forests ecoregion. The sky islands were isolated from one another and from the pine-oak woodlands of the Sierra Madre Occidental to the south by the warming and drying of the climate since the ice ages.

There are approximately 27 Madrean sky islands in the United States, and 15 in northern Mexico. The major Madrean sky island ranges in the United States are the Baboquivari Mountains, Chiricahua Mountains, Pinaleño Mountains, Santa Catalina Mountains, and Santa Rita Mountains.

See also

• Malpai Borderlands
• Madrean Region

External links

• Sky Island Alliance homepage
• Southwestern Sky Island Ecosystems (US Geologic Survey)
• Madrean Sky Islands Montane Forests images at bioimages.vanderbilt.edu (slow modem version)
• Sierra Madre Occidental pine-oak woodlands (World Wildlife Fund)